Messages in this thread Patch in this message | | | Date | Sun, 8 Mar 2009 15:51:41 GMT | From | Masami Hiramatsu <> | Subject | [tip:tracing/core] tracing, Text Edit Lock - SMP alternatives support |
| |
Commit-ID: 3945dab45aa8c89014893bfa8eb1e1661a409cef Gitweb: http://git.kernel.org/tip/3945dab45aa8c89014893bfa8eb1e1661a409cef Author: "Masami Hiramatsu" <mhiramat@redhat.com> AuthorDate: Fri, 6 Mar 2009 10:37:22 -0500 Commit: Ingo Molnar <mingo@elte.hu> CommitDate: Fri, 6 Mar 2009 16:49:00 +0100
tracing, Text Edit Lock - SMP alternatives support
Use the mutual exclusion provided by the text edit lock in alternatives code. Since alternative_smp_* will be called from module init code, etc, we'd better protect it from other subsystems.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> LKML-Reference: <49B14332.9030109@redhat.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
--- arch/x86/kernel/alternative.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c index 4c80f15..092a7b8 100644 --- a/arch/x86/kernel/alternative.c +++ b/arch/x86/kernel/alternative.c @@ -5,6 +5,7 @@ #include <linux/kprobes.h> #include <linux/mm.h> #include <linux/vmalloc.h> +#include <linux/memory.h> #include <asm/alternative.h> #include <asm/sections.h> #include <asm/pgtable.h> @@ -226,6 +227,7 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end) { u8 **ptr; + mutex_lock(&text_mutex); for (ptr = start; ptr < end; ptr++) { if (*ptr < text) continue; @@ -234,6 +236,7 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end) /* turn DS segment override prefix into lock prefix */ text_poke(*ptr, ((unsigned char []){0xf0}), 1); }; + mutex_unlock(&text_mutex); } static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end) @@ -243,6 +246,7 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end if (noreplace_smp) return; + mutex_lock(&text_mutex); for (ptr = start; ptr < end; ptr++) { if (*ptr < text) continue; @@ -251,6 +255,7 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end /* turn lock prefix into DS segment override prefix */ text_poke(*ptr, ((unsigned char []){0x3E}), 1); }; + mutex_unlock(&text_mutex); } struct smp_alt_module {
| |