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    Subject[PATCH v22 1/8] crash: move a few code bits to setup support of crash hotplug
    Date
    The crash hotplug support leans on the work for the kexec_file_load()
    syscall. To also support the kexec_load() syscall, a few bits of code
    need to be move outside of CONFIG_KEXEC_FILE. As such, these bits are
    moved out of kexec_file.c and into a common location crash_core.c.

    No functionality change intended.

    Signed-off-by: Eric DeVolder <eric.devolder@oracle.com>
    Reviewed-by: Sourabh Jain <sourabhjain@linux.ibm.com>
    Acked-by: Baoquan He <bhe@redhat.com>
    ---
    include/linux/kexec.h | 30 +++----
    kernel/crash_core.c | 182 ++++++++++++++++++++++++++++++++++++++++++
    kernel/kexec_file.c | 181 -----------------------------------------
    3 files changed, 197 insertions(+), 196 deletions(-)

    diff --git a/include/linux/kexec.h b/include/linux/kexec.h
    index 22b5cd24f581..811a90e09698 100644
    --- a/include/linux/kexec.h
    +++ b/include/linux/kexec.h
    @@ -105,6 +105,21 @@ struct compat_kexec_segment {
    };
    #endif

    +/* Alignment required for elf header segment */
    +#define ELF_CORE_HEADER_ALIGN 4096
    +
    +struct crash_mem {
    + unsigned int max_nr_ranges;
    + unsigned int nr_ranges;
    + struct range ranges[];
    +};
    +
    +extern int crash_exclude_mem_range(struct crash_mem *mem,
    + unsigned long long mstart,
    + unsigned long long mend);
    +extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
    + void **addr, unsigned long *sz);
    +
    #ifdef CONFIG_KEXEC_FILE
    struct purgatory_info {
    /*
    @@ -230,21 +245,6 @@ static inline int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)
    }
    #endif

    -/* Alignment required for elf header segment */
    -#define ELF_CORE_HEADER_ALIGN 4096
    -
    -struct crash_mem {
    - unsigned int max_nr_ranges;
    - unsigned int nr_ranges;
    - struct range ranges[];
    -};
    -
    -extern int crash_exclude_mem_range(struct crash_mem *mem,
    - unsigned long long mstart,
    - unsigned long long mend);
    -extern int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
    - void **addr, unsigned long *sz);
    -
    #ifndef arch_kexec_apply_relocations_add
    /*
    * arch_kexec_apply_relocations_add - apply relocations of type RELA
    diff --git a/kernel/crash_core.c b/kernel/crash_core.c
    index 90ce1dfd591c..b7c30b748a16 100644
    --- a/kernel/crash_core.c
    +++ b/kernel/crash_core.c
    @@ -10,6 +10,7 @@
    #include <linux/utsname.h>
    #include <linux/vmalloc.h>
    #include <linux/sizes.h>
    +#include <linux/kexec.h>

    #include <asm/page.h>
    #include <asm/sections.h>
    @@ -314,6 +315,187 @@ static int __init parse_crashkernel_dummy(char *arg)
    }
    early_param("crashkernel", parse_crashkernel_dummy);

