Messages in this thread Patch in this message | | | From | Andi Kleen <> | Subject | [PATCH] [225/275] x86: Cleanup highmap after brk is concluded | Date | Wed, 30 Mar 2011 14:07:50 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Yinghai Lu <yinghai@kernel.org>
commit e5f15b45ddf3afa2bbbb10c7ea34fb32b6de0a0e upstream.
Now cleanup_highmap actually is in two steps: one is early in head64.c and only clears above _end; a second one is in init_memory_mapping() and tries to clean from _brk_end to _end. It should check if those boundaries are PMD_SIZE aligned but currently does not. Also init_memory_mapping() is called several times for numa or memory hotplug, so we really should not handle initial kernel mappings there.
This patch moves cleanup_highmap() down after _brk_end is settled so we can do everything in one step. Also we honor max_pfn_mapped in the implementation of cleanup_highmap.
Signed-off-by: Yinghai Lu <yinghai@kernel.org> Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com> Signed-off-by: Andi Kleen <ak@linux.intel.com> LKML-Reference: <alpine.DEB.2.00.1103171739050.3382@kaball-desktop> Signed-off-by: H. Peter Anvin <hpa@zytor.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- arch/x86/kernel/head64.c | 3 --- arch/x86/kernel/setup.c | 5 +++++ arch/x86/mm/init.c | 19 ------------------- arch/x86/mm/init_64.c | 11 ++++++----- 4 files changed, 11 insertions(+), 27 deletions(-)
Index: linux-2.6.35.y/arch/x86/kernel/head64.c =================================================================== --- linux-2.6.35.y.orig/arch/x86/kernel/head64.c 2011-03-29 22:50:26.228587294 -0700 +++ linux-2.6.35.y/arch/x86/kernel/head64.c 2011-03-29 23:03:02.918225501 -0700 @@ -76,9 +76,6 @@ /* Make NULL pointers segfault */ zap_identity_mappings(); - /* Cleanup the over mapped high alias */ - cleanup_highmap(); - for (i = 0; i < NUM_EXCEPTION_VECTORS; i++) { #ifdef CONFIG_EARLY_PRINTK set_intr_gate(i, &early_idt_handlers[i]); Index: linux-2.6.35.y/arch/x86/kernel/setup.c =================================================================== --- linux-2.6.35.y.orig/arch/x86/kernel/setup.c 2011-03-29 22:50:26.228587294 -0700 +++ linux-2.6.35.y/arch/x86/kernel/setup.c 2011-03-29 23:03:02.918225501 -0700 @@ -296,6 +296,9 @@ static inline void init_gbpages(void) { } +static void __init cleanup_highmap(void) +{ +} #endif static void __init reserve_brk(void) @@ -926,6 +929,8 @@ reserve_brk(); + cleanup_highmap(); + /* * Find and reserve possible boot-time SMP configuration: */ Index: linux-2.6.35.y/arch/x86/mm/init.c =================================================================== --- linux-2.6.35.y.orig/arch/x86/mm/init.c 2011-03-29 22:50:26.228587294 -0700 +++ linux-2.6.35.y/arch/x86/mm/init.c 2011-03-29 23:03:02.920225449 -0700 @@ -277,25 +277,6 @@ load_cr3(swapper_pg_dir); #endif -#ifdef CONFIG_X86_64 - if (!after_bootmem && !start) { - pud_t *pud; - pmd_t *pmd; - - mmu_cr4_features = read_cr4(); - - /* - * _brk_end cannot change anymore, but it and _end may be - * located on different 2M pages. cleanup_highmap(), however, - * can only consider _end when it runs, so destroy any - * mappings beyond _brk_end here. - */ - pud = pud_offset(pgd_offset_k(_brk_end), _brk_end); - pmd = pmd_offset(pud, _brk_end - 1); - while (++pmd <= pmd_offset(pud, (unsigned long)_end - 1)) - pmd_clear(pmd); - } -#endif __flush_tlb_all(); if (!after_bootmem && e820_table_end > e820_table_start) Index: linux-2.6.35.y/arch/x86/mm/init_64.c =================================================================== --- linux-2.6.35.y.orig/arch/x86/mm/init_64.c 2011-03-29 22:50:26.228587294 -0700 +++ linux-2.6.35.y/arch/x86/mm/init_64.c 2011-03-29 23:03:02.921225423 -0700 @@ -50,6 +50,7 @@ #include <asm/numa.h> #include <asm/cacheflush.h> #include <asm/init.h> +#include <asm/setup.h> #include <linux/bootmem.h> static unsigned long dma_reserve __initdata; @@ -258,18 +259,18 @@ * to the compile time generated pmds. This results in invalid pmds up * to the point where we hit the physaddr 0 mapping. * - * We limit the mappings to the region from _text to _end. _end is - * rounded up to the 2MB boundary. This catches the invalid pmds as + * We limit the mappings to the region from _text to _brk_end. _brk_end + * is rounded up to the 2MB boundary. This catches the invalid pmds as * well, as they are located before _text: */ void __init cleanup_highmap(void) { unsigned long vaddr = __START_KERNEL_map; - unsigned long end = roundup((unsigned long)_end, PMD_SIZE) - 1; + unsigned long vaddr_end = __START_KERNEL_map + (max_pfn_mapped << PAGE_SHIFT); + unsigned long end = roundup((unsigned long)_brk_end, PMD_SIZE) - 1; pmd_t *pmd = level2_kernel_pgt; - pmd_t *last_pmd = pmd + PTRS_PER_PMD; - for (; pmd < last_pmd; pmd++, vaddr += PMD_SIZE) { + for (; vaddr + PMD_SIZE - 1 < vaddr_end; pmd++, vaddr += PMD_SIZE) { if (pmd_none(*pmd)) continue; if (vaddr < (unsigned long) _text || vaddr > end)
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