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authorMathias Krause <minipli@grsecurity.net>2021-07-06 15:27:14 +0200
committerJason A. Donenfeld <Jason@zx2c4.com>2021-08-08 22:35:06 +0200
commit8118c247a75ae95169f0a9a539dfc661ffda8bc5 (patch)
treea005776668b40c25b8bdb5030347ac063a991f6a /src/crypto
parent29747255f9672035ccf9cc310b7ff66b1f35f1d2 (diff)
crypto: curve25519-x86_64: solve register constraints with reserved registersHEADmaster
The register constraints for the inline assembly in fsqr() and fsqr2() are pretty tight on what the compiler may assign to the remaining three register variables. The clobber list only allows the following to be used: RDI, RSI, RBP and R12. With RAP reserving R12 and a kernel having CONFIG_FRAME_POINTER=y, claiming RBP, there are only two registers left so the compiler rightfully complains about impossible constraints. Provide alternatives that'll allow a memory reference for 'out' to solve the allocation constraint dilemma for this configuration. Signed-off-by: Mathias Krause <minipli@grsecurity.net> Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Diffstat (limited to 'src/crypto')
-rw-r--r--src/crypto/zinc/curve25519/curve25519-x86_64.c4
1 files changed, 2 insertions, 2 deletions
diff --git a/src/crypto/zinc/curve25519/curve25519-x86_64.c b/src/crypto/zinc/curve25519/curve25519-x86_64.c
index 79716c4..67f55af 100644
--- a/src/crypto/zinc/curve25519/curve25519-x86_64.c
+++ b/src/crypto/zinc/curve25519/curve25519-x86_64.c
@@ -581,7 +581,7 @@ static inline void fsqr(u64 *out, const u64 *f, u64 *tmp)
" cmovc %%rdx, %%rax;"
" add %%rax, %%r8;"
" movq %%r8, 0(%0);"
- : "+&r" (tmp), "+&r" (f), "+&r" (out)
+ : "+&r,&r" (tmp), "+&r,&r" (f), "+&r,m" (out)
:
: "%rax", "%rcx", "%rdx", "%r8", "%r9", "%r10", "%r11", "%rbx", "%r13", "%r14", "%r15", "memory", "cc"
);
@@ -743,7 +743,7 @@ static inline void fsqr2(u64 *out, const u64 *f, u64 *tmp)
" cmovc %%rdx, %%rax;"
" add %%rax, %%r8;"
" movq %%r8, 32(%0);"
- : "+&r" (tmp), "+&r" (f), "+&r" (out)
+ : "+&r,&r" (tmp), "+&r,&r" (f), "+&r,m" (out)
:
: "%rax", "%rcx", "%rdx", "%r8", "%r9", "%r10", "%r11", "%rbx", "%r13", "%r14", "%r15", "memory", "cc"
);