diff options
| author | Yinghai Lu <yinghai@kernel.org> | 2013-01-24 21:19:53 +0100 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2013-01-30 00:20:13 +0100 |
| commit | 6b9c75aca6cba4d99a6e8d8274b1788d4d4b50d9 (patch) | |
| tree | 14ced936eace998f2ad86ab10573ed198ff955d2 | |
| parent | x86, 64bit: Use a #PF handler to materialize early mappings on demand (diff) | |
| download | linux-6b9c75aca6cba4d99a6e8d8274b1788d4d4b50d9.tar.xz linux-6b9c75aca6cba4d99a6e8d8274b1788d4d4b50d9.zip | |
x86, 64bit: #PF handler set page to cover only 2M per #PF
We only map a single 2 MiB page per #PF, even though we should be able
to do this a full gigabyte at a time with no additional memory cost.
This is a workaround for a broken AMD reference BIOS (and its
derivatives in shipping system) which maps a large chunk of memory as
WB in the MTRR system but will #MC if the processor wanders off and
tries to prefetch that memory, which can happen any time the memory is
mapped in the TLB.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Link: http://lkml.kernel.org/r/1359058816-7615-13-git-send-email-yinghai@kernel.org
Cc: Alexander Duyck <alexander.h.duyck@intel.com>
[ hpa: rewrote the patch description ]
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
| -rw-r--r-- | arch/x86/kernel/head64.c | 42 |
1 files changed, 25 insertions, 17 deletions
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index f57df05ea126..816fc85c9bb3 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -53,15 +53,15 @@ int __init early_make_pgtable(unsigned long address) unsigned long physaddr = address - __PAGE_OFFSET; unsigned long i; pgdval_t pgd, *pgd_p; - pudval_t *pud_p; + pudval_t pud, *pud_p; pmdval_t pmd, *pmd_p; /* Invalid address or early pgt is done ? */ if (physaddr >= MAXMEM || read_cr3() != __pa(early_level4_pgt)) return -1; - i = (address >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1); - pgd_p = &early_level4_pgt[i].pgd; +again: + pgd_p = &early_level4_pgt[pgd_index(address)].pgd; pgd = *pgd_p; /* @@ -69,29 +69,37 @@ int __init early_make_pgtable(unsigned long address) * critical -- __PAGE_OFFSET would point us back into the dynamic * range and we might end up looping forever... */ - if (pgd && next_early_pgt < EARLY_DYNAMIC_PAGE_TABLES) { + if (pgd) pud_p = (pudval_t *)((pgd & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); - } else { - if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES-1) + else { + if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { reset_early_page_tables(); + goto again; + } pud_p = (pudval_t *)early_dynamic_pgts[next_early_pgt++]; for (i = 0; i < PTRS_PER_PUD; i++) pud_p[i] = 0; - *pgd_p = (pgdval_t)pud_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; } - i = (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1); - pud_p += i; - - pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; - pmd = (physaddr & PUD_MASK) + (__PAGE_KERNEL_LARGE & ~_PAGE_GLOBAL); - for (i = 0; i < PTRS_PER_PMD; i++) { - pmd_p[i] = pmd; - pmd += PMD_SIZE; - } + pud_p += pud_index(address); + pud = *pud_p; - *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; + if (pud) + pmd_p = (pmdval_t *)((pud & PTE_PFN_MASK) + __START_KERNEL_map - phys_base); + else { + if (next_early_pgt >= EARLY_DYNAMIC_PAGE_TABLES) { + reset_early_page_tables(); + goto again; + } + + pmd_p = (pmdval_t *)early_dynamic_pgts[next_early_pgt++]; + for (i = 0; i < PTRS_PER_PMD; i++) + pmd_p[i] = 0; + *pud_p = (pudval_t)pmd_p - __START_KERNEL_map + phys_base + _KERNPG_TABLE; + } + pmd = (physaddr & PMD_MASK) + (__PAGE_KERNEL_LARGE & ~_PAGE_GLOBAL); + pmd_p[pmd_index(address)] = pmd; return 0; } |