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android-kvm / linux / 7b82e90411826deee07c180ec35f64d31051d154 / . / arch / s390 / net / bpf_jit_comp.c
blob: f95d7e401b96ca13e27df188a03710d6b83c4ecc [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0
/*
* BPF Jit compiler for s390.
*
* Minimum build requirements:
*
* - HAVE_MARCH_Z196_FEATURES: laal, laalg
* - HAVE_MARCH_Z10_FEATURES: msfi, cgrj, clgrj
* - HAVE_MARCH_Z9_109_FEATURES: alfi, llilf, clfi, oilf, nilf
* - 64BIT
*
* Copyright IBM Corp. 2012,2015
*
* Author(s): Martin Schwidefsky <schwidefsky@de.ibm.com>
* Michael Holzheu <holzheu@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "bpf_jit"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/netdevice.h>
#include <linux/filter.h>
#include <linux/init.h>
#include <linux/bpf.h>
#include <linux/mm.h>
#include <linux/kernel.h>
#include <asm/cacheflush.h>
#include <asm/extable.h>
#include <asm/dis.h>
#include <asm/facility.h>
#include <asm/nospec-branch.h>
#include <asm/set_memory.h>
#include <asm/text-patching.h>
#include "bpf_jit.h"
struct bpf_jit {
u32 seen; /* Flags to remember seen eBPF instructions */
u32 seen_reg[16]; /* Array to remember which registers are used */
u32 *addrs; /* Array with relative instruction addresses */
u8 *prg_buf; /* Start of program */
int size; /* Size of program and literal pool */
int size_prg; /* Size of program */
int prg; /* Current position in program */
int lit32_start; /* Start of 32-bit literal pool */
int lit32; /* Current position in 32-bit literal pool */
int lit64_start; /* Start of 64-bit literal pool */
int lit64; /* Current position in 64-bit literal pool */
int base_ip; /* Base address for literal pool */
int exit_ip; /* Address of exit */
int r1_thunk_ip; /* Address of expoline thunk for 'br %r1' */
int r14_thunk_ip; /* Address of expoline thunk for 'br %r14' */
int tail_call_start; /* Tail call start offset */
int excnt; /* Number of exception table entries */
int prologue_plt_ret; /* Return address for prologue hotpatch PLT */
int prologue_plt; /* Start of prologue hotpatch PLT */
};
#define SEEN_MEM BIT(0) /* use mem[] for temporary storage */
#define SEEN_LITERAL BIT(1) /* code uses literals */
#define SEEN_FUNC BIT(2) /* calls C functions */
#define SEEN_STACK (SEEN_FUNC | SEEN_MEM)
/*
* s390 registers
*/
#define REG_W0 (MAX_BPF_JIT_REG + 0) /* Work register 1 (even) */
#define REG_W1 (MAX_BPF_JIT_REG + 1) /* Work register 2 (odd) */
#define REG_L (MAX_BPF_JIT_REG + 2) /* Literal pool register */
#define REG_15 (MAX_BPF_JIT_REG + 3) /* Register 15 */
#define REG_0 REG_W0 /* Register 0 */
#define REG_1 REG_W1 /* Register 1 */
#define REG_2 BPF_REG_1 /* Register 2 */
#define REG_3 BPF_REG_2 /* Register 3 */
#define REG_4 BPF_REG_3 /* Register 4 */
#define REG_7 BPF_REG_6 /* Register 7 */
#define REG_8 BPF_REG_7 /* Register 8 */
#define REG_14 BPF_REG_0 /* Register 14 */
/*
* Mapping of BPF registers to s390 registers
*/
static const int reg2hex[] = {
/* Return code */
[BPF_REG_0] = 14,
/* Function parameters */
[BPF_REG_1] = 2,
[BPF_REG_2] = 3,
[BPF_REG_3] = 4,
[BPF_REG_4] = 5,
[BPF_REG_5] = 6,
/* Call saved registers */
[BPF_REG_6] = 7,
[BPF_REG_7] = 8,
[BPF_REG_8] = 9,
[BPF_REG_9] = 10,
/* BPF stack pointer */
[BPF_REG_FP] = 13,
/* Register for blinding */
[BPF_REG_AX] = 12,
/* Work registers for s390x backend */
[REG_W0] = 0,
[REG_W1] = 1,
[REG_L] = 11,
[REG_15] = 15,
};
static inline u32 reg(u32 dst_reg, u32 src_reg)
{
return reg2hex[dst_reg] << 4 | reg2hex[src_reg];
}
static inline u32 reg_high(u32 reg)
{
return reg2hex[reg] << 4;
}
static inline void reg_set_seen(struct bpf_jit *jit, u32 b1)
{
u32 r1 = reg2hex[b1];
if (r1 >= 6 && r1 <= 15 && !jit->seen_reg[r1])
jit->seen_reg[r1] = 1;
}
#define REG_SET_SEEN(b1) \
({ \
reg_set_seen(jit, b1); \
})
#define REG_SEEN(b1) jit->seen_reg[reg2hex[(b1)]]
/*
* EMIT macros for code generation
*/
#define _EMIT2(op) \
({ \
if (jit->prg_buf) \
*(u16 *) (jit->prg_buf + jit->prg) = (op); \
jit->prg += 2; \
})
#define EMIT2(op, b1, b2) \
({ \
_EMIT2((op) | reg(b1, b2)); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define _EMIT4(op) \
({ \
if (jit->prg_buf) \
*(u32 *) (jit->prg_buf + jit->prg) = (op); \
jit->prg += 4; \
})
#define EMIT4(op, b1, b2) \
({ \
_EMIT4((op) | reg(b1, b2)); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT4_RRF(op, b1, b2, b3) \
({ \
_EMIT4((op) | reg_high(b3) << 8 | reg(b1, b2)); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
REG_SET_SEEN(b3); \
})
#define _EMIT4_DISP(op, disp) \
({ \
unsigned int __disp = (disp) & 0xfff; \
_EMIT4((op) | __disp); \
})
#define EMIT4_DISP(op, b1, b2, disp) \
({ \
_EMIT4_DISP((op) | reg_high(b1) << 16 | \
reg_high(b2) << 8, (disp)); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT4_IMM(op, b1, imm) \
({ \
unsigned int __imm = (imm) & 0xffff; \
_EMIT4((op) | reg_high(b1) << 16 | __imm); \
REG_SET_SEEN(b1); \
})
#define EMIT4_PCREL(op, pcrel) \
({ \
long __pcrel = ((pcrel) >> 1) & 0xffff; \
_EMIT4((op) | __pcrel); \
})
#define EMIT4_PCREL_RIC(op, mask, target) \
({ \
int __rel = ((target) - jit->prg) / 2; \
_EMIT4((op) | (mask) << 20 | (__rel & 0xffff)); \
})
#define _EMIT6(op1, op2) \
({ \
if (jit->prg_buf) { \
*(u32 *) (jit->prg_buf + jit->prg) = (op1); \
*(u16 *) (jit->prg_buf + jit->prg + 4) = (op2); \
} \
jit->prg += 6; \
})
#define _EMIT6_DISP(op1, op2, disp) \
({ \
unsigned int __disp = (disp) & 0xfff; \
_EMIT6((op1) | __disp, op2); \
})
#define _EMIT6_DISP_LH(op1, op2, disp) \
({ \
u32 _disp = (u32) (disp); \
unsigned int __disp_h = _disp & 0xff000; \
unsigned int __disp_l = _disp & 0x00fff; \
_EMIT6((op1) | __disp_l, (op2) | __disp_h >> 4); \
})
#define EMIT6_DISP_LH(op1, op2, b1, b2, b3, disp) \
({ \
_EMIT6_DISP_LH((op1) | reg(b1, b2) << 16 | \
reg_high(b3) << 8, op2, disp); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
REG_SET_SEEN(b3); \
})
#define EMIT6_PCREL_RIEB(op1, op2, b1, b2, mask, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
_EMIT6((op1) | reg(b1, b2) << 16 | (rel & 0xffff), \
(op2) | (mask) << 12); \
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT6_PCREL_RIEC(op1, op2, b1, imm, mask, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
_EMIT6((op1) | (reg_high(b1) | (mask)) << 16 | \
(rel & 0xffff), (op2) | ((imm) & 0xff) << 8); \
REG_SET_SEEN(b1); \
BUILD_BUG_ON(((unsigned long) (imm)) > 0xff); \
})
#define EMIT6_PCREL(op1, op2, b1, b2, i, off, mask) \
({ \
int rel = (addrs[(i) + (off) + 1] - jit->prg) / 2; \
_EMIT6((op1) | reg(b1, b2) << 16 | (rel & 0xffff), (op2) | (mask));\
REG_SET_SEEN(b1); \
REG_SET_SEEN(b2); \
})
#define EMIT6_PCREL_RILB(op, b, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
_EMIT6((op) | reg_high(b) << 16 | rel >> 16, rel & 0xffff);\
REG_SET_SEEN(b); \
})
#define EMIT6_PCREL_RIL(op, target) \
({ \
unsigned int rel = (int)((target) - jit->prg) / 2; \
_EMIT6((op) | rel >> 16, rel & 0xffff); \
})
#define EMIT6_PCREL_RILC(op, mask, target) \
({ \
EMIT6_PCREL_RIL((op) | (mask) << 20, (target)); \
})
#define _EMIT6_IMM(op, imm) \
({ \
unsigned int __imm = (imm); \
_EMIT6((op) | (__imm >> 16), __imm & 0xffff); \
})
#define EMIT6_IMM(op, b1, imm) \
({ \
_EMIT6_IMM((op) | reg_high(b1) << 16, imm); \
REG_SET_SEEN(b1); \
})
#define _EMIT_CONST_U32(val) \
({ \
unsigned int ret; \
ret = jit->lit32; \
if (jit->prg_buf) \
*(u32 *)(jit->prg_buf + jit->lit32) = (u32)(val);\
jit->lit32 += 4; \
ret; \
})
#define EMIT_CONST_U32(val) \
({ \
jit->seen |= SEEN_LITERAL; \
_EMIT_CONST_U32(val) - jit->base_ip; \
})
#define _EMIT_CONST_U64(val) \
({ \
unsigned int ret; \
ret = jit->lit64; \
if (jit->prg_buf) \
*(u64 *)(jit->prg_buf + jit->lit64) = (u64)(val);\
jit->lit64 += 8; \
ret; \
})
#define EMIT_CONST_U64(val) \
({ \
jit->seen |= SEEN_LITERAL; \
_EMIT_CONST_U64(val) - jit->base_ip; \
})
#define EMIT_ZERO(b1) \
({ \
if (!fp->aux->verifier_zext) { \
/* llgfr %dst,%dst (zero extend to 64 bit) */ \
EMIT4(0xb9160000, b1, b1); \
REG_SET_SEEN(b1); \
} \
})
/*
* Return whether this is the first pass. The first pass is special, since we
* don't know any sizes yet, and thus must be conservative.
