arch_syscall_match_sym_name has been previously added to allow arch to
override syscall_match_sym_name method, but only ppc arch implements it
and the only difference made is that a prefix is longer. This can be
simplified by using a #define specifying the prefix length difference
for a given arch.
Next commit will make syscall_match_sym_name implementation a bit
larger, so clean it up now to avoid further patching arch code whenever
the core method changes.
Signed-off-by: Marcin Nowakowski <marcin.nowakowski@xxxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
---
Documentation/trace/ftrace-design.txt | 4 ----
arch/powerpc/include/asm/ftrace.h | 15 ++-------------
kernel/trace/trace_syscalls.c | 14 ++++++++------
3 files changed, 10 insertions(+), 23 deletions(-)
diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt
index a273dd0..c30608e 100644
--- a/Documentation/trace/ftrace-design.txt
+++ b/Documentation/trace/ftrace-design.txt
@@ -237,10 +237,6 @@ You need very few things to get the syscalls tracing in an arch.
- If the system call table on this arch is more complicated than a simple array
of addresses of the system calls, implement an arch_syscall_addr to return
the address of a given system call.
-- If the symbol names of the system calls do not match the function names on
- this arch, define ARCH_HAS_SYSCALL_MATCH_SYM_NAME in asm/ftrace.h and
- implement arch_syscall_match_sym_name with the appropriate logic to return
- true if the function name corresponds with the symbol name.
- Tag this arch as HAVE_SYSCALL_TRACEPOINTS.
diff --git a/arch/powerpc/include/asm/ftrace.h b/arch/powerpc/include/asm/ftrace.h
index 686c5f7..f266051 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -67,20 +67,9 @@ struct dyn_arch_ftrace {
#endif
#endif
-#if defined(CONFIG_FTRACE_SYSCALLS) && !defined(__ASSEMBLY__)
#ifdef PPC64_ELF_ABI_v1
-#define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
-static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
-{
- /*
- * Compare the symbol name with the system call name. Skip the .sys or .SyS
- * prefix from the symbol name and the sys prefix from the system call name and
- * just match the rest. This is only needed on ppc64 since symbol names on
- * 32bit do not start with a period so the generic function will work.
- */
- return !strcmp(sym + 4, name + 3);
-}
+/* On ppc64 ABIv1 (BE) we have to skip the leading '.' in the symbol name */
+#define ARCH_SYM_NAME_SKIP_CHARS 1
#endif
-#endif /* CONFIG_FTRACE_SYSCALLS && !__ASSEMBLY__ */
#endif /* _ASM_POWERPC_FTRACE */
diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 9065db3..707a57c 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -31,8 +31,11 @@ extern struct syscall_metadata *__stop_syscalls_metadata[];
static struct syscall_metadata **syscalls_metadata;
-#ifndef ARCH_HAS_SYSCALL_MATCH_SYM_NAME
-static inline bool arch_syscall_match_sym_name(const char *sym, const char *name)
+#ifndef ARCH_SYM_NAME_SKIP_CHARS
+#define ARCH_SYM_NAME_SKIP_CHARS 0
+#endif
+
+static inline bool syscall_match_sym_name(const char *sym, const char *name)
{
/*
* Only compare after the "sys" prefix. Archs that use
@@ -40,9 +43,8 @@ static inline bool arch_syscall_match_sym_name(const char *sym, const char *name
* with ".SyS" or ".sys" instead of "sys", leading to an unwanted
* mismatch.
*/
- return !strcmp(sym + 3, name + 3);
+ return !strcmp(sym + 3 + ARCH_SYM_NAME_SKIP_CHARS, name + 3);
}
-#endif
#ifdef ARCH_COMPAT_SYSCALL_NUMBERS_OVERLAP
/*
@@ -86,11 +88,11 @@ find_syscall_meta(unsigned long syscall)
stop = __stop_syscalls_metadata;
kallsyms_lookup(syscall, NULL, NULL, NULL, str);
- if (arch_syscall_match_sym_name(str, "sys_ni_syscall"))
+ if (syscall_match_sym_name(str, "sys_ni_syscall"))
return NULL;
for ( ; start < stop; start++) {
- if ((*start)->name && arch_syscall_match_sym_name(str, (*start)->name))
+ if ((*start)->name && syscall_match_sym_name(str, (*start)->name))
return *start;
}
return NULL;
--
2.7.4
--
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