diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 5 | ||||
| -rw-r--r-- | arch/x86/Kconfig | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/setup.c | 28 |
3 files changed, 32 insertions, 3 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 2c85c0692b0..41ce93e71de 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2150,6 +2150,11 @@ and is between 256 and 4096 characters. It is defined in the file Reserves a hole at the top of the kernel virtual address space. + reservelow= [X86] + Format: nn[K] + Set the amount of memory to reserve for BIOS at + the bottom of the address space. + reset_devices [KNL] Force drivers to reset the underlying device during initialization. diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig index 683ae8f9bd0..d3590008c5d 100644 --- a/arch/x86/Kconfig +++ b/arch/x86/Kconfig @@ -1326,7 +1326,7 @@ config X86_BOOTPARAM_MEMORY_CORRUPTION_CHECK Set whether the default state of memory_corruption_check is on or off. -config X86_LOW_RESERVE +config X86_RESERVE_LOW int "Amount of low memory, in kilobytes, to reserve for the BIOS" default 64 range 4 640 diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index eb87f1c83f9..af277e369de 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -618,6 +618,8 @@ static __init void reserve_ibft_region(void) reserve_early_overlap_ok(addr, addr + size, "ibft"); } +static unsigned reserve_low = CONFIG_X86_RESERVE_LOW << 10; + static void __init trim_bios_range(void) { /* @@ -627,9 +629,9 @@ static void __init trim_bios_range(void) * * This typically reserves additional memory (64KiB by default) * since some BIOSes are known to corrupt low memory. See the - * Kconfig help text for X86_LOW_RESERVE. + * Kconfig help text for X86_RESERVE_LOW. */ - e820_update_range(0, ALIGN(CONFIG_X86_LOW_RESERVE << 10, PAGE_SIZE), + e820_update_range(0, ALIGN(reserve_low, PAGE_SIZE), E820_RAM, E820_RESERVED); /* @@ -641,6 +643,28 @@ static void __init trim_bios_range(void) sanitize_e820_map(e820.map, ARRAY_SIZE(e820.map), &e820.nr_map); } +static int __init parse_reservelow(char *p) +{ + unsigned long long size; + + if (!p) + return -EINVAL; + + size = memparse(p, &p); + + if (size < 4096) + size = 4096; + + if (size > 640*1024) + size = 640*1024; + + reserve_low = size; + + return 0; +} + +early_param("reservelow", parse_reservelow); + /* * Determine if we were loaded by an EFI loader. If so, then we have also been * passed the efi memmap, systab, etc., so we should use these data structures |