*/
static bool is_first_pass(struct bpf_jit *jit)
{
return jit->size == 0;
}
/*
* Return whether this is the code generation pass. The code generation pass is
* special, since we should change as little as possible.
*/
static bool is_codegen_pass(struct bpf_jit *jit)
{
return jit->prg_buf;
}
/*
* Return whether "rel" can be encoded as a short PC-relative offset
*/
static bool is_valid_rel(int rel)
{
return rel >= -65536 && rel <= 65534;
}
/*
* Return whether "off" can be reached using a short PC-relative offset
*/
static bool can_use_rel(struct bpf_jit *jit, int off)
{
return is_valid_rel(off - jit->prg);
}
/*
* Return whether given displacement can be encoded using
* Long-Displacement Facility
*/
static bool is_valid_ldisp(int disp)
{
return disp >= -524288 && disp <= 524287;
}
/*
* Return whether the next 32-bit literal pool entry can be referenced using
* Long-Displacement Facility
*/
static bool can_use_ldisp_for_lit32(struct bpf_jit *jit)
{
return is_valid_ldisp(jit->lit32 - jit->base_ip);
}
/*
* Return whether the next 64-bit literal pool entry can be referenced using
* Long-Displacement Facility
*/
static bool can_use_ldisp_for_lit64(struct bpf_jit *jit)
{
return is_valid_ldisp(jit->lit64 - jit->base_ip);
}
/*
* Fill whole space with illegal instructions
*/
static void jit_fill_hole(void *area, unsigned int size)
{
memset(area, 0, size);
}
/*
* Save registers from "rs" (register start) to "re" (register end) on stack
*/
static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
{
u32 off = STK_OFF_R6 + (rs - 6) * 8;
if (rs == re)
/* stg %rs,off(%r15) */
_EMIT6(0xe300f000 | rs << 20 | off, 0x0024);
else
/* stmg %rs,%re,off(%r15) */
_EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0024, off);
}
/*
* Restore registers from "rs" (register start) to "re" (register end) on stack
*/
static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re, u32 stack_depth)
{
u32 off = STK_OFF_R6 + (rs - 6) * 8;
if (jit->seen & SEEN_STACK)
off += STK_OFF + stack_depth;
if (rs == re)
/* lg %rs,off(%r15) */
_EMIT6(0xe300f000 | rs << 20 | off, 0x0004);
else
/* lmg %rs,%re,off(%r15) */
_EMIT6_DISP(0xeb00f000 | rs << 20 | re << 16, 0x0004, off);
}
/*
* Return first seen register (from start)
*/
static int get_start(struct bpf_jit *jit, int start)
{
int i;
for (i = start; i <= 15; i++) {
if (jit->seen_reg[i])
return i;
}
return 0;
}
/*
* Return last seen register (from start) (gap >= 2)
*/
static int get_end(struct bpf_jit *jit, int start)
{
int i;
for (i = start; i < 15; i++) {
if (!jit->seen_reg[i] && !jit->seen_reg[i + 1])
return i - 1;
}
return jit->seen_reg[15] ? 15 : 14;
}
#define REGS_SAVE 1
#define REGS_RESTORE 0
/*
* Save and restore clobbered registers (6-15) on stack.
* We save/restore registers in chunks with gap >= 2 registers.
*/
static void save_restore_regs(struct bpf_jit *jit, int op, u32 stack_depth)
{
const int last = 15, save_restore_size = 6;
int re = 6, rs;
if (is_first_pass(jit)) {
/*
* We don't know yet which registers are used. Reserve space
* conservatively.
*/
jit->prg += (last - re + 1) * save_restore_size;
return;
}
do {
rs = get_start(jit, re);
if (!rs)
break;
re = get_end(jit, rs + 1);
if (op == REGS_SAVE)
save_regs(jit, rs, re);
else
restore_regs(jit, rs, re, stack_depth);
re++;
} while (re <= last);
}
static void bpf_skip(struct bpf_jit *jit, int size)
{
if (size >= 6 && !is_valid_rel(size)) {
/* brcl 0xf,size */
EMIT6_PCREL_RIL(0xc0f4000000, size);
size -= 6;
} else if (size >= 4 && is_valid_rel(size)) {
/* brc 0xf,size */
EMIT4_PCREL(0xa7f40000, size);
size -= 4;
}
while (size >= 2) {
/* bcr 0,%0 */
_EMIT2(0x0700);
size -= 2;
}
}
/*
* PLT for hotpatchable calls. The calling convention is the same as for the
* ftrace hotpatch trampolines: %r0 is return address, %r1 is clobbered.
*/
extern const char bpf_plt[];
extern const char bpf_plt_ret[];
extern const char bpf_plt_target[];
extern const char bpf_plt_end[];
#define BPF_PLT_SIZE 32
asm(
".pushsection .rodata\n"
" .align 8\n"
"bpf_plt:\n"
" lgrl %r0,bpf_plt_ret\n"
" lgrl %r1,bpf_plt_target\n"
" br %r1\n"
" .align 8\n"
"bpf_plt_ret: .quad 0\n"
"bpf_plt_target: .quad 0\n"
"bpf_plt_end:\n"
" .popsection\n"
);
static void bpf_jit_plt(void *plt, void *ret, void *target)
{
memcpy(plt, bpf_plt, BPF_PLT_SIZE);
*(void **)((char *)plt + (bpf_plt_ret - bpf_plt)) = ret;
*(void **)((char *)plt + (bpf_plt_target - bpf_plt)) = target ?: ret;
}
/*
* Emit function prologue
*
* Save registers and create stack frame if necessary.
* See stack frame layout description in "bpf_jit.h"!
*/
static void bpf_jit_prologue(struct bpf_jit *jit, struct bpf_prog *fp,
u32 stack_depth)
{
/* No-op for hotpatching */
/* brcl 0,prologue_plt */
EMIT6_PCREL_RILC(0xc0040000, 0, jit->prologue_plt);
jit->prologue_plt_ret = jit->prg;
if (fp->aux->func_idx == 0) {
/* Initialize the tail call counter in the main program. */
/* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */
_EMIT6(0xd703f000 | STK_OFF_TCCNT, 0xf000 | STK_OFF_TCCNT);
} else {
/*
* Skip the tail call counter initialization in subprograms.
* Insert nops in order to have tail_call_start at a
* predictable offset.
*/
bpf_skip(jit, 6);
}
/* Tail calls have to skip above initialization */
jit->tail_call_start = jit->prg;
/* Save registers */
save_restore_regs(jit, REGS_SAVE, stack_depth);
/* Setup literal pool */
if (is_first_pass(jit) || (jit->seen & SEEN_LITERAL)) {
if (!is_first_pass(jit) &&
is_valid_ldisp(jit->size - (jit->prg + 2))) {
/* basr %l,0 */
EMIT2(0x0d00, REG_L, REG_0);
jit->base_ip = jit->prg;
} else {
/* larl %l,lit32_start */
EMIT6_PCREL_RILB(0xc0000000, REG_L, jit->lit32_start);
jit->base_ip = jit->lit32_start;
}
}
/* Setup stack and backchain */
if (is_first_pass(jit) || (jit->seen & SEEN_STACK)) {
if (is_first_pass(jit) || (jit->seen & SEEN_FUNC))
/* lgr %w1,%r15 (backchain) */
EMIT4(0xb9040000, REG_W1, REG_15);
/* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */
EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED);
/* aghi %r15,-STK_OFF */
EMIT4_IMM(0xa70b0000, REG_15, -(STK_OFF + stack_depth));
if (is_first_pass(jit) || (jit->seen & SEEN_FUNC))
/* stg %w1,152(%r15) (backchain) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
REG_15, 152);
}
}
/*
* Emit an expoline for a jump that follows
*/
static void emit_expoline(struct bpf_jit *jit)
{
/* exrl %r0,.+10 */
EMIT6_PCREL_RIL(0xc6000000, jit->prg + 10);
/* j . */
EMIT4_PCREL(0xa7f40000, 0);
}
/*
* Emit __s390_indirect_jump_r1 thunk if necessary
*/
static void emit_r1_thunk(struct bpf_jit *jit)
{
if (nospec_uses_trampoline()) {
jit->r1_thunk_ip = jit->prg;
emit_expoline(jit);
/* br %r1 */
_EMIT2(0x07f1);
}
}
/*
* Call r1 either directly or via __s390_indirect_jump_r1 thunk
*/
static void call_r1(struct bpf_jit *jit)
{
if (nospec_uses_trampoline())
/* brasl %r14,__s390_indirect_jump_r1 */
EMIT6_PCREL_RILB(0xc0050000, REG_14, jit->r1_thunk_ip);
else
/* basr %r14,%r1 */
EMIT2(0x0d00, REG_14, REG_1);
}
/*
* Function epilogue
*/
static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
{
jit->exit_ip = jit->prg;
/* Load exit code: lgr %r2,%b0 */
EMIT4(0xb9040000, REG_2, BPF_REG_0);
/* Restore registers */
save_restore_regs(jit, REGS_RESTORE, stack_depth);
if (nospec_uses_trampoline()) {
jit->r14_thunk_ip = jit->prg;
/* Generate __s390_indirect_jump_r14 thunk */
emit_expoline(jit);
}
/* br %r14 */
_EMIT2(0x07fe);
if (is_first_pass(jit) || (jit->seen & SEEN_FUNC))
emit_r1_thunk(jit);
jit->prg = ALIGN(jit->prg, 8);
jit->prologue_plt = jit->prg;
if (jit->prg_buf)
bpf_jit_plt(jit->prg_buf + jit->prg,
jit->prg_buf + jit->prologue_plt_ret, NULL);
jit->prg += BPF_PLT_SIZE;
}
static int get_probe_mem_regno(const u8 *insn)
{
/*
* insn must point to llgc, llgh, llgf or lg, which have destination
* register at the same position.
