Merge branch 'x86-bios-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-bios-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: x86, bios: Make the x86 early memory reservation a kernel option x86, bios: By default, reserve the low 64K for all BIOSes
This commit is contained in:
Linus Torvalds
commit
781c5a67f1
@ -2153,6 +2153,11 @@ and is between 256 and 4096 characters. It is defined in the file
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Reserves a hole at the top of the kernel virtual
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address space.
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reservelow= [X86]
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Format: nn[K]
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Set the amount of memory to reserve for BIOS at
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the bottom of the address space.
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reset_devices [KNL] Force drivers to reset the underlying device
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during initialization.
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@ -1341,25 +1341,34 @@ config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK
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Set whether the default state of memory_corruption_check is
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on or off.
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config X86_RESERVE_LOW_64K
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bool "Reserve low 64K of RAM on AMI/Phoenix BIOSen"
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default y
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config X86_RESERVE_LOW
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int "Amount of low memory, in kilobytes, to reserve for the BIOS"
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default 64
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range 4 640
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---help---
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Reserve the first 64K of physical RAM on BIOSes that are known
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to potentially corrupt that memory range. A numbers of BIOSes are
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known to utilize this area during suspend/resume, so it must not
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be used by the kernel.
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Specify the amount of low memory to reserve for the BIOS.
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Set this to N if you are absolutely sure that you trust the BIOS
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to get all its memory reservations and usages right.
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The first page contains BIOS data structures that the kernel
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must not use, so that page must always be reserved.
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If you have doubts about the BIOS (e.g. suspend/resume does not
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work or there's kernel crashes after certain hardware hotplug
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events) and it's not AMI or Phoenix, then you might want to enable
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X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check typical
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corruption patterns.
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By default we reserve the first 64K of physical RAM, as a
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number of BIOSes are known to corrupt that memory range
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during events such as suspend/resume or monitor cable
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insertion, so it must not be used by the kernel.
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Say Y if unsure.
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You can set this to 4 if you are absolutely sure that you
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trust the BIOS to get all its memory reservations and usages
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right. If you know your BIOS have problems beyond the
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default 64K area, you can set this to 640 to avoid using the
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entire low memory range.
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If you have doubts about the BIOS (e.g. suspend/resume does
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not work or there's kernel crashes after certain hardware
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hotplug events) then you might want to enable
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X86_CHECK_BIOS_CORRUPTION=y to allow the kernel to check
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typical corruption patterns.
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Leave this to the default value of 64 if you are unsure.
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config MATH_EMULATION
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bool
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@ -619,79 +619,7 @@ static __init void reserve_ibft_region(void)
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reserve_early_overlap_ok(addr, addr + size, "ibft");
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}
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#ifdef CONFIG_X86_RESERVE_LOW_64K
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static int __init dmi_low_memory_corruption(const struct dmi_system_id *d)
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{
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printk(KERN_NOTICE
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"%s detected: BIOS may corrupt low RAM, working around it.\n",
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d->ident);
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e820_update_range(0, 0x10000, E820_RAM, E820_RESERVED);
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sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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return 0;
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}
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#endif
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/* List of systems that have known low memory corruption BIOS problems */
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static struct dmi_system_id __initdata bad_bios_dmi_table[] = {
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#ifdef CONFIG_X86_RESERVE_LOW_64K
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{
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.callback = dmi_low_memory_corruption,
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.ident = "AMI BIOS",
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.matches = {
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DMI_MATCH(DMI_BIOS_VENDOR, "American Megatrends Inc."),
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},
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},
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{
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.callback = dmi_low_memory_corruption,
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.ident = "Phoenix BIOS",
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.matches = {
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DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix Technologies"),
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},
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},
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{
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.callback = dmi_low_memory_corruption,
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.ident = "Phoenix/MSC BIOS",
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.matches = {
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DMI_MATCH(DMI_BIOS_VENDOR, "Phoenix/MSC"),
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},
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},
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/*
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* AMI BIOS with low memory corruption was found on Intel DG45ID and
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* DG45FC boards.
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* It has a different DMI_BIOS_VENDOR = "Intel Corp.", for now we will
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* match only DMI_BOARD_NAME and see if there is more bad products
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* with this vendor.
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*/
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{
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.callback = dmi_low_memory_corruption,
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.ident = "AMI BIOS",
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.matches = {
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DMI_MATCH(DMI_BOARD_NAME, "DG45ID"),
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},
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},
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{
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.callback = dmi_low_memory_corruption,
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.ident = "AMI BIOS",
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.matches = {
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DMI_MATCH(DMI_BOARD_NAME, "DG45FC"),
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},
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},
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/*
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* The Dell Inspiron Mini 1012 has DMI_BIOS_VENDOR = "Dell Inc.", so
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* match on the product name.
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*/
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{
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.callback = dmi_low_memory_corruption,
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.ident = "Phoenix BIOS",
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.matches = {
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DMI_MATCH(DMI_PRODUCT_NAME, "Inspiron 1012"),
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},
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},
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#endif
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{}
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};
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static unsigned reserve_low = CONFIG_X86_RESERVE_LOW << 10;
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static void __init trim_bios_range(void)
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{
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@ -699,8 +627,14 @@ static void __init trim_bios_range(void)
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* A special case is the first 4Kb of memory;
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* This is a BIOS owned area, not kernel ram, but generally
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* not listed as such in the E820 table.
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*
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* This typically reserves additional memory (64KiB by default)
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* since some BIOSes are known to corrupt low memory. See the
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* Kconfig help text for X86_RESERVE_LOW.
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*/
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e820_update_range(0, PAGE_SIZE, E820_RAM, E820_RESERVED);
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e820_update_range(0, ALIGN(reserve_low, PAGE_SIZE),
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E820_RAM, E820_RESERVED);
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/*
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* special case: Some BIOSen report the PC BIOS
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* area (640->1Mb) as ram even though it is not.
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@ -710,6 +644,28 @@ static void __init trim_bios_range(void)
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sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map);
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}
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static int __init parse_reservelow(char *p)
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{
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unsigned long long size;
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if (!p)
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return -EINVAL;
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size = memparse(p, &p);
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if (size < 4096)
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size = 4096;
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if (size > 640*1024)
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size = 640*1024;
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reserve_low = size;
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return 0;
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}
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early_param("reservelow", parse_reservelow);
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/*
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* Determine if we were loaded by an EFI loader. If so, then we have also been
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* passed the efi memmap, systab, etc., so we should use these data structures
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@ -865,8 +821,6 @@ void __init setup_arch(char **cmdline_p)
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dmi_scan_machine();
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dmi_check_system(bad_bios_dmi_table);
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/*
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* VMware detection requires dmi to be available, so this
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* needs to be done after dmi_scan_machine, for the BP.
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