path: root/arch/x86/power
diff options
authorDavid Fries <david@fries.net>2008-08-17 23:03:40 -0500
committerIngo Molnar <mingo@elte.hu>2008-08-18 08:50:19 +0200
commite532c06f2a835b5cc4f4166f467437d9b09c1d0e (patch)
tree762fa0f0c22dc1af7d9d6e918f4d48ced8910a4e /arch/x86/power
parent39e00fe20aaad4326ed5e0e3221451732bc7f679 (diff)
x86: fix i486 suspend to disk CR4 oops
arch/x86/power/cpu_32.c __save_processor_state calls read_cr4() only a i486 CPU doesn't have the CR4 register. Trying to read it produces an invalid opcode oops during suspend to disk. Use the safe rc4 reading op instead. If the value to be written is zero the write is skipped. arch/x86/power/hibernate_asm_32.S done: swapped the use of %eax and %ecx to use jecxz for the zero test and jump over store to %cr4. restore_image: s/%ecx/%eax/ to be consistent with done: In addition to __save_processor_state, acpi_save_state_mem, efi_call_phys_prelog, and efi_call_phys_epilog had checks added (acpi restore was in assembly and already had a check for non-zero). There were other reads and writes of CR4, but MCE and virtualization shouldn't be executed on a i486 anyway. Signed-off-by: David Fries <david@fries.net> Acked-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'arch/x86/power')
2 files changed, 19 insertions, 13 deletions
diff --git a/arch/x86/power/cpu_32.c b/arch/x86/power/cpu_32.c
index 7dc5d5cf50a..d3e083dea72 100644
--- a/arch/x86/power/cpu_32.c
+++ b/arch/x86/power/cpu_32.c
@@ -45,7 +45,7 @@ static void __save_processor_state(struct saved_context *ctxt)
ctxt->cr0 = read_cr0();
ctxt->cr2 = read_cr2();
ctxt->cr3 = read_cr3();
- ctxt->cr4 = read_cr4();
+ ctxt->cr4 = read_cr4_safe();
/* Needed by apm.c */
@@ -98,7 +98,9 @@ static void __restore_processor_state(struct saved_context *ctxt)
* control registers
- write_cr4(ctxt->cr4);
+ /* cr4 was introduced in the Pentium CPU */
+ if (ctxt->cr4)
+ write_cr4(ctxt->cr4);
diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S
index b95aa6cfe3c..4fc7e872c85 100644
--- a/arch/x86/power/hibernate_asm_32.S
+++ b/arch/x86/power/hibernate_asm_32.S
@@ -28,9 +28,9 @@ ENTRY(swsusp_arch_suspend)
- movl resume_pg_dir, %ecx
- subl $__PAGE_OFFSET, %ecx
- movl %ecx, %cr3
+ movl resume_pg_dir, %eax
+ subl $__PAGE_OFFSET, %eax
+ movl %eax, %cr3
movl restore_pblist, %edx
.p2align 4,,7
@@ -52,17 +52,21 @@ copy_loop:
/* go back to the original page tables */
- movl $swapper_pg_dir, %ecx
- subl $__PAGE_OFFSET, %ecx
- movl %ecx, %cr3
+ movl $swapper_pg_dir, %eax
+ subl $__PAGE_OFFSET, %eax
+ movl %eax, %cr3
/* Flush TLB, including "global" things (vmalloc) */
- movl mmu_cr4_features, %eax
- movl %eax, %edx
+ movl mmu_cr4_features, %ecx
+ jecxz 1f # cr4 Pentium and higher, skip if zero
+ movl %ecx, %edx
andl $~(1<<7), %edx; # PGE
movl %edx, %cr4; # turn off PGE
- movl %cr3, %ecx; # flush TLB
- movl %ecx, %cr3
- movl %eax, %cr4; # turn PGE back on
+ movl %cr3, %eax; # flush TLB
+ movl %eax, %cr3
+ jecxz 1f # cr4 Pentium and higher, skip if zero
+ movl %ecx, %cr4; # turn PGE back on
movl saved_context_esp, %esp
movl saved_context_ebp, %ebp