    +int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
    + void **addr, unsigned long *sz)
    +{
    + Elf64_Ehdr *ehdr;
    + Elf64_Phdr *phdr;
    + unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
    + unsigned char *buf;
    + unsigned int cpu, i;
    + unsigned long long notes_addr;
    + unsigned long mstart, mend;
    +
    + /* extra phdr for vmcoreinfo ELF note */
    + nr_phdr = nr_cpus + 1;
    + nr_phdr += mem->nr_ranges;
    +
    + /*
    + * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
    + * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
    + * I think this is required by tools like gdb. So same physical
    + * memory will be mapped in two ELF headers. One will contain kernel
    + * text virtual addresses and other will have __va(physical) addresses.
    + */
    +
    + nr_phdr++;
    + elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
    + elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
    +
    + buf = vzalloc(elf_sz);
    + if (!buf)
    + return -ENOMEM;
    +
    + ehdr = (Elf64_Ehdr *)buf;
    + phdr = (Elf64_Phdr *)(ehdr + 1);
    + memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
    + ehdr->e_ident[EI_CLASS] = ELFCLASS64;
    + ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
    + ehdr->e_ident[EI_VERSION] = EV_CURRENT;
    + ehdr->e_ident[EI_OSABI] = ELF_OSABI;
    + memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
    + ehdr->e_type = ET_CORE;
    + ehdr->e_machine = ELF_ARCH;
    + ehdr->e_version = EV_CURRENT;
    + ehdr->e_phoff = sizeof(Elf64_Ehdr);
    + ehdr->e_ehsize = sizeof(Elf64_Ehdr);
    + ehdr->e_phentsize = sizeof(Elf64_Phdr);
    +
    + /* Prepare one phdr of type PT_NOTE for each present CPU */
    + for_each_present_cpu(cpu) {
    + phdr->p_type = PT_NOTE;
    + notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
    + phdr->p_offset = phdr->p_paddr = notes_addr;
    + phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
    + (ehdr->e_phnum)++;
    + phdr++;
    + }
    +
    + /* Prepare one PT_NOTE header for vmcoreinfo */
    + phdr->p_type = PT_NOTE;
    + phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
    + phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
    + (ehdr->e_phnum)++;
    + phdr++;
    +
    + /* Prepare PT_LOAD type program header for kernel text region */
    + if (need_kernel_map) {
    + phdr->p_type = PT_LOAD;
    + phdr->p_flags = PF_R|PF_W|PF_X;
    + phdr->p_vaddr = (unsigned long) _text;
    + phdr->p_filesz = phdr->p_memsz = _end - _text;
    + phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
    + ehdr->e_phnum++;
    + phdr++;
    + }
    +
    + /* Go through all the ranges in mem->ranges[] and prepare phdr */
    + for (i = 0; i < mem->nr_ranges; i++) {
    + mstart = mem->ranges[i].start;
    + mend = mem->ranges[i].end;
    +
    + phdr->p_type = PT_LOAD;
    + phdr->p_flags = PF_R|PF_W|PF_X;
    + phdr->p_offset = mstart;
    +
    + phdr->p_paddr = mstart;
    + phdr->p_vaddr = (unsigned long) __va(mstart);
    + phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
    + phdr->p_align = 0;
    + ehdr->e_phnum++;
    + pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
    + phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
    + ehdr->e_phnum, phdr->p_offset);
    + phdr++;
    + }
    +
    + *addr = buf;
    + *sz = elf_sz;
    + return 0;
    +}
    +
    +int crash_exclude_mem_range(struct crash_mem *mem,
    + unsigned long long mstart, unsigned long long mend)
    +{
    + int i, j;
    + unsigned long long start, end, p_start, p_end;
    + struct range temp_range = {0, 0};
    +
    + for (i = 0; i < mem->nr_ranges; i++) {
    + start = mem->ranges[i].start;
    + end = mem->ranges[i].end;
    + p_start = mstart;
    + p_end = mend;
    +
    + if (mstart > end || mend < start)
    + continue;
    +
    + /* Truncate any area outside of range */
    + if (mstart < start)
