Add riscv64 support

meson.build

@@ -86,6 +86,8 @@ elif arch == 'arm'
 	bitness = 32
 elif arch == 'aarch64'
 	bitness = 64
+elif arch == 'riscv64'
+	bitness = 64
 else
 	error('Architecture "@0@" is not supported.'.format(arch))
 endif

src/asm/trampoline-riscv64.S

@@ -0,0 +1,60 @@
+/*
+ * The MIT License (MIT)
+ *
+ * Copyright © 2018 Franklin "Snaipe" Mathieu <http://snai.pe/>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+#include "config.h"
+#include "mangling.h"
+
+#ifdef ASSEMBLER_SUPPORTS_HIDDEN
+.hidden MANGLE(bxfi_trampoline)
+#endif
+.globl MANGLE(bxfi_trampoline)
+MANGLE(bxfi_trampoline):
+    ld      a0, addr_data
+    jr      a0
+
+/*
+ *  On riscv64gc, these will expand into 3 instructions:
+ *  auipc   a0, 0x0         4 bytes
+ *  ld      a0, offset(a0)  4 bytes
+ *  jr      a0              2 bytes
+ *  <addr_data>
+ *  'offset' is the length between `auipc` and `addr_data`.
+ */
+
+.align 1
+
+#ifdef ASSEMBLER_SUPPORTS_HIDDEN
+.hidden MANGLE(bxfi_trampoline_addr)
+#endif
+.globl MANGLE(bxfi_trampoline_addr)
+MANGLE(bxfi_trampoline_addr):
+addr_data:
+.fill 8, 1, 0
+
+#ifdef ASSEMBLER_SUPPORTS_HIDDEN
+.hidden MANGLE(bxfi_trampoline_end)
+#endif
+.globl MANGLE(bxfi_trampoline_end)
+MANGLE(bxfi_trampoline_end):
+
+#include "stackfix.h"