[PATCH 4.14 120/189] powerpc/trace/syscalls: Update syscall name matching logic

Greg Kroah-Hartman
2018-06-18T08:34:52Z

From: "Naveen N. Rao" <naveen.n.rao@linux.vnet.ibm.com>

[ Upstream commit 0b7758aaf6543b9a10c8671db559e9d374a3fd95 ]

On powerpc64 ABIv1, we are enabling syscall tracing for only ~20
syscalls. This is due to commit e145242ea0df6 ("syscalls/core,
syscalls/x86: Clean up syscall stub naming convention") which has
changed the syscall entry wrapper prefix from "SyS" to "__se_sys".

Update the logic for ABIv1 to not just skip the initial dot, but also
the "__se_sys" prefix.

Fixes: commit e145242ea0df6 ("syscalls/core, syscalls/x86: Clean up syscall stub naming convention")
Reported-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/powerpc/include/asm/ftrace.h | 10 +++-------
1 file changed, 3 insertions(+), 7 deletions(-)

--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -73,13 +73,9 @@ struct dyn_arch_ftrace {
#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);
+ /* We need to skip past the initial dot, and the __se_sys alias */
+ return !strcmp(sym + 1, name) ||
+ (!strncmp(sym, ".__se_sys", 9) && !strcmp(sym + 6, name));
}
#endif
#endif /* CONFIG_FTRACE_SYSCALLS && !__ASSEMBLY__ */