Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754800Ab0LGEaa (ORCPT ); Mon, 6 Dec 2010 23:30:30 -0500 Received: from e23smtp08.au.ibm.com ([202.81.31.141]:54119 "EHLO e23smtp08.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754430Ab0LGE31 (ORCPT ); Mon, 6 Dec 2010 23:29:27 -0500 From: "Ian Munsie" To: Avantika Mathur Cc: Jason Baron , Ian Munsie , Randy Dunlap , Steven Rostedt , Frederic Weisbecker , Ingo Molnar , Mike Frysinger , Heiko Carstens , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 4/6] ftrace syscalls: Allow arch specific syscall symbol matching Date: Tue, 7 Dec 2010 15:29:09 +1100 Message-Id: <1291696151-4336-5-git-send-email-imunsie@au1.ibm.com> X-Mailer: git-send-email 1.7.2.3 In-Reply-To: <1291696151-4336-1-git-send-email-imunsie@au1.ibm.com> References: <1291696151-4336-1-git-send-email-imunsie@au1.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3381 Lines: 88 From: Ian Munsie Some architectures have unusual symbol names and the generic code to match the symbol name with the function name for the syscall metadata will fail. For example, symbols on PPC64 start with a period and the generic code will fail to match them. This patch splits out the match logic into a standalone weak function that can be overridden on archs with unusual symbol names. Signed-off-by: Ian Munsie --- Documentation/trace/ftrace-design.txt | 3 +++ include/linux/ftrace.h | 1 + kernel/trace/trace_syscalls.c | 19 ++++++++++++------- 3 files changed, 16 insertions(+), 7 deletions(-) diff --git a/Documentation/trace/ftrace-design.txt b/Documentation/trace/ftrace-design.txt index 6fca17b..d996d0a 100644 --- a/Documentation/trace/ftrace-design.txt +++ b/Documentation/trace/ftrace-design.txt @@ -250,6 +250,9 @@ 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, implement an 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/include/linux/ftrace.h b/include/linux/ftrace.h index dcd6a7c..8f6290a 100644 --- a/include/linux/ftrace.h +++ b/include/linux/ftrace.h @@ -527,6 +527,7 @@ extern enum ftrace_dump_mode ftrace_dump_on_oops; #ifdef CONFIG_FTRACE_SYSCALLS unsigned long arch_syscall_addr(int nr); +bool arch_syscall_match_sym_name(const char *sym, const char *name); #endif /* CONFIG_FTRACE_SYSCALLS */ diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c index b31ea2d..85983fd 100644 --- a/kernel/trace/trace_syscalls.c +++ b/kernel/trace/trace_syscalls.c @@ -81,13 +81,7 @@ static struct syscall_metadata *find_syscall_meta(unsigned long syscall) kallsyms_lookup(syscall, NULL, NULL, NULL, str); for ( ; start < stop; start++) { - /* - * Only compare after the "sys" prefix. Archs that use - * syscall wrappers may have syscalls symbols aliases prefixed - * with "SyS" instead of "sys", leading to an unwanted - * mismatch. - */ - if (start->name && !strcmp(start->name + 3, str + 3)) + if (start->name && arch_syscall_match_sym_name(str, start->name)) return start; } return NULL; @@ -452,6 +446,17 @@ unsigned long __init __weak arch_syscall_addr(int nr) return (unsigned long)sys_call_table[nr]; } +bool __weak arch_syscall_match_sym_name(const char *sym, const char *name) +{ + /* + * Only compare after the "sys" prefix. Archs that use + * syscall wrappers may have syscalls symbols aliases prefixed + * with "SyS" instead of "sys", leading to an unwanted + * mismatch. + */ + return (!strcmp(sym + 3, name + 3)); +} + int __init init_ftrace_syscalls(void) { struct syscall_metadata *meta; -- 1.7.2.3 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/