    + p_start = start;
    + if (mend > end)
    + p_end = end;
    +
    + /* Found completely overlapping range */
    + if (p_start == start && p_end == end) {
    + mem->ranges[i].start = 0;
    + mem->ranges[i].end = 0;
    + if (i < mem->nr_ranges - 1) {
    + /* Shift rest of the ranges to left */
    + for (j = i; j < mem->nr_ranges - 1; j++) {
    + mem->ranges[j].start =
    + mem->ranges[j+1].start;
    + mem->ranges[j].end =
    + mem->ranges[j+1].end;
    + }
    +
    + /*
    + * Continue to check if there are another overlapping ranges
    + * from the current position because of shifting the above
    + * mem ranges.
    + */
    + i--;
    + mem->nr_ranges--;
    + continue;
    + }
    + mem->nr_ranges--;
    + return 0;
    + }
    +
    + if (p_start > start && p_end < end) {
    + /* Split original range */
    + mem->ranges[i].end = p_start - 1;
    + temp_range.start = p_end + 1;
    + temp_range.end = end;
    + } else if (p_start != start)
    + mem->ranges[i].end = p_start - 1;
    + else
    + mem->ranges[i].start = p_end + 1;
    + break;
    + }
    +
    + /* If a split happened, add the split to array */
    + if (!temp_range.end)
    + return 0;
    +
    + /* Split happened */
    + if (i == mem->max_nr_ranges - 1)
    + return -ENOMEM;
    +
    + /* Location where new range should go */
    + j = i + 1;
    + if (j < mem->nr_ranges) {
    + /* Move over all ranges one slot towards the end */
    + for (i = mem->nr_ranges - 1; i >= j; i--)
    + mem->ranges[i + 1] = mem->ranges[i];
    + }
    +
    + mem->ranges[j].start = temp_range.start;
    + mem->ranges[j].end = temp_range.end;
    + mem->nr_ranges++;
    + return 0;
    +}
    +
    Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
    void *data, size_t data_len)
    {
    diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
    index f989f5f1933b..f8b1797b3ec9 100644
    --- a/kernel/kexec_file.c
    +++ b/kernel/kexec_file.c
    @@ -1138,184 +1138,3 @@ int kexec_purgatory_get_set_symbol(struct kimage *image, const char *name,
    return 0;
    }
    #endif /* CONFIG_ARCH_HAS_KEXEC_PURGATORY */
    -
    -int crash_exclude_mem_range(struct crash_mem *mem,
    - unsigned long long mstart, unsigned long long mend)
    -{
    - int i, j;
    - unsigned long long start, end, p_start, p_end;
    - struct range temp_range = {0, 0};
    -
    - for (i = 0; i < mem->nr_ranges; i++) {
    - start = mem->ranges[i].start;
    - end = mem->ranges[i].end;
    - p_start = mstart;
    - p_end = mend;
    -
    - if (mstart > end || mend < start)
    - continue;
    -
    - /* Truncate any area outside of range */
    - if (mstart < start)
    - p_start = start;
    - if (mend > end)
    - p_end = end;
    -
    - /* Found completely overlapping range */
    - if (p_start == start && p_end == end) {
    - mem->ranges[i].start = 0;
    - mem->ranges[i].end = 0;
    - if (i < mem->nr_ranges - 1) {
    - /* Shift rest of the ranges to left */
    - for (j = i; j < mem->nr_ranges - 1; j++) {
    - mem->ranges[j].start =
    - mem->ranges[j+1].start;
    - mem->ranges[j].end =
    - mem->ranges[j+1].end;
    - }
    -
    - /*
    - * Continue to check if there are another overlapping ranges
    - * from the current position because of shifting the above
    - * mem ranges.
    - */
    - i--;
    - mem->nr_ranges--;
    - continue;
    - }
    - mem->nr_ranges--;
    - return 0;
    - }
    -
    - if (p_start > start && p_end < end) {
    - /* Split original range */
    - mem->ranges[i].end = p_start - 1;
    - temp_range.start = p_end + 1;
    - temp_range.end = end;
    - } else if (p_start != start)
    - mem->ranges[i].end = p_start - 1;
    - else
    - mem->ranges[i].start = p_end + 1;
    - break;
    - }
    -
    - /* If a split happened, add the split to array */
    - if (!temp_range.end)
    - return 0;
    -
    - /* Split happened */
    - if (i == mem->max_nr_ranges - 1)
    - return -ENOMEM;
