diff options
Diffstat (limited to 'arch/riscv/kernel/mcount-dyn.S')
| -rw-r--r-- | arch/riscv/kernel/mcount-dyn.S | 218 |
1 files changed, 143 insertions, 75 deletions
diff --git a/arch/riscv/kernel/mcount-dyn.S b/arch/riscv/kernel/mcount-dyn.S index 669b8697aa38..48f6c4f7dca0 100644 --- a/arch/riscv/kernel/mcount-dyn.S +++ b/arch/riscv/kernel/mcount-dyn.S @@ -3,17 +3,16 @@ #include <linux/init.h> #include <linux/linkage.h> +#include <linux/export.h> #include <asm/asm.h> #include <asm/csr.h> #include <asm/unistd.h> #include <asm/thread_info.h> #include <asm/asm-offsets.h> -#include <asm-generic/export.h> #include <asm/ftrace.h> .text -#define FENTRY_RA_OFFSET 8 #define ABI_SIZE_ON_STACK 80 #define ABI_A0 0 #define ABI_A1 8 @@ -56,87 +55,156 @@ addi sp, sp, ABI_SIZE_ON_STACK .endm -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS - .macro SAVE_ALL - addi sp, sp, -PT_SIZE_ON_STACK - - REG_S t0, PT_EPC(sp) - REG_S x1, PT_RA(sp) - REG_S x2, PT_SP(sp) - REG_S x3, PT_GP(sp) - REG_S x4, PT_TP(sp) - REG_S x5, PT_T0(sp) - save_from_x6_to_x31 - .endm - - .macro RESTORE_ALL - REG_L x1, PT_RA(sp) - REG_L x2, PT_SP(sp) - REG_L x3, PT_GP(sp) - REG_L x4, PT_TP(sp) - /* Restore t0 with PT_EPC */ - REG_L x5, PT_EPC(sp) - restore_from_x6_to_x31 - - addi sp, sp, PT_SIZE_ON_STACK +/** +* SAVE_ABI_REGS - save regs against the ftrace_regs struct +* +* After the stack is established, +* +* 0(sp) stores the PC of the traced function which can be accessed +* by &(fregs)->epc in tracing function. +* +* 8(sp) stores the function return address (i.e. parent IP) that +* can be accessed by &(fregs)->ra in tracing function. +* +* The other regs are saved at the respective localtion and accessed +* by the respective ftrace_regs member. +* +* Here is the layout of stack for your reference. +* +* PT_SIZE_ON_STACK -> +++++++++ +* + ..... + +* + a0-a7 + --++++-> ftrace_caller saved +* + t1 + --++++-> direct tramp address +* + s0 + --+ // frame pointer +* + sp + + +* + ra + --+ // parent IP +* sp -> + epc + --+ // PC +* +++++++++ +**/ + .macro SAVE_ABI_REGS + addi sp, sp, -FREGS_SIZE_ON_STACK + REG_S t0, FREGS_EPC(sp) + REG_S x1, FREGS_RA(sp) +#ifdef HAVE_FUNCTION_GRAPH_FP_TEST + REG_S x8, FREGS_S0(sp) +#endif + REG_S x6, FREGS_T1(sp) +#ifdef CONFIG_CC_IS_CLANG + REG_S x7, FREGS_T2(sp) + REG_S x28, FREGS_T3(sp) + REG_S x29, FREGS_T4(sp) + REG_S x30, FREGS_T5(sp) + REG_S x31, FREGS_T6(sp) +#endif + // save the arguments + REG_S x10, FREGS_A0(sp) + REG_S x11, FREGS_A1(sp) + REG_S x12, FREGS_A2(sp) + REG_S x13, FREGS_A3(sp) + REG_S x14, FREGS_A4(sp) + REG_S x15, FREGS_A5(sp) + REG_S x16, FREGS_A6(sp) + REG_S x17, FREGS_A7(sp) + mv a0, sp + addi a0, a0, FREGS_SIZE_ON_STACK + REG_S a0, FREGS_SP(sp) // Put original SP on stack .endm -#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ - -ENTRY(ftrace_caller) - SAVE_ABI - - addi a0, t0, -FENTRY_RA_OFFSET - la a1, function_trace_op - REG_L a2, 0(a1) - mv a1, ra - mv a3, sp -ftrace_call: - .global ftrace_call - call ftrace_stub - -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - addi a0, sp, ABI_RA - REG_L a1, ABI_T0(sp) - addi a1, a1, -FENTRY_RA_OFFSET + .macro RESTORE_ABI_REGS + REG_L