forked from Minki/linux
5ff560fd48
There are CPUs which have errata causing RDMSR of a nonexistent MSR to not fault. We would then try to WRMSR to restore the value of that MSR, causing a crash. Specifically, some Pentium M variants would have this problem trying to save and restore the non-existent EFER, causing a crash on resume. Work around this by making sure we can write back the result at suspend time. Huge thanks to Christian Sünkenberg for finding the offending erratum that finally deciphered the mystery. Reported-and-tested-by: Johan Heinrich <onny@project-insanity.org> Debugged-by: Christian Sünkenberg <christian.suenkenberg@student.kit.edu> Acked-by: Rafael J. Wysocki <rjw@sisk.pl> Link: http://lkml.kernel.org/r/51DDC972.3010005@student.kit.edu Cc: <stable@vger.kernel.org> # v3.7+
130 lines
3.6 KiB
C
130 lines
3.6 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 <asm/realmode.h>
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#include "../../realmode/rm/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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* x86_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 x86_acpi_suspend_lowlevel(void)
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{
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struct wakeup_header *header =
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(struct wakeup_header *) __va(real_mode_header->wakeup_header);
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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->pmode_behavior = 0;
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#ifndef CONFIG_64BIT
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native_store_gdt((struct desc_ptr *)&header->pmode_gdt);
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/*
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* We have to check that we can write back the value, and not
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* just read it. At least on 90 nm Pentium M (Family 6, Model
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* 13), reading an invalid MSR is not guaranteed to trap, see
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* Erratum X4 in "Intel Pentium M Processor on 90 nm Process
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* with 2-MB L2 Cache and Intel® Processor A100 and A110 on 90
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* nm process with 512-KB L2 Cache Specification Update".
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*/
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if (!rdmsr_safe(MSR_EFER,
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&header->pmode_efer_low,
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&header->pmode_efer_high) &&
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!wrmsr_safe(MSR_EFER,
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header->pmode_efer_low,
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header->pmode_efer_high))
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header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_EFER);
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#endif /* !CONFIG_64BIT */
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header->pmode_cr0 = read_cr0();
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if (__this_cpu_read(cpu_info.cpuid_level) >= 0) {
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header->pmode_cr4 = read_cr4();
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header->pmode_behavior |= (1 << WAKEUP_BEHAVIOR_RESTORE_CR4);
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}
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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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!wrmsr_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_symbol(initial_page_table);
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saved_magic = 0x12345678;
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#else /* CONFIG_64BIT */
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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, "nonvs_s3", 8) == 0)
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acpi_nvs_nosave_s3();
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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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