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: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Will 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: Steven Rostedt (Google) <rostedt@goodmis.org>

diff --git a/arch/arm64/include/asm/ftrace.h b/arch/arm64/include/asm/ftrace.h
index 09210f853f12d762713d53d310684a543b4a0669..10e56522122aab9b0869dbe7595158ba39b3ef73 100644 (file)
--- a/arch/arm64/include/asm/ftrace.h
+++ b/arch/arm64/include/asm/ftrace.h
@@ -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);

diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index db481b336bca44774ab45ab5fd298e576ddcdcde..fe181bafdca4f21b019a8b2c32494cc1357320e5 100644 (file)
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -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)

diff --git a/arch/s390/include/asm/ftrace.h b/arch/s390/include/asm/ftrace.h
index 5c94c1fc1bc1c91efcaef9e3e017138c16cb6243..5b7cb49c41ee0c60a5b42fb17349463796cbf73b 100644 (file)
--- a/arch/s390/include/asm/ftrace.h
+++ b/arch/s390/include/asm/ftrace.h
@@ -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

diff --git a/arch/x86/include/asm/ftrace.h b/arch/x86/include/asm/ftrace.h
index d61407c680c281890e38b5fd2a64f972022f458d..7e06f8c7937aa63dc85426adf6065af4a8d6b29b 100644 (file)
--- 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 ad2b46e1d5b02d46088698d01af9fea5ed6c423b..6d29c640697cf0453c32e1c80ae609c81dfbc180 100644 (file)
--- 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.