qemu-e2k/linux-user/host/riscv/host-signal.h
Richard Henderson 4f3bbd9cfb linux-user/host/riscv: Improve host_signal_write
Do not read 4 bytes before we determine the size of the insn.
Simplify triple switches in favor of checking major opcodes.
Include the missing cases of compact fsd and fsdsp.

Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
2021-11-02 07:00:52 -04:00

59 lines
1.6 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 RISCV_HOST_SIGNAL_H
#define RISCV_HOST_SIGNAL_H
static inline uintptr_t host_signal_pc(ucontext_t *uc)
{
return uc->uc_mcontext.__gregs[REG_PC];
}
static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
{
/*
* Detect store by reading the instruction at the program counter.
* Do not read more than 16 bits, because we have not yet determined
* the size of the instruction.
*/
const uint16_t *pinsn = (const uint16_t *)host_signal_pc(uc);
uint16_t insn = pinsn[0];
/* 16-bit instructions */
switch (insn & 0xe003) {
case 0xa000: /* c.fsd */
case 0xc000: /* c.sw */
case 0xe000: /* c.sd (rv64) / c.fsw (rv32) */
case 0xa002: /* c.fsdsp */
case 0xc002: /* c.swsp */
case 0xe002: /* c.sdsp (rv64) / c.fswsp (rv32) */
return true;
}
/* 32-bit instructions, major opcodes */
switch (insn & 0x7f) {
case 0x23: /* store */
case 0x27: /* store-fp */
return true;
case 0x2f: /* amo */
/*
* The AMO function code is in bits 25-31, unread as yet.
* The AMO functions are LR (read), SC (write), and the
* rest are all read-modify-write.
*/
insn = pinsn[1];
return (insn >> 11) != 2; /* LR */
}
return false;
}
#endif