bdab3c4cfb
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.
35 lines
663 B
C
35 lines
663 B
C
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#include <stdint.h>
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#include <minix/minlib.h>
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#include <minix/cpufeature.h>
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#include <sys/vm_i386.h>
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int _cpufeature(int cpufeature)
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{
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u32_t cpuid_feature_edx = 0;
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int proc;
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proc = getprocessor();
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/* If processor supports CPUID and its CPUID supports enough
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* parameters, retrieve EDX feature flags to test against.
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*/
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if(proc >= 586) {
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u32_t params, a, b, c, d;
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_cpuid(0, ¶ms, &b, &c, &d);
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if(params > 0) {
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_cpuid(1, &a, &b, &c, &cpuid_feature_edx);
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}
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}
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switch(cpufeature) {
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case _CPUF_I386_PSE:
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return cpuid_feature_edx & CPUID1_EDX_PSE;
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case _CPUF_I386_PGE:
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return cpuid_feature_edx & CPUID1_EDX_PGE;
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}
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return 0;
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}
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