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>
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@ -5,6 +5,7 @@
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#include <linux/kprobes.h>
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#include <linux/mm.h>
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#include <linux/vmalloc.h>
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#include <linux/memory.h>
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#include <asm/alternative.h>
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#include <asm/sections.h>
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#include <asm/pgtable.h>
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@ -226,6 +227,7 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
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{
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u8 **ptr;
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mutex_lock(&text_mutex);
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for (ptr = start; ptr < end; ptr++) {
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if (*ptr < text)
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continue;
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@ -234,6 +236,7 @@ static void alternatives_smp_lock(u8 **start, u8 **end, u8 *text, u8 *text_end)
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/* turn DS segment override prefix into lock prefix */
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text_poke(*ptr, ((unsigned char []){0xf0}), 1);
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};
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mutex_unlock(&text_mutex);
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}
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static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end)
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@ -243,6 +246,7 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end
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if (noreplace_smp)
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return;
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mutex_lock(&text_mutex);
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for (ptr = start; ptr < end; ptr++) {
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if (*ptr < text)
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continue;
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@ -251,6 +255,7 @@ static void alternatives_smp_unlock(u8 **start, u8 **end, u8 *text, u8 *text_end
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/* turn lock prefix into DS segment override prefix */
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text_poke(*ptr, ((unsigned char []){0x3E}), 1);
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};
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mutex_unlock(&text_mutex);
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}
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struct smp_alt_module {
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