[ARM] 3108/2: old ABI compat: statfs64 and fstatfs64

Patch from Nicolas Pitre

struct statfs64 has extra padding with EABI growing its size from 84 to
88. This struct is now __attribute__((packed,aligned(4))) with a small
assembly wrapper to force the sz argument to 84 if it is 88 to avoid
copying the extra padding over user space memory unexpecting it.

Signed-off-by: Nicolas Pitre <nico@cam.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

2 files changed, 12 insertions, 2 deletions

diff --git a/arch/arm/kernel/calls.S b/arch/arm/kernel/calls.S
index 55076a75e5bf..8c0bf04814b1 100644
--- a/arch/arm/kernel/calls.S
+++ b/arch/arm/kernel/calls.S
@@ -280,8 +280,8 @@ __syscall_start:
                 .long   sys_clock_gettime
                 .long   sys_clock_getres
 /* 265 */       .long   sys_clock_nanosleep
-                .long   sys_statfs64
-                .long   sys_fstatfs64
+                .long   sys_statfs64_wrapper
+                .long   sys_fstatfs64_wrapper
                 .long   sys_tgkill
                 .long   sys_utimes
 /* 270 */       .long   sys_arm_fadvise64_64
diff --git a/arch/arm/kernel/entry-common.S b/arch/arm/kernel/entry-common.S
index 34826bcceb7a..ee63ee78d84f 100644
--- a/arch/arm/kernel/entry-common.S
+++ b/arch/arm/kernel/entry-common.S
@@ -262,6 +262,16 @@ sys_sigaltstack_wrapper:
                 ldr     r2, [sp, #S_OFF + S_SP]
                 b       do_sigaltstack
 
+sys_statfs64_wrapper:
+                teq     r1, #88
+                moveq   r1, #84
+                b       sys_statfs64
+
+sys_fstatfs64_wrapper:
+                teq     r1, #88
+                moveq   r1, #84
+                b       sys_fstatfs64
+
 /*
  * Note: off_4k (r5) is always units of 4K.  If we can't do the requested
  * offset, we return EINVAL.