37 lines
1.5 KiB
Diff
37 lines
1.5 KiB
Diff
|
From 7c847235e8f0e0b877c505f19733b417bb65ff2e Mon Sep 17 00:00:00 2001
|
||
|
|
From: Gilles Peskine <Gilles.Peskine@arm.com>
|
||
|
|
Date: Tue, 14 Sep 2021 00:13:05 +0200
|
||
|
|
Subject: [PATCH] x86_64 MULADDC assembly: add missing constraints about memory
|
||
|
|
|
||
|
|
MULADDC_CORE reads from (%%rsi) and writes to (%%rdi). This fragment is
|
||
|
|
repeated up to 16 times, and %%rsi and %%rdi are s and d on entry
|
||
|
|
respectively. Hence the complete asm statement reads 16 64-bit words
|
||
|
|
from memory starting at s, and writes 16 64-bit words starting at d.
|
||
|
|
|
||
|
|
Without any declaration of modified memory, Clang 12 and Clang 13 generated
|
||
|
|
non-working code for mbedtls_mpi_mod_exp. The constraints make the unit
|
||
|
|
tests pass with Clang 12.
|
||
|
|
|
||
|
|
Signed-off-by: Gilles Peskine <Gilles.Peskine@arm.com>
|
||
|
|
---
|
||
|
|
include/mbedtls/bn_mul.h | 6 +++---
|
||
|
|
1 file changed, 3 insertions(+), 3 deletions(-)
|
||
|
|
|
||
|
|
diff --git a/include/mbedtls/bn_mul.h b/include/mbedtls/bn_mul.h
|
||
|
|
index 6f1201bf50a..f84f9650ddc 100644
|
||
|
|
--- a/include/mbedtls/bn_mul.h
|
||
|
|
+++ b/include/mbedtls/bn_mul.h
|
||
|
|
@@ -256,9 +256,9 @@
|
||
|
|
"addq $8, %%rdi\n"
|
||
|
|
|
||
|
|
#define MULADDC_STOP \
|
||
|
|
- : "+c" (c), "+D" (d), "+S" (s) \
|
||
|
|
- : "b" (b) \
|
||
|
|
- : "rax", "rdx", "r8" \
|
||
|
|
+ : "+c" (c), "+D" (d), "+S" (s), "+m" (*(uint64_t (*)[16]) d) \
|
||
|
|
+ : "b" (b), "m" (*(const uint64_t (*)[16]) s) \
|
||
|
|
+ : "rax", "rdx", "r8" \
|
||
|
|
);
|
||
|
|
|
||
|
|
#endif /* AMD64 */
|