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>

1 files changed, 12 insertions, 22 deletions

diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index 6f0ec9f2e5c1..7b63de8a89b6 100644
--- 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;