From c4a0ebf87cebbfa28d56e7d93b2536e2311e30c9 Mon Sep 17 00:00:00 2001 From: Chengming Zhou Date: Thu, 21 Apr 2022 00:00:06 +0800 Subject: arm64/ftrace: Make function graph use ftrace directly As we do in commit 0c0593b45c9b ("x86/ftrace: Make function graph use ftrace directly"), we don't need special hook for graph tracer, but instead we use graph_ops:func function to install return_hooker. Since commit 3b23e4991fb6 ("arm64: implement ftrace with regs") add implementation for FTRACE_WITH_REGS on arm64, we can easily adopt the same cleanup on arm64. And this cleanup only changes the FTRACE_WITH_REGS implementation, so the mcount-based implementation is unaffected. While in theory it would be possible to make a similar cleanup for !FTRACE_WITH_REGS, this will require rework of the core code, and so for now we only change the FTRACE_WITH_REGS implementation. Tested-by: Mark Rutland Reviewed-by: Mark Rutland Signed-off-by: Chengming Zhou Link: https://lore.kernel.org/r/20220420160006.17880-2-zhouchengming@bytedance.com Signed-off-by: Catalin Marinas --- arch/arm64/include/asm/ftrace.h | 7 +++++++ arch/arm64/kernel/entry-ftrace.S | 17 ----------------- arch/arm64/kernel/ftrace.c | 17 +++++++++++++++++ 3 files changed, 24 insertions(+), 17 deletions(-) diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h index 1494cfa8639b..dbc45a4157fa 100644 --- a/arch/arm64/include/asm/ftrace.h +++ b/arch/arm64/include/asm/ftrace.h @@ -80,8 +80,15 @@ static inline unsigned long ftrace_call_adjust(unsigned long addr) #ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS struct dyn_ftrace; +struct ftrace_ops; +struct ftrace_regs; + int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec); #define ftrace_init_nop ftrace_init_nop + +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs); +#define ftrace_graph_func ftrace_graph_func #endif #define ftrace_return_address(n) return_address(n) diff --git a/arch/arm64/kernel/entry-ftrace.S b/arch/arm64/kernel/entry-ftrace.S index e535480a4069..d42a205ef625 100644 --- a/arch/arm64/kernel/entry-ftrace.S +++ b/arch/arm64/kernel/entry-ftrace.S @@ -97,12 +97,6 @@ SYM_CODE_START(ftrace_common) SYM_INNER_LABEL(ftrace_call, SYM_L_GLOBAL) bl ftrace_stub -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -SYM_INNER_LABEL(ftrace_graph_call, SYM_L_GLOBAL) // ftrace_graph_caller(); - nop // If enabled, this will be replaced - // "b ftrace_graph_caller" -#endif - /* * At the callsite x0-x8 and x19-x30 were live. Any C code will have preserved * x19-x29 per the AAPCS, and we created frame records upon entry, so we need @@ -127,17 +121,6 @@ ftrace_common_return: ret x9 SYM_CODE_END(ftrace_common) -#ifdef CONFIG_FUNCTION_GRAPH_TRACER -SYM_CODE_START(ftrace_graph_caller) - ldr x0, [sp, #S_PC] - sub x0, x0, #AARCH64_INSN_SIZE // ip (callsite's BL insn) - add x1, sp, #S_LR // parent_ip (callsite's LR) - ldr x2, [sp, #PT_REGS_SIZE] // parent fp (callsite's FP) - bl prepare_ftrace_return - b ftrace_common_return -SYM_CODE_END(ftrace_graph_caller) -#endif - #else /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ /* diff --git a/arch/arm64/kernel/ftrace.c b/arch/arm64/kernel/ftrace.c index 4506c4a90ac1..f447c4a36f69 100644 --- a/arch/arm64/kernel/ftrace.c +++ b/arch/arm64/kernel/ftrace.c @@ -268,6 +268,22 @@ void prepare_ftrace_return(unsigned long self_addr, unsigned long *parent, } #ifdef CONFIG_DYNAMIC_FTRACE + +#ifdef CONFIG_DYNAMIC_FTRACE_WITH_REGS +void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, + struct ftrace_ops *op, struct ftrace_regs *fregs) +{ + /* + * When DYNAMIC_FTRACE_WITH_REGS is selected, `fregs` can never be NULL + * and arch_ftrace_get_regs(fregs) will always give a non-NULL pt_regs + * in which we can safely modify the LR. + */ + struct pt_regs *regs = arch_ftrace_get_regs(fregs); + unsigned long *parent = (unsigned long *)&procedure_link_pointer(regs); + + prepare_ftrace_return(ip, parent, frame_pointer(regs)); +} +#else /* * Turn on/off the call to ftrace_graph_caller() in ftrace_caller() * depending on @enable. @@ -297,5 +313,6 @@ int ftrace_disable_ftrace_graph_caller(void) { return ftrace_modify_graph_caller(false); } +#endif /* CONFIG_DYNAMIC_FTRACE_WITH_REGS */ #endif /* CONFIG_DYNAMIC_FTRACE */ #endif /* CONFIG_FUNCTION_GRAPH_TRACER */ -- cgit v1.2.3-59-g8ed1b