*/
if (insn[0] != 0xe3) /* common llgc, llgh, llgf and lg prefix */
return -1;
if (insn[5] != 0x90 && /* llgc */
insn[5] != 0x91 && /* llgh */
insn[5] != 0x16 && /* llgf */
insn[5] != 0x04) /* lg */
return -1;
return insn[1] >> 4;
}
bool ex_handler_bpf(const struct exception_table_entry *x, struct pt_regs *regs)
{
regs->psw.addr = extable_fixup(x);
regs->gprs[x->data] = 0;
return true;
}
static int bpf_jit_probe_mem(struct bpf_jit *jit, struct bpf_prog *fp,
int probe_prg, int nop_prg)
{
struct exception_table_entry *ex;
int reg, prg;
s64 delta;
u8 *insn;
int i;
if (!fp->aux->extable)
/* Do nothing during early JIT passes. */
return 0;
insn = jit->prg_buf + probe_prg;
reg = get_probe_mem_regno(insn);
if (WARN_ON_ONCE(reg < 0))
/* JIT bug - unexpected probe instruction. */
return -1;
if (WARN_ON_ONCE(probe_prg + insn_length(*insn) != nop_prg))
/* JIT bug - gap between probe and nop instructions. */
return -1;
for (i = 0; i < 2; i++) {
if (WARN_ON_ONCE(jit->excnt >= fp->aux->num_exentries))
/* Verifier bug - not enough entries. */
return -1;
ex = &fp->aux->extable[jit->excnt];
/* Add extable entries for probe and nop instructions. */
prg = i == 0 ? probe_prg : nop_prg;
delta = jit->prg_buf + prg - (u8 *)&ex->insn;
if (WARN_ON_ONCE(delta < INT_MIN || delta > INT_MAX))
/* JIT bug - code and extable must be close. */
return -1;
ex->insn = delta;
/*
* Always land on the nop. Note that extable infrastructure
* ignores fixup field, it is handled by ex_handler_bpf().
*/
delta = jit->prg_buf + nop_prg - (u8 *)&ex->fixup;
if (WARN_ON_ONCE(delta < INT_MIN || delta > INT_MAX))
/* JIT bug - landing pad and extable must be close. */
return -1;
ex->fixup = delta;
ex->type = EX_TYPE_BPF;
ex->data = reg;
jit->excnt++;
}
return 0;
}
/*
* Sign-extend the register if necessary
*/
static int sign_extend(struct bpf_jit *jit, int r, u8 size, u8 flags)
{
if (!(flags & BTF_FMODEL_SIGNED_ARG))
return 0;
switch (size) {
case 1:
/* lgbr %r,%r */
EMIT4(0xb9060000, r, r);
return 0;
case 2:
/* lghr %r,%r */
EMIT4(0xb9070000, r, r);
return 0;
case 4:
/* lgfr %r,%r */
EMIT4(0xb9140000, r, r);
return 0;
case 8:
return 0;
default:
return -1;
}
}
/*
* Compile one eBPF instruction into s390x code
*
* NOTE: Use noinline because for gcov (-fprofile-arcs) gcc allocates a lot of
* stack space for the large switch statement.
*/
static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp,
int i, bool extra_pass, u32 stack_depth)
{
struct bpf_insn *insn = &fp->insnsi[i];
u32 dst_reg = insn->dst_reg;
u32 src_reg = insn->src_reg;
int last, insn_count = 1;
u32 *addrs = jit->addrs;
s32 imm = insn->imm;
s16 off = insn->off;
int probe_prg = -1;
unsigned int mask;
int nop_prg;
int err;
if (BPF_CLASS(insn->code) == BPF_LDX &&
BPF_MODE(insn->code) == BPF_PROBE_MEM)
probe_prg = jit->prg;
switch (insn->code) {
/*
* BPF_MOV
*/
case BPF_ALU | BPF_MOV | BPF_X: /* dst = (u32) src */
/* llgfr %dst,%src */
EMIT4(0xb9160000, dst_reg, src_reg);
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
case BPF_ALU64 | BPF_MOV | BPF_X: /* dst = src */
/* lgr %dst,%src */
EMIT4(0xb9040000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_MOV | BPF_K: /* dst = (u32) imm */
/* llilf %dst,imm */
EMIT6_IMM(0xc00f0000, dst_reg, imm);
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
case BPF_ALU64 | BPF_MOV | BPF_K: /* dst = imm */
/* lgfi %dst,imm */
EMIT6_IMM(0xc0010000, dst_reg, imm);
break;
/*
* BPF_LD 64
*/
case BPF_LD | BPF_IMM | BPF_DW: /* dst = (u64) imm */
{
/* 16 byte instruction that uses two 'struct bpf_insn' */
u64 imm64;
imm64 = (u64)(u32) insn[0].imm | ((u64)(u32) insn[1].imm) << 32;
/* lgrl %dst,imm */
EMIT6_PCREL_RILB(0xc4080000, dst_reg, _EMIT_CONST_U64(imm64));
insn_count = 2;
break;
}
/*
* BPF_ADD
*/
case BPF_ALU | BPF_ADD | BPF_X: /* dst = (u32) dst + (u32) src */
/* ar %dst,%src */
EMIT2(0x1a00, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_ADD | BPF_X: /* dst = dst + src */
/* agr %dst,%src */
EMIT4(0xb9080000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_ADD | BPF_K: /* dst = (u32) dst + (u32) imm */
if (imm != 0) {
/* alfi %dst,imm */
EMIT6_IMM(0xc20b0000, dst_reg, imm);
}
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_ADD | BPF_K: /* dst = dst + imm */
if (!imm)
break;
/* agfi %dst,imm */
EMIT6_IMM(0xc2080000, dst_reg, imm);
break;
/*
* BPF_SUB
*/
case BPF_ALU | BPF_SUB | BPF_X: /* dst = (u32) dst - (u32) src */
/* sr %dst,%src */
EMIT2(0x1b00, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_SUB | BPF_X: /* dst = dst - src */
/* sgr %dst,%src */
EMIT4(0xb9090000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_SUB | BPF_K: /* dst = (u32) dst - (u32) imm */
if (imm != 0) {
/* alfi %dst,-imm */
EMIT6_IMM(0xc20b0000, dst_reg, -imm);
}
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_SUB | BPF_K: /* dst = dst - imm */
if (!imm)
break;
if (imm == -0x80000000) {
/* algfi %dst,0x80000000 */
EMIT6_IMM(0xc20a0000, dst_reg, 0x80000000);
} else {
/* agfi %dst,-imm */
EMIT6_IMM(0xc2080000, dst_reg, -imm);
}
break;
/*
* BPF_MUL
*/
case BPF_ALU | BPF_MUL | BPF_X: /* dst = (u32) dst * (u32) src */
/* msr %dst,%src */
EMIT4(0xb2520000, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_MUL | BPF_X: /* dst = dst * src */
/* msgr %dst,%src */
EMIT4(0xb90c0000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_MUL | BPF_K: /* dst = (u32) dst * (u32) imm */
if (imm != 1) {
/* msfi %r5,imm */
EMIT6_IMM(0xc2010000, dst_reg, imm);
}
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_MUL | BPF_K: /* dst = dst * imm */
if (imm == 1)
break;
/* msgfi %dst,imm */
EMIT6_IMM(0xc2000000, dst_reg, imm);
break;
/*
* BPF_DIV / BPF_MOD
*/
case BPF_ALU | BPF_DIV | BPF_X: /* dst = (u32) dst / (u32) src */
case BPF_ALU | BPF_MOD | BPF_X: /* dst = (u32) dst % (u32) src */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
/* lhi %w0,0 */
EMIT4_IMM(0xa7080000, REG_W0, 0);
/* lr %w1,%dst */
EMIT2(0x1800, REG_W1, dst_reg);
/* dlr %w0,%src */
EMIT4(0xb9970000, REG_W0, src_reg);
/* llgfr %dst,%rc */
EMIT4(0xb9160000, dst_reg, rc_reg);
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
}
case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % src */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
/* lghi %w0,0 */
EMIT4_IMM(0xa7090000, REG_W0, 0);
/* lgr %w1,%dst */
EMIT4(0xb9040000, REG_W1, dst_reg);
/* dlgr %w0,%dst */
EMIT4(0xb9870000, REG_W0, src_reg);
/* lgr %dst,%rc */
EMIT4(0xb9040000, dst_reg, rc_reg);
break;
}
case BPF_ALU | BPF_DIV | BPF_K: /* dst = (u32) dst / (u32) imm */
case BPF_ALU | BPF_MOD | BPF_K: /* dst = (u32) dst % (u32) imm */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
if (imm == 1) {
if (BPF_OP(insn->code) == BPF_MOD)
/* lhgi %dst,0 */
EMIT4_IMM(0xa7090000, dst_reg, 0);
else
EMIT_ZERO(dst_reg);
break;
}
/* lhi %w0,0 */
EMIT4_IMM(0xa7080000, REG_W0, 0);
/* lr %w1,%dst */
EMIT2(0x1800, REG_W1, dst_reg);
if (!is_first_pass(jit) && can_use_ldisp_for_lit32(jit)) {
/* dl %w0,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0097, REG_W0, REG_0, REG_L,
EMIT_CONST_U32(imm));
} else {
/* lgfrl %dst,imm */
EMIT6_PCREL_RILB(0xc40c0000, dst_reg,
_EMIT_CONST_U32(imm));
jit->seen |= SEEN_LITERAL;
/* dlr %w0,%dst */
EMIT4(0xb9970000, REG_W0, dst_reg);
}
/* llgfr %dst,%rc */
EMIT4(0xb9160000, dst_reg, rc_reg);
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
}
case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % imm */
{
int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
if (imm == 1) {
if (BPF_OP(insn->code) == BPF_MOD)
/* lhgi %dst,0 */
EMIT4_IMM(0xa7090000, dst_reg, 0);
break;
}
/* lghi %w0,0 */
EMIT4_IMM(0xa7090000, REG_W0, 0);
/* lgr %w1,%dst */
EMIT4(0xb9040000, REG_W1, dst_reg);
if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
/* dlg %w0,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
EMIT_CONST_U64(imm));
} else {
/* lgrl %dst,imm */
EMIT6_PCREL_RILB(0xc4080000, dst_reg,
_EMIT_CONST_U64(imm));
jit->seen |= SEEN_LITERAL;
/* dlgr %w0,%dst */
EMIT4(0xb9870000, REG_W0, dst_reg);
}
/* lgr %dst,%rc */
EMIT4(0xb9040000, dst_reg, rc_reg);
break;
}
/*
* BPF_AND
*/
case BPF_ALU | BPF_AND | BPF_X: /* dst = (u32) dst & (u32) src */
/* nr %dst,%src */
EMIT2(0x1400, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_AND | BPF_X: /* dst = dst & src */
/* ngr %dst,%src */
EMIT4(0xb9800000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_AND | BPF_K: /* dst = (u32) dst & (u32) imm */
/* nilf %dst,imm */
EMIT6_IMM(0xc00b0000, dst_reg, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_AND | BPF_K: /* dst = dst & imm */
if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
/* ng %dst,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0080,
dst_reg, REG_0, REG_L,
EMIT_CONST_U64(imm));
} else {
/* lgrl %w0,imm */
EMIT6_PCREL_RILB(0xc4080000, REG_W0,
_EMIT_CONST_U64(imm));
jit->seen |= SEEN_LITERAL;
/* ngr %dst,%w0 */
EMIT4(0xb9800000, dst_reg, REG_W0);
}
break;
/*
* BPF_OR
*/
case BPF_ALU | BPF_OR | BPF_X: /* dst = (u32) dst | (u32) src */
/* or %dst,%src */
EMIT2(0x1600, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_OR | BPF_X: /* dst = dst | src */
/* ogr %dst,%src */
EMIT4(0xb9810000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_OR | BPF_K: /* dst = (u32) dst | (u32) imm */
/* oilf %dst,imm */
EMIT6_IMM(0xc00d0000, dst_reg, imm);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_OR | BPF_K: /* dst = dst | imm */
