[PATCH 13/19] accel/tcg: Fixed tsan warnings.

[Robert Foley <robert.foley@linaro.org>]

For example:
WARNING: ThreadSanitizer: data race (pid=35425)
  Write of size 4 at 0x7bbc000000ac by main thread (mutexes: write M875):
    #0 cpu_reset_interrupt hw/core/cpu.c:107:28 (qemu-system-aarch64+0x843790)
    #1 arm_cpu_set_irq target/arm/cpu.c (qemu-system-aarch64+0x616265)
    #2 qemu_set_irq hw/core/irq.c:44:5 (qemu-system-aarch64+0x8462ca)
  Previous atomic read of size 4 at 0x7bbc000000ac by thread T6:
    #0 __tsan_atomic32_load <null> (qemu-system-aarch64+0x394c1c)
    #1 cpu_handle_interrupt accel/tcg/cpu-exec.c:534:9 (qemu-system-aarch64+0x4b7e79)
    #2 cpu_exec accel/tcg/cpu-exec.c:720:17 (qemu-system-aarch64+0x4b7e79)
or
WARNING: ThreadSanitizer: data race (pid=25425)
  Read of size 8 at 0x7f8ad8e138d0 by thread T10:
    #0 tb_lookup_cmp accel/tcg/cpu-exec.c:307:13 (qemu-system-aarch64+0x4ac4d2)
    #1 qht_do_lookup util/qht.c:502:34 (qemu-system-aarch64+0xd05264)
  Previous write of size 8 at 0x7f8ad8e138d0 by thread T15 (mutexes: write M728311726235541804):
    #0 tb_link_page accel/tcg/translate-all.c:1625:26 (qemu-system-aarch64+0x4b0bf2)
    #1 tb_gen_code accel/tcg/translate-all.c:1865:19 (qemu-system-aarch64+0x4b0bf2)
    #2 tb_find accel/tcg/cpu-exec.c:407:14 (qemu-system-aarch64+0x4ad77c)

Cc: Richard Henderson <richard.henderson@linaro.org>
Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Robert Foley <robert.foley@linaro.org>
---
 accel/tcg/tcg-all.c       | 4 ++--
 accel/tcg/tcg-runtime.c   | 7 ++++++-
 accel/tcg/translate-all.c | 6 +++++-
 hw/core/cpu.c             | 2 +-
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/accel/tcg/tcg-all.c b/accel/tcg/tcg-all.c
index 3b4fda5640..f94ea4c4b3 100644
--- a/accel/tcg/tcg-all.c
+++ b/accel/tcg/tcg-all.c
@@ -54,8 +54,8 @@ static void tcg_handle_interrupt(CPUState *cpu, int mask)
     int old_mask;
     g_assert(qemu_mutex_iothread_locked());
 
-    old_mask = cpu->interrupt_request;
-    cpu->interrupt_request |= mask;
+    old_mask = atomic_read(&cpu->interrupt_request);
+    atomic_or(&cpu->interrupt_request, mask);
 
     /*
      * If called from iothread context, wake the target cpu in
diff --git a/accel/tcg/tcg-runtime.c b/accel/tcg/tcg-runtime.c
index 446465a09a..bd0cd77450 100644
--- a/accel/tcg/tcg-runtime.c
+++ b/accel/tcg/tcg-runtime.c
@@ -31,6 +31,7 @@
 #include "disas/disas.h"
 #include "exec/log.h"
 #include "tcg/tcg.h"
+#include "qemu/tsan.h"
 
 /* 32-bit helpers */
 
@@ -151,6 +152,7 @@ void *HELPER(lookup_tb_ptr)(CPUArchState *env)
     TranslationBlock *tb;
     target_ulong cs_base, pc;
     uint32_t flags;
+    void *tc_ptr;
 
     tb = tb_lookup__cpu_state(cpu, &pc, &cs_base, &flags, curr_cflags());
     if (tb == NULL) {
@@ -161,7 +163,10 @@ void *HELPER(lookup_tb_ptr)(CPUArchState *env)
                            TARGET_FMT_lx "/" TARGET_FMT_lx "/%#x] %s\n",
                            cpu->cpu_index, tb->tc.ptr, cs_base, pc, flags,
                            lookup_symbol(pc));
-    return tb->tc.ptr;
+    TSAN_ANNOTATE_IGNORE_READS_BEGIN();
+    tc_ptr = tb->tc.ptr;
+    TSAN_ANNOTATE_IGNORE_READS_END();
+    return tc_ptr;
 }
 
 void HELPER(exit_atomic)(CPUArchState *env)
diff --git a/accel/tcg/translate-all.c b/accel/tcg/translate-all.c
index 3fb71a1503..6c0e61994c 100644
--- a/accel/tcg/translate-all.c
+++ b/accel/tcg/translate-all.c
@@ -58,6 +58,7 @@
 #include "exec/log.h"
 #include "sysemu/cpus.h"
 #include "sysemu/tcg.h"
+#include "qemu/tsan.h"
 
 /* #define DEBUG_TB_INVALIDATE */
 /* #define DEBUG_TB_FLUSH */
@@ -1704,6 +1705,7 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
         max_insns = 1;
     }
 
+    TSAN_ANNOTATE_IGNORE_WRITES_BEGIN();
  buffer_overflow:
     tb = tcg_tb_alloc(tcg_ctx);
     if (unlikely(!tb)) {
@@ -1902,9 +1904,11 @@ TranslationBlock *tb_gen_code(CPUState *cpu,
         orig_aligned -= ROUND_UP(sizeof(*tb), qemu_icache_linesize);
         atomic_set(&tcg_ctx->code_gen_ptr, (void *)orig_aligned);
         tb_destroy(tb);
+        TSAN_ANNOTATE_IGNORE_WRITES_END();
         return existing_tb;
     }
     tcg_tb_insert(tb);
+    TSAN_ANNOTATE_IGNORE_WRITES_END();
     return tb;
 }
 
@@ -2409,7 +2413,7 @@ void dump_opcount_info(void)
 void cpu_interrupt(CPUState *cpu, int mask)
 {
     g_assert(qemu_mutex_iothread_locked());
-    cpu->interrupt_request |= mask;
+    atomic_or(&cpu->interrupt_request, mask);
     atomic_set(&cpu_neg(cpu)->icount_decr.u16.high, -1);
 }
 
diff --git a/hw/core/cpu.c b/hw/core/cpu.c
index 77703d62b7..6c16ccc426 100644
--- a/hw/core/cpu.c
+++ b/hw/core/cpu.c
@@ -104,7 +104,7 @@ void cpu_reset_interrupt(CPUState *cpu, int mask)
     if (need_lock) {
         qemu_mutex_lock_iothread();
     }
-    cpu->interrupt_request &= ~mask;
+    atomic_and(&cpu->interrupt_request, ~mask);
     if (need_lock) {
         qemu_mutex_unlock_iothread();
     }
-- 
2.17.1