c38fcb5dc3
We used to use performance cycle counter for cycles(), but it is kind of useless in userspace as each core has its own counter and hence not comparable between cores. Also, the cycle counter stops counting when the cores are idle. Most callers expect cycles() to return a high resolution timestamp instead, so do the best we can do here and enable the userspace generic timer virtual counter.
8 lines
194 B
ArmAsm
8 lines
194 B
ArmAsm
#define SYSREG(op0,op1,Cn,Cm,op2) SPR(((op0)<<19|(op1)<<16|(Cn)<<12|(Cm)<<8|(op2)<<5))
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#define CNTVCT_EL0 SYSREG(3,3,14,0,2)
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TEXT cycles(SB), 1, $-4
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MRS CNTVCT_EL0, R1
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MOV R1, (R0)
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RETURN
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