if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
/* og %dst,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0081,
dst_reg, REG_0, REG_L,
EMIT_CONST_U64(imm));
} else {
/* lgrl %w0,imm */
EMIT6_PCREL_RILB(0xc4080000, REG_W0,
_EMIT_CONST_U64(imm));
jit->seen |= SEEN_LITERAL;
/* ogr %dst,%w0 */
EMIT4(0xb9810000, dst_reg, REG_W0);
}
break;
/*
* BPF_XOR
*/
case BPF_ALU | BPF_XOR | BPF_X: /* dst = (u32) dst ^ (u32) src */
/* xr %dst,%src */
EMIT2(0x1700, dst_reg, src_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_XOR | BPF_X: /* dst = dst ^ src */
/* xgr %dst,%src */
EMIT4(0xb9820000, dst_reg, src_reg);
break;
case BPF_ALU | BPF_XOR | BPF_K: /* dst = (u32) dst ^ (u32) imm */
if (imm != 0) {
/* xilf %dst,imm */
EMIT6_IMM(0xc0070000, dst_reg, imm);
}
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_XOR | BPF_K: /* dst = dst ^ imm */
if (!is_first_pass(jit) && can_use_ldisp_for_lit64(jit)) {
/* xg %dst,<d(imm)>(%l) */
EMIT6_DISP_LH(0xe3000000, 0x0082,
dst_reg, REG_0, REG_L,
EMIT_CONST_U64(imm));
} else {
/* lgrl %w0,imm */
EMIT6_PCREL_RILB(0xc4080000, REG_W0,
_EMIT_CONST_U64(imm));
jit->seen |= SEEN_LITERAL;
/* xgr %dst,%w0 */
EMIT4(0xb9820000, dst_reg, REG_W0);
}
break;
/*
* BPF_LSH
*/
case BPF_ALU | BPF_LSH | BPF_X: /* dst = (u32) dst << (u32) src */
/* sll %dst,0(%src) */
EMIT4_DISP(0x89000000, dst_reg, src_reg, 0);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_LSH | BPF_X: /* dst = dst << src */
/* sllg %dst,%dst,0(%src) */
EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU | BPF_LSH | BPF_K: /* dst = (u32) dst << (u32) imm */
if (imm != 0) {
/* sll %dst,imm(%r0) */
EMIT4_DISP(0x89000000, dst_reg, REG_0, imm);
}
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_LSH | BPF_K: /* dst = dst << imm */
if (imm == 0)
break;
/* sllg %dst,%dst,imm(%r0) */
EMIT6_DISP_LH(0xeb000000, 0x000d, dst_reg, dst_reg, REG_0, imm);
break;
/*
* BPF_RSH
*/
case BPF_ALU | BPF_RSH | BPF_X: /* dst = (u32) dst >> (u32) src */
/* srl %dst,0(%src) */
EMIT4_DISP(0x88000000, dst_reg, src_reg, 0);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_RSH | BPF_X: /* dst = dst >> src */
/* srlg %dst,%dst,0(%src) */
EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU | BPF_RSH | BPF_K: /* dst = (u32) dst >> (u32) imm */
if (imm != 0) {
/* srl %dst,imm(%r0) */
EMIT4_DISP(0x88000000, dst_reg, REG_0, imm);
}
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_RSH | BPF_K: /* dst = dst >> imm */
if (imm == 0)
break;
/* srlg %dst,%dst,imm(%r0) */
EMIT6_DISP_LH(0xeb000000, 0x000c, dst_reg, dst_reg, REG_0, imm);
break;
/*
* BPF_ARSH
*/
case BPF_ALU | BPF_ARSH | BPF_X: /* ((s32) dst) >>= src */
/* sra %dst,%dst,0(%src) */
EMIT4_DISP(0x8a000000, dst_reg, src_reg, 0);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_ARSH | BPF_X: /* ((s64) dst) >>= src */
/* srag %dst,%dst,0(%src) */
EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, src_reg, 0);
break;
case BPF_ALU | BPF_ARSH | BPF_K: /* ((s32) dst >> imm */
if (imm != 0) {
/* sra %dst,imm(%r0) */
EMIT4_DISP(0x8a000000, dst_reg, REG_0, imm);
}
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_ARSH | BPF_K: /* ((s64) dst) >>= imm */
if (imm == 0)
break;
/* srag %dst,%dst,imm(%r0) */
EMIT6_DISP_LH(0xeb000000, 0x000a, dst_reg, dst_reg, REG_0, imm);
break;
/*
* BPF_NEG
*/
case BPF_ALU | BPF_NEG: /* dst = (u32) -dst */
/* lcr %dst,%dst */
EMIT2(0x1300, dst_reg, dst_reg);
EMIT_ZERO(dst_reg);
break;
case BPF_ALU64 | BPF_NEG: /* dst = -dst */
/* lcgr %dst,%dst */
EMIT4(0xb9030000, dst_reg, dst_reg);
break;
/*
* BPF_FROM_BE/LE
*/
case BPF_ALU | BPF_END | BPF_FROM_BE:
/* s390 is big endian, therefore only clear high order bytes */
switch (imm) {
case 16: /* dst = (u16) cpu_to_be16(dst) */
/* llghr %dst,%dst */
EMIT4(0xb9850000, dst_reg, dst_reg);
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
case 32: /* dst = (u32) cpu_to_be32(dst) */
if (!fp->aux->verifier_zext)
/* llgfr %dst,%dst */
EMIT4(0xb9160000, dst_reg, dst_reg);
break;
case 64: /* dst = (u64) cpu_to_be64(dst) */
break;
}
break;
case BPF_ALU | BPF_END | BPF_FROM_LE:
switch (imm) {
case 16: /* dst = (u16) cpu_to_le16(dst) */
/* lrvr %dst,%dst */
EMIT4(0xb91f0000, dst_reg, dst_reg);
/* srl %dst,16(%r0) */
EMIT4_DISP(0x88000000, dst_reg, REG_0, 16);
/* llghr %dst,%dst */
EMIT4(0xb9850000, dst_reg, dst_reg);
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
case 32: /* dst = (u32) cpu_to_le32(dst) */
/* lrvr %dst,%dst */
EMIT4(0xb91f0000, dst_reg, dst_reg);
if (!fp->aux->verifier_zext)
/* llgfr %dst,%dst */
EMIT4(0xb9160000, dst_reg, dst_reg);
break;
case 64: /* dst = (u64) cpu_to_le64(dst) */
/* lrvgr %dst,%dst */
EMIT4(0xb90f0000, dst_reg, dst_reg);
break;
}
break;
/*
* BPF_NOSPEC (speculation barrier)
*/
case BPF_ST | BPF_NOSPEC:
break;
/*
* BPF_ST(X)
*/
case BPF_STX | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = src_reg */
/* stcy %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0072, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_STX | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = src */
/* sthy %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0070, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_STX | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = src */
/* sty %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0050, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_STX | BPF_MEM | BPF_DW: /* (u64 *)(dst + off) = src */
/* stg %src,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0024, src_reg, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_B: /* *(u8 *)(dst + off) = imm */
/* lhi %w0,imm */
EMIT4_IMM(0xa7080000, REG_W0, (u8) imm);
/* stcy %w0,off(dst) */
EMIT6_DISP_LH(0xe3000000, 0x0072, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_H: /* (u16 *)(dst + off) = imm */
/* lhi %w0,imm */
EMIT4_IMM(0xa7080000, REG_W0, (u16) imm);
/* sthy %w0,off(dst) */
EMIT6_DISP_LH(0xe3000000, 0x0070, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_W: /* *(u32 *)(dst + off) = imm */
/* llilf %w0,imm */
EMIT6_IMM(0xc00f0000, REG_W0, (u32) imm);
/* sty %w0,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0050, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
case BPF_ST | BPF_MEM | BPF_DW: /* *(u64 *)(dst + off) = imm */
/* lgfi %w0,imm */
EMIT6_IMM(0xc0010000, REG_W0, imm);
/* stg %w0,off(%dst) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, dst_reg, REG_0, off);
jit->seen |= SEEN_MEM;
break;
/*
* BPF_ATOMIC
*/
case BPF_STX | BPF_ATOMIC | BPF_DW:
case BPF_STX | BPF_ATOMIC | BPF_W:
{
bool is32 = BPF_SIZE(insn->code) == BPF_W;
switch (insn->imm) {
/* {op32|op64} {%w0|%src},%src,off(%dst) */
#define EMIT_ATOMIC(op32, op64) do { \
EMIT6_DISP_LH(0xeb000000, is32 ? (op32) : (op64), \
(insn->imm & BPF_FETCH) ? src_reg : REG_W0, \
src_reg, dst_reg, off); \
if (is32 && (insn->imm & BPF_FETCH)) \
EMIT_ZERO(src_reg); \
} while (0)
case BPF_ADD:
case BPF_ADD | BPF_FETCH:
/* {laal|laalg} */
EMIT_ATOMIC(0x00fa, 0x00ea);
break;
case BPF_AND:
case BPF_AND | BPF_FETCH:
/* {lan|lang} */
EMIT_ATOMIC(0x00f4, 0x00e4);
break;
case BPF_OR:
case BPF_OR | BPF_FETCH:
/* {lao|laog} */
EMIT_ATOMIC(0x00f6, 0x00e6);
break;
case BPF_XOR:
case BPF_XOR | BPF_FETCH:
/* {lax|laxg} */
EMIT_ATOMIC(0x00f7, 0x00e7);
break;
#undef EMIT_ATOMIC
case BPF_XCHG:
/* {ly|lg} %w0,off(%dst) */
EMIT6_DISP_LH(0xe3000000,
is32 ? 0x0058 : 0x0004, REG_W0, REG_0,
dst_reg, off);
/* 0: {csy|csg} %w0,%src,off(%dst) */
EMIT6_DISP_LH(0xeb000000, is32 ? 0x0014 : 0x0030,
REG_W0, src_reg, dst_reg, off);
/* brc 4,0b */
EMIT4_PCREL_RIC(0xa7040000, 4, jit->prg - 6);
/* {llgfr|lgr} %src,%w0 */
EMIT4(is32 ? 0xb9160000 : 0xb9040000, src_reg, REG_W0);
if (is32 && insn_is_zext(&insn[1]))
insn_count = 2;
break;
case BPF_CMPXCHG:
/* 0: {csy|csg} %b0,%src,off(%dst) */
EMIT6_DISP_LH(0xeb000000, is32 ? 0x0014 : 0x0030,
BPF_REG_0, src_reg, dst_reg, off);
break;
default:
pr_err("Unknown atomic operation %02x\n", insn->imm);
return -1;
}
jit->seen |= SEEN_MEM;
break;
}
/*
* BPF_LDX
*/
case BPF_LDX | BPF_MEM | BPF_B: /* dst = *(u8 *)(ul) (src + off) */
case BPF_LDX | BPF_PROBE_MEM | BPF_B:
/* llgc %dst,0(off,%src) */
EMIT6_DISP_LH(0xe3000000, 0x0090, dst_reg, src_reg, REG_0, off);
jit->seen |= SEEN_MEM;
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
case BPF_LDX | BPF_MEM | BPF_H: /* dst = *(u16 *)(ul) (src + off) */
case BPF_LDX | BPF_PROBE_MEM | BPF_H:
/* llgh %dst,0(off,%src) */
EMIT6_DISP_LH(0xe3000000, 0x0091, dst_reg, src_reg, REG_0, off);
jit->seen |= SEEN_MEM;
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
case BPF_LDX | BPF_MEM | BPF_W: /* dst = *(u32 *)(ul) (src + off) */
case BPF_LDX | BPF_PROBE_MEM | BPF_W:
/* llgf %dst,off(%src) */
jit->seen |= SEEN_MEM;
EMIT6_DISP_LH(0xe3000000, 0x0016, dst_reg, src_reg, REG_0, off);
if (insn_is_zext(&insn[1]))
insn_count = 2;
break;
case BPF_LDX | BPF_MEM | BPF_DW: /* dst = *(u64 *)(ul) (src + off) */
case BPF_LDX | BPF_PROBE_MEM | BPF_DW:
/* lg %dst,0(off,%src) */
jit->seen |= SEEN_MEM;
EMIT6_DISP_LH(0xe3000000, 0x0004, dst_reg, src_reg, REG_0, off);
break;
/*
* BPF_JMP / CALL
*/
case BPF_JMP | BPF_CALL:
{
const struct btf_func_model *m;
bool func_addr_fixed;
int j, ret;
u64 func;
ret = bpf_jit_get_func_addr(fp, insn, extra_pass,
&func, &func_addr_fixed);
if (ret < 0)
return -1;
REG_SET_SEEN(BPF_REG_5);
jit->seen |= SEEN_FUNC;
/*
* Copy the tail call counter to where the callee expects it.
