dtracy: catch page faults
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6f30420136
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cc066d8130
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@ -511,6 +511,17 @@ TEXT _wrmsrinst(SB), $0
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MOVL BP, AX /* BP set to -1 if traped */
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RET
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/* fault-proof memcpy */
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TEXT peek(SB), $0
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MOVL $0, AX /* AX set to -1 if traped */
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MOVL src+0(FP), SI
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MOVL dst+4(FP), DI
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MOVL cnt+8(FP), CX
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CLD
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TEXT _peekinst(SB), $0
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REP; MOVSB
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RET
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/*
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* Try to determine the CPU type which requires fiddling with EFLAGS.
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* If the Id bit can be toggled then the CPUID instruction can be used
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@ -450,6 +450,7 @@ trap(Ureg* ureg)
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extern void _forkretiret(void);
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extern void _rdmsrinst(void);
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extern void _wrmsrinst(void);
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extern void _peekinst(void);
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extern void load_fs(ulong);
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extern void load_gs(ulong);
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@ -478,6 +479,12 @@ trap(Ureg* ureg)
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ureg->pc += 2;
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return;
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}
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} else if(pc == _peekinst){
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if(vno == VectorGPF){
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ureg->ax = -1;
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ureg->pc += 2;
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return;
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}
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}
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}
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@ -712,6 +719,14 @@ fault386(Ureg* ureg, void*)
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if(!user){
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if(vmapsync(addr))
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return;
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{
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extern void _peekinst(void);
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if((void(*)(void))ureg->pc == _peekinst){
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ureg->ax = -1;
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ureg->pc += 2;
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return;
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}
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}
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if(addr >= USTKTOP)
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panic("kernel fault: bad address pc=0x%.8lux addr=0x%.8lux", ureg->pc, addr);
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if(up == nil)
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@ -449,6 +449,18 @@ TEXT _wrmsrinst(SB), $0
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MOVQ BP, AX /* BP set to -1 if traped */
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RET
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/* fault-proof memcpy */
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TEXT peek(SB), 1, $-4
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MOVQ $0, AX
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MOVQ RARG, SI
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MOVQ dst+8(FP), DI
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MOVL cnt+16(FP), CX
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CLD
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TEXT _peekinst(SB), $0
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REP; MOVSB
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RET
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TEXT invlpg(SB), 1, $-4
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INVLPG (RARG)
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RET
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@ -440,6 +440,7 @@ trap(Ureg *ureg)
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extern void _rdmsrinst(void);
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extern void _wrmsrinst(void);
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extern void _peekinst(void);
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pc = (void*)ureg->pc;
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if(pc == _rdmsrinst || pc == _wrmsrinst){
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@ -448,6 +449,12 @@ trap(Ureg *ureg)
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ureg->pc += 2;
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return;
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}
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} else if(pc == _peekinst){
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if(vno == VectorGPF){
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ureg->ax = -1;
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ureg->pc += 2;
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return;
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}
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}
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}
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@ -672,6 +679,15 @@ faultamd64(Ureg* ureg, void*)
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read = !(ureg->error & 2);
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user = userureg(ureg);
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if(!user){
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{
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extern void _peekinst(void);
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if((void(*)(void))ureg->pc == _peekinst){
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ureg->ax = -1;
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ureg->pc += 2;
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return;
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}
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}
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if(addr >= USTKTOP)
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panic("kernel fault: bad address pc=%#p addr=%#p", ureg->pc, addr);
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if(up == nil)
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@ -518,10 +518,16 @@ dtgetvar(int v)
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}
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}
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int peek(char *, char *, int);
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int
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dtpeek(uvlong addr, void *buf, int len)
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{
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if((uintptr)addr != addr || up == nil || !okaddr((uintptr) addr, len, 0)) return -1;
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memmove(buf, (void *) addr, len);
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return 0;
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uintptr a;
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a = addr;
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if(len == 0) return 0;
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if(a != addr || a > -(uintptr)len || len < 0) return -1;
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if(up == nil || up->privatemem || a >= KZERO) return -1;
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return peek((void *)a, buf, len);
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}
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