4bfaaef01a
kexec: Avoid overwriting the current pgd (V4, x86_64) This patch upgrades the x86_64-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>
96 lines
3.1 KiB
C
96 lines
3.1 KiB
C
#ifndef _X86_64_KEXEC_H
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#define _X86_64_KEXEC_H
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#define PA_CONTROL_PAGE 0
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#define VA_CONTROL_PAGE 1
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#define PA_PGD 2
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#define VA_PGD 3
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#define PA_PUD_0 4
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#define VA_PUD_0 5
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#define PA_PMD_0 6
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#define VA_PMD_0 7
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#define PA_PTE_0 8
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#define VA_PTE_0 9
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#define PA_PUD_1 10
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#define VA_PUD_1 11
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#define PA_PMD_1 12
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#define VA_PMD_1 13
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#define PA_PTE_1 14
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#define VA_PTE_1 15
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#define PA_TABLE_PAGE 16
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#define PAGES_NR 17
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#ifndef __ASSEMBLY__
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#include <linux/string.h>
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#include <asm/page.h>
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#include <asm/ptrace.h>
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/*
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* KEXEC_SOURCE_MEMORY_LIMIT maximum page get_free_page can return.
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* I.e. Maximum page that is mapped directly into kernel memory,
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* and kmap is not required.
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*
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* So far x86_64 is limited to 40 physical address bits.
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*/
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/* Maximum physical address we can use pages from */
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#define KEXEC_SOURCE_MEMORY_LIMIT (0xFFFFFFFFFFUL)
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/* Maximum address we can reach in physical address mode */
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#define KEXEC_DESTINATION_MEMORY_LIMIT (0xFFFFFFFFFFUL)
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/* Maximum address we can use for the control pages */
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#define KEXEC_CONTROL_MEMORY_LIMIT (0xFFFFFFFFFFUL)
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/* Allocate one page for the pdp and the second for the code */
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#define KEXEC_CONTROL_CODE_SIZE (4096UL + 4096UL)
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/* The native architecture */
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#define KEXEC_ARCH KEXEC_ARCH_X86_64
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#define MAX_NOTE_BYTES 1024
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/*
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* Saving the registers of the cpu on which panic occured in
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* crash_kexec to save a valid sp. The registers of other cpus
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* will be saved in machine_crash_shutdown while shooting down them.
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*/
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static inline void crash_setup_regs(struct pt_regs *newregs,
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struct pt_regs *oldregs)
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{
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if (oldregs)
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memcpy(newregs, oldregs, sizeof(*newregs));
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else {
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__asm__ __volatile__("movq %%rbx,%0" : "=m"(newregs->rbx));
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__asm__ __volatile__("movq %%rcx,%0" : "=m"(newregs->rcx));
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__asm__ __volatile__("movq %%rdx,%0" : "=m"(newregs->rdx));
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__asm__ __volatile__("movq %%rsi,%0" : "=m"(newregs->rsi));
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__asm__ __volatile__("movq %%rdi,%0" : "=m"(newregs->rdi));
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__asm__ __volatile__("movq %%rbp,%0" : "=m"(newregs->rbp));
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__asm__ __volatile__("movq %%rax,%0" : "=m"(newregs->rax));
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__asm__ __volatile__("movq %%rsp,%0" : "=m"(newregs->rsp));
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__asm__ __volatile__("movq %%r8,%0" : "=m"(newregs->r8));
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__asm__ __volatile__("movq %%r9,%0" : "=m"(newregs->r9));
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__asm__ __volatile__("movq %%r10,%0" : "=m"(newregs->r10));
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__asm__ __volatile__("movq %%r11,%0" : "=m"(newregs->r11));
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__asm__ __volatile__("movq %%r12,%0" : "=m"(newregs->r12));
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__asm__ __volatile__("movq %%r13,%0" : "=m"(newregs->r13));
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__asm__ __volatile__("movq %%r14,%0" : "=m"(newregs->r14));
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__asm__ __volatile__("movq %%r15,%0" : "=m"(newregs->r15));
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__asm__ __volatile__("movl %%ss, %%eax;" :"=a"(newregs->ss));
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__asm__ __volatile__("movl %%cs, %%eax;" :"=a"(newregs->cs));
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__asm__ __volatile__("pushfq; popq %0" :"=m"(newregs->eflags));
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newregs->rip = (unsigned long)current_text_addr();
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}
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}
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NORET_TYPE void
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relocate_kernel(unsigned long indirection_page,
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unsigned long page_list,
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unsigned long start_address) ATTRIB_NORET;
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#endif /* __ASSEMBLY__ */
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#endif /* _X86_64_KEXEC_H */
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