[PATCH v3 21/29] bsd-user/arm/target_arch_signal.h: arm set_sigtramp_args

[Warner Losh <imp@bsdimp.com>]

Implement set_sigtramp_args to setup the arguments to the sigtramp
calls.

Signed-off-by: Stacey Son <sson@FreeBSD.org>
Signed-off-by: Warner Losh <imp@bsdimp.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/arm/target_arch_signal.h | 39 +++++++++++++++++++++++++++++++
 1 file changed, 39 insertions(+)

diff --git a/bsd-user/arm/target_arch_signal.h b/bsd-user/arm/target_arch_signal.h
index 4bdfcbb8d7..e673132c68 100644
--- a/bsd-user/arm/target_arch_signal.h
+++ b/bsd-user/arm/target_arch_signal.h
@@ -82,4 +82,43 @@ struct target_sigframe {
     target_mcontext_vfp_t sf_vfp; /* actual saved VFP context */
 };
 
+/*
+ * Compare to arm/arm/machdep.c sendsig()
+ * Assumes that target stack frame memory is locked.
+ */
+static inline abi_long
+set_sigtramp_args(CPUARMState *env, int sig, struct target_sigframe *frame,
+    abi_ulong frame_addr, struct target_sigaction *ka)
+{
+    /*
+     * Arguments to signal handler:
+     *  r0 = signal number
+     *  r1 = siginfo pointer
+     *  r2 = ucontext pointer
+     *  r5 = ucontext pointer
+     *  pc = signal handler pointer
+     *  sp = sigframe struct pointer
+     *  lr = sigtramp at base of user stack
+     */
+
+    env->regs[0] = sig;
+    env->regs[1] = frame_addr +
+        offsetof(struct target_sigframe, sf_si);
+    env->regs[2] = frame_addr +
+        offsetof(struct target_sigframe, sf_uc);
+
+    /* the trampoline uses r5 as the uc address */
+    env->regs[5] = frame_addr +
+        offsetof(struct target_sigframe, sf_uc);
+    env->regs[TARGET_REG_PC] = ka->_sa_handler & ~1;
+    env->regs[TARGET_REG_SP] = frame_addr;
+    env->regs[TARGET_REG_LR] = TARGET_PS_STRINGS - TARGET_SZSIGCODE;
+    /*
+     * Low bit indicates whether or not we're entering thumb mode.
+     */
+    cpsr_write(env, (ka->_sa_handler & 1) * CPSR_T, CPSR_T, CPSRWriteByInstr);
+
+    return 0;
+}
+
 #endif /* !_TARGET_ARCH_SIGNAL_H_ */
-- 
2.33.0