---

yaml --- r: 158708 b: refs/heads/master c: 5367b68 h: refs/heads/master v: v3
git-mirror · Sep 10, 2009 · e998ab7 · e998ab7
1 parent 033572f
commit e998ab7
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Showing 3 changed files with 15 additions and 5 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: b19ae3999891cad21a3995c34d313dda5df014e2
+refs/heads/master: 5367b6887e7d8c870a5da7d9b8c6e9c207684e43
diff --git a/trunk/arch/x86/include/asm/processor.h b/trunk/arch/x86/include/asm/processor.h
@@ -703,13 +703,23 @@ static inline void cpu_relax(void)
 	rep_nop();
 }
 
-/* Stop speculative execution: */
+/* Stop speculative execution and prefetching of modified code. */
 static inline void sync_core(void)
 {
 	int tmp;
 
-	asm volatile("cpuid" : "=a" (tmp) : "0" (1)
-		     : "ebx", "ecx", "edx", "memory");
+#if defined(CONFIG_M386) || defined(CONFIG_M486)
+	if (boot_cpu_data.x86 < 5)
+		/* There is no speculative execution.
+		 * jmp is a barrier to prefetching. */
+		asm volatile("jmp 1f\n1:\n" ::: "memory");
+	else
+#endif
+		/* cpuid is a barrier to speculative execution.
+		 * Prefetched instructions are automatically
+		 * invalidated when modified. */
+		asm volatile("cpuid" : "=a" (tmp) : "0" (1)
+			     : "ebx", "ecx", "edx", "memory");
 }
 
 static inline void __monitor(const void *eax, unsigned long ecx,

diff --git a/trunk/arch/x86/kernel/alternative.c b/trunk/arch/x86/kernel/alternative.c
@@ -490,8 +490,8 @@ void *text_poke_early(void *addr, const void *opcode, size_t len)
 	unsigned long flags;
 	local_irq_save(flags);
 	memcpy(addr, opcode, len);
-	local_irq_restore(flags);
 	sync_core();
+	local_irq_restore(flags);
 	/* Could also do a CLFLUSH here to speed up CPU recovery; but
 	   that causes hangs on some VIA CPUs. */
 	return addr;