From 8778ba2c8a5df11859dc6f2b2205700388b63fd3 Mon Sep 17 00:00:00 2001 From: Qing Zhang Date: Sat, 10 Dec 2022 22:40:15 +0800 Subject: [PATCH] LoongArch/ftrace: Add HAVE_DYNAMIC_FTRACE_WITH_REGS support This patch implements CONFIG_DYNAMIC_FTRACE_WITH_REGS on LoongArch, which allows a traced function's arguments (and some other registers) to be captured into a struct pt_regs, allowing these to be inspected and modified. Co-developed-by: Jinyang He Signed-off-by: Jinyang He Signed-off-by: Qing Zhang Signed-off-by: Huacai Chen --- arch/loongarch/Kconfig | 1 + arch/loongarch/include/asm/ftrace.h | 2 ++ arch/loongarch/kernel/ftrace_dyn.c | 15 +++++++++++++++ arch/loongarch/kernel/mcount_dyn.S | 35 +++++++++++++++++++++++++++++++++-- 4 files changed, 51 insertions(+), 2 deletions(-) diff --git a/arch/loongarch/Kconfig b/arch/loongarch/Kconfig index 6e9aaa7..f2d1b2a 100644 --- a/arch/loongarch/Kconfig +++ b/arch/loongarch/Kconfig @@ -89,6 +89,7 @@ config LOONGARCH select HAVE_DEBUG_STACKOVERFLOW select HAVE_DMA_CONTIGUOUS select HAVE_DYNAMIC_FTRACE + select HAVE_DYNAMIC_FTRACE_WITH_REGS select HAVE_EBPF_JIT select HAVE_EXIT_THREAD select HAVE_FAST_GUP diff --git a/arch/loongarch/include/asm/ftrace.h b/arch/loongarch/include/asm/ftrace.h index 09ff0f8..dd4a0c8 100644 --- a/arch/loongarch/include/asm/ftrace.h +++ b/arch/loongarch/include/asm/ftrace.h @@ -23,6 +23,8 @@ extern void prepare_ftrace_return(unsigned long self_addr, unsigned long callsit struct dyn_ftrace; struct dyn_arch_ftrace { }; +#define ARCH_SUPPORTS_FTRACE_OPS 1 + #define ftrace_init_nop ftrace_init_nop int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); diff --git a/arch/loongarch/kernel/ftrace_dyn.c b/arch/loongarch/kernel/ftrace_dyn.c index 5a801c3..d6f3091 100644 --- a/arch/loongarch/kernel/ftrace_dyn.c +++ b/arch/loongarch/kernel/ftrace_dyn.c @@ -28,6 +28,21 @@ static int ftrace_modify_code(unsigned long pc, u32 old, u32 new, bool validate) return 0; } +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +int ftrace_modify_call(struct dyn_ftrace *rec, unsigned long old_addr, unsigned long addr) +{ + u32 old, new; + unsigned long pc; + + pc = rec->ip + LOONGARCH_INSN_SIZE; + + new = larch_insn_gen_bl(pc, addr); + old = larch_insn_gen_bl(pc, old_addr); + + return ftrace_modify_code(pc, old, new, true); +} +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ + int ftrace_update_ftrace_func(ftrace_func_t func) { u32 new; diff --git a/arch/loongarch/kernel/mcount_dyn.S b/arch/loongarch/kernel/mcount_dyn.S index cce3daa..bbabf06 100644 --- a/arch/loongarch/kernel/mcount_dyn.S +++ b/arch/loongarch/kernel/mcount_dyn.S @@ -27,7 +27,7 @@ * follows the LoongArch's psABI as well. */ - .macro ftrace_regs_entry + .macro ftrace_regs_entry allregs=0 PTR_ADDI sp, sp, -PT_SIZE PTR_S t0, sp, PT_R1 /* Save parent ra at PT_R1(RA) */ PTR_S a0, sp, PT_R4 @@ -39,6 +39,30 @@ PTR_S a6, sp, PT_R10 PTR_S a7, sp, PT_R11 PTR_S fp, sp, PT_R22 + .if \allregs + PTR_S tp, sp, PT_R2 + PTR_S t0, sp, PT_R12 + PTR_S t1, sp, PT_R13 + PTR_S t2, sp, PT_R14 + PTR_S t3, sp, PT_R15 + PTR_S t4, sp, PT_R16 + PTR_S t5, sp, PT_R17 + PTR_S t6, sp, PT_R18 + PTR_S t7, sp, PT_R19 + PTR_S t8, sp, PT_R20 + PTR_S u0, sp, PT_R21 + PTR_S s0, sp, PT_R23 + PTR_S s1, sp, PT_R24 + PTR_S s2, sp, PT_R25 + PTR_S s3, sp, PT_R26 + PTR_S s4, sp, PT_R27 + PTR_S s5, sp, PT_R28 + PTR_S s6, sp, PT_R29 + PTR_S s7, sp, PT_R30 + PTR_S s8, sp, PT_R31 + /* Clear it for later use as a flag sometimes. */ + PTR_S zero, sp, PT_R0 + .endif PTR_S ra, sp, PT_ERA /* Save trace function ra at PT_ERA */ PTR_ADDI t8, sp, PT_SIZE PTR_S t8, sp, PT_R3 @@ -85,10 +109,17 @@ ftrace_common_return: SYM_CODE_END(ftrace_common) SYM_CODE_START(ftrace_caller) - ftrace_regs_entry + ftrace_regs_entry allregs=0 b ftrace_common SYM_CODE_END(ftrace_caller) +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +SYM_CODE_START(ftrace_regs_caller) + ftrace_regs_entry allregs=1 + b ftrace_common +SYM_CODE_END(ftrace_regs_caller) +#endif + #ifdef CONFIG_FUNCTION_GRAPH_TRACER SYM_CODE_START(ftrace_graph_caller) PTR_L a0, sp, PT_ERA -- 2.7.4