*
* Note 1: The callee can increment the tail call counter, but
* we do not load it back, since the x86 JIT does not do this
* either.
*
* Note 2: We assume that the verifier does not let us call the
* main program, which clears the tail call counter on entry.
*/
/* mvc STK_OFF_TCCNT(4,%r15),N(%r15) */
_EMIT6(0xd203f000 | STK_OFF_TCCNT,
0xf000 | (STK_OFF_TCCNT + STK_OFF + stack_depth));
/* Sign-extend the kfunc arguments. */
if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL) {
m = bpf_jit_find_kfunc_model(fp, insn);
if (!m)
return -1;
for (j = 0; j < m->nr_args; j++) {
if (sign_extend(jit, BPF_REG_1 + j,
m->arg_size[j],
m->arg_flags[j]))
return -1;
}
}
/* lgrl %w1,func */
EMIT6_PCREL_RILB(0xc4080000, REG_W1, _EMIT_CONST_U64(func));
/* %r1() */
call_r1(jit);
/* lgr %b0,%r2: load return value into %b0 */
EMIT4(0xb9040000, BPF_REG_0, REG_2);
break;
}
case BPF_JMP | BPF_TAIL_CALL: {
int patch_1_clrj, patch_2_clij, patch_3_brc;
/*
* Implicit input:
* B1: pointer to ctx
* B2: pointer to bpf_array
* B3: index in bpf_array
*
* if (index >= array->map.max_entries)
* goto out;
*/
/* llgf %w1,map.max_entries(%b2) */
EMIT6_DISP_LH(0xe3000000, 0x0016, REG_W1, REG_0, BPF_REG_2,
offsetof(struct bpf_array, map.max_entries));
/* if ((u32)%b3 >= (u32)%w1) goto out; */
/* clrj %b3,%w1,0xa,out */
patch_1_clrj = jit->prg;
EMIT6_PCREL_RIEB(0xec000000, 0x0077, BPF_REG_3, REG_W1, 0xa,
jit->prg);
/*
* if (tail_call_cnt++ >= MAX_TAIL_CALL_CNT)
* goto out;
*/
if (jit->seen & SEEN_STACK)
off = STK_OFF_TCCNT + STK_OFF + stack_depth;
else
off = STK_OFF_TCCNT;
/* lhi %w0,1 */
EMIT4_IMM(0xa7080000, REG_W0, 1);
/* laal %w1,%w0,off(%r15) */
EMIT6_DISP_LH(0xeb000000, 0x00fa, REG_W1, REG_W0, REG_15, off);
/* clij %w1,MAX_TAIL_CALL_CNT-1,0x2,out */
patch_2_clij = jit->prg;
EMIT6_PCREL_RIEC(0xec000000, 0x007f, REG_W1, MAX_TAIL_CALL_CNT - 1,
2, jit->prg);
/*
* prog = array->ptrs[index];
* if (prog == NULL)
* goto out;
*/
/* llgfr %r1,%b3: %r1 = (u32) index */
EMIT4(0xb9160000, REG_1, BPF_REG_3);
/* sllg %r1,%r1,3: %r1 *= 8 */
EMIT6_DISP_LH(0xeb000000, 0x000d, REG_1, REG_1, REG_0, 3);
/* ltg %r1,prog(%b2,%r1) */
EMIT6_DISP_LH(0xe3000000, 0x0002, REG_1, BPF_REG_2,
REG_1, offsetof(struct bpf_array, ptrs));
/* brc 0x8,out */
patch_3_brc = jit->prg;
EMIT4_PCREL_RIC(0xa7040000, 8, jit->prg);
/*
* Restore registers before calling function
*/
save_restore_regs(jit, REGS_RESTORE, stack_depth);
/*
* goto *(prog->bpf_func + tail_call_start);
*/
/* lg %r1,bpf_func(%r1) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, REG_1, REG_0,
offsetof(struct bpf_prog, bpf_func));
if (nospec_uses_trampoline()) {
jit->seen |= SEEN_FUNC;
/* aghi %r1,tail_call_start */
EMIT4_IMM(0xa70b0000, REG_1, jit->tail_call_start);
/* brcl 0xf,__s390_indirect_jump_r1 */
EMIT6_PCREL_RILC(0xc0040000, 0xf, jit->r1_thunk_ip);
} else {
/* bc 0xf,tail_call_start(%r1) */
_EMIT4(0x47f01000 + jit->tail_call_start);
}
/* out: */
if (jit->prg_buf) {
*(u16 *)(jit->prg_buf + patch_1_clrj + 2) =
(jit->prg - patch_1_clrj) >> 1;
*(u16 *)(jit->prg_buf + patch_2_clij + 2) =
(jit->prg - patch_2_clij) >> 1;
*(u16 *)(jit->prg_buf + patch_3_brc + 2) =
(jit->prg - patch_3_brc) >> 1;
}
break;
}
case BPF_JMP | BPF_EXIT: /* return b0 */
last = (i == fp->len - 1) ? 1 : 0;
if (last)
break;
if (!is_first_pass(jit) && can_use_rel(jit, jit->exit_ip))
/* brc 0xf, <exit> */
EMIT4_PCREL_RIC(0xa7040000, 0xf, jit->exit_ip);
else
/* brcl 0xf, <exit> */
EMIT6_PCREL_RILC(0xc0040000, 0xf, jit->exit_ip);
break;
/*
* Branch relative (number of skipped instructions) to offset on
* condition.
*
* Condition code to mask mapping:
*
* CC | Description | Mask
* ------------------------------
* 0 | Operands equal | 8
* 1 | First operand low | 4
* 2 | First operand high | 2
* 3 | Unused | 1
*
* For s390x relative branches: ip = ip + off_bytes
* For BPF relative branches: insn = insn + off_insns + 1
*
* For example for s390x with offset 0 we jump to the branch
* instruction itself (loop) and for BPF with offset 0 we
* branch to the instruction behind the branch.
