From 3bf2e77453a87c22eb57ed4926760ac131c84459 Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Sun, 13 Jul 2008 21:18:02 -0700 Subject: x86, suspend, acpi: enter Big Real Mode The explanation for recent video BIOS suspend quirk failures is that the VESA BIOS expects to be entered in Big Real Mode (*.limit = 0xffffffff) instead of ordinary Real Mode (*.limit = 0xffff). This patch changes the segment descriptors to Big Real Mode instead. The segment descriptor registers (what Intel calls "segment cache") is always active. The only thing that changes based on CR0.PE is how it is *loaded* and the interpretation of the CS flags. The segment descriptor registers contain of the following sub-registers: selector (the "visible" part), base, limit and flags. In protected mode or long mode, they are loaded from descriptors (or fs.base or gs.base can be manipulated directly in long mode.) In real mode, the only thing changed by a segment register load is the selector and the base, where the base <- selector << 4. In particular, *the limit and the flags are not changed*. As far as the handling of the CS flags: a code segment cannot be writable in protected mode, whereas it is "just another segment" in real mode, so there is some kind of quirk that kicks in for this when CR0.PE <- 0. I'm not sure if this is accomplished by actually changing the cs.flags register or just changing the interpretation; it might be something that is CPU-specific. In particular, the Transmeta CPUs had an explicit "CS is writable if you're in real mode" override, so even if you had loaded CS with an execute-only segment it'd be writable (but not readable!) on return to real mode. I'm not at all sure if that is how other CPUs behave. Signed-off-by: "H. Peter Anvin" Signed-off-by: Ingo Molnar --- arch/x86/kernel/acpi/sleep.c | 17 +++++++++++++---- 1 file changed, 13 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c index 36af01f029e..130711f1454 100644 --- a/arch/x86/kernel/acpi/sleep.c +++ b/arch/x86/kernel/acpi/sleep.c @@ -23,6 +23,15 @@ static unsigned long acpi_realmode; static char temp_stack[10240]; #endif +/* XXX: this macro should move to asm-x86/segment.h and be shared with the + boot code... */ +#define GDT_ENTRY(flags, base, limit) \ + (((u64)(base & 0xff000000) << 32) | \ + ((u64)flags << 40) | \ + ((u64)(limit & 0x00ff0000) << 32) | \ + ((u64)(base & 0x00ffffff) << 16) | \ + ((u64)(limit & 0x0000ffff))) + /** * acpi_save_state_mem - save kernel state * @@ -58,11 +67,11 @@ int acpi_save_state_mem(void) ((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; + header->wakeup_gdt[1] = + GDT_ENTRY(0x809b, acpi_wakeup_address, 0xfffff); /* GDT[2]: real-mode-like data segment */ - header->wakeup_gdt[2] = (0x0093ULL << 40) + - ((u64)acpi_wakeup_address << 16) + 0xffff; + header->wakeup_gdt[2] = + GDT_ENTRY(0x8093, acpi_wakeup_address, 0xfffff); #ifndef CONFIG_64BIT store_gdt((struct desc_ptr *)&header->pmode_gdt); -- cgit v1.2.3 From 065cb3dfe24978651caedfa54da585388ad15dde Mon Sep 17 00:00:00 2001 From: "H. Peter Anvin" Date: Mon, 14 Jul 2008 11:44:26 -0700 Subject: x86, suspend, acpi: correct and add comments about Big Real Mode Explain that we set up the descriptors for Big Real Mode, and why we do so. In particular, one system that is known to fail without it is the Lenovo X61. Signed-off-by: H. Peter Anvin --- arch/x86/kernel/acpi/sleep.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/acpi/sleep.c b/arch/x86/kernel/acpi/sleep.c index 130711f1454..41bb130c31d 100644 --- a/arch/x86/kernel/acpi/sleep.c +++ b/arch/x86/kernel/acpi/sleep.c @@ -60,16 +60,25 @@ int acpi_save_state_mem(void) 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)(acpi_wakeup_address + ((char *)&header->wakeup_gdt - (char *)acpi_realmode)) << 16); - /* GDT[1]: real-mode-like code segment */ + /* GDT[1]: big real mode-like code segment */ header->wakeup_gdt[1] = GDT_ENTRY(0x809b, acpi_wakeup_address, 0xfffff); - /* GDT[2]: real-mode-like data segment */ + /* GDT[2]: big real mode-like data segment */ header->wakeup_gdt[2] = GDT_ENTRY(0x8093, acpi_wakeup_address, 0xfffff); -- cgit v1.2.3 From aba3728ce2e8ce85e1e5f6b275131e9332256789 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 15 Jul 2008 14:48:48 +0200 Subject: x86: sanitize Kconfig Set default n for MEMTEST and MTRR_SANITIZER and fix the help texts. Signed-off-by: Thomas Gleixner --- arch/x86/Kconfig | 22 +++++++++------------- 1 file changed, 9 insertions(+), 13 deletions(-) diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 