minix/lib/i386/misc/_cpufeature.c
Ben Gras bdab3c4cfb Library call for cpu features; make kernel and vm use this to query cpu
features (specifically: 4MB pages and TLB global bit).  Only enable
these features in CR4 if available. 4MB pages to be used in the near
future.
2009-05-15 17:07:36 +00:00

34 lines
663 B
C

#include <stdint.h>
#include <minix/minlib.h>
#include <minix/cpufeature.h>
#include <sys/vm_i386.h>
int _cpufeature(int cpufeature)
{
u32_t cpuid_feature_edx = 0;
int proc;
proc = getprocessor();
/* If processor supports CPUID and its CPUID supports enough
* parameters, retrieve EDX feature flags to test against.
*/
if(proc >= 586) {
u32_t params, a, b, c, d;
_cpuid(0, &params, &b, &c, &d);
if(params > 0) {
_cpuid(1, &a, &b, &c, &cpuid_feature_edx);
}
}
switch(cpufeature) {
case _CPUF_I386_PSE:
return cpuid_feature_edx & CPUID1_EDX_PSE;
case _CPUF_I386_PGE:
return cpuid_feature_edx & CPUID1_EDX_PGE;
}
return 0;
}