t0, FREGS_EPC(sp) + REG_L x1, FREGS_RA(sp) #ifdef HAVE_FUNCTION_GRAPH_FP_TEST - mv a2, s0 + REG_L x8, FREGS_S0(sp) #endif -ftrace_graph_call: - .global ftrace_graph_call - call ftrace_stub + REG_L x6, FREGS_T1(sp) +#ifdef CONFIG_CC_IS_CLANG + REG_L x7, FREGS_T2(sp) + REG_L x28, FREGS_T3(sp) + REG_L x29, FREGS_T4(sp) + REG_L x30, FREGS_T5(sp) + REG_L x31, FREGS_T6(sp) #endif - RESTORE_ABI - jr t0 -ENDPROC(ftrace_caller) - -#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS -ENTRY(ftrace_regs_caller) - SAVE_ALL + // restore the arguments + REG_L x10, FREGS_A0(sp) + REG_L x11, FREGS_A1(sp) + REG_L x12, FREGS_A2(sp) + REG_L x13, FREGS_A3(sp) + REG_L x14, FREGS_A4(sp) + REG_L x15, FREGS_A5(sp) + REG_L x16, FREGS_A6(sp) + REG_L x17, FREGS_A7(sp) + + addi sp, sp, FREGS_SIZE_ON_STACK + .endm - addi a0, t0, -FENTRY_RA_OFFSET + .macro PREPARE_ARGS + addi a0, t0, -MCOUNT_JALR_SIZE // ip (callsite's jalr insn) +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS + mv a1, ra // parent_ip + REG_L a2, -16(t0) // op + REG_L ra, FTRACE_OPS_FUNC(a2) // op->func +#else la a1, function_trace_op - REG_L a2, 0(a1) - mv a1, ra - mv a3, sp - -ftrace_regs_call: - .global ftrace_regs_call - call ftrace_stub + REG_L a2, 0(a1) // op + mv a1, ra // parent_ip +#endif + mv a3, sp // regs + .endm -#ifdef CONFIG_FUNCTION_GRAPH_TRACER - addi a0, sp, PT_RA - REG_L a1, PT_EPC(sp) - addi a1, a1, -FENTRY_RA_OFFSET -#ifdef HAVE_FUNCTION_GRAPH_FP_TEST - mv a2, s0 +SYM_FUNC_START(ftrace_caller) +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS + /* + * When CALL_OPS is enabled (2 or 4) nops [8B] are placed before the + * function entry, these are later overwritten with the pointer to the + * associated struct ftrace_ops. + * + * -8: &ftrace_ops of the associated tracer function. + *<ftrace enable>: + * 0: auipc t0/ra, 0x? + * 4: jalr t0/ra, ?(t0/ra) + * + * -8: &ftrace_nop_ops + *<ftrace disable>: + * 0: nop + * 4: nop + * + * t0 is set to ip+8 after the jalr is executed at the callsite, + * so we find the associated op at t0-16. + */ + REG_L t1, -16(t0) // op Should be SZ_REG instead of 16 + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + /* + * If the op has a direct call, handle it immediately without + * saving/restoring registers. + */ + REG_L t1, FTRACE_OPS_DIRECT_CALL(t1) + bnez t1, ftrace_caller_direct +#endif +#endif + SAVE_ABI_REGS + PREPARE_ARGS + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_CALL_OPS + jalr ra +#else +SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) + REG_L ra, ftrace_call_dest + jalr ra, 0(ra) +#endif + RESTORE_ABI_REGS +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS + bnez t1, ftrace_caller_direct #endif -ftrace_graph_regs_call: - .global ftrace_graph_regs_call - call ftrace_stub + jr t0 +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +SYM_INNER_LABEL(ftrace_caller_direct, SYM_L_LOCAL) + jr t1 #endif +SYM_FUNC_END(ftrace_caller) - RESTORE_ALL - jr t0 -ENDPROC(ftrace_regs_caller) -#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS +SYM_CODE_START(ftrace_stub_direct_tramp) + jr t0 +SYM_CODE_END(ftrace_stub_direct_tramp) +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS */ |