61 lines
854 B
C
61 lines
854 B
C
#include <ddk.h>
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#define U64_C(x) x ## ULL
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#define BIT_64(n) (U64_C(1) << (n))
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struct e_msr {
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union {
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struct {
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u32 l;
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u32 h;
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};
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u64 q;
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};
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};
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static void _msr_read(u32 msr, struct e_msr *m)
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{
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__asm__ __volatile__(
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"rdmsr"
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:"=a"(m->l), "=d"(m->h)
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:"c"(msr)
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:"memory"
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);
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}
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static void _msr_write(u32 msr, struct e_msr *m)
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{
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__asm__ __volatile__(
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"wrmsr"
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::"a"(m->l), "d"(m->h), "c"(msr)
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:"memory"
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);
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}
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static int __flip_bit(u32 msr, u8 bit, bool set)
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{
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struct e_msr m, m1;
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if (bit > 63)
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return EINVAL;
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_msr_read(msr, &m);
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m1 = m;
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if (set)
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m1.q |= BIT_64(bit);
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else
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m1.q &= ~BIT_64(bit);
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if (m1.q == m.q)
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return 0;
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_msr_write(msr, &m1);
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return 1;
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}
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int e_msr_set_bit(u32 msr, u8 bit)
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{
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return __flip_bit(msr, bit, true);
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} |