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Subject[PATCH -mm 2/2] kexec/i386: kexec page table code clean up - page table setup in C
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Date
This patch transforms the kexec page tables setup code from assembler
code to C code in machine_kexec_prepare. This improves readability and
reduces code line number.

Signed-off-by: Huang Ying <ying.huang@intel.com>

---
arch/x86/kernel/machine_kexec_32.c | 50 +++++++++++----
arch/x86/kernel/relocate_kernel_32.S | 114 -----------------------------------
include/asm-x86/kexec_32.h | 18 -----
3 files changed, 40 insertions(+), 142 deletions(-)

--- a/arch/x86/kernel/machine_kexec_32.c
+++ b/arch/x86/kernel/machine_kexec_32.c
@@ -86,6 +86,42 @@ static void free_page_tables(struct kima
free_page((unsigned long)image->arch_kimage.pte1);
}

+static void page_table_set_one(pgd_t *pgd, pmd_t *pmd, pte_t *pte,
+ unsigned long vaddr, unsigned long paddr)
+{
+ pud_t *pud;
+
+ pgd += pgd_index(vaddr);
+#ifdef CONFIG_X86_PAE
+ if (!(pgd_val(*pgd) & _PAGE_PRESENT))
+ set_pgd(pgd, __pgd(__pa(pmd) | _PAGE_PRESENT));
+#endif
+ pud = pud_offset(pgd, vaddr);
+ pmd = pmd_offset(pud, vaddr);
+ if (!(pmd_val(*pmd) & _PAGE_PRESENT))
+ set_pmd(pmd, __pmd(__pa(pte) | _PAGE_TABLE));
+ pte = pte_offset_kernel(pmd, vaddr);
+ set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
+}
+
+static void prepare_page_tables(struct kimage *image)
+{
+ void *control_page;
+ pmd_t *pmd = 0;
+
+ control_page = page_address(image->control_code_page);
+#ifdef CONFIG_X86_PAE
+ pmd = image->arch_kimage.pmd0;
+#endif
+ page_table_set_one(image->arch_kimage.pgd, pmd, image->arch_kimage.pte0,
+ (unsigned long)relocate_kernel, __pa(control_page));
+#ifdef CONFIG_X86_PAE
+ pmd = image->arch_kimage.pmd1;
+#endif
+ page_table_set_one(image->arch_kimage.pgd, pmd, image->arch_kimage.pte1,
+ __pa(control_page), __pa(control_page));
+}
+
/*
* A architecture hook called to validate the
* proposed image and prepare the control pages
@@ -98,6 +134,7 @@ static void free_page_tables(struct kima
* later.
*
* - Allocate page tables
+ * - Setup page tables
*/
int machine_kexec_prepare(struct kimage *image)
{
@@ -112,6 +149,7 @@ int machine_kexec_prepare(struct kimage
free_page_tables(image);
return -ENOMEM;
}
+ prepare_page_tables(image);
return 0;
}

@@ -140,19 +178,7 @@ NORET_TYPE void machine_kexec(struct kim
memcpy(control_page, relocate_kernel, PAGE_SIZE);

page_list[PA_CONTROL_PAGE] = __pa(control_page);
- page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel;
page_list[PA_PGD] = __pa(image->arch_kimage.pgd);
- page_list[VA_PGD] = (unsigned long)image->arch_kimage.pgd;
-#ifdef CONFIG_X86_PAE
- page_list[PA_PMD_0] = __pa(image->arch_kimage.pmd0);
- page_list[VA_PMD_0] = (unsigned long)image->arch_kimage.pmd0;
- page_list[PA_PMD_1] = __pa(image->arch_kimage.pmd1);
- page_list[VA_PMD_1] = (unsigned long)image->arch_kimage.pmd1;
-#endif
- page_list[PA_PTE_0] = __pa(image->arch_kimage.pte0);
- page_list[VA_PTE_0] = (unsigned long)image->arch_kimage.pte0;
- page_list[PA_PTE_1] = __pa(image->arch_kimage.pte1);
- page_list[VA_PTE_1] = (unsigned long)image->arch_kimage.pte1;

/* The segment registers are funny things, they have both a
* visible and an invisible part. Whenever the visible part is
--- a/arch/x86/kernel/relocate_kernel_32.S
+++ b/arch/x86/kernel/relocate_kernel_32.S
@@ -16,126 +16,12 @@

