linux/arch/x86/include/asm/suspend_64.h
Konrad Rzeszutek Wilk cc456c4e7c 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>
2013-05-02 11:27:35 -07:00

49 lines
1.3 KiB
C

/*
* Copyright 2001-2003 Pavel Machek <pavel@suse.cz>
* Based on code
* Copyright 2001 Patrick Mochel <mochel@osdl.org>
*/
#ifndef _ASM_X86_SUSPEND_64_H
#define _ASM_X86_SUSPEND_64_H
#include <asm/desc.h>
#include <asm/i387.h>
/*
* Image of the saved processor state, used by the low level ACPI suspend to
* RAM code and by the low level hibernation code.
*
* If you modify it, fix arch/x86/kernel/acpi/wakeup_64.S and make sure that
* __save/__restore_processor_state(), defined in arch/x86/kernel/suspend_64.c,
* still work as required.
*/
struct saved_context {
struct pt_regs regs;
u16 ds, es, fs, gs, ss;
unsigned long gs_base, gs_kernel_base, fs_base;
unsigned long cr0, cr2, cr3, cr4, cr8;
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;
u16 ldt;
u16 tss;
unsigned long tr;
unsigned long safety;
unsigned long return_address;
} __attribute__((packed));
#define loaddebug(thread,register) \
set_debugreg((thread)->debugreg##register, register)
/* routines for saving/restoring kernel state */
extern int acpi_save_state_mem(void);
extern char core_restore_code;
extern char restore_registers;
#endif /* _ASM_X86_SUSPEND_64_H */