6672f76a5a
Currently the size of the per-cpu region reserved to save crash notes is set by the per-architecture value MAX_NOTE_BYTES. Which in turn is currently set to 1024 on all supported architectures. While testing ia64 I recently discovered that this value is in fact too small. The particular setup I was using actually needs 1172 bytes. This lead to very tedious failure mode where the tail of one elf note would overwrite the head of another if they ended up being alocated sequentially by kmalloc, which was often the case. It seems to me that a far better approach is to caclculate the size that the area needs to be. This patch does just that. If a simpler stop-gap patch for ia64 to be squeezed into 2.6.21(.X) is needed then this should be as easy as making MAX_NOTE_BYTES larger in arch/asm-ia64/kexec.h. Perhaps 2048 would be a good choice. However, I think that the approach in this patch is a much more robust idea. Acked-by: Vivek Goyal <vgoyal@in.ibm.com> Signed-off-by: Simon Horman <horms@verge.net.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
100 lines
3.3 KiB
C
100 lines
3.3 KiB
C
#ifndef _I386_KEXEC_H
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#define _I386_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_PTE_0 4
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#define VA_PTE_0 5
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#define PA_PTE_1 6
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#define VA_PTE_1 7
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#ifdef CONFIG_X86_PAE
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#define PA_PMD_0 8
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#define VA_PMD_0 9
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#define PA_PMD_1 10
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#define VA_PMD_1 11
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#define PAGES_NR 12
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#else
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#define PAGES_NR 8
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#endif
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#ifndef __ASSEMBLY__
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#include <asm/ptrace.h>
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#include <asm/string.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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/* Maximum physical address we can use pages from */
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#define KEXEC_SOURCE_MEMORY_LIMIT (-1UL)
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/* Maximum address we can reach in physical address mode */
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#define KEXEC_DESTINATION_MEMORY_LIMIT (-1UL)
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/* Maximum address we can use for the control code buffer */
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#define KEXEC_CONTROL_MEMORY_LIMIT TASK_SIZE
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#define KEXEC_CONTROL_CODE_SIZE 4096
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/* The native architecture */
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#define KEXEC_ARCH KEXEC_ARCH_386
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/* We can also handle crash dumps from 64 bit kernel. */
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#define vmcore_elf_check_arch_cross(x) ((x)->e_machine == EM_X86_64)
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/* CPU does not save ss and esp on stack if execution is already
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* running in kernel mode at the time of NMI occurrence. This code
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* fixes it.
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*/
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static inline void crash_fixup_ss_esp(struct pt_regs *newregs,
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struct pt_regs *oldregs)
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{
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memcpy(newregs, oldregs, sizeof(*newregs));
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newregs->esp = (unsigned long)&(oldregs->esp);
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__asm__ __volatile__(
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"xorl %%eax, %%eax\n\t"
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"movw %%ss, %%ax\n\t"
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:"=a"(newregs->xss));
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}
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/*
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* This function is responsible for capturing register states if coming
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* via panic otherwise just fix up the ss and esp if coming via kernel
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* mode exception.
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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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crash_fixup_ss_esp(newregs, oldregs);
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else {
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__asm__ __volatile__("movl %%ebx,%0" : "=m"(newregs->ebx));
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__asm__ __volatile__("movl %%ecx,%0" : "=m"(newregs->ecx));
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__asm__ __volatile__("movl %%edx,%0" : "=m"(newregs->edx));
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__asm__ __volatile__("movl %%esi,%0" : "=m"(newregs->esi));
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__asm__ __volatile__("movl %%edi,%0" : "=m"(newregs->edi));
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__asm__ __volatile__("movl %%ebp,%0" : "=m"(newregs->ebp));
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__asm__ __volatile__("movl %%eax,%0" : "=m"(newregs->eax));
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__asm__ __volatile__("movl %%esp,%0" : "=m"(newregs->esp));
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__asm__ __volatile__("movw %%ss, %%ax;" :"=a"(newregs->xss));
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__asm__ __volatile__("movw %%cs, %%ax;" :"=a"(newregs->xcs));
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__asm__ __volatile__("movw %%ds, %%ax;" :"=a"(newregs->xds));
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__asm__ __volatile__("movw %%es, %%ax;" :"=a"(newregs->xes));
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__asm__ __volatile__("pushfl; popl %0" :"=m"(newregs->eflags));
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newregs->eip = (unsigned long)current_text_addr();
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}
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}
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asmlinkage NORET_TYPE void
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relocate_kernel(unsigned long indirection_page,
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unsigned long control_page,
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unsigned long start_address,
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unsigned int has_pae) ATTRIB_NORET;
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#endif /* __ASSEMBLY__ */
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#endif /* _I386_KEXEC_H */
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