[4/8] x86-64 memrchr: Properly handle the length parameter [BZ# 24097]
Commit Message
On x32, the size_t parameter may be passed in the lower 32 bits of a
64-bit register with the non-zero upper 32 bits. The string/memory
functions written in assembly can only use the lower 32 bits of a
64-bit register as length or must clear the upper 32 bits before using
the full 64-bit register for length.
This pach fixes memrchr for x32. Tested on x86-64 and x32. On x86-64,
libc.so is the same with and withou the fix.
[BZ# 24097]
* sysdeps/x86_64/memrchr.S: Use RDX_LP for length.
* sysdeps/x86_64/multiarch/memrchr-avx2.S: Likewise.
* sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memrchr.
* sysdeps/x86_64/x32/tst-size_t-memrchr.c: New file.
---
sysdeps/x86_64/memrchr.S | 4 +-
sysdeps/x86_64/multiarch/memrchr-avx2.S | 4 +-
sysdeps/x86_64/x32/Makefile | 3 +-
sysdeps/x86_64/x32/tst-size_t-memrchr.c | 57 +++++++++++++++++++++++++
4 files changed, 63 insertions(+), 5 deletions(-)
create mode 100644 sysdeps/x86_64/x32/tst-size_t-memrchr.c
@@ -24,13 +24,13 @@
ENTRY (__memrchr)
movd %esi, %xmm1
- sub $16, %rdx
+ sub $16, %RDX_LP
jbe L(length_less16)
punpcklbw %xmm1, %xmm1
punpcklbw %xmm1, %xmm1
- add %rdx, %rdi
+ add %RDX_LP, %RDI_LP
pshufd $0, %xmm1, %xmm1
movdqu (%rdi), %xmm0
@@ -32,10 +32,10 @@ ENTRY (__memrchr_avx2)
vmovd %esi, %xmm0
vpbroadcastb %xmm0, %ymm0
- subq $VEC_SIZE, %rdx
+ sub $VEC_SIZE, %RDX_LP
jbe L(last_vec_or_less)
- addq %rdx, %rdi
+ add %RDX_LP, %RDI_LP
/* Check the last VEC_SIZE bytes. */
vpcmpeqb (%rdi), %ymm0, %ymm1
@@ -6,7 +6,8 @@ CFLAGS-s_llround.c += -fno-builtin-lround
endif
ifeq ($(subdir),string)
-tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy
+tests += tst-size_t-memchr tst-size_t-memcmp tst-size_t-memcpy \
+ tst-size_t-memrchr
endif
ifeq ($(subdir),wcsmbs)
new file mode 100644
@@ -0,0 +1,57 @@
+/* Test memrchr with size_t in the lower 32 bits of 64-bit register.
+ Copyright (C) 2019 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, see
+ <http://www.gnu.org/licenses/>. */
+
+#define TEST_NAME "memrchr"
+#include "test-size_t.h"
+
+IMPL (memchr, 1)
+
+typedef void * (*proto_t) (const void *, int, size_t);
+
+static void *
+__attribute__ ((noinline, noclone))
+do_memrchr (parameter_t a, parameter_t b)
+{
+ return CALL (b, a.p, (uintptr_t) b.p, a.len);
+}
+
+static int
+do_test (void)
+{
+ test_init ();
+
+ parameter_t src = { { page_size }, buf2 };
+ parameter_t c = { { 0 }, (void *) (uintptr_t) 0x12 };
+
+ int ret = 0;
+ FOR_EACH_IMPL (impl, 0)
+ {
+ c.fn = impl->fn;
+ void * res = do_memrchr (src, c);
+ if (res)
+ {
+ error (0, 0, "Wrong result in function %s: %p != NULL",
+ impl->name, res);
+ ret = 1;
+ }
+ }
+
+ return ret ? EXIT_FAILURE : EXIT_SUCCESS;
+}
+
+#include <support/test-driver.c>