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Message-ID: <20080818040340.GB17528@spacedout.fries.net>
Date: Sun, 17 Aug 2008 23:03:40 -0500
From: David Fries <david@...es.net>
To: linux-kernel@...r.kernel.org
Subject: [PATCH] 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.
Added the check (boot_cpu_data.x86 >= 5) before reading the
register. 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@...es.net>
---
arch/x86/kernel/acpi/sleep.c | 4 +++-
arch/x86/kernel/efi_32.c | 6 ++++--
arch/x86/power/cpu_32.c | 8 ++++++--
arch/x86/power/hibernate_asm_32.S | 26 +++++++++++++++-----------
4 files changed, 28 insertions(+), 16 deletions(-)
diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c
index 81e5ab6..bd0f2a3 100644
--- a/arch/x86/kernel/acpi/sleep.c
+++ b/arch/x86/kernel/acpi/sleep.c
@@ -86,7 +86,9 @@ int acpi_save_state_mem(void)
#endif /* !CONFIG_64BIT */
header->pmode_cr0 = read_cr0();
- header->pmode_cr4 = read_cr4();
+ /* cr4 was introduced in the Pentium CPU */
+ if (boot_cpu_data.x86 >= 5)
+ header->pmode_cr4 = read_cr4();
header->realmode_flags = acpi_realmode_flags;
header->real_magic = 0x12345678;
diff --git a/arch/x86/kernel/efi_32.c b/arch/x86/kernel/efi_32.c
index 4b63c8e..ad62d31 100644
--- a/arch/x86/kernel/efi_32.c
+++ b/arch/x86/kernel/efi_32.c
@@ -53,7 +53,8 @@ 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 was introduced in the Pentium CPU */
+ cr4 = boot_cpu_data.x86 >= 5 ? read_cr4() : 0;
if (cr4 & X86_CR4_PAE) {
efi_bak_pg_dir_pointer[0].pgd =
@@ -91,7 +92,8 @@ void efi_call_phys_epilog(void)
gdt_descr.size = GDT_SIZE - 1;
load_gdt(&gdt_descr);
- cr4 = read_cr4();
+ /* cr4 was introduced in the Pentium CPU */
+ cr4 = boot_cpu_data.x86 >= 5 ? read_cr4() : 0;
if (cr4 & X86_CR4_PAE) {
swapper_pg_dir[pgd_index(0)].pgd =
diff --git a/arch/x86/power/cpu_32.c b/arch/x86/power/cpu_32.c
index 7dc5d5c..c5647ea 100644
--- a/arch/x86/power/cpu_32.c
+++ b/arch/x86/power/cpu_32.c
@@ -45,7 +45,9 @@ 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();
+ /* cr4 was introduced in the Pentium CPU */
+ if (boot_cpu_data.x86 >= 5)
+ ctxt->cr4 = read_cr4();
}
/* Needed by apm.c */
@@ -98,7 +100,9 @@ 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);
write_cr3(ctxt->cr3);
write_cr2(ctxt->cr2);
write_cr0(ctxt->cr0);
diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S
index b95aa6c..4fc7e87 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)
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
--
1.4.4.4
--
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