3 files changed, 20 insertions, 5 deletions

diff --git a/arch/powerpc/include/asm/compat.h b/arch/powerpc/include/asm/compat.h
index 84fdf6857c31..a613d2c82fd9 100644
--- a/arch/powerpc/include/asm/compat.h
+++ b/arch/powerpc/include/asm/compat.h
@@ -200,10 +200,11 @@ static inline void __user *arch_compat_alloc_user_space(long len)
 
         /*
          * We can't access below the stack pointer in the 32bit ABI and
-         * can access 288 bytes in the 64bit ABI
+         * can access 288 bytes in the 64bit big-endian ABI,
+         * or 512 bytes with the new ELFv2 little-endian ABI.
          */
         if (!is_32bit_task())
-                usp -= 288;
+                usp -= USER_REDZONE_SIZE;
 
         return (void __user *) (usp - len);
 }
diff --git a/arch/powerpc/include/asm/ptrace.h b/arch/powerpc/include/asm/ptrace.h
index becc08e6a65c..279b80f3bb29 100644
--- a/arch/powerpc/include/asm/ptrace.h
+++ b/arch/powerpc/include/asm/ptrace.h
@@ -28,11 +28,23 @@
 
 #ifdef __powerpc64__
 
+/*
+ * Size of redzone that userspace is allowed to use below the stack
+ * pointer.  This is 288 in the 64-bit big-endian ELF ABI, and 512 in
+ * the new ELFv2 little-endian ABI, so we allow the larger amount.
+ *
+ * For kernel code we allow a 288-byte redzone, in order to conserve
+ * kernel stack space; gcc currently only uses 288 bytes, and will
+ * hopefully allow explicit control of the redzone size in future.
+ */
+#define USER_REDZONE_SIZE       512
+#define KERNEL_REDZONE_SIZE     288
+
 #define STACK_FRAME_OVERHEAD    112     /* size of minimum stack frame */
 #define STACK_FRAME_LR_SAVE     2       /* Location of LR in stack frame */
 #define STACK_FRAME_REGS_MARKER ASM_CONST(0x7265677368657265)
 #define STACK_INT_FRAME_SIZE    (sizeof(struct pt_regs) + \
-                                        STACK_FRAME_OVERHEAD + 288)
+                                 STACK_FRAME_OVERHEAD + KERNEL_REDZONE_SIZE)
 #define STACK_FRAME_MARKER      12
 
 /* Size of dummy stack frame allocated when calling signal handler. */
@@ -41,6 +53,8 @@
 
 #else /* __powerpc64__ */
 
+#define USER_REDZONE_SIZE       0
+#define KERNEL_REDZONE_SIZE     0
 #define STACK_FRAME_OVERHEAD    16      /* size of minimum stack frame */
 #define STACK_FRAME_LR_SAVE     1       /* Location of LR in stack frame */
 #define STACK_FRAME_REGS_MARKER ASM_CONST(0x72656773)
diff --git a/arch/powerpc/kernel/signal_64.c b/arch/powerpc/kernel/signal_64.c
index e35bf773df7a..8d253c29649b 100644
--- a/arch/powerpc/kernel/signal_64.c
+++ b/arch/powerpc/kernel/signal_64.c
@@ -65,8 +65,8 @@ struct rt_sigframe {
         struct siginfo __user *pinfo;
         void __user *puc;
         struct siginfo info;
-        /* 64 bit ABI allows for 288 bytes below sp before decrementing it. */
-        char abigap[288];
+        /* New 64 bit little-endian ABI allows redzone of 512 bytes below sp */
+        char abigap[USER_REDZONE_SIZE];
 } __attribute__ ((aligned (16)));
 
 static const char fmt32[] = KERN_INFO \