qemu/linux-user/include/host/s390/host-signal.h
Ilya Leoshkevich ab9ccfa850 linux-user/host/s390: Add vector instructions to host_signal_write()
The new noexec test fails on s390x with "unexpected SEGV". This test
overwrites code using libc's memcpy(), which uses VSTL instruction.
host_signal_write() does not recognize it, which causes SEGV to be
incorrectly forwarded to the test.

Add all vector instructions that write to memory to
host_signal_write().

Fixes: ab12c95d3f ("target/s390x: Make translator stop before the end of a page")
Reported-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
Message-Id: <20220920113907.334144-1-iii@linux.ibm.com>
Tested-by: Thomas Huth <thuth@redhat.com>
Signed-off-by: Thomas Huth <thuth@redhat.com>
2022-09-23 15:16:16 +02:00

139 lines
3.9 KiB
C

/*
* host-signal.h: signal info dependent on the host architecture
*
* Copyright (c) 2003-2005 Fabrice Bellard
* Copyright (c) 2021 Linaro Limited
*
* This work is licensed under the terms of the GNU LGPL, version 2.1 or later.
* See the COPYING file in the top-level directory.
*/
#ifndef S390_HOST_SIGNAL_H
#define S390_HOST_SIGNAL_H
/* The third argument to a SA_SIGINFO handler is ucontext_t. */
typedef ucontext_t host_sigcontext;
static inline uintptr_t host_signal_pc(host_sigcontext *uc)
{
return uc->uc_mcontext.psw.addr;
}
static inline void host_signal_set_pc(host_sigcontext *uc, uintptr_t pc)
{
uc->uc_mcontext.psw.addr = pc;
}
static inline void *host_signal_mask(host_sigcontext *uc)
{
return &uc->uc_sigmask;
}
static inline bool host_signal_write(siginfo_t *info, host_sigcontext *uc)
{
uint16_t *pinsn = (uint16_t *)host_signal_pc(uc);
/*
* ??? On linux, the non-rt signal handler has 4 (!) arguments instead
* of the normal 2 arguments. The 4th argument contains the "Translation-
* Exception Identification for DAT Exceptions" from the hardware (aka
* "int_parm_long"), which does in fact contain the is_write value.
* The rt signal handler, as far as I can tell, does not give this value
* at all. Not that we could get to it from here even if it were.
* So fall back to parsing instructions. Treat read-modify-write ones as
* writes, which is not fully correct, but for tracking self-modifying code
* this is better than treating them as reads. Checking si_addr page flags
* might be a viable improvement, albeit a racy one.
*/
/* ??? This is not even close to complete. */
switch (pinsn[0] >> 8) {
case 0x50: /* ST */
case 0x42: /* STC */
case 0x40: /* STH */
case 0x44: /* EX */
case 0xba: /* CS */
case 0xbb: /* CDS */
return true;
case 0xc4: /* RIL format insns */
switch (pinsn[0] & 0xf) {
case 0xf: /* STRL */
case 0xb: /* STGRL */
case 0x7: /* STHRL */
return true;
}
break;
case 0xc6: /* RIL-b format insns */
switch (pinsn[0] & 0xf) {
case 0x0: /* EXRL */
return true;
}
break;
case 0xc8: /* SSF format insns */
switch (pinsn[0] & 0xf) {
case 0x2: /* CSST */
return true;
}
break;
case 0xe3: /* RXY format insns */
switch (pinsn[2] & 0xff) {
case 0x50: /* STY */
case 0x24: /* STG */
case 0x72: /* STCY */
case 0x70: /* STHY */
case 0x8e: /* STPQ */
case 0x3f: /* STRVH */
case 0x3e: /* STRV */
case 0x2f: /* STRVG */
return true;
}
break;
case 0xe6:
switch (pinsn[2] & 0xff) {
case 0x09: /* VSTEBRH */
case 0x0a: /* VSTEBRG */
case 0x0b: /* VSTEBRF */
case 0x0e: /* VSTBR */
case 0x0f: /* VSTER */
case 0x3f: /* VSTRLR */
return true;
}
break;
case 0xe7:
switch (pinsn[2] & 0xff) {
case 0x08: /* VSTEB */
case 0x09: /* VSTEH */
case 0x0a: /* VSTEG */
case 0x0b: /* VSTEF */
case 0x0e: /* VST */
case 0x1a: /* VSCEG */
case 0x1b: /* VSCEF */
case 0x3e: /* VSTM */
case 0x3f: /* VSTL */
return true;
}
break;
case 0xeb: /* RSY format insns */
switch (pinsn[2] & 0xff) {
case 0x14: /* CSY */
case 0x30: /* CSG */
case 0x31: /* CDSY */
case 0x3e: /* CDSG */
case 0xe4: /* LANG */
case 0xe6: /* LAOG */
case 0xe7: /* LAXG */
case 0xe8: /* LAAG */
case 0xea: /* LAALG */
case 0xf4: /* LAN */
case 0xf6: /* LAO */
case 0xf7: /* LAX */
case 0xfa: /* LAAL */
case 0xf8: /* LAA */
return true;
}
break;
}
return false;
}
#endif