#define PTR(x) (x << 2)
#define PAGE_ALIGNED (1 << PAGE_SHIFT)
-#define PAGE_ATTR 0x63 /* _PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY */
-#define PAE_PGD_ATTR 0x01 /* _PAGE_PRESENT */

.text
.align PAGE_ALIGNED
.globl relocate_kernel
relocate_kernel:
movl 8(%esp), %ebp /* list of pages */
-
-#ifdef CONFIG_X86_PAE
- /* map the control page at its virtual address */
-
- movl PTR(VA_PGD)(%ebp), %edi
- movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
- andl $0xc0000000, %eax
- shrl $27, %eax
- addl %edi, %eax
-
- movl PTR(PA_PMD_0)(%ebp), %edx
- orl $PAE_PGD_ATTR, %edx
- movl %edx, (%eax)
-
- movl PTR(VA_PMD_0)(%ebp), %edi
- movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
- andl $0x3fe00000, %eax
- shrl $18, %eax
- addl %edi, %eax
-
- movl PTR(PA_PTE_0)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-
- movl PTR(VA_PTE_0)(%ebp), %edi
- movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
- andl $0x001ff000, %eax
- shrl $9, %eax
- addl %edi, %eax
-
- movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-
- /* identity map the control page at its physical address */
-
- movl PTR(VA_PGD)(%ebp), %edi
- movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
- andl $0xc0000000, %eax
- shrl $27, %eax
- addl %edi, %eax
-
- movl PTR(PA_PMD_1)(%ebp), %edx
- orl $PAE_PGD_ATTR, %edx
- movl %edx, (%eax)
-
- movl PTR(VA_PMD_1)(%ebp), %edi
- movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
- andl $0x3fe00000, %eax
- shrl $18, %eax
- addl %edi, %eax
-
- movl PTR(PA_PTE_1)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-
- movl PTR(VA_PTE_1)(%ebp), %edi
- movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
- andl $0x001ff000, %eax
- shrl $9, %eax
- addl %edi, %eax
-
- movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-#else
- /* map the control page at its virtual address */
-
- movl PTR(VA_PGD)(%ebp), %edi
- movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
- andl $0xffc00000, %eax
- shrl $20, %eax
- addl %edi, %eax
-
- movl PTR(PA_PTE_0)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-
- movl PTR(VA_PTE_0)(%ebp), %edi
- movl PTR(VA_CONTROL_PAGE)(%ebp), %eax
- andl $0x003ff000, %eax
- shrl $10, %eax
- addl %edi, %eax
-
- movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-
- /* identity map the control page at its physical address */
-
- movl PTR(VA_PGD)(%ebp), %edi
- movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
- andl $0xffc00000, %eax
- shrl $20, %eax
- addl %edi, %eax
-
- movl PTR(PA_PTE_1)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-
- movl PTR(VA_PTE_1)(%ebp), %edi
- movl PTR(PA_CONTROL_PAGE)(%ebp), %eax
- andl $0x003ff000, %eax
- shrl $10, %eax
- addl %edi, %eax
-
- movl PTR(PA_CONTROL_PAGE)(%ebp), %edx
- orl $PAGE_ATTR, %edx
- movl %edx, (%eax)
-#endif
-
-relocate_new_kernel:
/* read the arguments and say goodbye to the stack */
movl 4(%esp), %ebx /* page_list */
movl 8(%esp), %ebp /* list of pages */
--- a/include/asm-x86/kexec_32.h
+++ b/include/asm-x86/kexec_32.h
@@ -2,22 +2,8 @@
#define _I386_KEXEC_H

#define PA_CONTROL_PAGE 0
-#define VA_CONTROL_PAGE 1
-#define PA_PGD 2
-#define VA_PGD 3
-#define PA_PTE_0 4
-#define VA_PTE_0 5
-#define PA_PTE_1 6
-#define VA_PTE_1 7
-#ifdef CONFIG_X86_PAE
-#define PA_PMD_0 8
-#define VA_PMD_0 9
-#define PA_PMD_1 10
-#define VA_PMD_1 11
-#define PAGES_NR 12
-#else
-#define PAGES_NR 8
-#endif
+#define PA_PGD 1
+#define PAGES_NR 2

#ifndef __ASSEMBLY__



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