linux_dsm_epyc7002/arch/x86/kernel/acpi/sleep.c
Kees Cook 7a3136666b x86, suspend: Restore MISC_ENABLE MSR in realmode wakeup
Some BIOSes will reset the Intel MISC_ENABLE MSR (specifically the
XD_DISABLE bit) when resuming from S3, which can interact poorly with
ebba638ae7. In 32bit PAE mode, this can
lead to a fault when EFER is restored by the kernel wakeup routines,
due to it setting the NX bit for a CPU that (thanks to the BIOS reset)
now incorrectly thinks it lacks the NX feature. (64bit is not affected
because it uses a common CPU bring-up that specifically handles the
XD_DISABLE bit.)

The need for MISC_ENABLE being restored so early is specific to the S3
resume path. Normally, MISC_ENABLE is saved in save_processor_state(),
but this happens after the resume header is created, so just reproduce
the logic here. (acpi_suspend_lowlevel() creates the header, calls
do_suspend_lowlevel, which calls save_processor_state(), so the saved
processor context isn't available during resume header creation.)

[ hpa: Consider for stable if OK in mainline ]

Signed-off-by: Kees Cook <kees.cook@canonical.com>
Link: http://lkml.kernel.org/r/20110707011034.GA8523@outflux.net
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: <stable@kernel.org> 2.6.38+
2011-07-06 20:09:34 -07:00

134 lines
3.7 KiB
C

/*
* sleep.c - x86-specific ACPI sleep support.
*
* Copyright (C) 2001-2003 Patrick Mochel
* Copyright (C) 2001-2003 Pavel Machek <pavel@ucw.cz>
*/
#include <linux/acpi.h>
#include <linux/bootmem.h>
#include <linux/memblock.h>
#include <linux/dmi.h>
#include <linux/cpumask.h>
#include <asm/segment.h>
#include <asm/desc.h>
#include <asm/pgtable.h>
#include <asm/cacheflush.h>
#include "realmode/wakeup.h"
#include "sleep.h"
unsigned long acpi_realmode_flags;
#if defined(CONFIG_SMP) && defined(CONFIG_64BIT)
static char temp_stack[4096];
#endif
/**
* acpi_suspend_lowlevel - save kernel state
*
* Create an identity mapped page table and copy the wakeup routine to
* low memory.
*/
int acpi_suspend_lowlevel(void)
{
struct wakeup_header *header;
/* address in low memory of the wakeup routine. */
char *acpi_realmode;
acpi_realmode = TRAMPOLINE_SYM(acpi_wakeup_code);
header = (struct wakeup_header *)(acpi_realmode + WAKEUP_HEADER_OFFSET);
if (header->signature != WAKEUP_HEADER_SIGNATURE) {
printk(KERN_ERR "wakeup header does not match\n");
return -EINVAL;
}
header->video_mode = saved_video_mode;
header->wakeup_jmp_seg = acpi_wakeup_address >> 4;
/*
* Set up the wakeup GDT. We set these up as Big Real Mode,
* that is, with limits set to 4 GB. At least the Lenovo
* Thinkpad X61 is known to need this for the video BIOS
* initialization quirk to work; this is likely to also
* be the case for other laptops or integrated video devices.
*/
/* GDT[0]: GDT self-pointer */
header->wakeup_gdt[0] =
(u64)(sizeof(header->wakeup_gdt) - 1) +
((u64)__pa(&header->wakeup_gdt) << 16);
/* GDT[1]: big real mode-like code segment */
header->wakeup_gdt[1] =
GDT_ENTRY(0x809b, acpi_wakeup_address, 0xfffff);
/* GDT[2]: big real mode-like data segment */
header->wakeup_gdt[2] =
GDT_ENTRY(0x8093, acpi_wakeup_address, 0xfffff);
#ifndef CONFIG_64BIT
store_gdt((struct desc_ptr *)&header->pmode_gdt);
if (rdmsr_safe(MSR_EFER, &header->pmode_efer_low,
&header->pmode_efer_high))
header->pmode_efer_low = header->pmode_efer_high = 0;
#endif /* !CONFIG_64BIT */
header->pmode_cr0 = read_cr0();
header->pmode_cr4 = read_cr4_safe();
header->pmode_behavior = 0;
if (!rdmsr_safe(MSR_IA32_MISC_ENABLE,
&header->pmode_misc_en_low,
&header->pmode_misc_en_high))
header->pmode_behavior |=
(1 << WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE);
header->realmode_flags = acpi_realmode_flags;
header->real_magic = 0x12345678;
#ifndef CONFIG_64BIT
header->pmode_entry = (u32)&wakeup_pmode_return;
header->pmode_cr3 = (u32)__pa(&initial_page_table);
saved_magic = 0x12345678;
#else /* CONFIG_64BIT */
header->trampoline_segment = trampoline_address() >> 4;
#ifdef CONFIG_SMP
stack_start = (unsigned long)temp_stack + sizeof(temp_stack);
early_gdt_descr.address =
(unsigned long)get_cpu_gdt_table(smp_processor_id());
initial_gs = per_cpu_offset(smp_processor_id());
#endif
initial_code = (unsigned long)wakeup_long64;
saved_magic = 0x123456789abcdef0L;
#endif /* CONFIG_64BIT */
do_suspend_lowlevel();
return 0;
}
static int __init acpi_sleep_setup(char *str)
{
while ((str != NULL) && (*str != '\0')) {
if (strncmp(str, "s3_bios", 7) == 0)
acpi_realmode_flags |= 1;
if (strncmp(str, "s3_mode", 7) == 0)
acpi_realmode_flags |= 2;
if (strncmp(str, "s3_beep", 7) == 0)
acpi_realmode_flags |= 4;
#ifdef CONFIG_HIBERNATION
if (strncmp(str, "s4_nohwsig", 10) == 0)
acpi_no_s4_hw_signature();
#endif
if (strncmp(str, "nonvs", 5) == 0)
acpi_nvs_nosave();
if (strncmp(str, "old_ordering", 12) == 0)
acpi_old_suspend_ordering();
str = strchr(str, ',');
if (str != NULL)
str += strspn(str, ", \t");
}
return 1;
}
__setup("acpi_sleep=", acpi_sleep_setup);