| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Handle unaligned accesses by emulation. |
| * |
| * Copyright (C) 2020-2022 Loongson Technology Corporation Limited |
| * |
| * Derived from MIPS: |
| * Copyright (C) 1996, 1998, 1999, 2002 by Ralf Baechle |
| * Copyright (C) 1999 Silicon Graphics, Inc. |
| * Copyright (C) 2014 Imagination Technologies Ltd. |
| */ |
| #include <linux/mm.h> |
| #include <linux/sched.h> |
| #include <linux/signal.h> |
| #include <linux/debugfs.h> |
| #include <linux/perf_event.h> |
| |
| #include <asm/asm.h> |
| #include <asm/branch.h> |
| #include <asm/fpu.h> |
| #include <asm/inst.h> |
| |
| #include "access-helper.h" |
| |
| #ifdef CONFIG_DEBUG_FS |
| static u32 unaligned_instructions_user; |
| static u32 unaligned_instructions_kernel; |
| #endif |
| |
| static inline unsigned long read_fpr(unsigned int idx) |
| { |
| #define READ_FPR(idx, __value) \ |
| __asm__ __volatile__("movfr2gr.d %0, $f"#idx"\n\t" : "=r"(__value)); |
| |
| unsigned long __value; |
| |
| switch (idx) { |
| case 0: |
| READ_FPR(0, __value); |
| break; |
| case 1: |
| READ_FPR(1, __value); |
| break; |
| case 2: |
| READ_FPR(2, __value); |
| break; |
| case 3: |
| READ_FPR(3, __value); |
| break; |
| case 4: |
| READ_FPR(4, __value); |
| break; |
| case 5: |
| READ_FPR(5, __value); |
| break; |
| case 6: |
| READ_FPR(6, __value); |
| break; |
| case 7: |
| READ_FPR(7, __value); |
| break; |
| case 8: |
| READ_FPR(8, __value); |
| break; |
| case 9: |
| READ_FPR(9, __value); |
| break; |
| case 10: |
| READ_FPR(10, __value); |
| break; |
| case 11: |
| READ_FPR(11, __value); |
| break; |
| case 12: |
| READ_FPR(12, __value); |
| break; |
| case 13: |
| READ_FPR(13, __value); |
| break; |
| case 14: |
| READ_FPR(14, __value); |
| break; |
| case 15: |
| READ_FPR(15, __value); |
| break; |
| case 16: |
| READ_FPR(16, __value); |
| break; |
| case 17: |
| READ_FPR(17, __value); |
| break; |
| case 18: |
| READ_FPR(18, __value); |
| break; |
| case 19: |
| READ_FPR(19, __value); |
| break; |
| case 20: |
| READ_FPR(20, __value); |
| break; |
| case 21: |
| READ_FPR(21, __value); |
| break; |
| case 22: |
| READ_FPR(22, __value); |
| break; |
| case 23: |
| READ_FPR(23, __value); |
| break; |
| case 24: |
| READ_FPR(24, __value); |
| break; |
| case 25: |
| READ_FPR(25, __value); |
| break; |
| case 26: |
| READ_FPR(26, __value); |
| break; |
| case 27: |
| READ_FPR(27, __value); |
| break; |
| case 28: |
| READ_FPR(28, __value); |
| break; |
| case 29: |
| READ_FPR(29, __value); |
| break; |
| case 30: |
| READ_FPR(30, __value); |
| break; |
| case 31: |
| READ_FPR(31, __value); |
| break; |
| default: |
| panic("unexpected idx '%d'", idx); |
| } |
| #undef READ_FPR |
| return __value; |
| } |
| |
| static inline void write_fpr(unsigned int idx, unsigned long value) |
| { |
| #define WRITE_FPR(idx, value) \ |
| __asm__ __volatile__("movgr2fr.d $f"#idx", %0\n\t" :: "r"(value)); |
| |
| switch (idx) { |
| case 0: |
| WRITE_FPR(0, value); |
| break; |
| case 1: |
| WRITE_FPR(1, value); |
| break; |
| case 2: |
| WRITE_FPR(2, value); |
