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authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2013-05-01 21:53:30 -0400
committerH. Peter Anvin <hpa@linux.intel.com>2013-05-02 11:27:35 -0700
commitcc456c4e7cac3837a86aaa7ca3cb9f488d44d196 (patch)
treeba510e7fcb4baab33f5853299fef12d73d23343a /arch/x86/power
parent5a148af66932c31814e263366094b5812210b501 (diff)
x86, gdt, hibernate: Store/load GDT for hibernate path.
The git commite7a5cd063c7b4c58417f674821d63f5eb6747e37 ("x86-64, gdt: Store/load GDT for ACPI S3 or hibernate/resume path is not needed.") assumes that for the hibernate path the booting kernel and the resuming kernel MUST be the same. That is certainly the case for a 32-bit kernel (see check_image_kernel and CONFIG_ARCH_HIBERNATION_HEADER config option). However for 64-bit kernels it is OK to have a different kernel version (and size of the image) of the booting and resuming kernels. Hence the above mentioned git commit introduces an regression. This patch fixes it by introducing a 'struct desc_ptr gdt_desc' back in the 'struct saved_context'. However instead of having in the 'save_processor_state' and 'restore_processor_state' the store/load_gdt calls, we are only saving the GDT in the save_processor_state. For the restore path the lgdt operation is done in hibernate_asm_[32|64].S in the 'restore_registers' path. The apt reader of this description will recognize that only 64-bit kernels need this treatment, not 32-bit. This patch adds the logic in the 32-bit path to be more similar to 64-bit so that in the future the unification process can take advantage of this. [ hpa: this also reverts an inadvertent on-disk format change ] Suggested-by: "H. Peter Anvin" <hpa@zytor.com> Acked-by: "Rafael J. Wysocki" <rjw@sisk.pl> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> Link: http://lkml.kernel.org/r/1367459610-9656-2-git-send-email-konrad.wilk@oracle.com Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/power')
-rw-r--r--arch/x86/power/cpu.c15
-rw-r--r--arch/x86/power/hibernate_asm_32.S4
-rw-r--r--arch/x86/power/hibernate_asm_64.S3
3 files changed, 17 insertions, 5 deletions
diff --git a/arch/x86/power/cpu.c b/arch/x86/power/cpu.c
index 6d6e907cee46..1cf5b300305e 100644
--- a/arch/x86/power/cpu.c
+++ b/arch/x86/power/cpu.c
@@ -25,16 +25,12 @@
#include <asm/cpu.h>
#ifdef CONFIG_X86_32
-static struct saved_context saved_context;
-
unsigned long saved_context_ebx;
unsigned long saved_context_esp, saved_context_ebp;
unsigned long saved_context_esi, saved_context_edi;
unsigned long saved_context_eflags;
-#else
-/* CONFIG_X86_64 */
-struct saved_context saved_context;
#endif
+struct saved_context saved_context;
/**
* __save_processor_state - save CPU registers before creating a
@@ -67,6 +63,15 @@ static void __save_processor_state(struct saved_context *ctxt)
/* CONFIG_X86_64 */
store_idt((struct desc_ptr *)&ctxt->idt_limit);
#endif
+ /*
+ * We save it here, but restore it only in the hibernate case.
+ * For ACPI S3 resume, this is loaded via 'early_gdt_desc' in 64-bit
+ * mode in "secondary_startup_64". In 32-bit mode it is done via
+ * 'pmode_gdt' in wakeup_start.
+ */
+ ctxt->gdt_desc.size = GDT_SIZE - 1;
+ ctxt->gdt_desc.address = (unsigned long)get_cpu_gdt_table(smp_processor_id());
+
store_tr(ctxt->tr);
/* XMM0..XMM15 should be handled by kernel_fpu_begin(). */
diff --git a/arch/x86/power/hibernate_asm_32.S b/arch/x86/power/hibernate_asm_32.S
index ad47daeafa4e..1d0fa0e24070 100644
--- a/arch/x86/power/hibernate_asm_32.S
+++ b/arch/x86/power/hibernate_asm_32.S
@@ -75,6 +75,10 @@ done:
pushl saved_context_eflags
popfl
+ /* Saved in save_processor_state. */
+ movl $saved_context, %eax
+ lgdt saved_context_gdt_desc(%eax)
+
xorl %eax, %eax
ret
diff --git a/arch/x86/power/hibernate_asm_64.S b/arch/x86/power/hibernate_asm_64.S
index 9356547d8c01..3c4469a7a929 100644
--- a/arch/x86/power/hibernate_asm_64.S
+++ b/arch/x86/power/hibernate_asm_64.S
@@ -139,6 +139,9 @@ ENTRY(restore_registers)
pushq pt_regs_flags(%rax)
popfq
+ /* Saved in save_processor_state. */
+ lgdt saved_context_gdt_desc(%rax)
+
xorq %rax, %rax
/* tell the hibernation core that we've just restored the memory */