    -
    - /* Location where new range should go */
    - j = i + 1;
    - if (j < mem->nr_ranges) {
    - /* Move over all ranges one slot towards the end */
    - for (i = mem->nr_ranges - 1; i >= j; i--)
    - mem->ranges[i + 1] = mem->ranges[i];
    - }
    -
    - mem->ranges[j].start = temp_range.start;
    - mem->ranges[j].end = temp_range.end;
    - mem->nr_ranges++;
    - return 0;
    -}
    -
    -int crash_prepare_elf64_headers(struct crash_mem *mem, int need_kernel_map,
    - void **addr, unsigned long *sz)
    -{
    - Elf64_Ehdr *ehdr;
    - Elf64_Phdr *phdr;
    - unsigned long nr_cpus = num_possible_cpus(), nr_phdr, elf_sz;
    - unsigned char *buf;
    - unsigned int cpu, i;
    - unsigned long long notes_addr;
    - unsigned long mstart, mend;
    -
    - /* extra phdr for vmcoreinfo ELF note */
    - nr_phdr = nr_cpus + 1;
    - nr_phdr += mem->nr_ranges;
    -
    - /*
    - * kexec-tools creates an extra PT_LOAD phdr for kernel text mapping
    - * area (for example, ffffffff80000000 - ffffffffa0000000 on x86_64).
    - * I think this is required by tools like gdb. So same physical
    - * memory will be mapped in two ELF headers. One will contain kernel
    - * text virtual addresses and other will have __va(physical) addresses.
    - */
    -
    - nr_phdr++;
    - elf_sz = sizeof(Elf64_Ehdr) + nr_phdr * sizeof(Elf64_Phdr);
    - elf_sz = ALIGN(elf_sz, ELF_CORE_HEADER_ALIGN);
    -
    - buf = vzalloc(elf_sz);
    - if (!buf)
    - return -ENOMEM;
    -
    - ehdr = (Elf64_Ehdr *)buf;
    - phdr = (Elf64_Phdr *)(ehdr + 1);
    - memcpy(ehdr->e_ident, ELFMAG, SELFMAG);
    - ehdr->e_ident[EI_CLASS] = ELFCLASS64;
    - ehdr->e_ident[EI_DATA] = ELFDATA2LSB;
    - ehdr->e_ident[EI_VERSION] = EV_CURRENT;
    - ehdr->e_ident[EI_OSABI] = ELF_OSABI;
    - memset(ehdr->e_ident + EI_PAD, 0, EI_NIDENT - EI_PAD);
    - ehdr->e_type = ET_CORE;
    - ehdr->e_machine = ELF_ARCH;
    - ehdr->e_version = EV_CURRENT;
    - ehdr->e_phoff = sizeof(Elf64_Ehdr);
    - ehdr->e_ehsize = sizeof(Elf64_Ehdr);
    - ehdr->e_phentsize = sizeof(Elf64_Phdr);
    -
    - /* Prepare one phdr of type PT_NOTE for each present CPU */
    - for_each_present_cpu(cpu) {
    - phdr->p_type = PT_NOTE;
    - notes_addr = per_cpu_ptr_to_phys(per_cpu_ptr(crash_notes, cpu));
    - phdr->p_offset = phdr->p_paddr = notes_addr;
    - phdr->p_filesz = phdr->p_memsz = sizeof(note_buf_t);
    - (ehdr->e_phnum)++;
    - phdr++;
    - }
    -
    - /* Prepare one PT_NOTE header for vmcoreinfo */
    - phdr->p_type = PT_NOTE;
    - phdr->p_offset = phdr->p_paddr = paddr_vmcoreinfo_note();
    - phdr->p_filesz = phdr->p_memsz = VMCOREINFO_NOTE_SIZE;
    - (ehdr->e_phnum)++;
    - phdr++;
    -
    - /* Prepare PT_LOAD type program header for kernel text region */
    - if (need_kernel_map) {
    - phdr->p_type = PT_LOAD;
    - phdr->p_flags = PF_R|PF_W|PF_X;
    - phdr->p_vaddr = (unsigned long) _text;
    - phdr->p_filesz = phdr->p_memsz = _end - _text;
    - phdr->p_offset = phdr->p_paddr = __pa_symbol(_text);
    - ehdr->e_phnum++;
    - phdr++;
    - }
    -
    - /* Go through all the ranges in mem->ranges[] and prepare phdr */
    - for (i = 0; i < mem->nr_ranges; i++) {
    - mstart = mem->ranges[i].start;
    - mend = mem->ranges[i].end;
    -
    - phdr->p_type = PT_LOAD;
    - phdr->p_flags = PF_R|PF_W|PF_X;
    - phdr->p_offset = mstart;
    -
    - phdr->p_paddr = mstart;
    - phdr->p_vaddr = (unsigned long) __va(mstart);
    - phdr->p_filesz = phdr->p_memsz = mend - mstart + 1;
    - phdr->p_align = 0;
    - ehdr->e_phnum++;
    - pr_debug("Crash PT_LOAD ELF header. phdr=%p vaddr=0x%llx, paddr=0x%llx, sz=0x%llx e_phnum=%d p_offset=0x%llx\n",
    - phdr, phdr->p_vaddr, phdr->p_paddr, phdr->p_filesz,
    - ehdr->e_phnum, phdr->p_offset);
    - phdr++;
    - }
    -
    - *addr = buf;
    - *sz = elf_sz;
    - return 0;
    -}
    --
    2.31.1
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