*/
case BPF_JMP | BPF_JA: /* if (true) */
mask = 0xf000; /* j */
goto branch_oc;
case BPF_JMP | BPF_JSGT | BPF_K: /* ((s64) dst > (s64) imm) */
case BPF_JMP32 | BPF_JSGT | BPF_K: /* ((s32) dst > (s32) imm) */
mask = 0x2000; /* jh */
goto branch_ks;
case BPF_JMP | BPF_JSLT | BPF_K: /* ((s64) dst < (s64) imm) */
case BPF_JMP32 | BPF_JSLT | BPF_K: /* ((s32) dst < (s32) imm) */
mask = 0x4000; /* jl */
goto branch_ks;
case BPF_JMP | BPF_JSGE | BPF_K: /* ((s64) dst >= (s64) imm) */
case BPF_JMP32 | BPF_JSGE | BPF_K: /* ((s32) dst >= (s32) imm) */
mask = 0xa000; /* jhe */
goto branch_ks;
case BPF_JMP | BPF_JSLE | BPF_K: /* ((s64) dst <= (s64) imm) */
case BPF_JMP32 | BPF_JSLE | BPF_K: /* ((s32) dst <= (s32) imm) */
mask = 0xc000; /* jle */
goto branch_ks;
case BPF_JMP | BPF_JGT | BPF_K: /* (dst_reg > imm) */
case BPF_JMP32 | BPF_JGT | BPF_K: /* ((u32) dst_reg > (u32) imm) */
mask = 0x2000; /* jh */
goto branch_ku;
case BPF_JMP | BPF_JLT | BPF_K: /* (dst_reg < imm) */
case BPF_JMP32 | BPF_JLT | BPF_K: /* ((u32) dst_reg < (u32) imm) */
mask = 0x4000; /* jl */
goto branch_ku;
case BPF_JMP | BPF_JGE | BPF_K: /* (dst_reg >= imm) */
case BPF_JMP32 | BPF_JGE | BPF_K: /* ((u32) dst_reg >= (u32) imm) */
mask = 0xa000; /* jhe */
goto branch_ku;
case BPF_JMP | BPF_JLE | BPF_K: /* (dst_reg <= imm) */
case BPF_JMP32 | BPF_JLE | BPF_K: /* ((u32) dst_reg <= (u32) imm) */
mask = 0xc000; /* jle */
goto branch_ku;
case BPF_JMP | BPF_JNE | BPF_K: /* (dst_reg != imm) */
case BPF_JMP32 | BPF_JNE | BPF_K: /* ((u32) dst_reg != (u32) imm) */
mask = 0x7000; /* jne */
goto branch_ku;
case BPF_JMP | BPF_JEQ | BPF_K: /* (dst_reg == imm) */
case BPF_JMP32 | BPF_JEQ | BPF_K: /* ((u32) dst_reg == (u32) imm) */
mask = 0x8000; /* je */
goto branch_ku;
case BPF_JMP | BPF_JSET | BPF_K: /* (dst_reg & imm) */
case BPF_JMP32 | BPF_JSET | BPF_K: /* ((u32) dst_reg & (u32) imm) */
mask = 0x7000; /* jnz */
if (BPF_CLASS(insn->code) == BPF_JMP32) {
/* llilf %w1,imm (load zero extend imm) */
EMIT6_IMM(0xc00f0000, REG_W1, imm);
/* nr %w1,%dst */
EMIT2(0x1400, REG_W1, dst_reg);
} else {
/* lgfi %w1,imm (load sign extend imm) */
EMIT6_IMM(0xc0010000, REG_W1, imm);
/* ngr %w1,%dst */
EMIT4(0xb9800000, REG_W1, dst_reg);
}
goto branch_oc;
case BPF_JMP | BPF_JSGT | BPF_X: /* ((s64) dst > (s64) src) */
case BPF_JMP32 | BPF_JSGT | BPF_X: /* ((s32) dst > (s32) src) */
mask = 0x2000; /* jh */
goto branch_xs;
case BPF_JMP | BPF_JSLT | BPF_X: /* ((s64) dst < (s64) src) */
case BPF_JMP32 | BPF_JSLT | BPF_X: /* ((s32) dst < (s32) src) */
mask = 0x4000; /* jl */
goto branch_xs;
case BPF_JMP | BPF_JSGE | BPF_X: /* ((s64) dst >= (s64) src) */
case BPF_JMP32 | BPF_JSGE | BPF_X: /* ((s32) dst >= (s32) src) */
mask = 0xa000; /* jhe */
goto branch_xs;
case BPF_JMP | BPF_JSLE | BPF_X: /* ((s64) dst <= (s64) src) */
case BPF_JMP32 | BPF_JSLE | BPF_X: /* ((s32) dst <= (s32) src) */
mask = 0xc000; /* jle */
goto branch_xs;
case BPF_JMP | BPF_JGT | BPF_X: /* (dst > src) */
case BPF_JMP32 | BPF_JGT | BPF_X: /* ((u32) dst > (u32) src) */
mask = 0x2000; /* jh */
goto branch_xu;
case BPF_JMP | BPF_JLT | BPF_X: /* (dst < src) */
case BPF_JMP32 | BPF_JLT | BPF_X: /* ((u32) dst < (u32) src) */
mask = 0x4000; /* jl */
goto branch_xu;
case BPF_JMP | BPF_JGE | BPF_X: /* (dst >= src) */
case BPF_JMP32 | BPF_JGE | BPF_X: /* ((u32) dst >= (u32) src) */
mask = 0xa000; /* jhe */
goto branch_xu;
case BPF_JMP | BPF_JLE | BPF_X: /* (dst <= src) */
case BPF_JMP32 | BPF_JLE | BPF_X: /* ((u32) dst <= (u32) src) */
mask = 0xc000; /* jle */
goto branch_xu;
case BPF_JMP | BPF_JNE | BPF_X: /* (dst != src) */
case BPF_JMP32 | BPF_JNE | BPF_X: /* ((u32) dst != (u32) src) */
mask = 0x7000; /* jne */
goto branch_xu;
case BPF_JMP | BPF_JEQ | BPF_X: /* (dst == src) */
case BPF_JMP32 | BPF_JEQ | BPF_X: /* ((u32) dst == (u32) src) */
mask = 0x8000; /* je */
goto branch_xu;
case BPF_JMP | BPF_JSET | BPF_X: /* (dst & src) */
case BPF_JMP32 | BPF_JSET | BPF_X: /* ((u32) dst & (u32) src) */
{
bool is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
mask = 0x7000; /* jnz */
/* nrk or ngrk %w1,%dst,%src */
EMIT4_RRF((is_jmp32 ? 0xb9f40000 : 0xb9e40000),
REG_W1, dst_reg, src_reg);
goto branch_oc;
branch_ks:
is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
/* cfi or cgfi %dst,imm */
EMIT6_IMM(is_jmp32 ? 0xc20d0000 : 0xc20c0000,
dst_reg, imm);
if (!is_first_pass(jit) &&
can_use_rel(jit, addrs[i + off + 1])) {
/* brc mask,off */
EMIT4_PCREL_RIC(0xa7040000,
mask >> 12, addrs[i + off + 1]);
} else {
/* brcl mask,off */
EMIT6_PCREL_RILC(0xc0040000,
mask >> 12, addrs[i + off + 1]);
}
break;
branch_ku:
/* lgfi %w1,imm (load sign extend imm) */
src_reg = REG_1;
EMIT6_IMM(0xc0010000, src_reg, imm);
goto branch_xu;
branch_xs:
is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
if (!is_first_pass(jit) &&
can_use_rel(jit, addrs[i + off + 1])) {
/* crj or cgrj %dst,%src,mask,off */
EMIT6_PCREL(0xec000000, (is_jmp32 ? 0x0076 : 0x0064),
dst_reg, src_reg, i, off, mask);
} else {
/* cr or cgr %dst,%src */
if (is_jmp32)
EMIT2(0x1900, dst_reg, src_reg);
else
EMIT4(0xb9200000, dst_reg, src_reg);
/* brcl mask,off */
EMIT6_PCREL_RILC(0xc0040000,
mask >> 12, addrs[i + off + 1]);
}
break;
branch_xu:
is_jmp32 = BPF_CLASS(insn->code) == BPF_JMP32;
if (!is_first_pass(jit) &&
can_use_rel(jit, addrs[i + off + 1])) {
/* clrj or clgrj %dst,%src,mask,off */
EMIT6_PCREL(0xec000000, (is_jmp32 ? 0x0077 : 0x0065),
dst_reg, src_reg, i, off, mask);
} else {
/* clr or clgr %dst,%src */
if (is_jmp32)
EMIT2(0x1500, dst_reg, src_reg);
else
EMIT4(0xb9210000, dst_reg, src_reg);
/* brcl mask,off */
EMIT6_PCREL_RILC(0xc0040000,
mask >> 12, addrs[i + off + 1]);
}
break;
branch_oc:
if (!is_first_pass(jit) &&
can_use_rel(jit, addrs[i + off + 1])) {
/* brc mask,off */
EMIT4_PCREL_RIC(0xa7040000,
mask >> 12, addrs[i + off + 1]);
} else {
/* brcl mask,off */
EMIT6_PCREL_RILC(0xc0040000,
mask >> 12, addrs[i + off + 1]);
}
break;
}
default: /* too complex, give up */
pr_err("Unknown opcode %02x\n", insn->code);
return -1;
}
if (probe_prg != -1) {
/*
* Handlers of certain exceptions leave psw.addr pointing to
* the instruction directly after the failing one. Therefore,
* create two exception table entries and also add a nop in
* case two probing instructions come directly after each
* other.
*/
nop_prg = jit->prg;
/* bcr 0,%0 */
_EMIT2(0x0700);
err = bpf_jit_probe_mem(jit, fp, probe_prg, nop_prg);
if (err < 0)
return err;
}
return insn_count;
}
/*
* Return whether new i-th instruction address does not violate any invariant
*/
static bool bpf_is_new_addr_sane(struct bpf_jit *jit, int i)
{
/* On the first pass anything goes */
if (is_first_pass(jit))
return true;
/* The codegen pass must not change anything */
if (is_codegen_pass(jit))
return jit->addrs[i] == jit->prg;
/* Passes in between must not increase code size */
return jit->addrs[i] >= jit->prg;
}
/*
* Update the address of i-th instruction
*/
static int bpf_set_addr(struct bpf_jit *jit, int i)
{
int delta;
if (is_codegen_pass(jit)) {
delta = jit->prg - jit->addrs[i];
if (delta < 0)
bpf_skip(jit, -delta);
}
if (WARN_ON_ONCE(!bpf_is_new_addr_sane(jit, i)))
return -1;
jit->addrs[i] = jit->prg;
return 0;
}
/*
* Compile eBPF program into s390x code
*/
static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp,
bool extra_pass, u32 stack_depth)
{
int i, insn_count, lit32_size, lit64_size;
jit->lit32 = jit->lit32_start;
jit->lit64 = jit->lit64_start;
jit->prg = 0;
jit->excnt = 0;
bpf_jit_prologue(jit, fp, stack_depth);
if (bpf_set_addr(jit, 0) < 0)
return -1;
for (i = 0; i < fp->len; i += insn_count) {
insn_count = bpf_jit_insn(jit, fp, i, extra_pass, stack_depth);
if (insn_count < 0)
return -1;
/* Next instruction address */
if (bpf_set_addr(jit, i + insn_count) < 0)
return -1;
}
bpf_jit_epilogue(jit, stack_depth);
lit32_size = jit->lit32 - jit->lit32_start;
lit64_size = jit->lit64 - jit->lit64_start;
jit->lit32_start = jit->prg;
if (lit32_size)
jit->lit32_start = ALIGN(jit->lit32_start, 4);
jit->lit64_start = jit->lit32_start + lit32_size;
if (lit64_size)
jit->lit64_start = ALIGN(jit->lit64_start, 8);
jit->size = jit->lit64_start + lit64_size;
jit->size_prg = jit->prg;
if (WARN_ON_ONCE(fp->aux->extable &&
jit->excnt != fp->aux->num_exentries))
/* Verifier bug - too many entries. */
return -1;
return 0;
}
bool bpf_jit_needs_zext(void)
{
return true;
}
struct s390_jit_data {
struct bpf_binary_header *header;
struct bpf_jit ctx;
int pass;
};
static struct bpf_binary_header *bpf_jit_alloc(struct bpf_jit *jit,
struct bpf_prog *fp)
{
struct bpf_binary_header *header;
u32 extable_size;
u32 code_size;
/* We need two entries per insn. */
fp->aux->num_exentries *= 2;
code_size = roundup(jit->size,
__alignof__(struct exception_table_entry));
extable_size = fp->aux->num_exentries *
sizeof(struct exception_table_entry);
header = bpf_jit_binary_alloc(code_size + extable_size, &jit->prg_buf,
8, jit_fill_hole);
if (!header)
return NULL;
fp->aux->extable = (struct exception_table_entry *)
(jit->prg_buf + code_size);
return header;
}
/*
* Compile eBPF program "fp"
*/
struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
{
u32 stack_depth = round_up(fp->aux->stack_depth, 8);
struct bpf_prog *tmp, *orig_fp = fp;
struct bpf_binary_header *header;
struct s390_jit_data *jit_data;
bool tmp_blinded = false;
bool extra_pass = false;
struct bpf_jit jit;
int pass;
if (WARN_ON_ONCE(bpf_plt_end - bpf_plt != BPF_PLT_SIZE))
return orig_fp;
if (!fp->jit_requested)
return orig_fp;
tmp = bpf_jit_blind_constants(fp);
/*
* If blinding was requested and we failed during blinding,
* we must fall back to the interpreter.
