| /* SPDX-License-Identifier: GPL-2.0-or-later */ |
| /* |
| * Split from ftrace_64.S |
| */ |
| |
| #include <linux/export.h> |
| #include <linux/magic.h> |
| #include <asm/ppc_asm.h> |
| #include <asm/asm-offsets.h> |
| #include <asm/ftrace.h> |
| #include <asm/ppc-opcode.h> |
| #include <asm/thread_info.h> |
| #include <asm/bug.h> |
| #include <asm/ptrace.h> |
| |
| /* |
| * |
| * ftrace_caller()/ftrace_regs_caller() is the function that replaces _mcount() |
| * when ftrace is active. |
| * |
| * We arrive here after a function A calls function B, and we are the trace |
| * function for B. When we enter r1 points to A's stack frame, B has not yet |
| * had a chance to allocate one yet. |
| * |
| * Additionally r2 may point either to the TOC for A, or B, depending on |
| * whether B did a TOC setup sequence before calling us. |
| * |
| * On entry the LR points back to the _mcount() call site, and r0 holds the |
| * saved LR as it was on entry to B, ie. the original return address at the |
| * call site in A. |
| * |
| * Our job is to save the register state into a struct pt_regs (on the stack) |
| * and then arrange for the ftrace function to be called. |
| */ |
| .macro ftrace_regs_entry allregs |
| /* Create a minimal stack frame for representing B */ |
| PPC_STLU r1, -STACK_FRAME_MIN_SIZE(r1) |
| |
| /* Create our stack frame + pt_regs */ |
| PPC_STLU r1,-SWITCH_FRAME_SIZE(r1) |
| |
| /* Save all gprs to pt_regs */ |
| SAVE_GPR(0, r1) |
| SAVE_GPRS(3, 10, r1) |
| |
| #ifdef CONFIG_PPC64 |
| /* Save the original return address in A's stack frame */ |
| std r0, LRSAVE+SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE(r1) |
| /* Ok to continue? */ |
| lbz r3, PACA_FTRACE_ENABLED(r13) |
| cmpdi r3, 0 |
| beq ftrace_no_trace |
| #endif |
| |
| .if \allregs == 1 |
| SAVE_GPR(2, r1) |
| SAVE_GPRS(11, 31, r1) |
| .else |
| #ifdef CONFIG_LIVEPATCH_64 |
| SAVE_GPR(14, r1) |
| #endif |
| .endif |
| |
| /* Save previous stack pointer (r1) */ |
| addi r8, r1, SWITCH_FRAME_SIZE |
| PPC_STL r8, GPR1(r1) |
| |
| .if \allregs == 1 |
| /* Load special regs for save below */ |
| mfmsr r8 |
| mfctr r9 |
| mfxer r10 |
| mfcr r11 |
| .else |
| /* Clear MSR to flag as ftrace_caller versus frace_regs_caller */ |
| li r8, 0 |
| .endif |
| |
| /* Get the _mcount() call site out of LR */ |
| mflr r7 |
| /* Save it as pt_regs->nip */ |
| PPC_STL r7, _NIP(r1) |
| /* Also save it in B's stackframe header for proper unwind */ |
| PPC_STL r7, LRSAVE+SWITCH_FRAME_SIZE(r1) |
| /* Save the read LR in pt_regs->link */ |
| PPC_STL r0, _LINK(r1) |
| |
| #ifdef CONFIG_PPC64 |
| /* Save callee's TOC in the ABI compliant location */ |
| std r2, STK_GOT(r1) |
| LOAD_PACA_TOC() /* get kernel TOC in r2 */ |
| LOAD_REG_ADDR(r3, function_trace_op) |
| ld r5,0(r3) |
| #else |
| lis r3,function_trace_op@ha |
| lwz r5,function_trace_op@l(r3) |
| #endif |
| |
| #ifdef CONFIG_LIVEPATCH_64 |
| mr r14, r7 /* remember old NIP */ |
| #endif |
| |
| /* Calculate ip from nip-4 into r3 for call below */ |
| subi r3, r7, MCOUNT_INSN_SIZE |
| |
| /* Put the original return address in r4 as parent_ip */ |
| mr r4, r0 |
| |
| /* Save special regs */ |
| PPC_STL r8, _MSR(r1) |
| .if \allregs == 1 |
| PPC_STL r9, _CTR(r1) |
| PPC_STL r10, _XER(r1) |
| PPC_STL r11, _CCR(r1) |
| .endif |
| |
| /* Load &pt_regs in r6 for call below */ |
| addi r6, r1, STACK_INT_FRAME_REGS |
| .endm |
| |
| .macro ftrace_regs_exit allregs |
| /* Load ctr with the possibly modified NIP */ |
| PPC_LL r3, _NIP(r1) |
| mtctr r3 |
| |
| #ifdef CONFIG_LIVEPATCH_64 |
| cmpd r14, r3 /* has NIP been altered? */ |
| #endif |
| |
| /* Restore gprs */ |
| .if \allregs == 1 |
| REST_GPRS(2, 31, r1) |
| .else |
| REST_GPRS(3, 10, r1) |
| #ifdef CONFIG_LIVEPATCH_64 |
| REST_GPR(14, r1) |
| #endif |
| .endif |
| |
| /* Restore possibly modified LR */ |
| PPC_LL r0, _LINK(r1) |
| mtlr r0 |
| |
| #ifdef CONFIG_PPC64 |
| /* Restore callee's TOC */ |
| ld r2, STK_GOT(r1) |
| #endif |
| |
| /* Pop our stack frame */ |
