Do not directly access ucontext_t as the third signal parameter. This is preparation for a sparc64 fix. Reviewed-by: Peter Maydell <peter.maydell@linaro.org> Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org> Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
		
			
				
	
	
		
			107 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
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			107 lines
		
	
	
		
			3.1 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * host-signal.h: signal info dependent on the host architecture
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 *
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 * Copyright (c) 2003-2005 Fabrice Bellard
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 * Copyright (c) 2021 Linaro Limited
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 *
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 * This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
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 * See the COPYING file in the top-level directory.
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 */
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#ifndef S390_HOST_SIGNAL_H
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#define S390_HOST_SIGNAL_H
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/* The third argument to a SA_SIGINFO handler is ucontext_t. */
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typedef ucontext_t host_sigcontext;
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static inline uintptr_t host_signal_pc(host_sigcontext *uc)
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{
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    return uc->uc_mcontext.psw.addr;
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}
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static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
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{
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    uc->uc_mcontext.psw.addr = pc;
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}
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static inline void *host_signal_mask(host_sigcontext *uc)
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{
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    return &uc->uc_sigmask;
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}
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static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
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{
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    uint16_t *pinsn = (uint16_t *)host_signal_pc(uc);
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    /*
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     * ??? On linux, the non-rt signal handler has 4 (!) arguments instead
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     * of the normal 2 arguments.  The 4th argument contains the "Translation-
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     * Exception Identification for DAT Exceptions" from the hardware (aka
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     * "int_parm_long"), which does in fact contain the is_write value.
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     * The rt signal handler, as far as I can tell, does not give this value
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     * at all.  Not that we could get to it from here even if it were.
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     * So fall back to parsing instructions.  Treat read-modify-write ones as
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     * writes, which is not fully correct, but for tracking self-modifying code
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     * this is better than treating them as reads.  Checking si_addr page flags
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     * might be a viable improvement, albeit a racy one.
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     */
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    /* ??? This is not even close to complete.  */
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    switch (pinsn[0] >> 8) {
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    case 0x50: /* ST */
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    case 0x42: /* STC */
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    case 0x40: /* STH */
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    case 0xba: /* CS */
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    case 0xbb: /* CDS */
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        return true;
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    case 0xc4: /* RIL format insns */
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        switch (pinsn[0] & 0xf) {
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        case 0xf: /* STRL */
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        case 0xb: /* STGRL */
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        case 0x7: /* STHRL */
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            return true;
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        }
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        break;
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    case 0xc8: /* SSF format insns */
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        switch (pinsn[0] & 0xf) {
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        case 0x2: /* CSST */
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            return true;
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        }
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        break;
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    case 0xe3: /* RXY format insns */
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        switch (pinsn[2] & 0xff) {
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        case 0x50: /* STY */
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        case 0x24: /* STG */
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        case 0x72: /* STCY */
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        case 0x70: /* STHY */
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        case 0x8e: /* STPQ */
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        case 0x3f: /* STRVH */
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        case 0x3e: /* STRV */
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        case 0x2f: /* STRVG */
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            return true;
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        }
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        break;
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    case 0xeb: /* RSY format insns */
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        switch (pinsn[2] & 0xff) {
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        case 0x14: /* CSY */
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        case 0x30: /* CSG */
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        case 0x31: /* CDSY */
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        case 0x3e: /* CDSG */
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        case 0xe4: /* LANG */
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        case 0xe6: /* LAOG */
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        case 0xe7: /* LAXG */
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        case 0xe8: /* LAAG */
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        case 0xea: /* LAALG */
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        case 0xf4: /* LAN */
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        case 0xf6: /* LAO */
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        case 0xf7: /* LAX */
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        case 0xfa: /* LAAL */
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        case 0xf8: /* LAA */
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            return true;
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        }
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        break;
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    }
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    return false;
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}
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#endif
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