*/
if (IS_ERR(tmp))
return orig_fp;
if (tmp != fp) {
tmp_blinded = true;
fp = tmp;
}
jit_data = fp->aux->jit_data;
if (!jit_data) {
jit_data = kzalloc(sizeof(*jit_data), GFP_KERNEL);
if (!jit_data) {
fp = orig_fp;
goto out;
}
fp->aux->jit_data = jit_data;
}
if (jit_data->ctx.addrs) {
jit = jit_data->ctx;
header = jit_data->header;
extra_pass = true;
pass = jit_data->pass + 1;
goto skip_init_ctx;
}
memset(&jit, 0, sizeof(jit));
jit.addrs = kvcalloc(fp->len + 1, sizeof(*jit.addrs), GFP_KERNEL);
if (jit.addrs == NULL) {
fp = orig_fp;
goto free_addrs;
}
/*
* Three initial passes:
* - 1/2: Determine clobbered registers
* - 3: Calculate program size and addrs array
*/
for (pass = 1; pass <= 3; pass++) {
if (bpf_jit_prog(&jit, fp, extra_pass, stack_depth)) {
fp = orig_fp;
goto free_addrs;
}
}
/*
* Final pass: Allocate and generate program
*/
header = bpf_jit_alloc(&jit, fp);
if (!header) {
fp = orig_fp;
goto free_addrs;
}
skip_init_ctx:
if (bpf_jit_prog(&jit, fp, extra_pass, stack_depth)) {
bpf_jit_binary_free(header);
fp = orig_fp;
goto free_addrs;
}
if (bpf_jit_enable > 1) {
bpf_jit_dump(fp->len, jit.size, pass, jit.prg_buf);
print_fn_code(jit.prg_buf, jit.size_prg);
}
if (!fp->is_func || extra_pass) {
bpf_jit_binary_lock_ro(header);
} else {
jit_data->header = header;
jit_data->ctx = jit;
jit_data->pass = pass;
}
fp->bpf_func = (void *) jit.prg_buf;
fp->jited = 1;
fp->jited_len = jit.size;
if (!fp->is_func || extra_pass) {
bpf_prog_fill_jited_linfo(fp, jit.addrs + 1);
free_addrs:
kvfree(jit.addrs);
kfree(jit_data);
fp->aux->jit_data = NULL;
}
out:
if (tmp_blinded)
bpf_jit_prog_release_other(fp, fp == orig_fp ?
tmp : orig_fp);
return fp;
}
bool bpf_jit_supports_kfunc_call(void)
{
return true;
}
bool bpf_jit_supports_far_kfunc_call(void)
{
return true;
}
int bpf_arch_text_poke(void *ip, enum bpf_text_poke_type t,
void *old_addr, void *new_addr)
{
struct {
u16 opc;
s32 disp;
} __packed insn;
char expected_plt[BPF_PLT_SIZE];
char current_plt[BPF_PLT_SIZE];
char new_plt[BPF_PLT_SIZE];
char *plt;
char *ret;
int err;
/* Verify the branch to be patched. */
err = copy_from_kernel_nofault(&insn, ip, sizeof(insn));
if (err < 0)
return err;
if (insn.opc != (0xc004 | (old_addr ? 0xf0 : 0)))
return -EINVAL;
if (t == BPF_MOD_JUMP &&
insn.disp == ((char *)new_addr - (char *)ip) >> 1) {
/*
* The branch already points to the destination,
* there is no PLT.
*/
} else {
/* Verify the PLT. */
plt = (char *)ip + (insn.disp << 1);
err = copy_from_kernel_nofault(current_plt, plt, BPF_PLT_SIZE);
if (err < 0)
return err;
ret = (char *)ip + 6;
bpf_jit_plt(expected_plt, ret, old_addr);
if (memcmp(current_plt, expected_plt, BPF_PLT_SIZE))
return -EINVAL;
/* Adjust the call address. */
bpf_jit_plt(new_plt, ret, new_addr);
s390_kernel_write(plt + (bpf_plt_target - bpf_plt),
new_plt + (bpf_plt_target - bpf_plt),
sizeof(void *));
}
/* Adjust the mask of the branch. */
insn.opc = 0xc004 | (new_addr ? 0xf0 : 0);
s390_kernel_write((char *)ip + 1, (char *)&insn.opc + 1, 1);
/* Make the new code visible to the other CPUs. */
text_poke_sync_lock();
return 0;
}
struct bpf_tramp_jit {
struct bpf_jit common;
int orig_stack_args_off;/* Offset of arguments placed on stack by the
* func_addr's original caller
*/
int stack_size; /* Trampoline stack size */
int stack_args_off; /* Offset of stack arguments for calling
* func_addr, has to be at the top
*/
int reg_args_off; /* Offset of register arguments for calling
* func_addr
*/
int ip_off; /* For bpf_get_func_ip(), has to be at
* (ctx - 16)
*/
int arg_cnt_off; /* For bpf_get_func_arg_cnt(), has to be at
* (ctx - 8)
*/
int bpf_args_off; /* Offset of BPF_PROG context, which consists
* of BPF arguments followed by return value
*/
int retval_off; /* Offset of return value (see above) */
int r7_r8_off; /* Offset of saved %r7 and %r8, which are used
* for __bpf_prog_enter() return value and
* func_addr respectively
*/
int r14_off; /* Offset of saved %r14 */
int run_ctx_off; /* Offset of struct bpf_tramp_run_ctx */
int do_fexit; /* do_fexit: label */
};
static void load_imm64(struct bpf_jit *jit, int dst_reg, u64 val)
{
/* llihf %dst_reg,val_hi */
EMIT6_IMM(0xc00e0000, dst_reg, (val >> 32));
/* oilf %rdst_reg,val_lo */
EMIT6_IMM(0xc00d0000, dst_reg, val);
}
static int invoke_bpf_prog(struct bpf_tramp_jit *tjit,
const struct btf_func_model *m,
struct bpf_tramp_link *tlink, bool save_ret)
{
struct bpf_jit *jit = &tjit->common;
int cookie_off = tjit->run_ctx_off +
offsetof(struct bpf_tramp_run_ctx, bpf_cookie);
struct bpf_prog *p = tlink->link.prog;
int patch;
/*
* run_ctx.cookie = tlink->cookie;
*/
/* %r0 = tlink->cookie */
load_imm64(jit, REG_W0, tlink->cookie);
/* stg %r0,cookie_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W0, REG_0, REG_15, cookie_off);
/*
* if ((start = __bpf_prog_enter(p, &run_ctx)) == 0)
* goto skip;
*/
/* %r1 = __bpf_prog_enter */
load_imm64(jit, REG_1, (u64)bpf_trampoline_enter(p));
/* %r2 = p */
load_imm64(jit, REG_2, (u64)p);
/* la %r3,run_ctx_off(%r15) */
EMIT4_DISP(0x41000000, REG_3, REG_15, tjit->run_ctx_off);
/* %r1() */
call_r1(jit);
/* ltgr %r7,%r2 */
EMIT4(0xb9020000, REG_7, REG_2);
/* brcl 8,skip */
patch = jit->prg;
EMIT6_PCREL_RILC(0xc0040000, 8, 0);
/*
* retval = bpf_func(args, p->insnsi);
*/
/* %r1 = p->bpf_func */
load_imm64(jit, REG_1, (u64)p->bpf_func);
/* la %r2,bpf_args_off(%r15) */
EMIT4_DISP(0x41000000, REG_2, REG_15, tjit->bpf_args_off);
/* %r3 = p->insnsi */
if (!p->jited)
load_imm64(jit, REG_3, (u64)p->insnsi);
/* %r1() */
call_r1(jit);
/* stg %r2,retval_off(%r15) */
if (save_ret) {
if (sign_extend(jit, REG_2, m->ret_size, m->ret_flags))
return -1;
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_2, REG_0, REG_15,
tjit->retval_off);
}
/* skip: */
if (jit->prg_buf)
*(u32 *)&jit->prg_buf[patch + 2] = (jit->prg - patch) >> 1;
/*
* __bpf_prog_exit(p, start, &run_ctx);
*/
/* %r1 = __bpf_prog_exit */
load_imm64(jit, REG_1, (u64)bpf_trampoline_exit(p));
/* %r2 = p */
load_imm64(jit, REG_2, (u64)p);
/* lgr %r3,%r7 */
EMIT4(0xb9040000, REG_3, REG_7);
/* la %r4,run_ctx_off(%r15) */
EMIT4_DISP(0x41000000, REG_4, REG_15, tjit->run_ctx_off);
/* %r1() */
call_r1(jit);
return 0;
}
static int alloc_stack(struct bpf_tramp_jit *tjit, size_t size)
{
int stack_offset = tjit->stack_size;
tjit->stack_size += size;
return stack_offset;
}
/* ABI uses %r2 - %r6 for parameter passing. */
#define MAX_NR_REG_ARGS 5
/* The "L" field of the "mvc" instruction is 8 bits. */
#define MAX_MVC_SIZE 256
#define MAX_NR_STACK_ARGS (MAX_MVC_SIZE / sizeof(u64))
/* -mfentry generates a 6-byte nop on s390x. */
#define S390X_PATCH_SIZE 6
static int __arch_prepare_bpf_trampoline(struct bpf_tramp_image *im,
struct bpf_tramp_jit *tjit,
const struct btf_func_model *m,
u32 flags,
struct bpf_tramp_links *tlinks,
void *func_addr)
{
struct bpf_tramp_links *fmod_ret = &tlinks[BPF_TRAMP_MODIFY_RETURN];
struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];
struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
int nr_bpf_args, nr_reg_args, nr_stack_args;
struct bpf_jit *jit = &tjit->common;
int arg, bpf_arg_off;
int i, j;
/* Support as many stack arguments as "mvc" instruction can handle. */
nr_reg_args = min_t(int, m->nr_args, MAX_NR_REG_ARGS);
nr_stack_args = m->nr_args - nr_reg_args;
if (nr_stack_args > MAX_NR_STACK_ARGS)
return -ENOTSUPP;
/* Return to %r14, since func_addr and %r0 are not available. */
if (!func_addr && !(flags & BPF_TRAMP_F_ORIG_STACK))
flags |= BPF_TRAMP_F_SKIP_FRAME;
/*
* Compute how many arguments we need to pass to BPF programs.
