kexec/i386: allocate page table pages dynamically
Impact: save .text size when kexec is built in but not loaded This patch adds an architecture specific struct kimage_arch into struct kimage. The pointers to page table pages used by kexec are added to struct kimage_arch. The page tables pages are dynamically allocated in machine_kexec_prepare instead of statically from BSS segment. This will save up to 20k memory when kexec image is not loaded. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: Ingo Molnar <mingo@elte.hu>
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31498a0149
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@ -170,6 +170,20 @@ relocate_kernel(unsigned long indirection_page,
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unsigned long start_address) ATTRIB_NORET;
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#endif
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#ifdef CONFIG_X86_32
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#define ARCH_HAS_KIMAGE_ARCH
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struct kimage_arch {
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pgd_t *pgd;
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#ifdef CONFIG_X86_PAE
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pmd_t *pmd0;
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pmd_t *pmd1;
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#endif
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pte_t *pte0;
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pte_t *pte1;
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};
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#endif
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_X86_KEXEC_H */
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@ -13,6 +13,7 @@
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#include <linux/numa.h>
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#include <linux/ftrace.h>
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#include <linux/suspend.h>
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#include <linux/gfp.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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@ -25,15 +26,6 @@
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#include <asm/system.h>
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#include <asm/cacheflush.h>
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#define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
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static u32 kexec_pgd[1024] PAGE_ALIGNED;
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#ifdef CONFIG_X86_PAE
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static u32 kexec_pmd0[1024] PAGE_ALIGNED;
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static u32 kexec_pmd1[1024] PAGE_ALIGNED;
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#endif
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static u32 kexec_pte0[1024] PAGE_ALIGNED;
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static u32 kexec_pte1[1024] PAGE_ALIGNED;
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static void set_idt(void *newidt, __u16 limit)
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{
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struct desc_ptr curidt;
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@ -76,6 +68,37 @@ static void load_segments(void)
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#undef __STR
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}
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static void machine_kexec_free_page_tables(struct kimage *image)
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{
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free_page((unsigned long)image->arch.pgd);
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#ifdef CONFIG_X86_PAE
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free_page((unsigned long)image->arch.pmd0);
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free_page((unsigned long)image->arch.pmd1);
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#endif
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free_page((unsigned long)image->arch.pte0);
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free_page((unsigned long)image->arch.pte1);
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}
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static int machine_kexec_alloc_page_tables(struct kimage *image)
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{
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image->arch.pgd = (pgd_t *)get_zeroed_page(GFP_KERNEL);
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#ifdef CONFIG_X86_PAE
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image->arch.pmd0 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
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image->arch.pmd1 = (pmd_t *)get_zeroed_page(GFP_KERNEL);
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#endif
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image->arch.pte0 = (pte_t *)get_zeroed_page(GFP_KERNEL);
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image->arch.pte1 = (pte_t *)get_zeroed_page(GFP_KERNEL);
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if (!image->arch.pgd ||
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#ifdef CONFIG_X86_PAE
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!image->arch.pmd0 || !image->arch.pmd1 ||
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#endif
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!image->arch.pte0 || !image->arch.pte1) {
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machine_kexec_free_page_tables(image);
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return -ENOMEM;
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}
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return 0;
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}
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/*
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* A architecture hook called to validate the
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* proposed image and prepare the control pages
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@ -87,13 +110,14 @@ static void load_segments(void)
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* reboot code buffer to allow us to avoid allocations
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* later.
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*
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* Make control page executable.
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* - Make control page executable.
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* - Allocate page tables
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*/
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int machine_kexec_prepare(struct kimage *image)
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{
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if (nx_enabled)
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set_pages_x(image->control_code_page, 1);
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return 0;
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return machine_kexec_alloc_page_tables(image);
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}
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/*
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@ -104,6 +128,7 @@ void machine_kexec_cleanup(struct kimage *image)
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{
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if (nx_enabled)
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set_pages_nx(image->control_code_page, 1);
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machine_kexec_free_page_tables(image);
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}
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/*
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@ -150,18 +175,18 @@ void machine_kexec(struct kimage *image)
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relocate_kernel_ptr = control_page;
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page_list[PA_CONTROL_PAGE] = __pa(control_page);
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page_list[VA_CONTROL_PAGE] = (unsigned long)control_page;
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page_list[PA_PGD] = __pa(kexec_pgd);
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page_list[VA_PGD] = (unsigned long)kexec_pgd;
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page_list[PA_PGD] = __pa(image->arch.pgd);
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page_list[VA_PGD] = (unsigned long)image->arch.pgd;
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#ifdef CONFIG_X86_PAE
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page_list[PA_PMD_0] = __pa(kexec_pmd0);
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page_list[VA_PMD_0] = (unsigned long)kexec_pmd0;
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page_list[PA_PMD_1] = __pa(kexec_pmd1);
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page_list[VA_PMD_1] = (unsigned long)kexec_pmd1;
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page_list[PA_PMD_0] = __pa(image->arch.pmd0);
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page_list[VA_PMD_0] = (unsigned long)image->arch.pmd0;
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page_list[PA_PMD_1] = __pa(image->arch.pmd1);
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page_list[VA_PMD_1] = (unsigned long)image->arch.pmd1;
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#endif
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page_list[PA_PTE_0] = __pa(kexec_pte0);
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page_list[VA_PTE_0] = (unsigned long)kexec_pte0;
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page_list[PA_PTE_1] = __pa(kexec_pte1);
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page_list[VA_PTE_1] = (unsigned long)kexec_pte1;
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page_list[PA_PTE_0] = __pa(image->arch.pte0);
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page_list[VA_PTE_0] = (unsigned long)image->arch.pte0;
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page_list[PA_PTE_1] = __pa(image->arch.pte1);
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page_list[VA_PTE_1] = (unsigned long)image->arch.pte1;
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if (image->type == KEXEC_TYPE_DEFAULT)
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page_list[PA_SWAP_PAGE] = (page_to_pfn(image->swap_page)
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@ -100,6 +100,10 @@ struct kimage {
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#define KEXEC_TYPE_DEFAULT 0
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#define KEXEC_TYPE_CRASH 1
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unsigned int preserve_context : 1;
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#ifdef ARCH_HAS_KIMAGE_ARCH
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struct kimage_arch arch;
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#endif
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};
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