diff options
author | Magnus Damm <magnus@valinux.co.jp> | 2006-09-26 10:52:38 +0200 |
---|---|---|
committer | Andi Kleen <andi@basil.nowhere.org> | 2006-09-26 10:52:38 +0200 |
commit | 3566561bfadffcb5dbc85d576be80c0dbf2cccc9 (patch) | |
tree | eaafaf68156f9f2f1a2af8a7ffed95653fea8aa5 /arch/i386/kernel/machine_kexec.c | |
parent | 4bfaaef01a1badb9e8ffb0c0a37cd2379008d21f (diff) | |
download | kernel_samsung_espresso10-3566561bfadffcb5dbc85d576be80c0dbf2cccc9.zip kernel_samsung_espresso10-3566561bfadffcb5dbc85d576be80c0dbf2cccc9.tar.gz kernel_samsung_espresso10-3566561bfadffcb5dbc85d576be80c0dbf2cccc9.tar.bz2 |
[PATCH] i386: Avoid overwriting the current pgd (V4, i386)
kexec: Avoid overwriting the current pgd (V4, i386)
This patch upgrades the i386-specific kexec code to avoid overwriting the
current pgd. Overwriting the current pgd is bad when CONFIG_CRASH_DUMP is used
to start a secondary kernel that dumps the memory of the previous kernel.
The code introduces a new set of page tables. These tables are used to provide
an executable identity mapping without overwriting the current pgd.
Signed-off-by: Magnus Damm <magnus@valinux.co.jp>
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/i386/kernel/machine_kexec.c')
-rw-r--r-- | arch/i386/kernel/machine_kexec.c | 117 |
1 files changed, 27 insertions, 90 deletions
diff --git a/arch/i386/kernel/machine_kexec.c b/arch/i386/kernel/machine_kexec.c index 66c3dc9..91966ba 100644 --- a/arch/i386/kernel/machine_kexec.c +++ b/arch/i386/kernel/machine_kexec.c @@ -21,70 +21,13 @@ #include <asm/system.h> #define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE))) - -#define L0_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY) -#define L1_ATTR (_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED | _PAGE_DIRTY) -#define L2_ATTR (_PAGE_PRESENT) - -#define LEVEL0_SIZE (1UL << 12UL) - -#ifndef CONFIG_X86_PAE -#define LEVEL1_SIZE (1UL << 22UL) -static u32 pgtable_level1[1024] PAGE_ALIGNED; - -static void identity_map_page(unsigned long address) -{ - unsigned long level1_index, level2_index; - u32 *pgtable_level2; - - /* Find the current page table */ - pgtable_level2 = __va(read_cr3()); - - /* Find the indexes of the physical address to identity map */ - level1_index = (address % LEVEL1_SIZE)/LEVEL0_SIZE; - level2_index = address / LEVEL1_SIZE; - - /* Identity map the page table entry */ - pgtable_level1[level1_index] = address | L0_ATTR; - pgtable_level2[level2_index] = __pa(pgtable_level1) | L1_ATTR; - - /* Flush the tlb so the new mapping takes effect. - * Global tlb entries are not flushed but that is not an issue. - */ - load_cr3(pgtable_level2); -} - -#else -#define LEVEL1_SIZE (1UL << 21UL) -#define LEVEL2_SIZE (1UL << 30UL) -static u64 pgtable_level1[512] PAGE_ALIGNED; -static u64 pgtable_level2[512] PAGE_ALIGNED; - -static void identity_map_page(unsigned long address) -{ - unsigned long level1_index, level2_index, level3_index; - u64 *pgtable_level3; - - /* Find the current page table */ - pgtable_level3 = __va(read_cr3()); - - /* Find the indexes of the physical address to identity map */ - level1_index = (address % LEVEL1_SIZE)/LEVEL0_SIZE; - level2_index = (address % LEVEL2_SIZE)/LEVEL1_SIZE; - level3_index = address / LEVEL2_SIZE; - - /* Identity map the page table entry */ - pgtable_level1[level1_index] = address | L0_ATTR; - pgtable_level2[level2_index] = __pa(pgtable_level1) | L1_ATTR; - set_64bit(&pgtable_level3[level3_index], - __pa(pgtable_level2) | L2_ATTR); - - /* Flush the tlb so the new mapping takes effect. - * Global tlb entries are not flushed but that is not an issue. - */ - load_cr3(pgtable_level3); -} +static u32 kexec_pgd[1024] PAGE_ALIGNED; +#ifdef CONFIG_X86_PAE +static u32 kexec_pmd0[1024] PAGE_ALIGNED; +static u32 kexec_pmd1[1024] PAGE_ALIGNED; #endif +static u32 kexec_pte0[1024] PAGE_ALIGNED; +static u32 kexec_pte1[1024] PAGE_ALIGNED; static void set_idt(void *newidt, __u16 limit) { @@ -128,16 +71,6 @@ static void load_segments(void) #undef __STR } -typedef asmlinkage NORET_TYPE void (*relocate_new_kernel_t)( - unsigned long indirection_page, - unsigned long reboot_code_buffer, - unsigned long start_address, - unsigned int has_pae) ATTRIB_NORET; - -extern const unsigned char relocate_new_kernel[]; -extern void relocate_new_kernel_end(void); -extern const unsigned int relocate_new_kernel_size; - /* * A architecture hook called to validate the * proposed image and prepare the control pages @@ -170,25 +103,29 @@ void machine_kexec_cleanup(struct kimage *image) */ NORET_TYPE void machine_kexec(struct kimage *image) { - unsigned long page_list; - unsigned long reboot_code_buffer; - - relocate_new_kernel_t rnk; + unsigned long page_list[PAGES_NR]; + void *control_page; /* Interrupts aren't acceptable while we reboot */ local_irq_disable(); - /* Compute some offsets */ - reboot_code_buffer = page_to_pfn(image->control_code_page) - << PAGE_SHIFT; - page_list = image->head; - - /* Set up an identity mapping for the reboot_code_buffer */ - identity_map_page(reboot_code_buffer); - - /* copy it out */ - memcpy((void *)reboot_code_buffer, relocate_new_kernel, - relocate_new_kernel_size); + control_page = page_address(image->control_code_page); + 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(kexec_pgd); + page_list[VA_PGD] = (unsigned long)kexec_pgd; +#ifdef CONFIG_X86_PAE + page_list[PA_PMD_0] = __pa(kexec_pmd0); + page_list[VA_PMD_0] = (unsigned long)kexec_pmd0; + page_list[PA_PMD_1] = __pa(kexec_pmd1); + page_list[VA_PMD_1] = (unsigned long)kexec_pmd1; +#endif + page_list[PA_PTE_0] = __pa(kexec_pte0); + page_list[VA_PTE_0] = (unsigned long)kexec_pte0; + page_list[PA_PTE_1] = __pa(kexec_pte1); + page_list[VA_PTE_1] = (unsigned long)kexec_pte1; /* The segment registers are funny things, they have both a * visible and an invisible part. Whenever the visible part is @@ -207,8 +144,8 @@ NORET_TYPE void machine_kexec(struct kimage *image) set_idt(phys_to_virt(0),0); /* now call it */ - rnk = (relocate_new_kernel_t) reboot_code_buffer; - (*rnk)(page_list, reboot_code_buffer, image->start, cpu_has_pae); + relocate_kernel((unsigned long)image->head, (unsigned long)page_list, + image->start, cpu_has_pae); } /* crashkernel=size@addr specifies the location to reserve for |