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kexec/i386: setup kexec page table in C
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Impact: change the kexec bootstrap code implementation from assembly to C

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>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Huang Ying authored and Ingo Molnar committed Oct 31, 2008
1 parent 92be3d6 commit 9868ee6
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Showing 3 changed files with 49 additions and 141 deletions.
17 changes: 2 additions & 15 deletions arch/x86/include/asm/kexec.h
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Original file line number Diff line number Diff line change
Expand Up @@ -5,21 +5,8 @@
# 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
# define PA_SWAP_PAGE 8
# ifdef CONFIG_X86_PAE
# define PA_PMD_0 9
# define VA_PMD_0 10
# define PA_PMD_1 11
# define VA_PMD_1 12
# define PAGES_NR 13
# else
# define PAGES_NR 9
# endif
# define PA_SWAP_PAGE 3
# define PAGES_NR 4
#else
# define PA_CONTROL_PAGE 0
# define VA_CONTROL_PAGE 1
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59 changes: 47 additions & 12 deletions arch/x86/kernel/machine_kexec_32.c
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Original file line number Diff line number Diff line change
Expand Up @@ -99,6 +99,45 @@ static int machine_kexec_alloc_page_tables(struct kimage *image)
return 0;
}

static void machine_kexec_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 machine_kexec_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.pmd0;
#endif
machine_kexec_page_table_set_one(
image->arch.pgd, pmd, image->arch.pte0,
(unsigned long)control_page, __pa(control_page));
#ifdef CONFIG_X86_PAE
pmd = image->arch.pmd1;
#endif
machine_kexec_page_table_set_one(
image->arch.pgd, pmd, image->arch.pte1,
__pa(control_page), __pa(control_page));
}

/*
* A architecture hook called to validate the
* proposed image and prepare the control pages
Expand All @@ -112,12 +151,19 @@ static int machine_kexec_alloc_page_tables(struct kimage *image)
*
* - Make control page executable.
* - Allocate page tables
* - Setup page tables
*/
int machine_kexec_prepare(struct kimage *image)
{
int error;

if (nx_enabled)
set_pages_x(image->control_code_page, 1);
return machine_kexec_alloc_page_tables(image);
error = machine_kexec_alloc_page_tables(image);
if (error)
return error;
machine_kexec_prepare_page_tables(image);
return 0;
}

/*
Expand Down Expand Up @@ -176,17 +222,6 @@ void machine_kexec(struct kimage *image)
page_list[PA_CONTROL_PAGE] = __pa(control_page);
page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
page_list[PA_PGD] = __pa(image->arch.pgd);
page_list[VA_PGD] = (unsigned long)image->arch.pgd;
#ifdef CONFIG_X86_PAE
page_list[PA_PMD_0] = __pa(image->arch.pmd0);
page_list[VA_PMD_0] = (unsigned long)image->arch.pmd0;
page_list[PA_PMD_1] = __pa(image->arch.pmd1);
page_list[VA_PMD_1] = (unsigned long)image->arch.pmd1;
#endif
page_list[PA_PTE_0] = __pa(image->arch.pte0);
page_list[VA_PTE_0] = (unsigned long)image->arch.pte0;
page_list[PA_PTE_1] = __pa(image->arch.pte1);
page_list[VA_PTE_1] = (unsigned long)image->arch.pte1;

if (image->type == KEXEC_TYPE_DEFAULT)
page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
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114 changes: 0 additions & 114 deletions arch/x86/kernel/relocate_kernel_32.S
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Original file line number Diff line number Diff line change
Expand Up @@ -10,15 +10,12 @@
#include <asm/page.h>
#include <asm/kexec.h>
#include <asm/processor-flags.h>
#include <asm/pgtable.h>

/*
* Must be relocatable PIC code callable as a C function
*/

#define PTR(x) (x << 2)
#define PAGE_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY)
#define PAE_PGD_ATTR (_PAGE_PRESENT)

/* control_page + KEXEC_CONTROL_CODE_MAX_SIZE
* ~ control_page + PAGE_SIZE are used as data storage and stack for
Expand Down Expand Up @@ -59,117 +56,6 @@ relocate_kernel:
movl %cr4, %eax
movl %eax, CR4(%edi)

#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 20+4(%esp), %ebx /* page_list */
movl 20+8(%esp), %ebp /* list of pages */
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