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kernel/kexec_file.c: split up __kexec_load_puragory
When inspecting __kexec_load_purgatory you find that it has two tasks 1) setting up the kexec_buffer for the new kernel and, 2) setting up pi->sechdrs for the final load address. The two tasks are independent of each other. To improve readability split up __kexec_load_purgatory into two functions, one for each task, and call them directly from kexec_load_purgatory. Link: http://lkml.kernel.org/r/20180321112751.22196-7-prudo@linux.vnet.ibm.com Signed-off-by: Philipp Rudo <prudo@linux.vnet.ibm.com> Acked-by: Dave Young <dyoung@redhat.com> Cc: AKASHI Takahiro <takahiro.akashi@linaro.org> Cc: Eric Biederman <ebiederm@xmission.com> Cc: Heiko Carstens <heiko.carstens@de.ibm.com> Cc: Ingo Molnar <mingo@kernel.org> Cc: Martin Schwidefsky <schwidefsky@de.ibm.com> Cc: Michael Ellerman <mpe@ellerman.id.au> Cc: Thiago Jung Bauermann <bauerman@linux.vnet.ibm.com> Cc: Vivek Goyal <vgoyal@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Philipp Rudo
Linus Torvalds
parent
8aec395b84
commit
930457057a
1 changed files with 103 additions and 97 deletions
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@ -710,39 +710,97 @@ static int kexec_calculate_store_digests(struct kimage *image)
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}
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#ifdef CONFIG_ARCH_HAS_KEXEC_PURGATORY
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/* Actually load purgatory. Lot of code taken from kexec-tools */
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static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
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unsigned long max, int top_down)
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/*
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* kexec_purgatory_setup_kbuf - prepare buffer to load purgatory.
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* @pi: Purgatory to be loaded.
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* @kbuf: Buffer to setup.
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*
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* Allocates the memory needed for the buffer. Caller is responsible to free
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* the memory after use.
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*
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* Return: 0 on success, negative errno on error.
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*/
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static int kexec_purgatory_setup_kbuf(struct purgatory_info *pi,
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struct kexec_buf *kbuf)
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{
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struct purgatory_info *pi = &image->purgatory_info;
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unsigned long align, bss_align, bss_sz, bss_pad;
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unsigned long entry, load_addr, curr_load_addr, bss_addr, offset;
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unsigned char *buf_addr, *src;
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int i, ret = 0, entry_sidx = -1;
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const Elf_Shdr *sechdrs_c;
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Elf_Shdr *sechdrs = NULL;
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struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1,
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.buf_min = min, .buf_max = max,
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.top_down = top_down };
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const Elf_Shdr *sechdrs;
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unsigned long bss_align;
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unsigned long bss_sz;
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unsigned long align;
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int i, ret;
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/*
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* sechdrs_c points to section headers in purgatory and are read
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* only. No modifications allowed.
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*/
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sechdrs_c = (void *)pi->ehdr + pi->ehdr->e_shoff;
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sechdrs = (void *)pi->ehdr + pi->ehdr->e_shoff;
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bss_align = 1;
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bss_sz = 0;
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for (i = 0; i < pi->ehdr->e_shnum; i++) {
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if (!(sechdrs[i].sh_flags & SHF_ALLOC))
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continue;
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align = sechdrs[i].sh_addralign;
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if (sechdrs[i].sh_type != SHT_NOBITS) {
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if (kbuf->buf_align < align)
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kbuf->buf_align = align;
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kbuf->bufsz = ALIGN(kbuf->bufsz, align);
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kbuf->bufsz += sechdrs[i].sh_size;
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} else {
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if (bss_align < align)
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bss_align = align;
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bss_sz = ALIGN(bss_sz, align);
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bss_sz += sechdrs[i].sh_size;
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}
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}
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kbuf->bufsz = ALIGN(kbuf->bufsz, bss_align);
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kbuf->memsz = kbuf->bufsz + bss_sz;
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if (kbuf->buf_align < bss_align)
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kbuf->buf_align = bss_align;
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kbuf->buffer = vzalloc(kbuf->bufsz);
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if (!kbuf->buffer)
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return -ENOMEM;
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pi->purgatory_buf = kbuf->buffer;
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ret = kexec_add_buffer(kbuf);
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if (ret)
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goto out;
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pi->purgatory_load_addr = kbuf->mem;
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return 0;
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out:
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vfree(pi->purgatory_buf);
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pi->purgatory_buf = NULL;
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return ret;
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}
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/*
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* kexec_purgatory_setup_sechdrs - prepares the pi->sechdrs buffer.
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* @pi: Purgatory to be loaded.
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* @kbuf: Buffer prepared to store purgatory.
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*
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* Allocates the memory needed for the buffer. Caller is responsible to free
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* the memory after use.
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*
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* Return: 0 on success, negative errno on error.
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*/
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static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
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struct kexec_buf *kbuf)
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{
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unsigned long curr_load_addr;
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unsigned long load_addr;
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unsigned long bss_addr;
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unsigned long offset;
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unsigned char *buf_addr;
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unsigned char *src;
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Elf_Shdr *sechdrs;
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int entry_sidx = -1;
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int i;
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/*
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* We can not modify sechdrs_c[] and its fields. It is read only.
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* Copy it over to a local copy where one can store some temporary
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* data and free it at the end. We need to modify ->sh_addr and
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* ->sh_offset fields to keep track of permanent and temporary
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* locations of sections.
