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[Qemu-devel] [PATCH 06/11] tcg/s390: Make direct jump patching thread-sa
From: |
Sergey Fedorov |
Subject: |
[Qemu-devel] [PATCH 06/11] tcg/s390: Make direct jump patching thread-safe |
Date: |
Thu, 7 Apr 2016 18:53:48 +0300 |
From: Sergey Fedorov <address@hidden>
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 <address@hidden>
Signed-off-by: Sergey Fedorov <address@hidden>
---
include/exec/exec-all.h | 2 +-
tcg/s390/tcg-target.inc.c | 6 ++++++
2 files changed, 7 insertions(+), 1 deletion(-)
diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index 82399175fe80..e18cc24e50f0 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -320,7 +320,7 @@ static inline void tb_set_jmp_target1(uintptr_t jmp_addr,
uintptr_t addr)
{
/* 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__)
diff --git a/tcg/s390/tcg-target.inc.c b/tcg/s390/tcg-target.inc.c
index fbf97bb2e15d..84221dfb68c9 100644
--- a/tcg/s390/tcg-target.inc.c
+++ b/tcg/s390/tcg-target.inc.c
@@ -219,6 +219,8 @@ typedef enum S390Opcode {
RX_ST = 0x50,
RX_STC = 0x42,
RX_STH = 0x40,
+
+ NOP = 0x0707,
} S390Opcode;
#ifndef NDEBUG
@@ -1716,6 +1718,10 @@ static inline void tcg_out_op(TCGContext *s, TCGOpcode
opc,
case INDEX_op_goto_tb:
if (s->tb_jmp_offset) {
+ /* align branch displacement for atomic pathing */
+ if (((uintptr_t)s->code_ptr & 3) == 0) {
+ 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;
--
2.8.1
[Qemu-devel] [PATCH 06/11] tcg/s390: Make direct jump patching thread-safe,
Sergey Fedorov <=
[Qemu-devel] [PATCH 01/11] tci: Fix build regression, Sergey Fedorov, 2016/04/07
[Qemu-devel] [PATCH 05/11] tcg/i386: Make direct jump patching thread-safe, Sergey Fedorov, 2016/04/07