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authorSergey Fedorov <serge.fdrv@gmail.com>2016-04-22 19:08:49 +0300
committerRichard Henderson <rth@twiddle.net>2016-05-12 14:06:41 -1000
commit7d14e0e2d661479985197203589c38840e1066df (patch)
tree9c1d6052fd56ceb3484ecbbcc99d211523876acf /tcg
parented3d51ecd7fe248d3959e469d53890ac9ffe0cd2 (diff)
downloadqemu-7d14e0e2d661479985197203589c38840e1066df.tar.gz
tcg/arm: Make direct jump patching thread-safe
Ensure direct jump patching in ARM is atomic by 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: <1461341333-19646-8-git-send-email-sergey.fedorov@linaro.org> Signed-off-by: Richard Henderson <rth@twiddle.net>
Diffstat (limited to 'tcg')
-rw-r--r--tcg/arm/tcg-target.inc.c18
1 files changed, 18 insertions, 0 deletions
diff --git a/tcg/arm/tcg-target.inc.c b/tcg/arm/tcg-target.inc.c
index 2b7fbddbf0..977baa05c5 100644
--- a/tcg/arm/tcg-target.inc.c
+++ b/tcg/arm/tcg-target.inc.c
@@ -121,6 +121,14 @@ static inline void reloc_pc24(tcg_insn_unit *code_ptr, tcg_insn_unit *target)
*code_ptr = (*code_ptr & ~0xffffff) | (offset & 0xffffff);
}
+static inline void reloc_pc24_atomic(tcg_insn_unit *code_ptr, tcg_insn_unit *target)
+{
+ ptrdiff_t offset = (tcg_ptr_byte_diff(target, code_ptr) - 8) >> 2;
+ tcg_insn_unit insn = atomic_read(code_ptr);
+ tcg_debug_assert(offset == sextract32(offset, 0, 24));
+ atomic_set(code_ptr, deposit32(insn, 0, 24, offset));
+}
+
static void patch_reloc(tcg_insn_unit *code_ptr, int type,
intptr_t value, intptr_t addend)
{
@@ -1038,6 +1046,16 @@ static void tcg_out_call(TCGContext *s, tcg_insn_unit *addr)
}
}
+void arm_tb_set_jmp_target(uintptr_t jmp_addr, uintptr_t addr)
+{
+ tcg_insn_unit *code_ptr = (tcg_insn_unit *)jmp_addr;
+ tcg_insn_unit *target = (tcg_insn_unit *)addr;
+
+ /* we could use a ldr pc, [pc, #-4] kind of branch and avoid the flush */
+ reloc_pc24_atomic(code_ptr, target);
+ flush_icache_range(jmp_addr, jmp_addr + 4);
+}
+
static inline void tcg_out_goto_label(TCGContext *s, int cond, TCGLabel *l)
{
if (l->has_value) {