[PATCH 11/30] bsd-user/host/arm/host-signal.h: Implement host_signal_*

[Warner Losh]

Implement host_signal_pc, host_signal_set_pc and host_signal_write for
arm.

Signed-off-by: Kyle Evans <kevans@freebsd.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
---
 bsd-user/host/arm/host-signal.h | 39 +++++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)
 create mode 100644 bsd-user/host/arm/host-signal.h

diff --git a/bsd-user/host/arm/host-signal.h b/bsd-user/host/arm/host-signal.h
new file mode 100644
index 00000000000..e403c26caed
--- /dev/null
+++ b/bsd-user/host/arm/host-signal.h
@@ -0,0 +1,39 @@
+/*
+ * host-signal.h: signal info dependent on the host architecture
+ *
+ * Copyright (c) 2021 Warner Losh
+ *
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#ifndef ARM_HOST_SIGNAL_H
+#define ARM_HOST_SIGNAL_H
+
+#include <sys/ucontext.h>
+
+static inline uintptr_t host_signal_pc(ucontext_t *uc)
+{
+    return uc->uc_mcontext.__gregs[_REG_PC];
+}
+
+static inline void host_signal_set_pc(ucontext_t *uc, uintptr_t pc)
+{
+    uc->uc_mcontext.__gregs[_REG_PC] = pc;
+}
+
+static inline bool host_signal_write(siginfo_t *info, ucontext_t *uc)
+{
+    /*
+     * In the FSR, bit 11 is WnR. FreeBSD returns this as part of the
+     * si_info.si_trapno which we don't have access to here.  We assume that uc
+     * is part of a trapframe and reach around to get to the si_info that's in
+     * the sigframe just before it, though this may be unwise.
+     */
+    siginfo_t *si;
+    si = &((siginfo_t *)uc)[-1];
+    uint32_t fsr = si->si_trapno;
+
+    return extract32(fsr, 11, 1);
+}
+
+#endif
-- 
2.33.1