Applied. thanks, -Len On Tue, 24 Jun 2008, Rafael J. Wysocki wrote: > Hi, > > The patch below fixes the regression described at > http://bugzilla.kernel.org/show_bug.cgi?id=10927 > which is caused by the fact that some BIOSes call the kernel's resume code with > post-protected mode garbage in segment registers. > > Apart from Dell laptops referred to in the chagelog it has a potential to fix > some other systems on which resume from suspend to RAM fails in a mysterious > way and the probability of it breaking things is rather small, so IMO it would > be nice to have in 2.6.26. > > Thanks, > Rafael > > > --- > From: H. Peter Anvin <hpa@xxxxxxxxx> > > x86 ACPI: normalize segment descriptor register on resume > > Some Dell laptops enter resume with apparent garbage in the segment > descriptor registers (almost certainly the result of a botched > transition from protected to real mode.) The only way to clean that > up is to enter protected mode ourselves and clean out the descriptor > registers. > > This fixes resume on Dell XPS M1210 and Dell D620. > > Reference: http://bugzilla.kernel.org/show_bug.cgi?id=10927 > > Signed-off-by: H. Peter Anvin <hpa@xxxxxxxxx> > Tested-by: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx> > Signed-off-by: Rafael J. Wysocki <rjw@xxxxxxx> > --- > arch/x86/kernel/acpi/realmode/wakeup.S | 38 ++++++++++++++++++++++++++++++++- > arch/x86/kernel/acpi/realmode/wakeup.h | 5 ++++ > arch/x86/kernel/acpi/sleep.c | 16 +++++++++++++ > drivers/acpi/sleep/main.c | 5 +--- > 4 files changed, 59 insertions(+), 5 deletions(-) > > Index: linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.S > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/acpi/realmode/wakeup.S > +++ linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.S > @@ -5,6 +5,7 @@ > #include <asm/msr-index.h> > #include <asm/page.h> > #include <asm/pgtable.h> > +#include <asm/processor-flags.h> > > .code16 > .section ".header", "a" > @@ -24,6 +25,11 @@ pmode_gdt: .quad 0 > realmode_flags: .long 0 > real_magic: .long 0 > trampoline_segment: .word 0 > +_pad1: .byte 0 > +wakeup_jmp: .byte 0xea /* ljmpw */ > +wakeup_jmp_off: .word 3f > +wakeup_jmp_seg: .word 0 > +wakeup_gdt: .quad 0, 0, 0 > signature: .long 0x51ee1111 > > .text > @@ -34,11 +40,34 @@ _start: > cli > cld > > + /* Apparently some dimwit BIOS programmers don't know how to > + program a PM to RM transition, and we might end up here with > + junk in the data segment descriptor registers. The only way > + to repair that is to go into PM and fix it ourselves... */ > + movw $16, %cx > + lgdtl %cs:wakeup_gdt > + movl %cr0, %eax > + orb $X86_CR0_PE, %al > + movl %eax, %cr0 > + jmp 1f > +1: ljmpw $8, $2f > +2: > + movw %cx, %ds > + movw %cx, %es > + movw %cx, %ss > + movw %cx, %fs > + movw %cx, %gs > + > + andb $~X86_CR0_PE, %al > + movl %eax, %cr0 > + jmp wakeup_jmp > +3: > /* Set up segments */ > movw %cs, %ax > movw %ax, %ds > movw %ax, %es > movw %ax, %ss > + lidtl wakeup_idt > > movl $wakeup_stack_end, %esp > > @@ -98,7 +127,14 @@ bogus_real_magic: > jmp 1b > > .data > - .balign 4 > + .balign 8 > + > + /* This is the standard real-mode IDT */ > +wakeup_idt: > + .word 0xffff /* limit */ > + .long 0 /* address */ > + .word 0 > + > .globl HEAP, heap_end > HEAP: > .long wakeup_heap > Index: linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.h > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/acpi/realmode/wakeup.h > +++ linux-2.6/arch/x86/kernel/acpi/realmode/wakeup.h > @@ -24,6 +24,11 @@ struct wakeup_header { > u32 realmode_flags; > u32 real_magic; > u16 trampoline_segment; /* segment with trampoline code, 64-bit only */ > + u8 _pad1; > + u8 wakeup_jmp; > + u16 wakeup_jmp_off; > + u16 wakeup_jmp_seg; > + u64 wakeup_gdt[3]; > u32 signature; /* To check we have correct structure */ > } __attribute__((__packed__)); > > Index: linux-2.6/arch/x86/kernel/acpi/sleep.c > =================================================================== > --- linux-2.6.orig/arch/x86/kernel/acpi/sleep.c > +++ linux-2.6/arch/x86/kernel/acpi/sleep.c > @@ -50,6 +50,20 @@ int acpi_save_state_mem(void) > > header->video_mode = saved_video_mode; > > + header->wakeup_jmp_seg = acpi_wakeup_address >> 4; > + /* GDT[0]: GDT self-pointer */ > + header->wakeup_gdt[0] = > + (u64)(sizeof(header->wakeup_gdt) - 1) + > + ((u64)(acpi_wakeup_address + > + ((char *)&header->wakeup_gdt - (char *)acpi_realmode)) > + << 16); > + /* GDT[1]: real-mode-like code segment */ > + header->wakeup_gdt[1] = (0x009bULL << 40) + > + ((u64)acpi_wakeup_address << 16) + 0xffff; > + /* GDT[2]: real-mode-like data segment */ > + header->wakeup_gdt[2] = (0x0093ULL << 40) + > + ((u64)acpi_wakeup_address << 16) + 0xffff; > + > #ifndef CONFIG_64BIT > store_gdt((struct desc_ptr *)&header->pmode_gdt); > > @@ -111,7 +125,7 @@ void __init acpi_reserve_bootmem(void) > return; > } > > - acpi_wakeup_address = acpi_realmode; > + acpi_wakeup_address = virt_to_phys((void *)acpi_realmode); > } > > > Index: linux-2.6/drivers/acpi/sleep/main.c > =================================================================== > --- linux-2.6.orig/drivers/acpi/sleep/main.c > +++ linux-2.6/drivers/acpi/sleep/main.c > @@ -32,9 +32,8 @@ static int acpi_sleep_prepare(u32 acpi_s > if (!acpi_wakeup_address) { > return -EFAULT; > } > - acpi_set_firmware_waking_vector((acpi_physical_address) > - virt_to_phys((void *) > - acpi_wakeup_address)); > + acpi_set_firmware_waking_vector( > + (acpi_physical_address)acpi_wakeup_address); > > } > ACPI_FLUSH_CPU_CACHE(); > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
