diff options
Diffstat (limited to 'releases/2.6.32.58/crypto-sha512-avoid-stack-bloat-on-i386.patch')
| -rw-r--r-- | releases/2.6.32.58/crypto-sha512-avoid-stack-bloat-on-i386.patch | 111 |
1 files changed, 111 insertions, 0 deletions
diff --git a/releases/2.6.32.58/crypto-sha512-avoid-stack-bloat-on-i386.patch b/releases/2.6.32.58/crypto-sha512-avoid-stack-bloat-on-i386.patch new file mode 100644 index 0000000..2b7b393 --- /dev/null +++ b/releases/2.6.32.58/crypto-sha512-avoid-stack-bloat-on-i386.patch @@ -0,0 +1,111 @@ +From 3a92d687c8015860a19213e3c102cad6b722f83c Mon Sep 17 00:00:00 2001 +From: Herbert Xu <herbert@gondor.apana.org.au> +Date: Sun, 5 Feb 2012 15:09:28 +1100 +Subject: crypto: sha512 - Avoid stack bloat on i386 + +From: Herbert Xu <herbert@gondor.apana.org.au> + +commit 3a92d687c8015860a19213e3c102cad6b722f83c upstream. + +Unfortunately in reducing W from 80 to 16 we ended up unrolling +the loop twice. As gcc has issues dealing with 64-bit ops on +i386 this means that we end up using even more stack space (>1K). + +This patch solves the W reduction by moving LOAD_OP/BLEND_OP +into the loop itself, thus avoiding the need to duplicate it. + +While the stack space still isn't great (>0.5K) it is at least +in the same ball park as the amount of stack used for our C sha1 +implementation. + +Note that this patch basically reverts to the original code so +the diff looks bigger than it really is. + +Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> + +--- + crypto/sha512_generic.c | 68 ++++++++++++++++++++++-------------------------- + 1 file changed, 32 insertions(+), 36 deletions(-) + +--- a/crypto/sha512_generic.c ++++ b/crypto/sha512_generic.c +@@ -89,46 +89,42 @@ sha512_transform(u64 *state, const u8 *i + int i; + u64 W[16]; + +- /* load the input */ +- for (i = 0; i < 16; i++) +- LOAD_OP(i, W, input); +- + /* load the state into our registers */ + a=state[0]; b=state[1]; c=state[2]; d=state[3]; + e=state[4]; f=state[5]; g=state[6]; h=state[7]; + +-#define SHA512_0_15(i, a, b, c, d, e, f, g, h) \ +- t1 = h + e1(e) + Ch(e, f, g) + sha512_K[i] + W[i]; \ +- t2 = e0(a) + Maj(a, b, c); \ +- d += t1; \ +- h = t1 + t2 +- +-#define SHA512_16_79(i, a, b, c, d, e, f, g, h) \ +- BLEND_OP(i, W); \ +- t1 = h + e1(e) + Ch(e, f, g) + sha512_K[i] + W[(i)&15]; \ +- t2 = e0(a) + Maj(a, b, c); \ +- d += t1; \ +- h = t1 + t2 +- +- for (i = 0; i < 16; i += 8) { +- SHA512_0_15(i, a, b, c, d, e, f, g, h); +- SHA512_0_15(i + 1, h, a, b, c, d, e, f, g); +- SHA512_0_15(i + 2, g, h, a, b, c, d, e, f); +- SHA512_0_15(i + 3, f, g, h, a, b, c, d, e); +- SHA512_0_15(i + 4, e, f, g, h, a, b, c, d); +- SHA512_0_15(i + 5, d, e, f, g, h, a, b, c); +- SHA512_0_15(i + 6, c, d, e, f, g, h, a, b); +- SHA512_0_15(i + 7, b, c, d, e, f, g, h, a); +- } +- for (i = 16; i < 80; i += 8) { +- SHA512_16_79(i, a, b, c, d, e, f, g, h); +- SHA512_16_79(i + 1, h, a, b, c, d, e, f, g); +- SHA512_16_79(i + 2, g, h, a, b, c, d, e, f); +- SHA512_16_79(i + 3, f, g, h, a, b, c, d, e); +- SHA512_16_79(i + 4, e, f, g, h, a, b, c, d); +- SHA512_16_79(i + 5, d, e, f, g, h, a, b, c); +- SHA512_16_79(i + 6, c, d, e, f, g, h, a, b); +- SHA512_16_79(i + 7, b, c, d, e, f, g, h, a); ++ /* now iterate */ ++ for (i=0; i<80; i+=8) { ++ if (!(i & 8)) { ++ int j; ++ ++ if (i < 16) { ++ /* load the input */ ++ for (j = 0; j < 16; j++) ++ LOAD_OP(i + j, W, input); ++ } else { ++ for (j = 0; j < 16; j++) { ++ BLEND_OP(i + j, W); ++ } ++ } ++ } ++ ++ t1 = h + e1(e) + Ch(e,f,g) + sha512_K[i ] + W[(i & 15)]; ++ t2 = e0(a) + Maj(a,b,c); d+=t1; h=t1+t2; ++ t1 = g + e1(d) + Ch(d,e,f) + sha512_K[i+1] + W[(i & 15) + 1]; ++ t2 = e0(h) + Maj(h,a,b); c+=t1; g=t1+t2; ++ t1 = f + e1(c) + Ch(c,d,e) + sha512_K[i+2] + W[(i & 15) + 2]; ++ t2 = e0(g) + Maj(g,h,a); b+=t1; f=t1+t2; ++ t1 = e + e1(b) + Ch(b,c,d) + sha512_K[i+3] + W[(i & 15) + 3]; ++ t2 = e0(f) + Maj(f,g,h); a+=t1; e=t1+t2; ++ t1 = d + e1(a) + Ch(a,b,c) + sha512_K[i+4] + W[(i & 15) + 4]; ++ t2 = e0(e) + Maj(e,f,g); h+=t1; d=t1+t2; ++ t1 = c + e1(h) + Ch(h,a,b) + sha512_K[i+5] + W[(i & 15) + 5]; ++ t2 = e0(d) + Maj(d,e,f); g+=t1; c=t1+t2; ++ t1 = b + e1(g) + Ch(g,h,a) + sha512_K[i+6] + W[(i & 15) + 6]; ++ t2 = e0(c) + Maj(c,d,e); f+=t1; b=t1+t2; ++ t1 = a + e1(f) + Ch(f,g,h) + sha512_K[i+7] + W[(i & 15) + 7]; ++ t2 = e0(b) + Maj(b,c,d); e+=t1; a=t1+t2; + } + + state[0] += a; state[1] += b; state[2] += c; state[3] += d; |