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authorPranith Kumar <bobby.prani@gmail.com>2017-02-23 18:29:15 +0000
committerAlex Bennée <alex.bennee@linaro.org>2017-02-24 10:32:45 +0000
commit08e73c48b053566bfe0c994f154f73991cd0ff0e (patch)
tree5a2a033b6acfc8d41d65424a695943c6f9480337 /cpu-exec.c
parent372579427a5040a26dfee78464b50e2bdf27ef26 (diff)
downloadqemu-arm-08e73c48b053566bfe0c994f154f73991cd0ff0e.tar.gz
tcg: handle EXCP_ATOMIC exception for system emulation
The patch enables handling atomic code in the guest. This should be preferably done in cpu_handle_exception(), but the current assumptions regarding when we can execute atomic sections cause a deadlock. The current mechanism discards the flags which were set in atomic execution. We ensure they are properly saved by calling the cc->cpu_exec_enter/leave() functions around the loop. As we are running cpu_exec_step_atomic() from the outermost loop we need to avoid an abort() when single stepping over atomic code since debug exception longjmp will point to the the setlongjmp in cpu_exec(). We do this by setting a new jmp_env so that it jumps back here on an exception. Signed-off-by: Pranith Kumar <bobby.prani@gmail.com> [AJB: tweak title, merge with new patches, add mmap_lock] Signed-off-by: Alex Bennée <alex.bennee@linaro.org> Reviewed-by: Richard Henderson <rth@twiddle.net> CC: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'cpu-exec.c')
-rw-r--r--cpu-exec.c43
1 files changed, 31 insertions, 12 deletions
diff --git a/cpu-exec.c b/cpu-exec.c
index 2edd26e823..1a5ad4889d 100644
--- a/cpu-exec.c
+++ b/cpu-exec.c
@@ -228,24 +228,43 @@ static void cpu_exec_nocache(CPUState *cpu, int max_cycles,
static void cpu_exec_step(CPUState *cpu)
{
+ CPUClass *cc = CPU_GET_CLASS(cpu);
CPUArchState *env = (CPUArchState *)cpu->env_ptr;
TranslationBlock *tb;
target_ulong cs_base, pc;
uint32_t flags;
cpu_get_tb_cpu_state(env, &pc, &cs_base, &flags);
- tb_lock();
- tb = tb_gen_code(cpu, pc, cs_base, flags,
- 1 | CF_NOCACHE | CF_IGNORE_ICOUNT);
- tb->orig_tb = NULL;
- tb_unlock();
- /* execute the generated code */
- trace_exec_tb_nocache(tb, pc);
- cpu_tb_exec(cpu, tb);
- tb_lock();
- tb_phys_invalidate(tb, -1);
- tb_free(tb);
- tb_unlock();
+ if (sigsetjmp(cpu->jmp_env, 0) == 0) {
+ mmap_lock();
+ tb_lock();
+ tb = tb_gen_code(cpu, pc, cs_base, flags,
+ 1 | CF_NOCACHE | CF_IGNORE_ICOUNT);
+ tb->orig_tb = NULL;
+ tb_unlock();
+ mmap_unlock();
+
+ cc->cpu_exec_enter(cpu);
+ /* execute the generated code */
+ trace_exec_tb_nocache(tb, pc);
+ cpu_tb_exec(cpu, tb);
+ cc->cpu_exec_exit(cpu);
+
+ tb_lock();
+ tb_phys_invalidate(tb, -1);
+ tb_free(tb);
+ tb_unlock();
+ } else {
+ /* We may have exited due to another problem here, so we need
+ * to reset any tb_locks we may have taken but didn't release.
+ * The mmap_lock is dropped by tb_gen_code if it runs out of
+ * memory.
+ */
+#ifndef CONFIG_SOFTMMU
+ tcg_debug_assert(!have_mmap_lock());
+#endif
+ tb_lock_reset();
+ }
}
void cpu_exec_step_atomic(CPUState *cpu)