[PATCH v2] mips: increase stack alignment in clone to match the ABI

[Xi Ruoyao]

v2: change the comment along with the code

I must have been too sleepy in recent two days...

--
In "mips: align stack in clone [BZ #28223]"
(commit 1f51cd9a860ee45eee8a56fb2ba925267a2a7bfe) I made a mistake: I
misbelieved one "word" was 2-byte and "doubleword" should be 4-byte.
But in MIPS ABI one "word" is defined 32-bit (4-byte), so "doubleword" is
8-byte [1], and "quadword" is 16-byte [2].

[1]: "System V Application Binary Interface: MIPS(R) RISC Processor
      Supplement, 3rd edition", page 3-31
[2]: "MIPSpro(TM) 64-Bit Porting and Transition Guide", page 23
---
 sysdeps/unix/sysv/linux/mips/clone.S | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/sysdeps/unix/sysv/linux/mips/clone.S b/sysdeps/unix/sysv/linux/mips/clone.S
index 43a5ad3a40..fd71b5ca2e 100644
--- a/sysdeps/unix/sysv/linux/mips/clone.S
+++ b/sysdeps/unix/sysv/linux/mips/clone.S
@@ -55,11 +55,11 @@ NESTED(__clone,4*SZREG,sp)
 	.set		at
 #endif
 
-	/* Align stack to 4/8 bytes per the ABI.  */
+	/* Align stack to 8/16 bytes per the ABI.  */
 #if _MIPS_SIM == _ABIO32
-	li		t0,-4
-#else
 	li		t0,-8
+#else
+	li		t0,-16
 #endif
 	and		a1,a1,t0
 
-- 
2.32.0



On Fri, 2021-08-13 at 18:43 +0800, Xi Ruoyao wrote:
> Hi Joseph,
> 
> Sorry for this, but I have to admit I've made an error in the previous
> patch.  In MIPS documentations one "word" is defined 32-bit (4-byte), so
> a "doubleword" is 8-byte and a "quadword" is 16-byte.  I misinterpreted
> "doubleword" as a "dword" we normally uses for 4-byte, so the alignment
> is actually insufficient.