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7a3136666b
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+
133 lines
3.7 KiB
C
133 lines
3.7 KiB
C
/*
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* sleep.c - x86-specific ACPI sleep support.
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*
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* Copyright (C) 2001-2003 Patrick Mochel
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* Copyright (C) 2001-2003 Pavel Machek <pavel@ucw.cz>
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*/
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#include <linux/acpi.h>
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#include <linux/bootmem.h>
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#include <linux/memblock.h>
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#include <linux/dmi.h>
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#include <linux/cpumask.h>
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#include <asm/segment.h>
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#include <asm/desc.h>
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#include <asm/pgtable.h>
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#include <asm/cacheflush.h>
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#include "realmode/wakeup.h"
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#include "sleep.h"
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unsigned long acpi_realmode_flags;
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#if defined(CONFIG_SMP) && defined(CONFIG_64BIT)
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static char temp_stack[4096];
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#endif
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/**
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* acpi_suspend_lowlevel - save kernel state
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*
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* Create an identity mapped page table and copy the wakeup routine to
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* low memory.
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*/
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int acpi_suspend_lowlevel(void)
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{
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struct wakeup_header *header;
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/* address in low memory of the wakeup routine. */
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char *acpi_realmode;
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acpi_realmode = TRAMPOLINE_SYM(acpi_wakeup_code);
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header = (struct wakeup_header *)(acpi_realmode + WAKEUP_HEADER_OFFSET);
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if (header->signature != WAKEUP_HEADER_SIGNATURE) {
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printk(KERN_ERR "wakeup header does not match\n");
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return -EINVAL;
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}
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header->video_mode = saved_video_mode;
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header->wakeup_jmp_seg = acpi_wakeup_address >> 4;
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/*
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* Set up the wakeup GDT. We set these up as Big Real Mode,
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* that is, with limits set to 4 GB. At least the Lenovo
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* Thinkpad X61 is known to need this for the video BIOS
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* initialization quirk to work; this is likely to also
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* be the case for other laptops or integrated video devices.
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*/
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/* GDT[0]: GDT self-pointer */
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header->wakeup_gdt[0] =
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(u64)(sizeof(header->wakeup_gdt) - 1) +
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((u64)__pa(&header->wakeup_gdt) << 16);
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/* GDT[1]: big real mode-like code segment */
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header->wakeup_gdt[1] =
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GDT_ENTRY(0x809b, acpi_wakeup_address, 0xfffff);
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/* GDT[2]: big real mode-like data segment */
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header->wakeup_gdt[2] =
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GDT_ENTRY(0x8093, acpi_wakeup_address, 0xfffff);
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#ifndef CONFIG_64BIT
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store_gdt((struct desc_ptr *)&header->pmode_gdt);
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if (rdmsr_safe(MSR_EFER, &header->pmode_efer_low,
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&header->pmode_efer_high))
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header->pmode_efer_low = header->pmode_efer_high = 0;
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#endif /* !CONFIG_64BIT */
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header->pmode_cr0 = read_cr0();
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header->pmode_cr4 = read_cr4_safe();
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header->pmode_behavior = 0;
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if (!rdmsr_safe(MSR_IA32_MISC_ENABLE,
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&header->pmode_misc_en_low,
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&header->pmode_misc_en_high))
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header->pmode_behavior |=
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(1 << WAKEUP_BEHAVIOR_RESTORE_MISC_ENABLE);
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header->realmode_flags = acpi_realmode_flags;
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header->real_magic = 0x12345678;
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#ifndef CONFIG_64BIT
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header->pmode_entry = (u32)&wakeup_pmode_return;
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header->pmode_cr3 = (u32)__pa(&initial_page_table);
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saved_magic = 0x12345678;
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#else /* CONFIG_64BIT */
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header->trampoline_segment = trampoline_address() >> 4;
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#ifdef CONFIG_SMP
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stack_start = (unsigned long)temp_stack + sizeof(temp_stack);
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early_gdt_descr.address =
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(unsigned long)get_cpu_gdt_table(smp_processor_id());
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initial_gs = per_cpu_offset(smp_processor_id());
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#endif
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initial_code = (unsigned long)wakeup_long64;
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saved_magic = 0x123456789abcdef0L;
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#endif /* CONFIG_64BIT */
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do_suspend_lowlevel();
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return 0;
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}
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static int __init acpi_sleep_setup(char *str)
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{
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while ((str != NULL) && (*str != '\0')) {
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if (strncmp(str, "s3_bios", 7) == 0)
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acpi_realmode_flags |= 1;
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if (strncmp(str, "s3_mode", 7) == 0)
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acpi_realmode_flags |= 2;
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if (strncmp(str, "s3_beep", 7) == 0)
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acpi_realmode_flags |= 4;
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#ifdef CONFIG_HIBERNATION
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if (strncmp(str, "s4_nohwsig", 10) == 0)
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acpi_no_s4_hw_signature();
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#endif
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if (strncmp(str, "nonvs", 5) == 0)
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acpi_nvs_nosave();
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if (strncmp(str, "old_ordering", 12) == 0)
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acpi_old_suspend_ordering();
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str = strchr(str, ',');
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if (str != NULL)
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str += strspn(str, ", \t");
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}
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return 1;
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}
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__setup("acpi_sleep=", acpi_sleep_setup);
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