From 5e628dd118807981bdd880731e6fdf019f64a245 Mon Sep 17 00:00:00 2001 From: Tulio Magno Quites Machado Filho Date: Wed, 28 Dec 2016 11:38:56 -0200 Subject: powerpc: Fix powerpc32/power7 memchr for large input sizes The same error fixed in commit b224637928e9fc04e3cef3e10d02ccf042d01584 happens in the 32-bit implementation of memchr for power7. This patch adopts the same solution, with a minimal change: it implements a saturated addition where overflows sets the maximum pointer size to UINTPTR_MAX. --- ChangeLog | 5 +++++ sysdeps/powerpc/powerpc32/power7/memchr.S | 11 ++++++++++- 2 files changed, 15 insertions(+), 1 deletion(-) diff --git a/ChangeLog b/ChangeLog index d9b2c98..1ad6867 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,8 @@ +2016-12-28 Tulio Magno Quites Machado Filho + + * sysdeps/powerpc/powerpc32/power7/memchr.S (__memchr): Avoid an + overflow in pointer addition. + 2016-12-28 Rajalakshmi Srinivasaraghavan * sysdeps/powerpc/powerpc64/multiarch/Makefile diff --git a/sysdeps/powerpc/powerpc32/power7/memchr.S b/sysdeps/powerpc/powerpc32/power7/memchr.S index 318168b..5ce2bb0 100644 --- a/sysdeps/powerpc/powerpc32/power7/memchr.S +++ b/sysdeps/powerpc/powerpc32/power7/memchr.S @@ -26,7 +26,16 @@ ENTRY (__memchr) dcbt 0,r3 clrrwi r8,r3,2 insrwi r4,r4,8,16 /* Replicate byte to word. */ - add r7,r3,r5 /* Calculate the last acceptable address. */ + + /* Calculate the last acceptable address and check for possible + addition overflow by using satured math: + r7 = r3 + r5 + r7 |= -(r7 < x) */ + add r7,r3,r5 + subfc r6,r3,r7 + subfe r9,r9,r9 + or r7,r7,r9 + insrwi r4,r4,16,0 cmplwi r5,16 li r9, -1 -- cgit v1.1