[PATCH v2 07/17] bsd-user: Add RISC-V signal trampoline setup function

[Ajeet Singh]

From: Mark Corbin <mark@dibsco.co.uk>

Implemented the `setup_sigtramp` function for setting up the signal
trampoline code in the RISC-V architecture.

Signed-off-by: Mark Corbin <mark@dibsco.co.uk>
Signed-off-by: Ajeet Singh <itachis@FreeBSD.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
---
 bsd-user/riscv/target_arch_sigtramp.h | 46 +++++++++++++++++++++++++++
 1 file changed, 46 insertions(+)
 create mode 100644 bsd-user/riscv/target_arch_sigtramp.h

diff --git a/bsd-user/riscv/target_arch_sigtramp.h 
b/bsd-user/riscv/target_arch_sigtramp.h
new file mode 100644
index 0000000000..39c878db22
--- /dev/null
+++ b/bsd-user/riscv/target_arch_sigtramp.h
@@ -0,0 +1,46 @@
+/*
+ * RISC-V sigcode
+ *
+ * Copyright (c) 2019 Mark Corbin
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef TARGET_ARCH_SIGTRAMP_H
+#define TARGET_ARCH_SIGTRAMP_H
+
+/* Compare with sigcode() in riscv/riscv/locore.S */
+static inline abi_long setup_sigtramp(abi_ulong offset, unsigned sigf_uc,
+        unsigned sys_sigreturn)
+{
+    int i;
+    uint32_t sys_exit = TARGET_FREEBSD_NR_exit;
+
+    uint32_t sigtramp_code[] = {
+    /* 1 */ 0x00010513,                         /* mv a0, sp */
+    /* 2 */ 0x00050513 + (sigf_uc << 20),       /* addi a0, a0, sigf_uc */
+    /* 3 */ 0x00000293 + (sys_sigreturn << 20), /* li t0, sys_sigreturn */
+    /* 4 */ 0x00000073,                         /* ecall */
+    /* 5 */ 0x00000293 + (sys_exit << 20),      /* li t0, sys_exit */
+    /* 6 */ 0x00000073,                         /* ecall */
+    /* 7 */ 0xFF1FF06F                          /* b -16 */
+    };
+
+    for (i = 0; i < 7; i++) {
+        tswap32s(&sigtramp_code[i]);
+    }
+
+    return memcpy_to_target(offset, sigtramp_code, TARGET_SZSIGCODE);
+}
+#endif /* TARGET_ARCH_SIGTRAMP_H */
-- 
2.34.1