linux/include/asm-x86_64/kexec.h
Magnus Damm 4bfaaef01a [PATCH] Avoid overwriting the current pgd (V4, x86_64)
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>
2006-09-26 10:52:38 +02:00

97 lines
3.1 KiB
C

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