diff options
Diffstat (limited to 'crypto/bn/asm/x86_64-mont5.pl')
| -rwxr-xr-x | crypto/bn/asm/x86_64-mont5.pl | 22 |
1 files changed, 22 insertions, 0 deletions
diff --git a/crypto/bn/asm/x86_64-mont5.pl b/crypto/bn/asm/x86_64-mont5.pl index 235979181f54..99243ae3ec2c 100755 --- a/crypto/bn/asm/x86_64-mont5.pl +++ b/crypto/bn/asm/x86_64-mont5.pl @@ -84,6 +84,20 @@ bn_mul_mont_gather5: mov %rax,8(%rsp,$num,8) # tp[num+1]=%rsp .Lmul_body: + # Some OSes, *cough*-dows, insist on stack being "wired" to + # physical memory in strictly sequential manner, i.e. if stack + # allocation spans two pages, then reference to farmost one can + # be punishable by SEGV. But page walking can do good even on + # other OSes, because it guarantees that villain thread hits + # the guard page before it can make damage to innocent one... + sub %rsp,%rax + and \$-4096,%rax +.Lmul_page_walk: + mov (%rsp,%rax),%r11 + sub \$4096,%rax + .byte 0x2e # predict non-taken + jnc .Lmul_page_walk + lea 128($bp),%r12 # reassign $bp (+size optimization) ___ $bp="%r12"; @@ -407,6 +421,14 @@ bn_mul4x_mont_gather5: mov %rax,8(%rsp,$num,8) # tp[num+1]=%rsp .Lmul4x_body: + sub %rsp,%rax + and \$-4096,%rax +.Lmul4x_page_walk: + mov (%rsp,%rax),%r11 + sub \$4096,%rax + .byte 0x2e # predict non-taken + jnc .Lmul4x_page_walk + mov $rp,16(%rsp,$num,8) # tp[num+2]=$rp lea 128(%rdx),%r12 # reassign $bp (+size optimization) ___ |