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init_fpu: only call xgetbv if we have XSAVE cpuid

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xgetbv crashes on cpu without avx, the XSAVE bit seems to indicate
that it is ok to call xgetbv
This commit is contained in:
Dominique Martinet
2017-09-11 07:17:59 +00:00
committed by Balazs Gerofi
parent 99a45f20c2
commit 230272438f
1 changed files with 8 additions and 9 deletions
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17
arch/x86/kernel/cpu.c
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@ -225,12 +225,6 @@ void init_fpu(void)
dkprintf("init_fpu(): SSE init: CR4 = 0x%016lX\n", reg);
/* Set xcr0[2:1] to enable avx ops */
if(cpuid01_ecx & (1 << 28)) {
reg = xgetbv(0);
reg |= 0x6;
xsetbv(0, reg);
dkprintf("init_fpu(): AVX init: XCR0 = 0x%016lX\n", reg);
}
if(xsave_available){
unsigned long eax;
unsigned long ebx;
@ -246,11 +240,16 @@ void init_fpu(void)
reg |= 0xe6;
xsetbv(0, reg);
dkprintf("init_fpu(): AVX-512 init: XCR0 = 0x%016lX\n", reg);
} else {
reg = xgetbv(0);
reg |= 0x6;
xsetbv(0, reg);
dkprintf("init_fpu(): AVX init: XCR0 = 0x%016lX\n", reg);
}
}
xsave_mask = xgetbv(0);
dkprintf("init_fpu(): xsave_mask = 0x%016lX\n", xsave_mask);
xsave_mask = xgetbv(0);
dkprintf("init_fpu(): xsave_mask = 0x%016lX\n", xsave_mask);
}
/* TODO: set MSR_IA32_XSS to enable xsaves/xrstors */