[PATCH] fix kexec asm

While testing kexec and kdump we hit problems where the new kernel would
freeze or instantly reboot. The easiest way to trigger it was to kexec a
kernel compiled for CONFIG_M586 on an athlon cpu. Compiling for CONFIG_MK7
instead would work fine.

The patch fixes a few problems with the kexec inline asm.

Signed-off-by: Chris Mason <[e-mail]>
Acked-by: "Eric W. Biederman" <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
Signed-off-by: Linus Torvalds <[e-mail]>

arch/i386/kernel/machine_kexec.c

···
 	__asm__ __volatile__ (
 		"\tljmp $"STR(__KERNEL_CS)",$1f\n"
 		"\t1:\n"
-		"\tmovl $"STR(__KERNEL_DS)",%eax\n"
-		"\tmovl %eax,%ds\n"
-		"\tmovl %eax,%es\n"
-		"\tmovl %eax,%fs\n"
-		"\tmovl %eax,%gs\n"
-		"\tmovl %eax,%ss\n"
-		);
+		"\tmovl $"STR(__KERNEL_DS)",%%eax\n"
+		"\tmovl %%eax,%%ds\n"
+		"\tmovl %%eax,%%es\n"
+		"\tmovl %%eax,%%fs\n"
+		"\tmovl %%eax,%%gs\n"
+		"\tmovl %%eax,%%ss\n"
+		::: "eax", "memory");
 #undef STR
 #undef __STR
 }

arch/x86_64/kernel/machine_kexec.c

···
 		"\tmovl %0,%%ss\n"
 		"\tmovl %0,%%fs\n"
 		"\tmovl %0,%%gs\n"
-		: : "a" (__KERNEL_DS)
+		: : "a" (__KERNEL_DS) : "memory"
 		);
 }
 

include/asm-powerpc/kexec.h

···
 			"mfxer  %0\n"
 			"std    %0, 296(%2)\n"
 			: "=&r" (tmp1), "=&r" (tmp2)
-			: "b" (newregs));
+			: "b" (newregs)
+			: "memory");
 	}
 }
 #else