From: zhong jiang <zhongjiang@xxxxxxxxxx>
when image is loaded into kernel, we need set up page table for it. and
all valid pfn also set up new mapping. it will tend to establish a pmd
page table in the form of a large page if pud_present is true. relocate_kernel
points to code segment can locate in the pmd huge entry in init_transtion_pgtable.
therefore, we need to take the situation into account.
Signed-off-by: zhong jiang <zhongjiang@xxxxxxxxxx>
---
arch/x86/kernel/machine_kexec_64.c | 20 ++++++++++++++++++--
1 file changed, 18 insertions(+), 2 deletions(-)
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index 5a294e4..c33e344 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -14,6 +14,7 @@
#include <linux/gfp.h>
#include <linux/reboot.h>
#include <linux/numa.h>
+#include <linux/hugetlb.h>
#include <linux/ftrace.h>
#include <linux/io.h>
#include <linux/suspend.h>
@@ -34,6 +35,17 @@ static struct kexec_file_ops *kexec_file_loaders[] = {
};
#endif
+static void split_pmd(pmd_t *pmd, pte_t *pte)
+{
+ unsigned long pfn = pmd_pfn(*pmd);
+ int i = 0;
+
+ do {
+ set_pte(pte, pfn_pte(pfn, PAGE_KERNEL_EXEC));
+ pfn++;
+ } while (pte++, i++, i < PTRS_PER_PTE);
+}
+
static void free_transition_pgtable(struct kimage *image)
{
free_page((unsigned long)image->arch.pud);
@@ -68,15 +80,19 @@ static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
}
pmd = pmd_offset(pud, vaddr);
- if (!pmd_present(*pmd)) {
+ if (!pmd_present(*pmd) || pmd_huge(*pmd)) {
pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
if (!pte)
goto err;
image->arch.pte = pte;
- set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
+ if (pmd_huge(*pmd))
+ split_pmd(pmd, pte);
+ else
+ set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
}
pte = pte_offset_kernel(pmd, vaddr);
set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
+
return 0;
err:
free_transition_pgtable(image);
--
1.8.3.1
--
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