Ensure direct jump patching in s390 is atomic by:
* naturally aligning a location of direct jump address;
* using atomic_read()/atomic_set() for code patching.
Signed-off-by: Sergey Fedorov <serge.fdrv@gmail.com>
Signed-off-by: Sergey Fedorov <sergey.fedorov@linaro.org>
Message-Id: <
1461341333-19646-7-git-send-email-sergey.fedorov@linaro.org>
Signed-off-by: Richard Henderson <rth@twiddle.net>
{
/* patch the branch destination */
intptr_t disp = addr - (jmp_addr - 2);
- stl_be_p((void*)jmp_addr, disp / 2);
+ atomic_set((int32_t *)jmp_addr, disp / 2);
/* no need to flush icache explicitly */
}
#elif defined(__aarch64__)
RX_ST = 0x50,
RX_STC = 0x42,
RX_STH = 0x40,
+
+ NOP = 0x0707,
} S390Opcode;
#ifdef CONFIG_DEBUG_TCG
case INDEX_op_goto_tb:
if (s->tb_jmp_offset) {
+ /* branch displacement must be aligned for atomic patching;
+ * see if we need to add extra nop before branch
+ */
+ if (!QEMU_PTR_IS_ALIGNED(s->code_ptr + 1, 4)) {
+ tcg_out16(s, NOP);
+ }
tcg_out16(s, RIL_BRCL | (S390_CC_ALWAYS << 4));
s->tb_jmp_offset[args[0]] = tcg_current_code_size(s);
s->code_ptr += 2;