The branch master has been updated
via adc4f1fc25b2cac90076f1e1695b05b7aeeae501 (commit)
from 56cd71b46e5fe4f403c6247d83c2ad88e537b6c3 (commit)
- Log -----------------------------------------------------------------
commit adc4f1fc25b2cac90076f1e1695b05b7aeeae501
Author: Andy Polyakov <[email protected]>
Date: Fri Mar 4 11:39:11 2016 +0100
bn/asm/x86[_64]-mont*.pl: complement alloca with page-walking.
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...
Reviewed-by: Rich Salz <[email protected]>
-----------------------------------------------------------------------
Summary of changes:
crypto/bn/asm/x86-mont.pl | 15 +++++++++++
crypto/bn/asm/x86_64-mont.pl | 42 ++++++++++++++++++++++++++++-
crypto/bn/asm/x86_64-mont5.pl | 61 ++++++++++++++++++++++++++++++++++++++++++-
3 files changed, 116 insertions(+), 2 deletions(-)
diff --git a/crypto/bn/asm/x86-mont.pl b/crypto/bn/asm/x86-mont.pl
index e8f6b05..89f4de6 100755
--- a/crypto/bn/asm/x86-mont.pl
+++ b/crypto/bn/asm/x86-mont.pl
@@ -85,6 +85,21 @@ $frame=32; # size of above frame
rounded up to 16n
&and ("esp",-64); # align to cache line
+ # 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...
+ &mov ("eax","ebp");
+ &sub ("eax","esp");
+ &and ("eax",-4096);
+&set_label("page_walk");
+ &mov ("edx",&DWP(0,"esp","eax"));
+ &sub ("eax",4096);
+ &data_byte(0x2e);
+ &jnc (&label("page_walk"));
+
################################# load argument block...
&mov ("eax",&DWP(0*4,"esi"));# BN_ULONG *rp
&mov ("ebx",&DWP(1*4,"esi"));# const BN_ULONG *ap
diff --git a/crypto/bn/asm/x86_64-mont.pl b/crypto/bn/asm/x86_64-mont.pl
index 29ba122..8fb6c99 100755
--- a/crypto/bn/asm/x86_64-mont.pl
+++ b/crypto/bn/asm/x86_64-mont.pl
@@ -130,6 +130,20 @@ $code.=<<___;
mov %r11,8(%rsp,$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,%r11
+ and \$-4096,%r11
+.Lmul_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x66,0x2e # predict non-taken
+ jnc .Lmul_page_walk
+
mov $bp,%r12 # reassign $bp
___
$bp="%r12";
@@ -342,6 +356,14 @@ $code.=<<___;
mov %r11,8(%rsp,$num,8) # tp[num+1]=%rsp
.Lmul4x_body:
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lmul4x_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x2e # predict non-taken
+ jnc .Lmul4x_page_walk
+
mov $rp,16(%rsp,$num,8) # tp[num+2]=$rp
mov %rdx,%r12 # reassign $bp
___
@@ -795,6 +817,15 @@ bn_sqr8x_mont:
sub %r11,%rsp
.Lsqr8x_sp_done:
and \$-64,%rsp
+ mov %rax,%r11
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lsqr8x_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x2e # predict non-taken
+ jnc .Lsqr8x_page_walk
+
mov $num,%r10
neg $num
@@ -932,8 +963,17 @@ bn_mulx4x_mont:
sub $num,%r10 # -$num
mov ($n0),$n0 # *n0
lea -72(%rsp,%r10),%rsp # alloca(frame+$num+8)
- lea ($bp,$num),%r10
and \$-128,%rsp
+ mov %rax,%r11
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lmulx4x_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x66,0x2e # predict non-taken
+ jnc .Lmulx4x_page_walk
+
+ lea ($bp,$num),%r10
##############################################################
# Stack layout
# +0 num
diff --git a/crypto/bn/asm/x86_64-mont5.pl b/crypto/bn/asm/x86_64-mont5.pl
index 2e8c9db..938e170 100755
--- a/crypto/bn/asm/x86_64-mont5.pl
+++ b/crypto/bn/asm/x86_64-mont5.pl
@@ -115,6 +115,20 @@ $code.=<<___;
mov %rax,8(%rsp,$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";
@@ -469,6 +483,15 @@ $code.=<<___;
sub %r11,%rsp
.Lmul4xsp_done:
and \$-64,%rsp
+ mov %rax,%r11
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lmul4x_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x2e # predict non-taken
+ jnc .Lmul4x_page_walk
+
neg $num
mov %rax,40(%rsp)
@@ -1058,6 +1081,15 @@ $code.=<<___;
sub %r11,%rsp
.Lpwr_sp_done:
and \$-64,%rsp
+ mov %rax,%r11
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lpwr_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x2e # predict non-taken
+ jnc .Lpwr_page_walk
+
mov $num,%r10
neg $num
@@ -2028,7 +2060,16 @@ bn_from_mont8x:
sub %r11,%rsp
.Lfrom_sp_done:
and \$-64,%rsp
- mov $num,%r10
+ mov %rax,%r11
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lfrom_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x2e # predict non-taken
+ jnc .Lfrom_page_walk
+
+ mov $num,%r10
neg $num
##############################################################
@@ -2173,6 +2214,15 @@ bn_mulx4x_mont_gather5:
sub %r11,%rsp
.Lmulx4xsp_done:
and \$-64,%rsp # ensure alignment
+ mov %rax,%r11
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lmulx4x_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x2e # predict non-taken
+ jnc .Lmulx4x_page_walk
+
##############################################################
# Stack layout
# +0 -num
@@ -2619,6 +2669,15 @@ bn_powerx5:
sub %r11,%rsp
.Lpwrx_sp_done:
and \$-64,%rsp
+ mov %rax,%r11
+ sub %rsp,%r11
+ and \$-4096,%r11
+.Lpwrx_page_walk:
+ mov (%rsp,%r11),%r10
+ sub \$4096,%r11
+ .byte 0x2e # predict non-taken
+ jnc .Lpwrx_page_walk
+
mov $num,%r10
neg $num
_____
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