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![Simon Horman](/assets/img/avatar_default.png)
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>
94 lines
3.1 KiB
C
94 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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/*
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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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