On 9/19/21 11:24 AM, Philippe Mathieu-Daudé wrote:
On 9/19/21 20:22, Philippe Mathieu-Daudé wrote:
On 9/18/21 20:45, Richard Henderson wrote:
Add a new user-only interface for updating cpu state before
raising a signal. This will replace tlb_fill for user-only
and should result in less boilerplate for each guest.
Signed-off-by: Richard Henderson <richard.hender...@linaro.org>
---
include/hw/core/tcg-cpu-ops.h | 26 ++++++++++++++++++++++++++
1 file changed, 26 insertions(+)
diff --git a/include/hw/core/tcg-cpu-ops.h b/include/hw/core/tcg-cpu-ops.h
index 4a4c4053e3..e229a40772 100644
--- a/include/hw/core/tcg-cpu-ops.h
+++ b/include/hw/core/tcg-cpu-ops.h
@@ -114,6 +114,32 @@ struct TCGCPUOps {
*/
bool (*io_recompile_replay_branch)(CPUState *cpu,
const TranslationBlock *tb);
+#else
+ /**
+ * record_sigsegv:
+ * @cpu: cpu context
+ * @addr: faulting guest address
+ * @access_type: access was read/write/execute
+ * @maperr: true for invalid page, false for permission fault
+ * @ra: host pc for unwinding
+ *
+ * We are about to raise SIGSEGV with si_code set for @maperr,
+ * and si_addr set for @addr. Record anything further needed
+ * for the signal ucontext_t.
+ *
+ * If the emulated kernel does not provide anything to the signal
+ * handler with anything besides the user context registers, and
+ * the siginfo_t, then this hook need do nothing and may be omitted.
+ * Otherwise, record the data and return; the caller will raise
+ * the signal, unwind the cpu state, and return to the main loop.
+ *
+ * If it is simpler to re-use the sysemu tlb_fill code, @ra is provided
+ * so that a "normal" cpu exception can be raised. In this case,
+ * the signal must be raised by the architecture cpu_loop.
+ */
Shouldn't it have the QEMU_NORETURN attribute?
Eh now I saw the next patch and understood raise_sigsegv() is
where QEMU_NORETURN belong :)
Well, I had intended the hook to be able to return, so that the hook can merely set some
env->fields, and return to raise the signal. But in the end, all 4 targets that use the
hook raise the exception themselves -- sometimes because env->exception_index is part of
the data to be passed to the signal handler.
r~
