diff options
Diffstat (limited to 'arch/x86/kernel')
| -rw-r--r-- | arch/x86/kernel/ebda.c | 114 | ||||
| -rw-r--r-- | arch/x86/kernel/head32.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/head64.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/head_64.S | 3 | ||||
| -rw-r--r-- | arch/x86/kernel/platform-quirks.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/setup.c | 3 |
6 files changed, 79 insertions, 49 deletions
diff --git a/arch/x86/kernel/ebda.c b/arch/x86/kernel/ebda.c index afe65df..4312f8a 100644 --- a/arch/x86/kernel/ebda.c +++ b/arch/x86/kernel/ebda.c @@ -6,66 +6,92 @@ #include <asm/bios_ebda.h> /* + * This function reserves all conventional PC system BIOS related + * firmware memory areas (some of which are data, some of which + * are code), that must not be used by the kernel as available + * RAM. + * * The BIOS places the EBDA/XBDA at the top of conventional * memory, and usually decreases the reported amount of - * conventional memory (int 0x12) too. This also contains a - * workaround for Dell systems that neglect to reserve EBDA. - * The same workaround also avoids a problem with the AMD768MPX - * chipset: reserve a page before VGA to prevent PCI prefetch - * into it (errata #56). Usually the page is reserved anyways, - * unless you have no PS/2 mouse plugged in. + * conventional memory (int 0x12) too. + * + * This means that as a first approximation on most systems we can + * guess the reserved BIOS area by looking at the low BIOS RAM size + * value and assume that everything above that value (up to 1MB) is + * reserved. + * + * But life in firmware country is not that simple: + * + * - This code also contains a quirk for Dell systems that neglect + * to reserve the EBDA area in the 'RAM size' value ... + * + * - The same quirk also avoids a problem with the AMD768MPX + * chipset: reserve a page before VGA to prevent PCI prefetch + * into it (errata #56). (Usually the page is reserved anyways, + * unless you have no PS/2 mouse plugged in.) + * + * - Plus paravirt systems don't have a reliable value in the + * 'BIOS RAM size' pointer we can rely on, so we must quirk + * them too. + * + * Due to those various problems this function is deliberately + * very conservative and tries to err on the side of reserving + * too much, to not risk reserving too little. + * + * Losing a small amount of memory in the bottom megabyte is + * rarely a problem, as long as we have enough memory to install + * the SMP bootup trampoline which *must* be in this area. * - * This functions is deliberately very conservative. Losing - * memory in the bottom megabyte is rarely a problem, as long - * as we have enough memory to install the trampoline. Using - * memory that is in use by the BIOS or by some DMA device - * the BIOS didn't shut down *is* a big problem. + * Using memory that is in use by the BIOS or by some DMA device + * the BIOS didn't shut down *is* a big problem to the kernel, + * obviously. */ -#define BIOS_LOWMEM_KILOBYTES 0x413 -#define LOWMEM_CAP 0x9f000U /* Absolute maximum */ -#define INSANE_CUTOFF 0x20000U /* Less than this = insane */ +#define BIOS_RAM_SIZE_KB_PTR 0x413 -void __init reserve_ebda_region(void) +#define BIOS_START_MIN 0x20000U /* 128K, less than this is insane */ +#define BIOS_START_MAX 0x9f000U /* 640K, absolute maximum */ + +void __init reserve_bios_regions(void) { - unsigned int lowmem, ebda_addr; + unsigned int bios_start, ebda_start; /* - * To determine the position of the EBDA and the - * end of conventional memory, we need to look at - * the BIOS data area. In a paravirtual environment - * that area is absent. We'll just have to assume - * that the paravirt case can handle memory setup - * correctly, without our help. + * NOTE: In a paravirtual environment the BIOS reserved + * area is absent. We'll just have to assume that the + * paravirt case can handle memory setup correctly, + * without our help. */ - if (!x86_platform.legacy.ebda_search) + if (!x86_platform.legacy.reserve_bios_regions) return; - /* end of low (conventional) memory */ - lowmem = *(unsigned short *)__va(BIOS_LOWMEM_KILOBYTES); - lowmem <<= 10; - - /* start of EBDA area */ - ebda_addr = get_bios_ebda(); - /* - * Note: some old Dells seem to need 4k EBDA without - * reporting so, so just consider the memory above 0x9f000 - * to be off limits (bugzilla 2990). + * BIOS RAM size is encoded in kilobytes, convert it + * to bytes to get a first guess at where the BIOS + * firmware area starts: */ + bios_start = *(unsigned short *)__va(BIOS_RAM_SIZE_KB_PTR); + bios_start <<= 10; - /* If the EBDA address is below 128K, assume it is bogus */ - if (ebda_addr < INSANE_CUTOFF) - ebda_addr = LOWMEM_CAP; + /* + * If bios_start is less than 128K, assume it is bogus + * and bump it up to 640K. Similarly, if bios_start is above 640K, + * don't trust it. + */ + if (bios_start < BIOS_START_MIN || bios_start > BIOS_START_MAX) + bios_start = BIOS_START_MAX; - /* If lowmem is less than 128K, assume it is bogus */ - if (lowmem < INSANE_CUTOFF) - lowmem = LOWMEM_CAP; + /* Get the start address of the EBDA page: */ + ebda_start = get_bios_ebda(); - /* Use the lower of the lowmem and EBDA markers as the cutoff */ - lowmem = min(lowmem, ebda_addr); - lowmem = min(lowmem, LOWMEM_CAP); /* Absolute cap */ + /* + * If the EBDA start address is sane and is below the BIOS region, + * then also reserve everything from the EBDA start address up to + * the BIOS region. + */ + if (ebda_start >= BIOS_START_MIN && ebda_start < bios_start) + bios_start = ebda_start; - /* reserve all memory between lowmem and the 1MB mark */ - memblock_reserve(lowmem, 0x100000 - lowmem); + /* Reserve all memory between bios_start and the 1MB mark: */ + memblock_reserve(bios_start, 0x100000 - bios_start); } diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index d784bb5..2dda0bc 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -26,7 +26,7 @@ static void __init i386_default_early_setup(void) x86_init.resources.reserve_resources = i386_reserve_resources; x86_init.mpparse.setup_ioapic_ids = setup_ioapic_ids_from_mpc; - reserve_ebda_region(); + reserve_bios_regions(); } asmlinkage __visible void __init i386_start_kernel(void) diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index b72fb0b..99d48e7 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -183,7 +183,7 @@ void __init x86_64_start_reservations(char *real_mode_data) copy_bootdata(__va(real_mode_data)); x86_early_init_platform_quirks(); - reserve_ebda_region(); + reserve_bios_regions(); switch (boot_params.hdr.hardware_subarch) { case X86_SUBARCH_INTEL_MID: diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index 5df831e..9f8efc9 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -38,7 +38,7 @@ #define pud_index(x) (((x) >> PUD_SHIFT) & (PTRS_PER_PUD-1)) -L4_PAGE_OFFSET = pgd_index(__PAGE_OFFSET) +L4_PAGE_OFFSET = pgd_index(__PAGE_OFFSET_BASE) L4_START_KERNEL = pgd_index(__START_KERNEL_map) L3_START_KERNEL = pud_index(__START_KERNEL_map) @@ -299,6 +299,7 @@ ENTRY(secondary_startup_64) pushq $__KERNEL_CS # set correct cs pushq %rax # target address in negative space lretq +ENDPROC(secondary_startup_64) #include "verify_cpu.S" diff --git a/arch/x86/kernel/platform-quirks.c b/arch/x86/kernel/platform-quirks.c index b2f8a33..24a5030 100644 --- a/arch/x86/kernel/platform-quirks.c +++ b/arch/x86/kernel/platform-quirks.c @@ -7,12 +7,12 @@ void __init x86_early_init_platform_quirks(void) { x86_platform.legacy.rtc = 1; - x86_platform.legacy.ebda_search = 0; + x86_platform.legacy.reserve_bios_regions = 0; x86_platform.legacy.devices.pnpbios = 1; switch (boot_params.hdr.hardware_subarch) { case X86_SUBARCH_PC: - x86_platform.legacy.ebda_search = 1; + x86_platform.legacy.reserve_bios_regions = 1; break; case X86_SUBARCH_XEN: case X86_SUBARCH_LGUEST: diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c index c4e7b39..a261658 100644 --- a/arch/x86/kernel/setup.c +++ b/arch/x86/kernel/setup.c @@ -113,6 +113,7 @@ #include <asm/prom.h> #include <asm/microcode.h> #include <asm/mmu_context.h> +#include <asm/kaslr.h> /* * max_low_pfn_mapped: highest direct mapped pfn under 4GB @@ -942,6 +943,8 @@ void __init setup_arch(char **cmdline_p) x86_init.oem.arch_setup(); + kernel_randomize_memory(); + iomem_resource.end = (1ULL << boot_cpu_data.x86_phys_bits) - 1; setup_memory_map(); parse_setup_data(); |