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cryptlib.c: OPENSSL_ia32cap environment variable to interpret ~ as cpuid mask.

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This commit is contained in:
Andy Polyakov 2011-07-23 12:10:26 +00:00
parent 66b86a4fd5
commit 2667162d33
2 changed files with 10 additions and 7 deletions
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9
crypto/cryptlib.c
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@ -144,12 +144,15 @@ void OPENSSL_cpuid_setup(void)
if (trigger) return;
trigger=1;
if ((env=getenv("OPENSSL_ia32cap")))
if ((env=getenv("OPENSSL_ia32cap"))) {
int off = (env[0]=='~')?1:0;
#if defined(_WIN32)
{ if (!sscanf(env,"%I64i",&vec)) vec = strtoul(env,NULL,0); }
if (!sscanf(env+off,"%I64i",&vec)) vec = strtoul(env+off,NULL,0);
#else
vec = strtoull(env,NULL,0);
vec = strtoull(env+off,NULL,0);
#endif
if (off) vec = OPENSSL_ia32_cpuid()&~vec;
}
else
vec = OPENSSL_ia32_cpuid();

8
doc/crypto/OPENSSL_ia32cap.pod
View File

@ -61,10 +61,10 @@ capable CPU, but under control of OS that does not enable XMM
registers. Even though you can manipulate the value programmatically,
you most likely will find it more appropriate to set up an environment
variable with the same name prior starting target application, e.g. on
Intel P4 processor 'env OPENSSL_ia32cap=0x16980010 apps/openssl', to
achieve same effect without modifying the application source code.
Alternatively you can reconfigure the toolkit with no-sse2 option and
recompile.
Intel P4 processor 'env OPENSSL_ia32cap=0x16980010 apps/openssl', or
better yet 'env OPENSSL_ia32cap=~0x1000000 apps/openssl' to achieve same
effect without modifying the application source code. Alternatively you
can reconfigure the toolkit with no-sse2 option and recompile.
Less intuituve is clearing bit #28. The truth is that it's not copied
from CPUID output verbatim, but is adjusted to reflect whether or not