| break; |
| case 3: |
| WRITE_FPR(3, value); |
| break; |
| case 4: |
| WRITE_FPR(4, value); |
| break; |
| case 5: |
| WRITE_FPR(5, value); |
| break; |
| case 6: |
| WRITE_FPR(6, value); |
| break; |
| case 7: |
| WRITE_FPR(7, value); |
| break; |
| case 8: |
| WRITE_FPR(8, value); |
| break; |
| case 9: |
| WRITE_FPR(9, value); |
| break; |
| case 10: |
| WRITE_FPR(10, value); |
| break; |
| case 11: |
| WRITE_FPR(11, value); |
| break; |
| case 12: |
| WRITE_FPR(12, value); |
| break; |
| case 13: |
| WRITE_FPR(13, value); |
| break; |
| case 14: |
| WRITE_FPR(14, value); |
| break; |
| case 15: |
| WRITE_FPR(15, value); |
| break; |
| case 16: |
| WRITE_FPR(16, value); |
| break; |
| case 17: |
| WRITE_FPR(17, value); |
| break; |
| case 18: |
| WRITE_FPR(18, value); |
| break; |
| case 19: |
| WRITE_FPR(19, value); |
| break; |
| case 20: |
| WRITE_FPR(20, value); |
| break; |
| case 21: |
| WRITE_FPR(21, value); |
| break; |
| case 22: |
| WRITE_FPR(22, value); |
| break; |
| case 23: |
| WRITE_FPR(23, value); |
| break; |
| case 24: |
| WRITE_FPR(24, value); |
| break; |
| case 25: |
| WRITE_FPR(25, value); |
| break; |
| case 26: |
| WRITE_FPR(26, value); |
| break; |
| case 27: |
| WRITE_FPR(27, value); |
| break; |
| case 28: |
| WRITE_FPR(28, value); |
| break; |
| case 29: |
| WRITE_FPR(29, value); |
| break; |
| case 30: |
| WRITE_FPR(30, value); |
| break; |
| case 31: |
| WRITE_FPR(31, value); |
| break; |
| default: |
| panic("unexpected idx '%d'", idx); |
| } |
| #undef WRITE_FPR |
| } |
| |
| void emulate_load_store_insn(struct pt_regs *regs, void __user *addr, unsigned int *pc) |
| { |
| bool fp = false; |
| bool sign, write; |
| bool user = user_mode(regs); |
| unsigned int res, size = 0; |
| unsigned long value = 0; |
| union loongarch_instruction insn; |
| |
| perf_sw_event(PERF_COUNT_SW_EMULATION_FAULTS, 1, regs, 0); |
| |
| __get_inst(&insn.word, pc, user); |
| |
| switch (insn.reg2i12_format.opcode) { |
| case ldh_op: |
| size = 2; |
| sign = true; |
| write = false; |
| break; |
| case ldhu_op: |
| size = 2; |
| sign = false; |
| write = false; |
| break; |
| case sth_op: |
| size = 2; |
| sign = true; |
| write = true; |
| break; |
| case ldw_op: |
| size = 4; |
| sign = true; |
| write = false; |
| break; |
| case ldwu_op: |
| size = 4; |
| sign = false; |
| write = false; |
| break; |
| case stw_op: |
| size = 4; |
| sign = true; |
| write = true; |
| break; |
| case ldd_op: |
| size = 8; |
| sign = true; |
| write = false; |
| break; |
| case std_op: |
| size = 8; |
| sign = true; |
| write = true; |
| break; |
| case flds_op: |
| size = 4; |
| fp = true; |
| sign = true; |
| write = false; |
| break; |
| case fsts_op: |
| size = 4; |
| fp = true; |
| sign = true; |
| write = true; |
| break; |
| case fldd_op: |
| size = 8; |
| fp = true; |
| sign = true; |
| write = false; |
| break; |
| case fstd_op: |
| size = 8; |
| fp = true; |
| sign = true; |
| write = true; |
| break; |
| } |
| |
| switch (insn.reg2i14_format.opcode) { |
| case ldptrw_op: |
| size = 4; |
| sign = true; |
| write = false; |
| break; |