| addi r1, r1, SWITCH_FRAME_SIZE+STACK_FRAME_MIN_SIZE |
| |
| #ifdef CONFIG_LIVEPATCH_64 |
| /* Based on the cmpd above, if the NIP was altered handle livepatch */ |
| bne- livepatch_handler |
| #endif |
| bctr /* jump after _mcount site */ |
| .endm |
| |
| _GLOBAL(ftrace_regs_caller) |
| ftrace_regs_entry 1 |
| /* ftrace_call(r3, r4, r5, r6) */ |
| .globl ftrace_regs_call |
| ftrace_regs_call: |
| bl ftrace_stub |
| nop |
| ftrace_regs_exit 1 |
| |
| _GLOBAL(ftrace_caller) |
| ftrace_regs_entry 0 |
| /* ftrace_call(r3, r4, r5, r6) */ |
| .globl ftrace_call |
| ftrace_call: |
| bl ftrace_stub |
| nop |
| ftrace_regs_exit 0 |
| |
| _GLOBAL(ftrace_stub) |
| blr |
| |
| #ifdef CONFIG_PPC64 |
| ftrace_no_trace: |
| mflr r3 |
| mtctr r3 |
| REST_GPR(3, r1) |
| addi r1, r1, SWITCH_FRAME_SIZE |
| mtlr r0 |
| bctr |
| #endif |
| |
| #ifdef CONFIG_LIVEPATCH_64 |
| /* |
| * This function runs in the mcount context, between two functions. As |
| * such it can only clobber registers which are volatile and used in |
| * function linkage. |
| * |
| * We get here when a function A, calls another function B, but B has |
| * been live patched with a new function C. |
| * |
| * On entry: |
| * - we have no stack frame and can not allocate one |
| * - LR points back to the original caller (in A) |
| * - CTR holds the new NIP in C |
| * - r0, r11 & r12 are free |
| */ |
| livepatch_handler: |
| ld r12, PACA_THREAD_INFO(r13) |
| |
| /* Allocate 3 x 8 bytes */ |
| ld r11, TI_livepatch_sp(r12) |
| addi r11, r11, 24 |
| std r11, TI_livepatch_sp(r12) |
| |
| /* Save toc & real LR on livepatch stack */ |
| std r2, -24(r11) |
| mflr r12 |
| std r12, -16(r11) |
| |
| /* Store stack end marker */ |
| lis r12, STACK_END_MAGIC@h |
| ori r12, r12, STACK_END_MAGIC@l |
| std r12, -8(r11) |
| |
| /* Put ctr in r12 for global entry and branch there */ |
| mfctr r12 |
| bctrl |
| |
| /* |
| * Now we are returning from the patched function to the original |
| * caller A. We are free to use r11, r12 and we can use r2 until we |
| * restore it. |
| */ |
| |
| ld r12, PACA_THREAD_INFO(r13) |
| |
| ld r11, TI_livepatch_sp(r12) |
| |
| /* Check stack marker hasn't been trashed */ |
| lis r2, STACK_END_MAGIC@h |
| ori r2, r2, STACK_END_MAGIC@l |
| ld r12, -8(r11) |
| 1: tdne r12, r2 |
| EMIT_BUG_ENTRY 1b, __FILE__, __LINE__ - 1, 0 |
| |
| /* Restore LR & toc from livepatch stack */ |
| ld r12, -16(r11) |
| mtlr r12 |
| ld r2, -24(r11) |
| |
| /* Pop livepatch stack frame */ |
| ld r12, PACA_THREAD_INFO(r13) |
| subi r11, r11, 24 |
| std r11, TI_livepatch_sp(r12) |
| |
| /* Return to original caller of live patched function */ |
| blr |
| #endif /* CONFIG_LIVEPATCH */ |
| |
| #ifndef CONFIG_ARCH_USING_PATCHABLE_FUNCTION_ENTRY |
| _GLOBAL(mcount) |
| _GLOBAL(_mcount) |
| EXPORT_SYMBOL(_mcount) |
| mflr r12 |
| mtctr r12 |
| mtlr r0 |
| bctr |
| #endif |
| |
| #ifdef CONFIG_FUNCTION_GRAPH_TRACER |
| _GLOBAL(return_to_handler) |
| /* need to save return values */ |
| #ifdef CONFIG_PPC64 |
| std r4, -32(r1) |
| std r3, -24(r1) |
| /* save TOC */ |
| std r2, -16(r1) |
| std r31, -8(r1) |
| mr r31, r1 |
| stdu r1, -112(r1) |
| |
| /* |
| * We might be called from a module. |
| * Switch to our TOC to run inside the core kernel. |
| */ |
| LOAD_PACA_TOC() |
| #else |
| stwu r1, -16(r1) |
| stw r3, 8(r1) |
| stw r4, 12(r1) |
| #endif |
| |
| bl ftrace_return_to_handler |
| nop |
| |
| /* return value has real return address */ |
| mtlr r3 |
| |
| #ifdef CONFIG_PPC64 |
| ld r1, 0(r1) |
| ld r4, -32(r1) |
| ld r3, -24(r1) |
| ld r2, -16(r1) |
| ld r31, -8(r1) |
| #else |
| lwz r3, 8(r1) |
| lwz r4, 12(r1) |
| addi r1, r1, 16 |
| #endif |
| |
| /* Jump back to real return address */ |
| blr |
| #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ |
| |
| .pushsection ".tramp.ftrace.text","aw",@progbits; |
| .globl ftrace_tramp_text |
| ftrace_tramp_text: |
| .space 32 |
| .popsection |
| |
| .pushsection ".tramp.ftrace.init","aw",@progbits; |
| .globl ftrace_tramp_init |
| ftrace_tramp_init: |
| .space 32 |
| .popsection |
