kernel/kexec_file.c: remove unneeded variables in kexec_purgatory_setup_sechdrs

The main loop currently uses quite a lot of variables to update the
section headers.  Some of them are unnecessary.  So clean them up a
little.

Link: http://lkml.kernel.org/r/20180321112751.22196-9-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>

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 6f0ec9f2e5c149ff622423e13f0203a763a83bad..7b63de8a89b65fab7ae6dc36862fc98d3bb84666 100644 (file)
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c
@@ -785,12 +785,8 @@ out:
 static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
                                         struct kexec_buf *kbuf)
 {
-       unsigned long curr_load_addr;
-       unsigned long load_addr;
        unsigned long bss_addr;
        unsigned long offset;
-       unsigned char *buf_addr;
-       unsigned char *src;
        Elf_Shdr *sechdrs;
        int i;
 
@@ -823,20 +819,18 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
                                                sechdrs[i].sh_offset;
        }
 
-       /* Load SHF_ALLOC sections */
-       buf_addr = kbuf->buffer;
-       load_addr = curr_load_addr = kbuf->mem;
-       bss_addr = load_addr + kbuf->bufsz;
+       offset = 0;
+       bss_addr = kbuf->mem + kbuf->bufsz;
        kbuf->image->start = pi->ehdr->e_entry;
 
        for (i = 0; i < pi->ehdr->e_shnum; i++) {
                unsigned long align;
+               void *src, *dst;
 
                if (!(sechdrs[i].sh_flags & SHF_ALLOC))
                        continue;
 
                align = sechdrs[i].sh_addralign;
-
                if (sechdrs[i].sh_type == SHT_NOBITS) {
                        bss_addr = ALIGN(bss_addr, align);
                        sechdrs[i].sh_addr = bss_addr;
@@ -844,31 +838,27 @@ static int kexec_purgatory_setup_sechdrs(struct purgatory_info *pi,
                        continue;
                }
 
-               curr_load_addr = ALIGN(curr_load_addr, align);
-               offset = curr_load_addr - load_addr;
-               /* We already modifed ->sh_offset to keep src addr */
-               src = (char *)sechdrs[i].sh_offset;
-               memcpy(buf_addr + offset, src, sechdrs[i].sh_size);
-
+               offset = ALIGN(offset, align);
                if (sechdrs[i].sh_flags & SHF_EXECINSTR &&
                    pi->ehdr->e_entry >= sechdrs[i].sh_addr &&
                    pi->ehdr->e_entry < (sechdrs[i].sh_addr
                                         + sechdrs[i].sh_size)) {
                        kbuf->image->start -= sechdrs[i].sh_addr;
-                       kbuf->image->start += curr_load_addr;
+                       kbuf->image->start += kbuf->mem + offset;
                }
 
-               /* Store load address and source address of section */
-               sechdrs[i].sh_addr = curr_load_addr;
+               src = (void *)sechdrs[i].sh_offset;
+               dst = pi->purgatory_buf + offset;
+               memcpy(dst, src, sechdrs[i].sh_size);
+
+               sechdrs[i].sh_addr = kbuf->mem + offset;
 
                /*
                 * This section got copied to temporary buffer. Update
                 * ->sh_offset accordingly.
                 */
-               sechdrs[i].sh_offset = (unsigned long)(buf_addr + offset);
-
-               /* Advance to the next address */
-               curr_load_addr += sechdrs[i].sh_size;
+               sechdrs[i].sh_offset = (unsigned long)dst;
+               offset += sechdrs[i].sh_size;
        }
 
        return 0;