[PATCH 02/13] vmcore: round up buffer size of ELF headers by PAGE_SIZE

[HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>]

To satisfy mmap() page-size boundary requirement, reound up buffer
size of ELF headers by PAGE_SIZE. The resulting value becomes offset
of ELF note segments and it's assigned in unique PT_NOTE program
header entry.

Also, some part that assumes past ELF headers' size is replaced by
this new rounded-up value.

Signed-off-by: HATAYAMA Daisuke <d.hatayama@jp.fujitsu.com>
---

 fs/proc/vmcore.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 85714c3..5010ead 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -313,7 +313,7 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 	phdr.p_flags   = 0;
 	note_off = sizeof(Elf64_Ehdr) +
 			(ehdr_ptr->e_phnum - nr_ptnote +1) * sizeof(Elf64_Phdr);
-	phdr.p_offset  = note_off;
+	phdr.p_offset  = roundup(note_off, PAGE_SIZE);
 	phdr.p_vaddr   = phdr.p_paddr = 0;
 	phdr.p_filesz  = phdr.p_memsz = phdr_sz;
 	phdr.p_align   = 0;
@@ -331,6 +331,8 @@ static int __init merge_note_headers_elf64(char *elfptr, size_t *elfsz,
 	/* Modify e_phnum to reflect merged headers. */
 	ehdr_ptr->e_phnum = ehdr_ptr->e_phnum - nr_ptnote + 1;
 
+	*elfsz = roundup(*elfsz, PAGE_SIZE);
+
 	return 0;
 }
 
@@ -431,9 +433,8 @@ static int __init process_ptload_program_headers_elf64(char *elfptr,
 	phdr_ptr = (Elf64_Phdr*)(elfptr + sizeof(Elf64_Ehdr)); /* PT_NOTE hdr */
 
 	/* First program header is PT_NOTE header. */
-	vmcore_off = sizeof(Elf64_Ehdr) +
-			(ehdr_ptr->e_phnum) * sizeof(Elf64_Phdr) +
-			phdr_ptr->p_memsz; /* Note sections */
+	vmcore_off = phdr_ptr->p_offset + roundup(phdr_ptr->p_memsz,
+						  PAGE_SIZE);
 
 	for (i = 0; i < ehdr_ptr->e_phnum; i++, phdr_ptr++) {
 		if (phdr_ptr->p_type != PT_LOAD)