Messages in this thread | | | Date | Thu, 8 Jun 2023 21:57:19 -0400 | From | Steven Rostedt <> | Subject | Re: [PATCH v11 3/8] ARM: ftrace: Enable HAVE_FUNCTION_GRAPH_RETVAL |
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On Sat, 8 Apr 2023 05:42:17 -0700 Donglin Peng <pengdonglin@sangfor.com.cn> wrote:
> The previous patch ("function_graph: Support recording and printing > the return value of function") has laid the groundwork for the for > the funcgraph-retval, and this modification makes it available on > the ARM platform. > > We introduce a new structure called fgraph_ret_regs for the ARM platform > to hold return registers and the frame pointer. We then fill its content > in the return_to_handler and pass its address to the function > ftrace_return_to_handler to record the return value. > > Signed-off-by: Donglin Peng <pengdonglin@sangfor.com.cn>
I really don't want to add this without an ack from an arm maintainer.
I have the patches queued (for testing), but I may remove the ones that do not have the appropriate acks.
-- Steve
> --- > v10: > - Use CONFIG_FUNCTION_GRAPH_TRACER to control fgraph_ret_regs definition > > v9: > - Fix stack pointer align issues > - Update the commit message > > v8: > - Modify the control range of CONFIG_HAVE_FUNCTION_GRAPH_RETVAL > --- > arch/arm/Kconfig | 1 + > arch/arm/include/asm/ftrace.h | 22 ++++++++++++++++++++++ > arch/arm/kernel/asm-offsets.c | 8 +++++++- > arch/arm/kernel/entry-ftrace.S | 10 ++++++---- > 4 files changed, 36 insertions(+), 5 deletions(-) > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > index e24a9820e12f..73061379855a 100644 > --- a/arch/arm/Kconfig > +++ b/arch/arm/Kconfig > @@ -98,6 +98,7 @@ config ARM > select HAVE_FAST_GUP if ARM_LPAE > select HAVE_FTRACE_MCOUNT_RECORD if !XIP_KERNEL > select HAVE_FUNCTION_ERROR_INJECTION > + select HAVE_FUNCTION_GRAPH_RETVAL if HAVE_FUNCTION_GRAPH_TRACER > select HAVE_FUNCTION_GRAPH_TRACER > select HAVE_FUNCTION_TRACER if !XIP_KERNEL > select HAVE_GCC_PLUGINS > diff --git a/arch/arm/include/asm/ftrace.h b/arch/arm/include/asm/ftrace.h > index 7e9251ca29fe..3c457902b355 100644 > --- a/arch/arm/include/asm/ftrace.h > +++ b/arch/arm/include/asm/ftrace.h > @@ -77,4 +77,26 @@ static inline bool arch_syscall_match_sym_name(const char *sym, > > #endif /* ifndef __ASSEMBLY__ */ > > +#ifndef __ASSEMBLY__ > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER > +struct fgraph_ret_regs { > + /* r0 - r3 */ > + unsigned long regs[4]; > + > + unsigned long fp; > + unsigned long __unused; > +}; > + > +static inline unsigned long fgraph_ret_regs_return_value(struct fgraph_ret_regs *ret_regs) > +{ > + return ret_regs->regs[0]; > +} > + > +static inline unsigned long fgraph_ret_regs_frame_pointer(struct fgraph_ret_regs *ret_regs) > +{ > + return ret_regs->fp; > +} > +#endif /* ifdef CONFIG_FUNCTION_GRAPH_TRACER */ > +#endif > + > #endif /* _ASM_ARM_FTRACE */ > diff --git a/arch/arm/kernel/asm-offsets.c b/arch/arm/kernel/asm-offsets.c > index 38121c59cbc2..18bb85115b21 100644 > --- a/arch/arm/kernel/asm-offsets.c > +++ b/arch/arm/kernel/asm-offsets.c > @@ -23,6 +23,7 @@ > #include <asm/suspend.h> > #include <asm/vdso_datapage.h> > #include <asm/hardware/cache-l2x0.h> > +#include <asm/ftrace.h> > #include <linux/kbuild.h> > #include <linux/arm-smccc.h> > #include "signal.h" > @@ -170,5 +171,10 @@ int main(void) > DEFINE(KEXEC_INDIR_PAGE, offsetof(struct kexec_relocate_data, kexec_indirection_page)); > DEFINE(KEXEC_MACH_TYPE, offsetof(struct kexec_relocate_data, kexec_mach_type)); > DEFINE(KEXEC_R2, offsetof(struct kexec_relocate_data, kexec_r2)); > - return 0; > +#ifdef CONFIG_FUNCTION_GRAPH_TRACER > + BLANK(); > + DEFINE(FGRET_REGS_SIZE, sizeof(struct fgraph_ret_regs)); > + BLANK(); > +#endif > + return 0; > } > diff --git a/arch/arm/kernel/entry-ftrace.S b/arch/arm/kernel/entry-ftrace.S > index 3e7bcaca5e07..d41a1676608c 100644 > --- a/arch/arm/kernel/entry-ftrace.S > +++ b/arch/arm/kernel/entry-ftrace.S > @@ -257,11 +257,13 @@ ENDPROC(ftrace_graph_regs_caller) > > #ifdef CONFIG_FUNCTION_GRAPH_TRACER > ENTRY(return_to_handler) > - stmdb sp!, {r0-r3} > - add r0, sp, #16 @ sp at exit of instrumented routine > + mov ip, sp @ sp at exit of instrumented routine > + stmdb sp!, {r0-r3, ip, lr} @ fill fgraph_ret_regs > + mov r0, sp > bl ftrace_return_to_handler > - mov lr, r0 @ r0 has real ret addr > - ldmia sp!, {r0-r3} > + mov lr, r0 @ r0 has real ret addr > + ldmia sp, {r0-r3} > + add sp, sp, #FGRET_REGS_SIZE @ restore stack pointer > ret lr > ENDPROC(return_to_handler) > #endif
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