---

yaml --- r: 16369 b: refs/heads/master c: ff6e8c0 h: refs/heads/master i: 16367: 2d5e057 v: v3
git-mirror · Jan 6, 2006 · 71f6ba4 · 71f6ba4
1 parent 2352e72
commit 71f6ba4
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Showing 3 changed files with 15 additions and 4 deletions.
diff --git a/[refs] b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: eb05c3249a8e8a675e79d221f4a0874dc10ec903
+refs/heads/master: ff6e8c0d5e47f0ceeebde86ec2f5919dbd5beb67
diff --git a/trunk/arch/i386/kernel/process.c b/trunk/arch/i386/kernel/process.c
@@ -308,9 +308,7 @@ void show_regs(struct pt_regs * regs)
 	cr0 = read_cr0();
 	cr2 = read_cr2();
 	cr3 = read_cr3();
-	if (current_cpu_data.x86 > 4) {
-		cr4 = read_cr4();
-	}
+	cr4 = read_cr4_safe();
 	printk("CR0: %08lx CR2: %08lx CR3: %08lx CR4: %08lx\n", cr0, cr2, cr3, cr4);
 	show_trace(NULL, &regs->esp);
 }

diff --git a/trunk/include/asm-i386/system.h b/trunk/include/asm-i386/system.h
@@ -140,6 +140,19 @@ static inline unsigned long _get_base(char * addr)
 		:"=r" (__dummy)); \
 	__dummy; \
 })
+
+#define read_cr4_safe() ({			      \
+	unsigned int __dummy;			      \
+	/* This could fault if %cr4 does not exist */ \
+	__asm__("1: movl %%cr4, %0		\n"   \
+		"2:				\n"   \
+		".section __ex_table,\"a\"	\n"   \
+		".long 1b,2b			\n"   \
+		".previous			\n"   \
+		: "=r" (__dummy): "0" (0));	      \
+	__dummy;				      \
+})
+
 #define write_cr4(x) \
 	__asm__ __volatile__("movl %0,%%cr4": :"r" (x));
 #define stts() write_cr0(8 | read_cr0())