Commit d5d01b71 authored by Masami Hiramatsu (Google)'s avatar Masami Hiramatsu (Google) Committed by Steven Rostedt (Google)
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tracing: Add ftrace_fill_perf_regs() for perf event 



Add ftrace_fill_perf_regs() which should be compatible with the
perf_fetch_caller_regs(). In other words, the pt_regs returned from the
ftrace_fill_perf_regs() must satisfy 'user_mode(regs) == false' and can be
used for stack tracing.

Signed-off-by: default avatarMasami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: default avatarWill Deacon <will@kernel.org>
Acked-by: Heiko Carstens <hca@linux.ibm.com> # s390
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: Florent Revest <revest@chromium.org>
Cc: Martin KaFai Lau <martin.lau@linux.dev>
Cc: bpf <bpf@vger.kernel.org>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Alan Maguire <alan.maguire@oracle.com>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Naveen N Rao <naveen@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Link: https://lore.kernel.org/173518997908.391279.15910334347345106424.stgit@devnote2


Signed-off-by: default avatarSteven Rostedt (Google) <rostedt@goodmis.org>
parent b9b55c89

arch/arm64/include/asm/ftrace.h

+7 −0
Original line number Diff line number Diff line
@@ -148,6 +148,13 @@ ftrace_partial_regs(const struct ftrace_regs *fregs, struct pt_regs *regs) 
	return regs;

}



#define arch_ftrace_fill_perf_regs(fregs, _regs) do {		\

		(_regs)->pc = arch_ftrace_regs(fregs)->pc;			\

		(_regs)->regs[29] = arch_ftrace_regs(fregs)->fp;		\

		(_regs)->sp = arch_ftrace_regs(fregs)->sp;			\

		(_regs)->pstate = PSR_MODE_EL1h;		\

	} while (0)



int ftrace_regs_query_register_offset(const char *name);



int ftrace_init_nop(struct module *mod, struct dyn_ftrace *rec);

arch/powerpc/include/asm/ftrace.h

+7 −0
Original line number Diff line number Diff line
@@ -43,6 +43,13 @@ static __always_inline struct pt_regs *arch_ftrace_get_regs(struct ftrace_regs * 
	return arch_ftrace_regs(fregs)->regs.msr ? &arch_ftrace_regs(fregs)->regs : NULL;

}



#define arch_ftrace_fill_perf_regs(fregs, _regs) do {		\

		(_regs)->result = 0;				\

		(_regs)->nip = arch_ftrace_regs(fregs)->regs.nip;		\

		(_regs)->gpr[1] = arch_ftrace_regs(fregs)->regs.gpr[1];		\

		asm volatile("mfmsr %0" : "=r" ((_regs)->msr));	\

	} while (0)



static __always_inline void

ftrace_regs_set_instruction_pointer(struct ftrace_regs *fregs,

				    unsigned long ip)

arch/s390/include/asm/ftrace.h

+6 −0
Original line number Diff line number Diff line
@@ -76,6 +76,12 @@ ftrace_regs_get_frame_pointer(struct ftrace_regs *fregs) 
	return ftrace_regs_get_stack_pointer(fregs);

}



#define arch_ftrace_fill_perf_regs(fregs, _regs)	 do {		\

		(_regs)->psw.mask = 0;					\

		(_regs)->psw.addr = arch_ftrace_regs(fregs)->regs.psw.addr;		\

		(_regs)->gprs[15] = arch_ftrace_regs(fregs)->regs.gprs[15];		\

	} while (0)



#ifdef CONFIG_DYNAMIC_FTRACE_WITH_DIRECT_CALLS

/*

 * When an ftrace registered caller is tracing a function that is

arch/x86/include/asm/ftrace.h

+7 −0
Original line number Diff line number Diff line
@@ -47,6 +47,13 @@ arch_ftrace_get_regs(struct ftrace_regs *fregs) 
	return &arch_ftrace_regs(fregs)->regs;

}



#define arch_ftrace_fill_perf_regs(fregs, _regs) do {	\

		(_regs)->ip = arch_ftrace_regs(fregs)->regs.ip;		\

		(_regs)->sp = arch_ftrace_regs(fregs)->regs.sp;		\

		(_regs)->cs = __KERNEL_CS;		\

		(_regs)->flags = 0;			\

	} while (0)



#define ftrace_regs_set_instruction_pointer(fregs, _ip)	\

	do { arch_ftrace_regs(fregs)->regs.ip = (_ip); } while (0)

include/linux/ftrace.h

+31 −0
Original line number Diff line number Diff line
@@ -207,6 +207,37 @@ ftrace_partial_regs(struct ftrace_regs *fregs, struct pt_regs *regs) 


#endif /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS || CONFIG_HAVE_FTRACE_REGS_HAVING_PT_REGS */



#ifdef CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS



/*

 * Please define arch dependent pt_regs which compatible to the

 * perf_arch_fetch_caller_regs() but based on ftrace_regs.

 * This requires

 *   - user_mode(_regs) returns false (always kernel mode).

 *   - able to use the _regs for stack trace.

 */

#ifndef arch_ftrace_fill_perf_regs

/* As same as perf_arch_fetch_caller_regs(), do nothing by default */

#define arch_ftrace_fill_perf_regs(fregs, _regs) do {} while (0)

#endif



static __always_inline struct pt_regs *

ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)

{

	arch_ftrace_fill_perf_regs(fregs, regs);

	return regs;

}



#else /* !CONFIG_HAVE_DYNAMIC_FTRACE_WITH_ARGS */



static __always_inline struct pt_regs *

ftrace_fill_perf_regs(struct ftrace_regs *fregs, struct pt_regs *regs)

{

	return &arch_ftrace_regs(fregs)->regs;

}



#endif



/*

 * 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.