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Re: PATCH: Remove the `q' suffix in x86_64 PTR_MANGLE/PTR_DEMANGLE
On Fri, Mar 16, 2012 at 4:35 PM, Roland McGrath <roland@hack.frob.com> wrote:
>> defines LP_SIZE. ?We can simple use $2*LP_SIZE+1 instead of $17.
>> It works for me.
>
> That seems less obvious than just using sizeof (void *).
> You only need that macro for assembly code, where you cannot
> use generic C logic.
>
Here is the updated patch to use LP_SIZE. It is consistent
between asm statement and asm code. But I don't mind to use
sizeof (void *) in asm statement.
Thanks.
--
H.J.
2012-03-16 H.J. Lu <hongjiu.lu@intel.com>
* sysdeps/unix/sysv/linux/x86_64/sysdep.h (PTR_MANGLE): Remove the
`q' suffix from xor/rol instructions. Use $2*LP_SIZE+1 instead of
$17.
(PTR_DEMANGLE): Likewise.
diff --git a/sysdeps/unix/sysv/linux/x86_64/sysdep.h b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
index c9c4dbd..aae4cb0 100644
--- a/sysdeps/unix/sysv/linux/x86_64/sysdep.h
+++ b/sysdeps/unix/sysv/linux/x86_64/sysdep.h
@@ -342,33 +342,33 @@
/* We cannot use the thread descriptor because in ld.so we use setjmp
earlier than the descriptor is initialized. */
# ifdef __ASSEMBLER__
-# define PTR_MANGLE(reg) xorq __pointer_chk_guard_local(%rip), reg; \
- rolq $17, reg
-# define PTR_DEMANGLE(reg) rorq $17, reg; \
- xorq __pointer_chk_guard_local(%rip), reg
+# define PTR_MANGLE(reg) xor __pointer_chk_guard_local(%rip), reg; \
+ rol $2*LP_SIZE+1, reg
+# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
+ xor __pointer_chk_guard_local(%rip), reg
# else
-# define PTR_MANGLE(reg) asm ("xorq __pointer_chk_guard_local(%%rip), %0\n" \
- "rolq $17, %0" \
+# define PTR_MANGLE(reg) asm ("xor __pointer_chk_guard_local(%%rip), %0\n" \
+ "rol $2*" LP_SIZE "+1, %0" \
: "=r" (reg) : "0" (reg))
-# define PTR_DEMANGLE(reg) asm ("rorq $17, %0\n" \
- "xorq __pointer_chk_guard_local(%%rip), %0" \
+# define PTR_DEMANGLE(reg) asm ("ror $2*" LP_SIZE "+1, %0\n" \
+ "xor __pointer_chk_guard_local(%%rip), %0" \
: "=r" (reg) : "0" (reg))
# endif
#else
# ifdef __ASSEMBLER__
-# define PTR_MANGLE(reg) xorq %fs:POINTER_GUARD, reg; \
- rolq $17, reg
-# define PTR_DEMANGLE(reg) rorq $17, reg; \
- xorq %fs:POINTER_GUARD, reg
+# define PTR_MANGLE(reg) xor %fs:POINTER_GUARD, reg; \
+ rol $2*LP_SIZE+1, reg
+# define PTR_DEMANGLE(reg) ror $2*LP_SIZE+1, reg; \
+ xor %fs:POINTER_GUARD, reg
# else
-# define PTR_MANGLE(var) asm ("xorq %%fs:%c2, %0\n" \
- "rolq $17, %0" \
+# define PTR_MANGLE(var) asm ("xor %%fs:%c2, %0\n" \
+ "rol $2*" LP_SIZE "+1, %0" \
: "=r" (var) \
: "0" (var), \
"i" (offsetof (tcbhead_t, \
pointer_guard)))
-# define PTR_DEMANGLE(var) asm ("rorq $17, %0\n" \
- "xorq %%fs:%c2, %0" \
+# define PTR_DEMANGLE(var) asm ("ror $2*" LP_SIZE "+1, %0\n" \
+ "xor %%fs:%c2, %0" \
: "=r" (var) \
: "0" (var), \
"i" (offsetof (tcbhead_t, \