Messages in this thread | | | Date | Tue, 25 Oct 2022 17:40:01 +0900 | From | Masami Hiramatsu (Google) <> | Subject | Re: [PATCH 3/4] ftrace: abstract DYNAMIC_FTRACE_WITH_ARGS accesses |
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Hi Mark,
On Mon, 24 Oct 2022 15:08:45 +0100 Mark Rutland <mark.rutland@arm.com> wrote:
> In subsequent patches we'll arrange for architectures to have an > ftrace_regs which is entirely distinct from pt_regs. In preparation for > this, we need to minimize the use of pt_regs to where strictly necessary > in the core ftrace code. > > This patch adds new ftrace_regs_{get,set}_*() helpers which can be used > to manipulate ftrace_regs. When CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=y, > these can always be used on any ftrace_regs, and when > CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS=n these can be used when regs are > available. A new ftrace_regs_has_args(fregs) helper is added which code > can use to check when these are usable.
Can you also add the ftrace_regs_query_register_offset() as a wrapper of regs_query_register_offset()? I would like to use it for fprobe_events.
Thank you,
> > Co-developed-by: Florent Revest <revest@chromium.org> > Signed-off-by: Florent Revest <revest@chromium.org> > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Cc: Masami Hiramatsu <mhiramat@kernel.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > --- > arch/powerpc/include/asm/ftrace.h | 17 +++++++++++++++++ > arch/s390/include/asm/ftrace.h | 17 +++++++++++++++++ > arch/x86/include/asm/ftrace.h | 14 ++++++++++++++ > include/linux/ftrace.h | 27 +++++++++++++++++++++++++++ > kernel/trace/Kconfig | 6 +++--- > 5 files changed, 78 insertions(+), 3 deletions(-) > > diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h > index c3eb48f67566..faecb20d78bf 100644 > --- a/arch/powerpc/include/asm/ftrace.h > +++ b/arch/powerpc/include/asm/ftrace.h > @@ -44,6 +44,23 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, > regs_set_return_ip(&fregs->regs, ip); > } > > +static __always_inline unsigned long > +ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs) > +{ > + return instruction_pointer(&fregs->regs) > +} > + > +#define ftrace_regs_get_argument(fregs, n) \ > + regs_get_kernel_argument(&(fregs)->regs, n) > +#define ftrace_regs_get_stack_pointer(fregs) \ > + kernel_stack_pointer(&(fregs)->regs) > +#define ftrace_regs_return_value(fregs) \ > + regs_return_value(&(fregs)->regs) > +#define ftrace_regs_set_return_value(fregs, ret) \ > + regs_set_return_value(&(fregs)->regs, ret) > +#define ftrace_override_function_with_return(fregs) \ > + override_function_with_return(&(fregs)->regs) > + > struct ftrace_ops; > > #define ftrace_graph_func ftrace_graph_func > diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h > index b8957882404f..5fdc806458aa 100644 > --- a/arch/s390/include/asm/ftrace.h > +++ b/arch/s390/include/asm/ftrace.h > @@ -54,6 +54,12 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs * > return NULL; > } > > +static __always_inline unsigned long > +ftrace_regs_get_instruction_pointer(const struct ftrace_regs *fregs) > +{ > + return fregs->regs.psw.addr; > +} > + > static __always_inline void > ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, > unsigned long ip) > @@ -61,6 +67,17 @@ ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs, > fregs->regs.psw.addr = ip; > } > > +#define ftrace_regs_get_argument(fregs, n) \ > + regs_get_kernel_argument(&(fregs)->regs, n) > +#define ftrace_regs_get_stack_pointer(fregs) \ > + kernel_stack_pointer(&(fregs)->regs) > +#define ftrace_regs_return_value(fregs) \ > + regs_return_value(&(fregs)->regs) > +#define ftrace_regs_set_return_value(fregs, ret) \ > + regs_set_return_value(&(fregs)->regs, ret) > +#define ftrace_override_function_with_return(fregs) \ > + override_function_with_return(&(fregs)->regs) > + > /* > * When an ftrace registered caller is tracing a function that is > * also set by a register_ftrace_direct() call, it needs to be > diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h > index b73e858bd96f..b3737b42e8a1 100644 > --- a/arch/x86/include/asm/ftrace.h > +++ b/arch/x86/include/asm/ftrace.h > @@ -51,6 +51,20 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs) > #define ftrace_regs_set_instruction_pointer(fregs, _ip) \ > do { (fregs)->regs.ip = (_ip); } while (0) > > +#define ftrace_regs_get_instruction_pointer(fregs) \ > + ((fregs)->regs.ip) > + > +#define ftrace_regs_get_argument(fregs, n) \ > + regs_get_kernel_argument(&(fregs)->regs, n) > +#define ftrace_regs_get_stack_pointer(fregs) \ > + kernel_stack_pointer(&(fregs)->regs) > +#define ftrace_regs_return_value(fregs) \ > + regs_return_value(&(fregs)->regs) > +#define ftrace_regs_set_return_value(fregs, ret) \ > + regs_set_return_value(&(fregs)->regs, ret) > +#define ftrace_override_function_with_return(fregs) \ > + override_function_with_return(&(fregs)->regs) > + > struct ftrace_ops; > #define ftrace_graph_func ftrace_graph_func > void ftrace_graph_func(unsigned long ip, unsigned long parent_ip, > diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h > index e9905f741916..3b13e3c21438 100644 > --- a/include/linux/ftrace.h > +++ b/include/linux/ftrace.h > @@ -125,6 +125,33 @@ static __always_inline struct pt_regs *ftrace_get_regs(struct ftrace_regs *fregs > return arch_ftrace_get_regs(fregs); > } > > +/* > + * When true, the ftrace_regs_{get,set}_*() functions may be used on fregs. > + * Note: this can be true even when ftrace_get_regs() cannot provide a pt_regs. > + */ > +static __always_inline bool ftrace_regs_has_args(struct ftrace_regs *fregs) > +{ > + if (IS_ENABLED(CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS)) > + return true; > + > + return ftrace_get_regs(fregs) != NULL; > +} > + > +#ifndef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS > +#define ftrace_regs_get_instruction_pointer(fregs) \ > + instruction_pointer(ftrace_get_regs(fregs)) > +#define ftrace_regs_get_argument(fregs, n) \ > + regs_get_kernel_argument(ftrace_get_regs(fregs), n) > +#define ftrace_regs_get_stack_pointer(fregs) \ > + kernel_stack_pointer(ftrace_get_regs(fregs)) > +#define ftrace_regs_return_value(fregs) \ > + regs_return_value(ftrace_get_regs(fregs)) > +#define ftrace_regs_set_return_value(fregs, ret) \ > + regs_set_return_value(ftrace_get_regs(fregs), ret) > +#define ftrace_override_function_with_return(fregs) \ > + override_function_with_return(ftrace_get_regs(fregs)) > +#endif > + > typedef void (*ftrace_func_t)(unsigned long ip, unsigned long parent_ip, > struct ftrace_ops *op, struct ftrace_regs *fregs); > > diff --git a/kernel/trace/Kconfig b/kernel/trace/Kconfig > index e9e95c790b8e..2c6611c13f99 100644 > --- a/kernel/trace/Kconfig > +++ b/kernel/trace/Kconfig > @@ -46,10 +46,10 @@ config HAVE_DYNAMIC_FTRACE_WITH_ARGS > bool > help > If this is set, then arguments and stack can be found from > - the pt_regs passed into the function callback regs parameter > + the ftrace_regs passed into the function callback regs parameter > by default, even without setting the REGS flag in the ftrace_ops. > - This allows for use of regs_get_kernel_argument() and > - kernel_stack_pointer(). > + This allows for use of ftrace_regs_get_argument() and > + ftrace_regs_get_stack_pointer(). > > config HAVE_DYNAMIC_FTRACE_NO_PATCHABLE > bool > -- > 2.30.2 >
-- Masami Hiramatsu (Google) <mhiramat@kernel.org>
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