On 2022-12-05 00:34, Michael Ellerman wrote:
Michael Jeanson <mjean...@efficios.com> writes:
In v5.7 the powerpc syscall entry/exit logic was rewritten in C, on
PPC64_ELF_ABI_V1 this resulted in the symbols in the syscall table
changing from their dot prefixed variant to the non-prefixed ones.

Since ftrace prefixes a dot to the syscall names when matching them to
build its syscall event list, this resulted in no syscall events being
available.

Remove the PPC64_ELF_ABI_V1 specific version of
arch_syscall_match_sym_name to have the same behavior across all powerpc
variants.

This doesn't seem to work for me.

Event with it applied I still don't see anything in 
/sys/kernel/debug/tracing/events/syscalls

Did we break it in some other way recently?

cheers

I've just tried this change on top of v6.1-rc8 in qemu with a base config of 'corenet32_smp_defconfig' and these options on top:

CONFIG_FTRACE=y
CONFIG_FTRACE_SYSCALLS=y

And I can trace syscalls with ftrace.

What kernel tree and config are you using?

Thanks for looking into this.



Fixes: 68b34588e202 ("powerpc/64/sycall: Implement syscall entry/exit logic in 
C")
Cc: sta...@vger.kernel.org # v5.7+
Cc: Steven Rostedt <rost...@goodmis.org>
Cc: Masami Hiramatsu <mhira...@kernel.org>
Cc: Mark Rutland <mark.rutl...@arm.com>
Cc: Michael Ellerman <m...@ellerman.id.au>
Cc: Nicholas Piggin <npig...@gmail.com>
Cc: Christophe Leroy <christophe.le...@csgroup.eu>
Cc: Michal Suchanek <msucha...@suse.de>
Cc: linuxppc-dev@lists.ozlabs.org
Cc: linux-ker...@vger.kernel.org
Signed-off-by: Michael Jeanson <mjean...@efficios.com>
Reviewed-by: Mathieu Desnoyers <mathieu.desnoy...@efficios.com>
---
  arch/powerpc/include/asm/ftrace.h | 12 ------------
  1 file changed, 12 deletions(-)

diff --git a/arch/powerpc/include/asm/ftrace.h 
b/arch/powerpc/include/asm/ftrace.h
index 3cee7115441b..e3d1f377bc5b 100644
--- a/arch/powerpc/include/asm/ftrace.h
+++ b/arch/powerpc/include/asm/ftrace.h
@@ -64,17 +64,6 @@ void ftrace_graph_func(unsigned long ip, unsigned long 
parent_ip,
   * those.
   */
  #define ARCH_HAS_SYSCALL_MATCH_SYM_NAME
-#ifdef CONFIG_PPC64_ELF_ABI_V1
-static inline bool arch_syscall_match_sym_name(const char *sym, const char 
*name)
-{
-       /* 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)) ||
-               (!strncmp(sym, ".ppc_", 5) && !strcmp(sym + 5, name + 4)) ||
-               (!strncmp(sym, ".ppc32_", 7) && !strcmp(sym + 7, name + 4)) ||
-               (!strncmp(sym, ".ppc64_", 7) && !strcmp(sym + 7, name + 4));
-}
-#else
  static inline bool arch_syscall_match_sym_name(const char *sym, const char 
*name)
  {
        return !strcmp(sym, name) ||
@@ -83,7 +72,6 @@ static inline bool arch_syscall_match_sym_name(const char 
*sym, const char *name
                (!strncmp(sym, "ppc32_", 6) && !strcmp(sym + 6, name + 4)) ||
                (!strncmp(sym, "ppc64_", 6) && !strcmp(sym + 6, name + 4));
  }
-#endif /* CONFIG_PPC64_ELF_ABI_V1 */
  #endif /* CONFIG_FTRACE_SYSCALLS */
#if defined(CONFIG_PPC64) && defined(CONFIG_FUNCTION_TRACER)
--
2.34.1

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