| case stptrw_op: |
| size = 4; |
| sign = true; |
| write = true; |
| break; |
| case ldptrd_op: |
| size = 8; |
| sign = true; |
| write = false; |
| break; |
| case stptrd_op: |
| size = 8; |
| sign = true; |
| write = true; |
| break; |
| } |
| |
| switch (insn.reg3_format.opcode) { |
| case ldxh_op: |
| size = 2; |
| sign = true; |
| write = false; |
| break; |
| case ldxhu_op: |
| size = 2; |
| sign = false; |
| write = false; |
| break; |
| case stxh_op: |
| size = 2; |
| sign = true; |
| write = true; |
| break; |
| case ldxw_op: |
| size = 4; |
| sign = true; |
| write = false; |
| break; |
| case ldxwu_op: |
| size = 4; |
| sign = false; |
| write = false; |
| break; |
| case stxw_op: |
| size = 4; |
| sign = true; |
| write = true; |
| break; |
| case ldxd_op: |
| size = 8; |
| sign = true; |
| write = false; |
| break; |
| case stxd_op: |
| size = 8; |
| sign = true; |
| write = true; |
| break; |
| case fldxs_op: |
| size = 4; |
| fp = true; |
| sign = true; |
| write = false; |
| break; |
| case fstxs_op: |
| size = 4; |
| fp = true; |
| sign = true; |
| write = true; |
| break; |
| case fldxd_op: |
| size = 8; |
| fp = true; |
| sign = true; |
| write = false; |
| break; |
| case fstxd_op: |
| size = 8; |
| fp = true; |
| sign = true; |
| write = true; |
| break; |
| } |
| |
| if (!size) |
| goto sigbus; |
| if (user && !access_ok(addr, size)) |
| goto sigbus; |
| |
| if (!write) { |
| res = unaligned_read(addr, &value, size, sign); |
| if (res) |
| goto fault; |
| |
| /* Rd is the same field in any formats */ |
| if (!fp) |
| regs->regs[insn.reg3_format.rd] = value; |
| else { |
| if (is_fpu_owner()) |
| write_fpr(insn.reg3_format.rd, value); |
| else |
| set_fpr64(¤t->thread.fpu.fpr[insn.reg3_format.rd], 0, value); |
| } |
| } else { |
| /* Rd is the same field in any formats */ |
| if (!fp) |
| value = regs->regs[insn.reg3_format.rd]; |
| else { |
| if (is_fpu_owner()) |
| value = read_fpr(insn.reg3_format.rd); |
| else |
| value = get_fpr64(¤t->thread.fpu.fpr[insn.reg3_format.rd], 0); |
| } |
| |
| res = unaligned_write(addr, value, size); |
| if (res) |
| goto fault; |
| } |
| |
| #ifdef CONFIG_DEBUG_FS |
| if (user) |
| unaligned_instructions_user++; |
| else |
| unaligned_instructions_kernel++; |
| #endif |
| |
| compute_return_era(regs); |
| |
| return; |
| |
| fault: |
| /* Did we have an exception handler installed? */ |
| if (fixup_exception(regs)) |
| return; |
| |
| die_if_kernel("Unhandled kernel unaligned access", regs); |
| force_sig(SIGSEGV); |
| |
| return; |
| |
| sigbus: |
| die_if_kernel("Unhandled kernel unaligned access", regs); |
| force_sig(SIGBUS); |
| |
| return; |
| } |
| |
| #ifdef CONFIG_DEBUG_FS |
| static int __init debugfs_unaligned(void) |
| { |
| struct dentry *d; |
| |
| d = debugfs_create_dir("loongarch", NULL); |
| |
| debugfs_create_u32("unaligned_instructions_user", |
| S_IRUGO, d, &unaligned_instructions_user); |
| debugfs_create_u32("unaligned_instructions_kernel", |
| S_IRUGO, d, &unaligned_instructions_kernel); |
| |
| return 0; |
| } |
| arch_initcall(debugfs_unaligned); |
| #endif |
