From 12ed56407e60371d45ffa3b7f2fd00c4d7efa580 Mon Sep 17 00:00:00 2001
From: Richard Henderson <richard.henderson@linaro.org>
Date: Mon, 4 Oct 2021 10:06:10 -0700
Subject: [PATCH] linux-user: Add cpu_loop_exit_sigbus
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This is a new interface to be provided by the os emulator for
raising SIGBUS on fault.  Use the new record_sigbus target hook.

Reviewed-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
---
 include/exec/exec-all.h | 14 ++++++++++++++
 linux-user/signal.c     | 14 ++++++++++++++
 2 files changed, 28 insertions(+)

diff --git a/include/exec/exec-all.h b/include/exec/exec-all.h
index f74578500c..6bb2a0f7ec 100644
--- a/include/exec/exec-all.h
+++ b/include/exec/exec-all.h
@@ -700,6 +700,20 @@ void QEMU_NORETURN cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr,
                                          MMUAccessType access_type,
                                          bool maperr, uintptr_t ra);
 
+/**
+ * cpu_loop_exit_sigbus:
+ * @cpu: the cpu context
+ * @addr: the guest address of the alignment fault
+ * @access_type: access was read/write/execute
+ * @ra: host pc for unwinding
+ *
+ * Use the TCGCPUOps hook to record cpu state, do guest operating system
+ * specific things to raise SIGBUS, and jump to the main cpu loop.
+ */
+void QEMU_NORETURN cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr,
+                                        MMUAccessType access_type,
+                                        uintptr_t ra);
+
 #else
 static inline void mmap_lock(void) {}
 static inline void mmap_unlock(void) {}
diff --git a/linux-user/signal.c b/linux-user/signal.c
index 9d60abc038..df2c8678d0 100644
--- a/linux-user/signal.c
+++ b/linux-user/signal.c
@@ -706,6 +706,20 @@ void cpu_loop_exit_sigsegv(CPUState *cpu, target_ulong addr,
     cpu_loop_exit_restore(cpu, ra);
 }
 
+void cpu_loop_exit_sigbus(CPUState *cpu, target_ulong addr,
+                          MMUAccessType access_type, uintptr_t ra)
+{
+    const struct TCGCPUOps *tcg_ops = CPU_GET_CLASS(cpu)->tcg_ops;
+
+    if (tcg_ops->record_sigbus) {
+        tcg_ops->record_sigbus(cpu, addr, access_type, ra);
+    }
+
+    force_sig_fault(TARGET_SIGBUS, TARGET_BUS_ADRALN, addr);
+    cpu->exception_index = EXCP_INTERRUPT;
+    cpu_loop_exit_restore(cpu, ra);
+}
+
 /* abort execution with signal */
 static void QEMU_NORETURN dump_core_and_abort(int target_sig)
 {