ppc64 ELF allows the 288 bytes below the stack pointer to be accessed.
git-svn-id: svn://svn.valgrind.org/valgrind/trunk@5425 a5019735-40e9-0310-863c-91ae7b9d1cf9
diff --git a/include/pub_tool_machine.h b/include/pub_tool_machine.h
index 948df5a..f4cd312 100644
--- a/include/pub_tool_machine.h
+++ b/include/pub_tool_machine.h
@@ -36,7 +36,7 @@
# define VG_MAX_INSTR_SZB 16 // max length of native instruction
# define VG_CLREQ_SZB 18 // length of a client request, may
// be larger than VG_MAX_INSTR_SZB
-# define VG_STACK_REDZONE_SZB 0 // number of addressable bytes below SP
+# define VG_STACK_REDZONE_SZB 0 // number of addressable bytes below %RSP
#elif defined(VGA_amd64)
# define VG_MIN_INSTR_SZB 1
# define VG_MAX_INSTR_SZB 16
@@ -51,7 +51,8 @@
# define VG_MIN_INSTR_SZB 4
# define VG_MAX_INSTR_SZB 4
# define VG_CLREQ_SZB 24
-# define VG_STACK_REDZONE_SZB 0
+# define VG_STACK_REDZONE_SZB 288 // number of addressable bytes below R1
+ // from 64-bit PowerPC ELF ABI Supplement 1.7
#else
# error Unknown arch
#endif