[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 <mason@suse.com>
Acked-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

3 files changed, 10 insertions, 9 deletions

diff --git a/arch/i386/kernel/machine_kexec.c b/arch/i386/kernel/machine_kexec.c
index a912fed48482..f73d7374a2ba 100644
--- a/arch/i386/kernel/machine_kexec.c
+++ b/arch/i386/kernel/machine_kexec.c
@@ -116,13 +116,13 @@ static void load_segments(void)
         __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
 }
diff --git a/arch/x86_64/kernel/machine_kexec.c b/arch/x86_64/kernel/machine_kexec.c
index 89fab51e20f4..25ac8a3faae6 100644
--- a/arch/x86_64/kernel/machine_kexec.c
+++ b/arch/x86_64/kernel/machine_kexec.c
@@ -140,7 +140,7 @@ static void load_segments(void)
                 "\tmovl %0,%%ss\n"
                 "\tmovl %0,%%fs\n"
                 "\tmovl %0,%%gs\n"
-                : : "a" (__KERNEL_DS)
+                : : "a" (__KERNEL_DS) : "memory"
                 );
 }
 
diff --git a/include/asm-powerpc/kexec.h b/include/asm-powerpc/kexec.h
index bda2f217e6fe..6a2af2f6853b 100644
--- a/include/asm-powerpc/kexec.h
+++ b/include/asm-powerpc/kexec.h
@@ -93,7 +93,8 @@ static inline void crash_setup_regs(struct pt_regs *newregs,
                         "mfxer  %0\n"
                         "std    %0, 296(%2)\n"
                         : "=&r" (tmp1), "=&r" (tmp2)
-                        : "b" (newregs));
+                        : "b" (newregs)
+                        : "memory");
         }
 }
 #else