From bbee3aec3472fc2ca10b6b1020aec84567ea25ce Mon Sep 17 00:00:00 2001 From: Alexander Duyck Date: Mon, 19 Nov 2012 10:31:37 -0800 Subject: [PATCH 1/2] x86: Fix warning about cast from pointer to integer of different size This patch fixes a warning reported by the kbuild test robot where we were casting a pointer to a physical address which represents an integer of a different size. Per the suggestion of Peter Anvin I am replacing it and one other spot where I made a similar cast with an unsigned long. Signed-off-by: Alexander Duyck Link: http://lkml.kernel.org/r/20121119182927.3655.7641.stgit@ahduyck-cp1.jf.intel.com Signed-off-by: H. Peter Anvin --- arch/x86/kernel/head32.c | 2 +- arch/x86/kernel/head64.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/head32.c b/arch/x86/kernel/head32.c index f15db0c40713..e17554832991 100644 --- a/arch/x86/kernel/head32.c +++ b/arch/x86/kernel/head32.c @@ -31,7 +31,7 @@ static void __init i386_default_early_setup(void) void __init i386_start_kernel(void) { memblock_reserve(__pa_symbol(_text), - (phys_addr_t)__bss_stop - (phys_addr_t)_text); + (unsigned long)__bss_stop - (unsigned long)_text); #ifdef CONFIG_BLK_DEV_INITRD /* Reserve INITRD */ diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c index 42f5df134341..7b215a50ec1e 100644 --- a/arch/x86/kernel/head64.c +++ b/arch/x86/kernel/head64.c @@ -98,7 +98,7 @@ void __init x86_64_start_reservations(char *real_mode_data) copy_bootdata(__va(real_mode_data)); memblock_reserve(__pa_symbol(_text), - (phys_addr_t)__bss_stop - (phys_addr_t)_text); + (unsigned long)__bss_stop - (unsigned long)_text); #ifdef CONFIG_BLK_DEV_INITRD /* Reserve INITRD */ From 5e4bf1a55da976a5ed60901bb8801f1024ef9774 Mon Sep 17 00:00:00 2001 From: Ingo Molnar Date: Tue, 20 Nov 2012 13:02:51 +0100 Subject: [PATCH 2/2] x86/mm: Don't flush the TLB on #WP pmd fixups If we have a write protection #PF and fix up the pmd then the hugetlb code [the only user of pmdp_set_access_flags], in its do_huge_pmd_wp_page() page fault resolution function calls pmdp_set_access_flags() to mark the pmd permissive again, and flushes the TLB. This TLB flush is unnecessary: a flush on #PF is guaranteed on most (all?) x86 CPUs, and even in the worst-case we'll generate a spurious fault. So remove it. Cc: Linus Torvalds Cc: Andrew Morton Cc: Peter Zijlstra Cc: Paul Turner Cc: Lee Schermerhorn Cc: Andrea Arcangeli Cc: Rik van Riel Cc: Johannes Weiner Cc: Christoph Lameter Cc: Mel Gorman Cc: Hugh Dickins Link: http://lkml.kernel.org/r/20121120120251.GA15742@gmail.com Signed-off-by: Ingo Molnar --- arch/x86/mm/pgtable.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index 8573b83a63d0..8a828d773e58 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -328,7 +328,12 @@ int pmdp_set_access_flags(struct vm_area_struct *vma, if (changed && dirty) { *pmdp = entry; pmd_update_defer(vma->vm_mm, address, pmdp); - flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE); + /* + * We had a write-protection fault here and changed the pmd + * to to more permissive. No need to flush the TLB for that, + * #PF is architecturally guaranteed to do that and in the + * worst-case we'll generate a spurious fault. + */ } return changed;