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authorHuang Ying <ying.huang@intel.com>2009-02-03 01:22:48 -0500
committerH. Peter Anvin <hpa@zytor.com>2009-02-03 21:29:18 -0500
commitf5deb79679af6eb41b61112fadcda28b2a4cfb0d (patch)
tree5de5beef9b17d72e99a9691f8bbd4459c9228e45 /arch/x86/kernel/machine_kexec_64.c
parentc415b3dce30dfb41234e118662e8720f47343a4f (diff)
x86: kexec: Use one page table in x86_64 machine_kexec
Impact: reduce kernel BSS size by 7 pages, improve code readability Two page tables are used in current x86_64 kexec implementation. One is used to jump from kernel virtual address to identity map address, the other is used to map all physical memory. In fact, on x86_64, there is no conflict between kernel virtual address space and physical memory space, so just one page table is sufficient. The page table pages used to map control page are dynamically allocated to save memory if kexec image is not loaded. ASM code used to map control page is replaced by C code too. Signed-off-by: Huang Ying <ying.huang@intel.com> Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/kernel/machine_kexec_64.c')
-rw-r--r--arch/x86/kernel/machine_kexec_64.c82
1 files changed, 55 insertions, 27 deletions
diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index c43caa3a91f3..6993d51b7fd8 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -18,15 +18,6 @@
18#include <asm/mmu_context.h> 18#include <asm/mmu_context.h>
19#include <asm/io.h> 19#include <asm/io.h>
20 20
21#define PAGE_ALIGNED __attribute__ ((__aligned__(PAGE_SIZE)))
22static u64 kexec_pgd[512] PAGE_ALIGNED;
23static u64 kexec_pud0[512] PAGE_ALIGNED;
24static u64 kexec_pmd0[512] PAGE_ALIGNED;
25static u64 kexec_pte0[512] PAGE_ALIGNED;
26static u64 kexec_pud1[512] PAGE_ALIGNED;
27static u64 kexec_pmd1[512] PAGE_ALIGNED;
28static u64 kexec_pte1[512] PAGE_ALIGNED;
29
30static void init_level2_page(pmd_t *level2p, unsigned long addr) 21static void init_level2_page(pmd_t *level2p, unsigned long addr)
31{ 22{
32 unsigned long end_addr; 23 unsigned long end_addr;
@@ -107,12 +98,65 @@ out:
107 return result; 98 return result;
108} 99}
109 100
101static void free_transition_pgtable(struct kimage *image)
102{
103 free_page((unsigned long)image->arch.pud);
104 free_page((unsigned long)image->arch.pmd);
105 free_page((unsigned long)image->arch.pte);
106}
107
108static int init_transition_pgtable(struct kimage *image, pgd_t *pgd)
109{
110 pud_t *pud;
111 pmd_t *pmd;
112 pte_t *pte;
113 unsigned long vaddr, paddr;
114 int result = -ENOMEM;
115
116 vaddr = (unsigned long)relocate_kernel;
117 paddr = __pa(page_address(image->control_code_page)+PAGE_SIZE);
118 pgd += pgd_index(vaddr);
119 if (!pgd_present(*pgd)) {
120 pud = (pud_t *)get_zeroed_page(GFP_KERNEL);
121 if (!pud)
122 goto err;
123 image->arch.pud = pud;
124 set_pgd(pgd, __pgd(__pa(pud) | _KERNPG_TABLE));
125 }
126 pud = pud_offset(pgd, vaddr);
127 if (!pud_present(*pud)) {
128 pmd = (pmd_t *)get_zeroed_page(GFP_KERNEL);
129 if (!pmd)
130 goto err;
131 image->arch.pmd = pmd;
132 set_pud(pud, __pud(__pa(pmd) | _KERNPG_TABLE));
133 }
134 pmd = pmd_offset(pud, vaddr);
135 if (!pmd_present(*pmd)) {
136 pte = (pte_t *)get_zeroed_page(GFP_KERNEL);
137 if (!pte)
138 goto err;
139 image->arch.pte = pte;
140 set_pmd(pmd, __pmd(__pa(pte) | _KERNPG_TABLE));
141 }
142 pte = pte_offset_kernel(pmd, vaddr);
143 set_pte(pte, pfn_pte(paddr >> PAGE_SHIFT, PAGE_KERNEL_EXEC));
144 return 0;
145err:
146 free_transition_pgtable(image);
147 return result;
148}
149
110 150
111static int init_pgtable(struct kimage *image, unsigned long start_pgtable) 151static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
112{ 152{
113 pgd_t *level4p; 153 pgd_t *level4p;
154 int result;
114 level4p = (pgd_t *)__va(start_pgtable); 155 level4p = (pgd_t *)__va(start_pgtable);
115 return init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT); 156 result = init_level4_page(image, level4p, 0, max_pfn << PAGE_SHIFT);
157 if (result)
158 return result;
159 return init_transition_pgtable(image, level4p);
116} 160}
117 161
118static void set_idt(void *newidt, u16 limit) 162static void set_idt(void *newidt, u16 limit)
@@ -174,7 +218,7 @@ int machine_kexec_prepare(struct kimage *image)
174 218
175void machine_kexec_cleanup(struct kimage *image) 219void machine_kexec_cleanup(struct kimage *image)
176{ 220{
177 return; 221 free_transition_pgtable(image);
178} 222}
179 223
180/* 224/*
@@ -195,22 +239,6 @@ void machine_kexec(struct kimage *image)
195 memcpy(control_page, relocate_kernel, PAGE_SIZE); 239 memcpy(control_page, relocate_kernel, PAGE_SIZE);
196 240
197 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page); 241 page_list[PA_CONTROL_PAGE] = virt_to_phys(control_page);
198 page_list[VA_CONTROL_PAGE] = (unsigned long)relocate_kernel;
199 page_list[PA_PGD] = virt_to_phys(&kexec_pgd);
200 page_list[VA_PGD] = (unsigned long)kexec_pgd;
201 page_list[PA_PUD_0] = virt_to_phys(&kexec_pud0);
202 page_list[VA_PUD_0] = (unsigned long)kexec_pud0;
203 page_list[PA_PMD_0] = virt_to_phys(&kexec_pmd0);
204 page_list[VA_PMD_0] = (unsigned long)kexec_pmd0;
205 page_list[PA_PTE_0] = virt_to_phys(&kexec_pte0);
206 page_list[VA_PTE_0] = (unsigned long)kexec_pte0;
207 page_list[PA_PUD_1] = virt_to_phys(&kexec_pud1);
208 page_list[VA_PUD_1] = (unsigned long)kexec_pud1;
209 page_list[PA_PMD_1] = virt_to_phys(&kexec_pmd1);
210 page_list[VA_PMD_1] = (unsigned long)kexec_pmd1;
211 page_list[PA_PTE_1] = virt_to_phys(&kexec_pte1);
212 page_list[VA_PTE_1] = (unsigned long)kexec_pte1;
213
214 page_list[PA_TABLE_PAGE] = 242 page_list[PA_TABLE_PAGE] =
215 (unsigned long)__pa(page_address(image->control_code_page)); 243 (unsigned long)__pa(page_address(image->control_code_page));
216 244
generated by cgit v1.2.2 (git 2.25.0) at 2025-03-22 16:14:33 -0400