* BPF ABI mirrors that of x86_64: arguments that are 16 bytes or
* smaller are packed into 1 or 2 registers; larger arguments are
* passed via pointers.
* In s390x ABI, arguments that are 8 bytes or smaller are packed into
* a register; larger arguments are passed via pointers.
* We need to deal with this difference.
*/
nr_bpf_args = 0;
for (i = 0; i < m->nr_args; i++) {
if (m->arg_size[i] <= 8)
nr_bpf_args += 1;
else if (m->arg_size[i] <= 16)
nr_bpf_args += 2;
else
return -ENOTSUPP;
}
/*
* Calculate the stack layout.
*/
/* Reserve STACK_FRAME_OVERHEAD bytes for the callees. */
tjit->stack_size = STACK_FRAME_OVERHEAD;
tjit->stack_args_off = alloc_stack(tjit, nr_stack_args * sizeof(u64));
tjit->reg_args_off = alloc_stack(tjit, nr_reg_args * sizeof(u64));
tjit->ip_off = alloc_stack(tjit, sizeof(u64));
tjit->arg_cnt_off = alloc_stack(tjit, sizeof(u64));
tjit->bpf_args_off = alloc_stack(tjit, nr_bpf_args * sizeof(u64));
tjit->retval_off = alloc_stack(tjit, sizeof(u64));
tjit->r7_r8_off = alloc_stack(tjit, 2 * sizeof(u64));
tjit->r14_off = alloc_stack(tjit, sizeof(u64));
tjit->run_ctx_off = alloc_stack(tjit,
sizeof(struct bpf_tramp_run_ctx));
/* The caller has already reserved STACK_FRAME_OVERHEAD bytes. */
tjit->stack_size -= STACK_FRAME_OVERHEAD;
tjit->orig_stack_args_off = tjit->stack_size + STACK_FRAME_OVERHEAD;
/* aghi %r15,-stack_size */
EMIT4_IMM(0xa70b0000, REG_15, -tjit->stack_size);
/* stmg %r2,%rN,fwd_reg_args_off(%r15) */
if (nr_reg_args)
EMIT6_DISP_LH(0xeb000000, 0x0024, REG_2,
REG_2 + (nr_reg_args - 1), REG_15,
tjit->reg_args_off);
for (i = 0, j = 0; i < m->nr_args; i++) {
if (i < MAX_NR_REG_ARGS)
arg = REG_2 + i;
else
arg = tjit->orig_stack_args_off +
(i - MAX_NR_REG_ARGS) * sizeof(u64);
bpf_arg_off = tjit->bpf_args_off + j * sizeof(u64);
if (m->arg_size[i] <= 8) {
if (i < MAX_NR_REG_ARGS)
/* stg %arg,bpf_arg_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, arg,
REG_0, REG_15, bpf_arg_off);
else
/* mvc bpf_arg_off(8,%r15),arg(%r15) */
_EMIT6(0xd207f000 | bpf_arg_off,
0xf000 | arg);
j += 1;
} else {
if (i < MAX_NR_REG_ARGS) {
/* mvc bpf_arg_off(16,%r15),0(%arg) */
_EMIT6(0xd20ff000 | bpf_arg_off,
reg2hex[arg] << 12);
} else {
/* lg %r1,arg(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_1, REG_0,
REG_15, arg);
/* mvc bpf_arg_off(16,%r15),0(%r1) */
_EMIT6(0xd20ff000 | bpf_arg_off, 0x1000);
}
j += 2;
}
}
/* stmg %r7,%r8,r7_r8_off(%r15) */
EMIT6_DISP_LH(0xeb000000, 0x0024, REG_7, REG_8, REG_15,
tjit->r7_r8_off);
/* stg %r14,r14_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_14, REG_0, REG_15, tjit->r14_off);
if (flags & BPF_TRAMP_F_ORIG_STACK) {
/*
* The ftrace trampoline puts the return address (which is the
* address of the original function + S390X_PATCH_SIZE) into
* %r0; see ftrace_shared_hotpatch_trampoline_br and
* ftrace_init_nop() for details.
*/
/* lgr %r8,%r0 */
EMIT4(0xb9040000, REG_8, REG_0);
} else {
/* %r8 = func_addr + S390X_PATCH_SIZE */
load_imm64(jit, REG_8, (u64)func_addr + S390X_PATCH_SIZE);
}
/*
* ip = func_addr;
* arg_cnt = m->nr_args;
*/
if (flags & BPF_TRAMP_F_IP_ARG) {
/* %r0 = func_addr */
load_imm64(jit, REG_0, (u64)func_addr);
/* stg %r0,ip_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_0, REG_0, REG_15,
tjit->ip_off);
}
/* lghi %r0,nr_bpf_args */
EMIT4_IMM(0xa7090000, REG_0, nr_bpf_args);
/* stg %r0,arg_cnt_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_0, REG_0, REG_15,
tjit->arg_cnt_off);
if (flags & BPF_TRAMP_F_CALL_ORIG) {
/*
* __bpf_tramp_enter(im);
*/
/* %r1 = __bpf_tramp_enter */
load_imm64(jit, REG_1, (u64)__bpf_tramp_enter);
/* %r2 = im */
load_imm64(jit, REG_2, (u64)im);
/* %r1() */
call_r1(jit);
}
for (i = 0; i < fentry->nr_links; i++)
if (invoke_bpf_prog(tjit, m, fentry->links[i],
flags & BPF_TRAMP_F_RET_FENTRY_RET))
return -EINVAL;
if (fmod_ret->nr_links) {
/*
* retval = 0;
*/
/* xc retval_off(8,%r15),retval_off(%r15) */
_EMIT6(0xd707f000 | tjit->retval_off,
0xf000 | tjit->retval_off);
for (i = 0; i < fmod_ret->nr_links; i++) {
if (invoke_bpf_prog(tjit, m, fmod_ret->links[i], true))
return -EINVAL;
/*
* if (retval)
* goto do_fexit;
*/
/* ltg %r0,retval_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0002, REG_0, REG_0, REG_15,
tjit->retval_off);
/* brcl 7,do_fexit */
EMIT6_PCREL_RILC(0xc0040000, 7, tjit->do_fexit);
}
}
if (flags & BPF_TRAMP_F_CALL_ORIG) {
/*
* retval = func_addr(args);
*/
/* lmg %r2,%rN,reg_args_off(%r15) */
if (nr_reg_args)
EMIT6_DISP_LH(0xeb000000, 0x0004, REG_2,
REG_2 + (nr_reg_args - 1), REG_15,
tjit->reg_args_off);
/* mvc stack_args_off(N,%r15),orig_stack_args_off(%r15) */
if (nr_stack_args)
_EMIT6(0xd200f000 |
(nr_stack_args * sizeof(u64) - 1) << 16 |
tjit->stack_args_off,
0xf000 | tjit->orig_stack_args_off);
/* lgr %r1,%r8 */
EMIT4(0xb9040000, REG_1, REG_8);
/* %r1() */
call_r1(jit);
/* stg %r2,retval_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0024, REG_2, REG_0, REG_15,
tjit->retval_off);
im->ip_after_call = jit->prg_buf + jit->prg;
/*
* The following nop will be patched by bpf_tramp_image_put().
*/
/* brcl 0,im->ip_epilogue */
EMIT6_PCREL_RILC(0xc0040000, 0, (u64)im->ip_epilogue);
}
/* do_fexit: */
tjit->do_fexit = jit->prg;
for (i = 0; i < fexit->nr_links; i++)
if (invoke_bpf_prog(tjit, m, fexit->links[i], false))
return -EINVAL;
if (flags & BPF_TRAMP_F_CALL_ORIG) {
im->ip_epilogue = jit->prg_buf + jit->prg;
/*
* __bpf_tramp_exit(im);
*/
/* %r1 = __bpf_tramp_exit */
load_imm64(jit, REG_1, (u64)__bpf_tramp_exit);
/* %r2 = im */
load_imm64(jit, REG_2, (u64)im);
/* %r1() */
call_r1(jit);
}
/* lmg %r2,%rN,reg_args_off(%r15) */
if ((flags & BPF_TRAMP_F_RESTORE_REGS) && nr_reg_args)
EMIT6_DISP_LH(0xeb000000, 0x0004, REG_2,
REG_2 + (nr_reg_args - 1), REG_15,
tjit->reg_args_off);
/* lgr %r1,%r8 */
if (!(flags & BPF_TRAMP_F_SKIP_FRAME))
EMIT4(0xb9040000, REG_1, REG_8);
/* lmg %r7,%r8,r7_r8_off(%r15) */
EMIT6_DISP_LH(0xeb000000, 0x0004, REG_7, REG_8, REG_15,
tjit->r7_r8_off);
/* lg %r14,r14_off(%r15) */
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_14, REG_0, REG_15, tjit->r14_off);
/* lg %r2,retval_off(%r15) */
if (flags & (BPF_TRAMP_F_CALL_ORIG | BPF_TRAMP_F_RET_FENTRY_RET))
EMIT6_DISP_LH(0xe3000000, 0x0004, REG_2, REG_0, REG_15,
tjit->retval_off);
/* aghi %r15,stack_size */
EMIT4_IMM(0xa70b0000, REG_15, tjit->stack_size);
/* Emit an expoline for the following indirect jump. */
if (nospec_uses_trampoline())
emit_expoline(jit);
if (flags & BPF_TRAMP_F_SKIP_FRAME)
/* br %r14 */
_EMIT2(0x07fe);
else
/* br %r1 */
_EMIT2(0x07f1);
emit_r1_thunk(jit);
return 0;
}
int arch_prepare_bpf_trampoline(struct bpf_tramp_image *im, void *image,
void *image_end, const struct btf_func_model *m,
u32 flags, struct bpf_tramp_links *tlinks,
void *func_addr)
{
struct bpf_tramp_jit tjit;
int ret;
int i;
for (i = 0; i < 2; i++) {
if (i == 0) {
/* Compute offsets, check whether the code fits. */
memset(&tjit, 0, sizeof(tjit));
} else {
/* Generate the code. */
tjit.common.prg = 0;
tjit.common.prg_buf = image;
}
ret = __arch_prepare_bpf_trampoline(im, &tjit, m, flags,
tlinks, func_addr);
if (ret < 0)
return ret;
if (tjit.common.prg > (char *)image_end - (char *)image)
/*
* Use the same error code as for exceeding
* BPF_MAX_TRAMP_LINKS.
*/
return -E2BIG;
}
return ret;
}
bool bpf_jit_supports_subprog_tailcalls(void)
{
return true;
}