RISC-V GDB Stub

GDB Register read and write routines.

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Signed-off-by: Sagar Karandikar <sagark@eecs.berkeley.edu>
Signed-off-by: Michael Clark <mjc@sifive.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/target/riscv/gdbstub.c b/target/riscv/gdbstub.c
new file mode 100644
index 0000000000..4f919b6c34
--- /dev/null
+++ b/target/riscv/gdbstub.c
@@ -0,0 +1,62 @@
+/*
+ * RISC-V GDB Server Stub
+ *
+ * Copyright (c) 2016-2017 Sagar Karandikar, sagark@eecs.berkeley.edu
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "exec/gdbstub.h"
+#include "cpu.h"
+
+int riscv_cpu_gdb_read_register(CPUState *cs, uint8_t *mem_buf, int n)
+{
+    RISCVCPU *cpu = RISCV_CPU(cs);
+    CPURISCVState *env = &cpu->env;
+
+    if (n < 32) {
+        return gdb_get_regl(mem_buf, env->gpr[n]);
+    } else if (n == 32) {
+        return gdb_get_regl(mem_buf, env->pc);
+    } else if (n < 65) {
+        return gdb_get_reg64(mem_buf, env->fpr[n - 33]);
+    } else if (n < 4096 + 65) {
+        return gdb_get_regl(mem_buf, csr_read_helper(env, n - 65));
+    }
+    return 0;
+}
+
+int riscv_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
+{
+    RISCVCPU *cpu = RISCV_CPU(cs);
+    CPURISCVState *env = &cpu->env;
+
+    if (n == 0) {
+        /* discard writes to x0 */
+        return sizeof(target_ulong);
+    } else if (n < 32) {
+        env->gpr[n] = ldtul_p(mem_buf);
+        return sizeof(target_ulong);
+    } else if (n == 32) {
+        env->pc = ldtul_p(mem_buf);
+        return sizeof(target_ulong);
+    } else if (n < 65) {
+        env->fpr[n - 33] = ldq_p(mem_buf); /* always 64-bit */
+        return sizeof(uint64_t);
+    } else if (n < 4096 + 65) {
+        csr_write_helper(env, ldtul_p(mem_buf), n - 65);
+    }
+    return 0;
+}