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*/
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sechdrs = vzalloc(pi->ehdr->e_shnum * sizeof(Elf_Shdr));
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if (!sechdrs)
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return -ENOMEM;
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memcpy(sechdrs, sechdrs_c, pi->ehdr->e_shnum * sizeof(Elf_Shdr));
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memcpy(sechdrs, (void *)pi->ehdr + pi->ehdr->e_shoff,
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pi->ehdr->e_shnum * sizeof(Elf_Shdr));
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pi->sechdrs = sechdrs;
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/*
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* We seem to have multiple copies of sections. First copy is which
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@ -770,7 +828,7 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
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* Identify entry point section and make entry relative to section
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* start.
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*/
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entry = pi->ehdr->e_entry;
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kbuf->image->start = pi->ehdr->e_entry;
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for (i = 0; i < pi->ehdr->e_shnum; i++) {
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if (!(sechdrs[i].sh_flags & SHF_ALLOC))
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continue;
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@ -783,63 +841,19 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
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((sechdrs[i].sh_addr + sechdrs[i].sh_size) >
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pi->ehdr->e_entry)) {
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entry_sidx = i;
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entry -= sechdrs[i].sh_addr;
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kbuf->image->start -= sechdrs[i].sh_addr;
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break;
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}
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}
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/* Determine how much memory is needed to load relocatable object. */
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bss_align = 1;
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bss_sz = 0;
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for (i = 0; i < pi->ehdr->e_shnum; i++) {
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if (!(sechdrs[i].sh_flags & SHF_ALLOC))
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continue;
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align = sechdrs[i].sh_addralign;
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if (sechdrs[i].sh_type != SHT_NOBITS) {
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if (kbuf.buf_align < align)
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kbuf.buf_align = align;
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kbuf.bufsz = ALIGN(kbuf.bufsz, align);
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kbuf.bufsz += sechdrs[i].sh_size;
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} else {
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/* bss section */
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if (bss_align < align)
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bss_align = align;
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bss_sz = ALIGN(bss_sz, align);
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bss_sz += sechdrs[i].sh_size;
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}
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}
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/* Determine the bss padding required to align bss properly */
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bss_pad = 0;
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if (kbuf.bufsz & (bss_align - 1))
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bss_pad = bss_align - (kbuf.bufsz & (bss_align - 1));
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kbuf.memsz = kbuf.bufsz + bss_pad + bss_sz;
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/* Allocate buffer for purgatory */
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kbuf.buffer = vzalloc(kbuf.bufsz);
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if (!kbuf.buffer) {
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ret = -ENOMEM;
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goto out;
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}
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if (kbuf.buf_align < bss_align)
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kbuf.buf_align = bss_align;
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/* Add buffer to segment list */
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ret = kexec_add_buffer(&kbuf);
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if (ret)
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goto out;
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pi->purgatory_load_addr = kbuf.mem;
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/* Load SHF_ALLOC sections */
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buf_addr = kbuf.buffer;
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load_addr = curr_load_addr = pi->purgatory_load_addr;
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bss_addr = load_addr + kbuf.bufsz + bss_pad;
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buf_addr = kbuf->buffer;
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load_addr = curr_load_addr = kbuf->mem;
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bss_addr = load_addr + kbuf->bufsz;
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for (i = 0; i < pi->ehdr->e_shnum; i++) {
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unsigned long align;
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if (!(sechdrs[i].sh_flags & SHF_ALLOC))
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continue;
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@ -871,24 +885,9 @@ static int __kexec_load_purgatory(struct kimage *image, unsigned long min,
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/* Update entry point based on load address of text section */
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if (entry_sidx >= 0)
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entry += sechdrs[entry_sidx].sh_addr;
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kbuf->image->start += sechdrs[entry_sidx].sh_addr;
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/* Make kernel jump to purgatory after shutdown */
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image->start = entry;
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/* Used later to get/set symbol values */
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pi->sechdrs = sechdrs;
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/*
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* Used later to identify which section is purgatory and skip it
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* from checksumming.
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*/
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pi->purgatory_buf = kbuf.buffer;
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return ret;
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out:
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vfree(sechdrs);
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vfree(kbuf.buffer);
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return ret;
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return 0;
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}
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static int kexec_apply_relocations(struct kimage *image)
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@ -958,16 +957,23 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min,
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{
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struct purgatory_info *pi = &image->purgatory_info;
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int ret;
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struct kexec_buf kbuf = { .image = image, .bufsz = 0, .buf_align = 1,
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.buf_min = min, .buf_max = max,
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.top_down = top_down };
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if (kexec_purgatory_size <= 0)
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return -EINVAL;
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pi->ehdr = (const Elf_Ehdr *)kexec_purgatory;
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ret = __kexec_load_purgatory(image, min, max, top_down);
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ret = kexec_purgatory_setup_kbuf(pi, &kbuf);
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if (ret)
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return ret;
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ret = kexec_purgatory_setup_sechdrs(pi, &kbuf);
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if (ret)
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goto out_free_kbuf;
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ret = kexec_apply_relocations(image);
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if (ret)
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goto out;
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@ -977,7 +983,7 @@ int kexec_load_purgatory(struct kimage *image, unsigned long min,
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out:
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vfree(pi->sechdrs);
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pi->sechdrs = NULL;
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out_free_kbuf:
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vfree(pi->purgatory_buf);
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pi->purgatory_buf = NULL;
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return ret;
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