diff mbox series

[v16,09/18] tracing: Add ftrace_fill_perf_regs() for perf event

Message ID 172895581574.107311.17609909207681074574.stgit@devnote2 (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series tracing: fprobe: function_graph: Multi-function graph and fprobe on fgraph | expand

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Context Check Description
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bpf/vmtest-bpf-PR fail merge-conflict

Commit Message

Masami Hiramatsu (Google) Oct. 15, 2024, 1:30 a.m. UTC 
From: Masami Hiramatsu (Google) <mhiramat@kernel.org>

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: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
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: Heiko Carstens <hca@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>

---
  Changes from previous series: NOTHING, just forward ported.
---
 arch/arm64/include/asm/ftrace.h   |    7 +++++++
 arch/powerpc/include/asm/ftrace.h |    7 +++++++
 arch/s390/include/asm/ftrace.h    |    5 +++++
 arch/x86/include/asm/ftrace.h     |    7 +++++++
 include/linux/ftrace.h            |   31 +++++++++++++++++++++++++++++++
 5 files changed, 57 insertions(+)

Comments

Heiko Carstens Oct. 15, 2024, 6:18 p.m. UTC | #1 
On Tue, Oct 15, 2024 at 10:30:15AM +0900, Masami Hiramatsu (Google) wrote:
> From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> 
> 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: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> ---
>   Changes from previous series: NOTHING, just forward ported.
> ---
>  arch/s390/include/asm/ftrace.h    |    5 +++++

...

> diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
> index 5c94c1fc1bc1..f1c0e677a325 100644
> --- a/arch/s390/include/asm/ftrace.h
> +++ b/arch/s390/include/asm/ftrace.h
> @@ -76,6 +76,11 @@ 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.addr = arch_ftrace_regs(fregs)->regs.psw.addr;		\
> +		(_regs)->gprs[15] = arch_ftrace_regs(fregs)->regs.gprs[15];		\
> +	} while (0)
> +

This misses the feedback I gave for v15:
https://lore.kernel.org/all/20241009100502.8007-E-hca@linux.ibm.com
Masami Hiramatsu (Google) Oct. 15, 2024, 11:34 p.m. UTC | #2 
On Tue, 15 Oct 2024 20:18:02 +0200
Heiko Carstens <hca@linux.ibm.com> wrote:

> On Tue, Oct 15, 2024 at 10:30:15AM +0900, Masami Hiramatsu (Google) wrote:
> > From: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > 
> > 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: Masami Hiramatsu (Google) <mhiramat@kernel.org>
> > ---
> >   Changes from previous series: NOTHING, just forward ported.
> > ---
> >  arch/s390/include/asm/ftrace.h    |    5 +++++
> 
> ...
> 
> > diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
> > index 5c94c1fc1bc1..f1c0e677a325 100644
> > --- a/arch/s390/include/asm/ftrace.h
> > +++ b/arch/s390/include/asm/ftrace.h
> > @@ -76,6 +76,11 @@ 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.addr = arch_ftrace_regs(fregs)->regs.psw.addr;		\
> > +		(_regs)->gprs[15] = arch_ftrace_regs(fregs)->regs.gprs[15];		\
> > +	} while (0)
> > +
> 
> This misses the feedback I gave for v15:
> https://lore.kernel.org/all/20241009100502.8007-E-hca@linux.ibm.com

Oops, sorry. And thanks for your feedback!
diff mbox series

Patch

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index d344c69eb01e..6493a575664f 100644
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -146,6 +146,13 @@  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);
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index 0edfb874eb02..407ce6eccc04 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -40,6 +40,13 @@  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)
diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 5c94c1fc1bc1..f1c0e677a325 100644
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -76,6 +76,11 @@  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.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
diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index d61407c680c2..7e06f8c7937a 100644
--- a/arch/x86/include/asm/ftrace.h
+++ b/arch/x86/include/asm/ftrace.h
@@ -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)
 
diff --git a/include/linux/ftrace.h b/include/linux/ftrace.h
index ad2b46e1d5b0..6d29c640697c 100644
--- a/include/linux/ftrace.h
+++ b/include/linux/ftrace.h
@@ -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.