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Commit cc456c4e authored by Konrad Rzeszutek Wilk's avatar Konrad Rzeszutek Wilk Committed by H. Peter Anvin
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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: default avatar"H. Peter Anvin" <hpa@zytor.com>
Acked-by: default avatar"Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: default avatarKonrad 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: default avatarH. Peter Anvin <hpa@linux.intel.com>
parent 5a148af6

arch/x86/include/asm/suspend_32.h

+1 −0
Original line number Diff line number Diff line
@@ -15,6 +15,7 @@ struct saved_context { 
	unsigned long cr0, cr2, cr3, cr4;

	u64 misc_enable;

	bool misc_enable_saved;

	struct desc_ptr gdt_desc;

	struct desc_ptr idt;

	u16 ldt;

	u16 tss;

arch/x86/include/asm/suspend_64.h

+2 −0
Original line number Diff line number Diff line
@@ -25,6 +25,8 @@ struct saved_context { 
	u64 misc_enable;

	bool misc_enable_saved;

	unsigned long efer;

	u16 gdt_pad; /* Unused */

	struct desc_ptr gdt_desc;

	u16 idt_pad;

	u16 idt_limit;

	unsigned long idt_base;

arch/x86/kernel/asm-offsets_32.c

+3 −0
Original line number Diff line number Diff line
@@ -60,6 +60,9 @@ void foo(void) 
	OFFSET(IA32_RT_SIGFRAME_sigcontext, rt_sigframe, uc.uc_mcontext);

	BLANK();



	OFFSET(saved_context_gdt_desc, saved_context, gdt_desc);

	BLANK();



	/* Offset from the sysenter stack to tss.sp0 */

	DEFINE(TSS_sysenter_sp0, offsetof(struct tss_struct, x86_tss.sp0) -

		 sizeof(struct tss_struct));

arch/x86/kernel/asm-offsets_64.c

+1 −0
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ int main(void) 
	ENTRY(cr3);

	ENTRY(cr4);

	ENTRY(cr8);

	ENTRY(gdt_desc);

	BLANK();

#undef ENTRY

arch/x86/power/cpu.c

+10 −5
Original line number Diff line number Diff line
@@ -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(). */