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authorHuang Ying <ying.huang@intel.com>2009-03-10 10:57:04 +0800
committerH. Peter Anvin <hpa@zytor.com>2009-03-10 18:13:25 -0700
commit5359454701ce51a4626b1ef6eb7b16ec35bd458d (patch)
tree44f8d60b3cb1d06ec215387eb7e35fdbb64e70c8 /arch
parentfef3a7a17418814733ebde0b40d8e32747677c8f (diff)
x86, kexec: x86_64: add identity map for pages at image->start
Impact: Fix corner case that cannot yet occur image->start may be outside of 0 ~ max_pfn, for example when jumping back to original kernel from kexeced kenrel. This patch add identity map for pages at image->start. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch')
-rw-r--r--arch/x86/kernel/machine_kexec_64.c42
1 files changed, 42 insertions, 0 deletions
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index f8c796fffa0..7cc5d3d0148 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -18,6 +18,41 @@
#include <asm/tlbflush.h>
#include <asm/mmu_context.h>
+static int init_one_level2_page(struct kimage *image, pgd_t *pgd,
+ unsigned long addr)
+{
+ pud_t *pud;
+ pmd_t *pmd;
+ struct page *page;
+ int result = -ENOMEM;
+
+ addr &= PMD_MASK;
+ pgd += pgd_index(addr);
+ if (!pgd_present(*pgd)) {
+ page = kimage_alloc_control_pages(image, 0);
+ if (!page)
+ goto out;
+ pud = (pud_t *)page_address(page);
+ memset(pud, 0, PAGE_SIZE);
+ set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
+ }
+ pud = pud_offset(pgd, addr);
+ if (!pud_present(*pud)) {
+ page = kimage_alloc_control_pages(image, 0);
+ if (!page)
+ goto out;
+ pmd = (pmd_t *)page_address(page);
+ memset(pmd, 0, PAGE_SIZE);
+ set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
+ }
+ pmd = pmd_offset(pud, addr);
+ if (!pmd_present(*pmd))
+ set_pmd(pmd, __pmd(addr | __PAGE_KERNEL_LARGE_EXEC));
+ result = 0;
+out:
+ return result;
+}
+
static void init_level2_page(pmd_t *level2p, unsigned long addr)
{
unsigned long end_addr;
@@ -155,6 +190,13 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
if (result)
return result;
+ /*
+ * image->start may be outside 0 ~ max_pfn, for example when
+ * jump back to original kernel from kexeced kernel
+ */
+ result = init_one_level2_page(image, level4p, image->start);
+ if (result)
+ return result;
return init_transition_pgtable(image, level4p);
}