6958d6bcaf7..2642b4bf41b 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -447,7 +447,6 @@ config PARAVIRT_DEBUG config MEMTEST bool "Memtest" depends on X86_64 - default y help This option adds a kernel parameter 'memtest', which allows memtest to be set. @@ -455,7 +454,7 @@ config MEMTEST memtest=1, mean do 1 test pattern; ... memtest=4, mean do 4 test patterns. - If you are unsure how to answer this question, answer Y. + If you are unsure how to answer this question, answer N. config X86_SUMMIT_NUMA def_bool y @@ -1135,21 +1134,18 @@ config MTRR See for more information. config MTRR_SANITIZER - def_bool y + bool prompt "MTRR cleanup support" depends on MTRR help - Convert MTRR layout from continuous to discrete, so some X driver - could add WB entries. + Convert MTRR layout from continuous to discrete, so X drivers can + add writeback entries. - Say N here if you see bootup problems (boot crash, boot hang, - spontaneous reboots). + Can be disabled with disable_mtrr_cleanup on the kernel command line. + The largest mtrr entry size for a continous block can be set with + mtrr_chunk_size. - Could be disabled with disable_mtrr_cleanup. Also mtrr_chunk_size - could be used to send largest mtrr entry size for continuous block - to hold holes (aka. UC entries) - - If unsure, say Y. + If unsure, say N. config MTRR_SANITIZER_ENABLE_DEFAULT int "MTRR cleanup enable value (0-1)" @@ -1166,7 +1162,7 @@ config MTRR_SANITIZER_SPARE_REG_NR_DEFAULT depends on MTRR_SANITIZER help mtrr cleanup spare entries default, it can be changed via - mtrr_spare_reg_nr= + mtrr_spare_reg_nr=N on the kernel command line. config X86_PAT bool -- cgit v1.2.3 From d3af01f18bf18e9b2a95711894fc239daeab5e2e Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 15 Jul 2008 15:04:56 +0200 Subject: Documentation: document debugpat commandline option Signed-off-by: Thomas Gleixner --- Documentation/kernel-parameters.txt | 2 ++ 1 file changed, 2 insertions(+) diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index b3a5aad7e62..681d6152e00 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -571,6 +571,8 @@ and is between 256 and 4096 characters. It is defined in the file debug_objects [KNL] Enable object debugging + debugpat [X86] Enable PAT debugging + decnet.addr= [HW,NET] Format: [,] See also Documentation/networking/decnet.txt. -- cgit v1.2.3 From 3f1c38723eb467d34d704d0ee6e7b796ba4981ee Mon Sep 17 00:00:00 2001 From: Kevin Winchester Date: Mon, 14 Jul 2008 21:36:13 -0300 Subject: x86: Fix compile error with CONFIG_AS_CFI=n AS arch/x86/lib/csum-copy_64.o arch/x86/lib/csum-copy_64.S: Assembler messages: arch/x86/lib/csum-copy_64.S:48: Error: Macro `ignore' was already defined make[1]: *** [arch/x86/lib/csum-copy_64.o] Error 1 make: *** [arch/x86/lib] Error 2 It appears that csum-copy_64.S and dwarf2.h both define an ignore macro. I would expect one of them can be renamed quite easily, unless they are references elsewhere. Caused-by-commit: 392a0fc96bd059b38564f5f8fb58327460cb5a9d x86: merge dwarf2 headers Signed-off-by: Thomas Gleixner --- include/asm-x86/dwarf2.h | 30 +++++++++++++++--------------- 1 file changed, 15 insertions(+), 15 deletions(-) diff --git a/include/asm-x86/dwarf2.h b/include/asm-x86/dwarf2.h index 0bfe250894f..738bb9fb3e5 100644 --- a/include/asm-x86/dwarf2.h +++ b/include/asm-x86/dwarf2.h @@ -38,23 +38,23 @@ /* Due to the structure of pre-exisiting code, don't use assembler line comment character # to ignore the arguments. Instead, use a dummy macro. */ -.macro ignore a=0, b=0, c=0, d=0 +.macro cfi_ignore a=0, b=0, c=0, d=0 .endm -#define CFI_STARTPROC ignore -#define CFI_ENDPROC ignore -#define CFI_DEF_CFA ignore -#define CFI_DEF_CFA_REGISTER ignore -#define CFI_DEF_CFA_OFFSET ignore -#define CFI_ADJUST_CFA_OFFSET ignore -#define CFI_OFFSET ignore -#define CFI_REL_OFFSET ignore -#define CFI_REGISTER ignore -#define CFI_RESTORE ignore -#define CFI_REMEMBER_STATE ignore -#define CFI_RESTORE_STATE ignore -#define CFI_UNDEFINED ignore -#define CFI_SIGNAL_FRAME ignore +#define CFI_STARTPROC cfi_ignore +#define CFI_ENDPROC cfi_ignore +#define CFI_DEF_CFA cfi_ignore +#define CFI_DEF_CFA_REGISTER cfi_ignore +#define CFI_DEF_CFA_OFFSET cfi_ignore +#define CFI_ADJUST_CFA_OFFSET cfi_ignore +#define CFI_OFFSET cfi_ignore +#define CFI_REL_OFFSET cfi_ignore +#define CFI_REGISTER cfi_ignore +#define CFI_RESTORE cfi_ignore +#define CFI_REMEMBER_STATE cfi_ignore +#define CFI_RESTORE_STATE cfi_ignore +#define CFI_UNDEFINED cfi_ignore +#define CFI_SIGNAL_FRAME cfi_ignore #endif -- cgit v1.2.3