1 files changed, 15 insertions, 1 deletions

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)