Commit e532c06f authored by David Fries's avatar David Fries Committed by Ingo Molnar
Browse files

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: default avatarDavid Fries <david@fries.net>
Acked-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 39e00fe2

arch/x86/kernel/acpi/sleep.c

+1 −1
Original line number Diff line number Diff line
@@ -86,7 +86,7 @@ int acpi_save_state_mem(void) 
#endif /* !CONFIG_64BIT */



	header->pmode_cr0 = read_cr0();

	header->pmode_cr4 = read_cr4();

	header->pmode_cr4 = read_cr4_safe();

	header->realmode_flags = acpi_realmode_flags;

	header->real_magic = 0x12345678;

arch/x86/kernel/efi_32.c

+2 −2
Original line number Diff line number Diff line
@@ -53,7 +53,7 @@ void efi_call_phys_prelog(void) 
	 * directory. If I have PAE, I just need to duplicate one entry in

	 * page directory.

	 */

	cr4 = read_cr4();

	cr4 = read_cr4_safe();



	if (cr4 & X86_CR4_PAE) {

		efi_bak_pg_dir_pointer[0].pgd =
@@ -91,7 +91,7 @@ void efi_call_phys_epilog(void) 
	gdt_descr.size = GDT_SIZE - 1;

	load_gdt(&gdt_descr);



	cr4 = read_cr4();

	cr4 = read_cr4_safe();



	if (cr4 & X86_CR4_PAE) {

		swapper_pg_dir[pgd_index(0)].pgd =

arch/x86/power/cpu_32.c

+4 −2
Original line number Diff line number Diff line
@@ -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 */
@@ -98,6 +98,8 @@ static void __restore_processor_state(struct saved_context *ctxt) 
	/*

	 * control registers

	 */

	/* cr4 was introduced in the Pentium CPU */

	if (ctxt->cr4)

		write_cr4(ctxt->cr4);

	write_cr3(ctxt->cr3);

	write_cr2(ctxt->cr2);

arch/x86/power/hibernate_asm_32.S

+15 −11
Original line number Diff line number Diff line
@@ -28,9 +28,9 @@ ENTRY(swsusp_arch_suspend) 
	ret



ENTRY(restore_image)

	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: 


done:

	/* 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

1:

	movl	%cr3, %eax;  # flush TLB

	movl	%eax, %cr3

	jecxz	1f	# cr4 Pentium and higher, skip if zero

	movl	%ecx, %cr4;  # turn PGE back on

1:



	movl saved_context_esp, %esp

	movl saved_context_ebp, %ebp

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