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authorMike Frysinger <vapier@gentoo.org>2010-06-04 14:14:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2010-06-04 15:21:44 -0700
commit2e94de8acbe524d919f1ea8807913d7b005e1578 (patch)
tree4633b23444fbd08466b71bfc403e24f7d2db47b1 /fs/binfmt_flat.c
parent55adaa495edc429be84399f83df80dfb7f36598b (diff)
fs/binfmt_flat.c: split the stack & data alignments
The stack and data have different alignment requirements, so don't force them to wear the same shoe. Increase the data alignment to match that which the elf2flt linker script has always been using: 0x20 bytes. Not only does this bring the kernel loader in line with the toolchain, but it also fixes a swath of gcc tests which try to force larger alignment values but randomly fail when the FLAT loader fails to deliver. Signed-off-by: Mike Frysinger <vapier@gentoo.org> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: David Woodhouse <David.Woodhouse@intel.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Acked-by: David McCullough <davidm@snapgear.com> Acked-by: Greg Ungerer <gerg@uclinux.org> Cc: Paul Mundt <lethal@linux-sh.org> Tested-by: Michal Simek <monstr@monstr.eu> Cc: Hirokazu Takata <takata@linux-m32r.org> Cc: Yoshinori Sato <ysato@users.sourceforge.jp> Cc: Geert Uytterhoeven <geert@linux-m68k.org> Cc: Jie Zhang <jie@codesourcery.com> Cc: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/binfmt_flat.c')
-rw-r--r--fs/binfmt_flat.c23
1 files changed, 15 insertions, 8 deletions
diff --git a/fs/binfmt_flat.c b/fs/binfmt_flat.c
index 49566c1687d..b8656225b34 100644
--- a/fs/binfmt_flat.c
+++ b/fs/binfmt_flat.c
@@ -56,15 +56,22 @@
#endif
/*
- * User data (stack, data section and bss) needs to be aligned
- * for the same reasons as SLAB memory is, and to the same amount.
- * Avoid duplicating architecture specific code by using the same
- * macro as with SLAB allocation:
+ * User data (data section and bss) needs to be aligned.
+ * We pick 0x20 here because it is the max value elf2flt has always
+ * used in producing FLAT files, and because it seems to be large
+ * enough to make all the gcc alignment related tests happy.
+ */
+#define FLAT_DATA_ALIGN (0x20)
+
+/*
+ * User data (stack) also needs to be aligned.
+ * Here we can be a bit looser than the data sections since this
+ * needs to only meet arch ABI requirements.
*/
#ifdef ARCH_SLAB_MINALIGN
-#define FLAT_DATA_ALIGN (ARCH_SLAB_MINALIGN)
+#define FLAT_STACK_ALIGN (ARCH_SLAB_MINALIGN)
#else
-#define FLAT_DATA_ALIGN (sizeof(void *))
+#define FLAT_STACK_ALIGN (sizeof(void *))
#endif
#define RELOC_FAILED 0xff00ff01 /* Relocation incorrect somewhere */
@@ -129,7 +136,7 @@ static unsigned long create_flat_tables(
sp = (unsigned long *)p;
sp -= (envc + argc + 2) + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
- sp = (unsigned long *) ((unsigned long)sp & -FLAT_DATA_ALIGN);
+ sp = (unsigned long *) ((unsigned long)sp & -FLAT_STACK_ALIGN);
argv = sp + 1 + (flat_argvp_envp_on_stack() ? 2 : 0);
envp = argv + (argc + 1);
@@ -876,7 +883,7 @@ static int load_flat_binary(struct linux_binprm * bprm, struct pt_regs * regs)
stack_len = TOP_OF_ARGS - bprm->p; /* the strings */
stack_len += (bprm->argc + 1) * sizeof(char *); /* the argv array */
stack_len += (bprm->envc + 1) * sizeof(char *); /* the envp array */
- stack_len += FLAT_DATA_ALIGN - 1; /* reserve for upcoming alignment */
+ stack_len += FLAT_STACK_ALIGN - 1; /* reserve for upcoming alignment */
res = load_flat_file(bprm, &libinfo, 0, &stack_len);
if (IS_ERR_VALUE(res))