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>
164 lines
4.5 KiB
C
164 lines
4.5 KiB
C
#ifndef LINUX_KEXEC_H
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#define LINUX_KEXEC_H
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#ifdef CONFIG_KEXEC
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#include <linux/types.h>
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#include <linux/list.h>
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#include <linux/linkage.h>
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#include <linux/compat.h>
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#include <linux/ioport.h>
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#include <linux/elfcore.h>
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#include <linux/elf.h>
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#include <asm/kexec.h>
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/* Verify architecture specific macros are defined */
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#ifndef KEXEC_SOURCE_MEMORY_LIMIT
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#error KEXEC_SOURCE_MEMORY_LIMIT not defined
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#endif
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#ifndef KEXEC_DESTINATION_MEMORY_LIMIT
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#error KEXEC_DESTINATION_MEMORY_LIMIT not defined
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#endif
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#ifndef KEXEC_CONTROL_MEMORY_LIMIT
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#error KEXEC_CONTROL_MEMORY_LIMIT not defined
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#endif
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#ifndef KEXEC_CONTROL_CODE_SIZE
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#error KEXEC_CONTROL_CODE_SIZE not defined
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#endif
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#ifndef KEXEC_ARCH
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#error KEXEC_ARCH not defined
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#endif
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#define KEXEC_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
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#define KEXEC_CORE_NOTE_NAME "CORE"
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#define KEXEC_CORE_NOTE_NAME_BYTES ALIGN(sizeof(KEXEC_CORE_NOTE_NAME), 4)
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#define KEXEC_CORE_NOTE_DESC_BYTES ALIGN(sizeof(struct elf_prstatus), 4)
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/*
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* The per-cpu notes area is a list of notes terminated by a "NULL"
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* note header. For kdump, the code in vmcore.c runs in the context
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* of the second kernel to combine them into one note.
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*/
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#define KEXEC_NOTE_BYTES ( (KEXEC_NOTE_HEAD_BYTES * 2) + \
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KEXEC_CORE_NOTE_NAME_BYTES + \
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KEXEC_CORE_NOTE_DESC_BYTES )
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/*
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* This structure is used to hold the arguments that are used when loading
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* kernel binaries.
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*/
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typedef unsigned long kimage_entry_t;
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#define IND_DESTINATION 0x1
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#define IND_INDIRECTION 0x2
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#define IND_DONE 0x4
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#define IND_SOURCE 0x8
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#define KEXEC_SEGMENT_MAX 16
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struct kexec_segment {
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void __user *buf;
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size_t bufsz;
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unsigned long mem; /* User space sees this as a (void *) ... */
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size_t memsz;
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};
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#ifdef CONFIG_COMPAT
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struct compat_kexec_segment {
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compat_uptr_t buf;
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compat_size_t bufsz;
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compat_ulong_t mem; /* User space sees this as a (void *) ... */
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compat_size_t memsz;
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};
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#endif
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struct kimage {
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kimage_entry_t head;
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kimage_entry_t *entry;
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kimage_entry_t *last_entry;
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unsigned long destination;
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unsigned long start;
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struct page *control_code_page;
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unsigned long nr_segments;
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struct kexec_segment segment[KEXEC_SEGMENT_MAX];
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struct list_head control_pages;
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struct list_head dest_pages;
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struct list_head unuseable_pages;
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/* Address of next control page to allocate for crash kernels. */
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unsigned long control_page;
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/* Flags to indicate special processing */
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unsigned int type : 1;
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#define KEXEC_TYPE_DEFAULT 0
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#define KEXEC_TYPE_CRASH 1
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};
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/* kexec interface functions */
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extern NORET_TYPE void machine_kexec(struct kimage *image) ATTRIB_NORET;
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extern int machine_kexec_prepare(struct kimage *image);
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extern void machine_kexec_cleanup(struct kimage *image);
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extern asmlinkage long sys_kexec_load(unsigned long entry,
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unsigned long nr_segments,
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struct kexec_segment __user *segments,
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unsigned long flags);
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#ifdef CONFIG_COMPAT
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extern asmlinkage long compat_sys_kexec_load(unsigned long entry,
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unsigned long nr_segments,
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struct compat_kexec_segment __user *segments,
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unsigned long flags);
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#endif
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extern struct page *kimage_alloc_control_pages(struct kimage *image,
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unsigned int order);
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extern void crash_kexec(struct pt_regs *);
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int kexec_should_crash(struct task_struct *);
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void crash_save_cpu(struct pt_regs *regs, int cpu);
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extern struct kimage *kexec_image;
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extern struct kimage *kexec_crash_image;
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#ifndef kexec_flush_icache_page
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#define kexec_flush_icache_page(page)
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#endif
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#define KEXEC_ON_CRASH 0x00000001
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#define KEXEC_ARCH_MASK 0xffff0000
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/* These values match the ELF architecture values.
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* Unless there is a good reason that should continue to be the case.
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*/
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#define KEXEC_ARCH_DEFAULT ( 0 << 16)
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#define KEXEC_ARCH_386 ( 3 << 16)
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#define KEXEC_ARCH_X86_64 (62 << 16)
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#define KEXEC_ARCH_PPC (20 << 16)
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#define KEXEC_ARCH_PPC64 (21 << 16)
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#define KEXEC_ARCH_IA_64 (50 << 16)
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#define KEXEC_ARCH_ARM (40 << 16)
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#define KEXEC_ARCH_S390 (22 << 16)
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#define KEXEC_ARCH_SH (42 << 16)
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#define KEXEC_ARCH_MIPS_LE (10 << 16)
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#define KEXEC_ARCH_MIPS ( 8 << 16)
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#define KEXEC_FLAGS (KEXEC_ON_CRASH) /* List of defined/legal kexec flags */
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/* Location of a reserved region to hold the crash kernel.
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*/
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extern struct resource crashk_res;
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typedef u32 note_buf_t[KEXEC_NOTE_BYTES/4];
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extern note_buf_t *crash_notes;
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#else /* !CONFIG_KEXEC */
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struct pt_regs;
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struct task_struct;
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static inline void crash_kexec(struct pt_regs *regs) { }
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static inline int kexec_should_crash(struct task_struct *p) { return 0; }
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#endif /* CONFIG_KEXEC */
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#endif /* LINUX_KEXEC_H */
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