[PATCH 23/23] Add get_ucontext_sigreturn function

[Ajeet Singh <itachis6234@gmail.com>]

From: Stacey Son <sson@FreeBSD.org>

Function checks the processor state to ensure that the current
execution mode is EL0 and no flags indicating interrupts or
exceptions are set

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Ajeet Singh <itachis@FreeBSD.org>
---
 bsd-user/aarch64/signal.c | 18 ++++++++++++++++++
 1 file changed, 18 insertions(+)

diff --git a/bsd-user/aarch64/signal.c b/bsd-user/aarch64/signal.c
index 13faac8ce6..ad81531ec5 100644
--- a/bsd-user/aarch64/signal.c
+++ b/bsd-user/aarch64/signal.c
@@ -117,3 +117,21 @@ abi_long set_mcontext(CPUARMState *regs, target_mcontext_t *mcp, int srflag)
 
     return err;
 }
+
+/* Compare to sys_sigreturn() in  arm64/arm64/machdep.c */
+abi_long get_ucontext_sigreturn(CPUARMState *regs, abi_ulong target_sf,
+                                abi_ulong *target_uc)
+{
+    uint32_t pstate = pstate_read(regs);
+
+    *target_uc = 0;
+
+    if ((pstate & PSTATE_M) != PSTATE_MODE_EL0t  ||
+        (pstate & (PSTATE_F | PSTATE_I | PSTATE_A | PSTATE_D)) != 0) {
+        return -TARGET_EINVAL;
+    }
+
+    *target_uc = target_sf;
+
+    return 0;
+}
-- 
2.34.1