target/loongarch: Add gdb support.

Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220606124333.2060567-42-yangxiaojuan@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

8 files changed, 198 insertions, 0 deletions

diff --git a/MAINTAINERS b/MAINTAINERS
index e8938db694..954fb95218 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1137,6 +1137,7 @@ F: include/hw/intc/loongarch_*.h
 F: hw/intc/loongarch_*.c
 F: include/hw/pci-host/ls7a.h
 F: hw/rtc/ls7a_rtc.c
+F: gdb-xml/loongarch*.xml
 
 M68K Machines
 -------------
diff --git a/configs/targets/loongarch64-softmmu.mak b/configs/targets/loongarch64-softmmu.mak
index 666154022f..7bc06c850c 100644
--- a/configs/targets/loongarch64-softmmu.mak
+++ b/configs/targets/loongarch64-softmmu.mak
@@ -1,3 +1,4 @@
 TARGET_ARCH=loongarch64
 TARGET_BASE_ARCH=loongarch
 TARGET_SUPPORTS_MTTCG=y
+TARGET_XML_FILES= gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu64.xml
diff --git a/gdb-xml/loongarch-base64.xml b/gdb-xml/loongarch-base64.xml
new file mode 100644
index 0000000000..4962bdbd28
--- /dev/null
+++ b/gdb-xml/loongarch-base64.xml
@@ -0,0 +1,44 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2021 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.loongarch.base">
+  <reg name="r0" bitsize="64" type="uint64" group="general"/>
+  <reg name="r1" bitsize="64" type="uint64" group="general"/>
+  <reg name="r2" bitsize="64" type="uint64" group="general"/>
+  <reg name="r3" bitsize="64" type="uint64" group="general"/>
+  <reg name="r4" bitsize="64" type="uint64" group="general"/>
+  <reg name="r5" bitsize="64" type="uint64" group="general"/>
+  <reg name="r6" bitsize="64" type="uint64" group="general"/>
+  <reg name="r7" bitsize="64" type="uint64" group="general"/>
+  <reg name="r8" bitsize="64" type="uint64" group="general"/>
+  <reg name="r9" bitsize="64" type="uint64" group="general"/>
+  <reg name="r10" bitsize="64" type="uint64" group="general"/>
+  <reg name="r11" bitsize="64" type="uint64" group="general"/>
+  <reg name="r12" bitsize="64" type="uint64" group="general"/>
+  <reg name="r13" bitsize="64" type="uint64" group="general"/>
+  <reg name="r14" bitsize="64" type="uint64" group="general"/>
+  <reg name="r15" bitsize="64" type="uint64" group="general"/>
+  <reg name="r16" bitsize="64" type="uint64" group="general"/>
+  <reg name="r17" bitsize="64" type="uint64" group="general"/>
+  <reg name="r18" bitsize="64" type="uint64" group="general"/>
+  <reg name="r19" bitsize="64" type="uint64" group="general"/>
+  <reg name="r20" bitsize="64" type="uint64" group="general"/>
+  <reg name="r21" bitsize="64" type="uint64" group="general"/>
+  <reg name="r22" bitsize="64" type="uint64" group="general"/>
+  <reg name="r23" bitsize="64" type="uint64" group="general"/>
+  <reg name="r24" bitsize="64" type="uint64" group="general"/>
+  <reg name="r25" bitsize="64" type="uint64" group="general"/>
+  <reg name="r26" bitsize="64" type="uint64" group="general"/>
+  <reg name="r27" bitsize="64" type="uint64" group="general"/>
+  <reg name="r28" bitsize="64" type="uint64" group="general"/>
+  <reg name="r29" bitsize="64" type="uint64" group="general"/>
+  <reg name="r30" bitsize="64" type="uint64" group="general"/>
+  <reg name="r31" bitsize="64" type="uint64" group="general"/>
+  <reg name="pc" bitsize="64" type="code_ptr" group="general"/>
+  <reg name="badvaddr" bitsize="64" type="code_ptr" group="general"/>
+</feature>
diff --git a/gdb-xml/loongarch-fpu64.xml b/gdb-xml/loongarch-fpu64.xml
new file mode 100644
index 0000000000..e52cf89fbc
--- /dev/null
+++ b/gdb-xml/loongarch-fpu64.xml
@@ -0,0 +1,57 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2021 Free Software Foundation, Inc.
+
+     Copying and distribution of this file, with or without modification,
+     are permitted in any medium without royalty provided the copyright
+     notice and this notice are preserved.  -->
+
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<feature name="org.gnu.gdb.loongarch.fpu">
+
+  <union id="fpu64type">
+    <field name="f" type="ieee_single"/>
+    <field name="d" type="ieee_double"/>
+  </union>
+
+  <reg name="f0" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f1" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f2" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f3" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f4" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f5" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f6" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f7" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f8" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f9" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f10" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f11" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f12" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f13" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f14" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f15" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f16" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f17" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f18" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f19" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f20" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f21" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f22" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f23" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f24" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f25" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f26" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f27" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f28" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f29" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f30" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="f31" bitsize="64" type="fpu64type" group="float"/>
+  <reg name="fcc0" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcc1" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcc2" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcc3" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcc4" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcc5" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcc6" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcc7" bitsize="8" type="uint8" group="float"/>
+  <reg name="fcsr" bitsize="32" type="uint32" group="float"/>
+</feature>
diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index 3b7d6289d2..4c8f96bc3a 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -487,6 +487,8 @@ static void loongarch_cpu_realizefn(DeviceState *dev, Error **errp)
         return;
     }
 
+    loongarch_cpu_register_gdb_regs_for_features(cs);
+
     cpu_reset(cs);
     qemu_init_vcpu(cs);
 
@@ -640,6 +642,13 @@ static void loongarch_cpu_class_init(ObjectClass *c, void *data)
     dc->vmsd = &vmstate_loongarch_cpu;
     cc->sysemu_ops = &loongarch_sysemu_ops;
     cc->disas_set_info = loongarch_cpu_disas_set_info;
+    cc->gdb_read_register = loongarch_cpu_gdb_read_register;
+    cc->gdb_write_register = loongarch_cpu_gdb_write_register;
+    cc->disas_set_info = loongarch_cpu_disas_set_info;
+    cc->gdb_num_core_regs = 34;
+    cc->gdb_core_xml_file = "loongarch-base64.xml";
+    cc->gdb_stop_before_watchpoint = true;
+
 #ifdef CONFIG_TCG
     cc->tcg_ops = &loongarch_tcg_ops;
 #endif
diff --git a/target/loongarch/gdbstub.c b/target/loongarch/gdbstub.c
new file mode 100644
index 0000000000..0c48834201
--- /dev/null
+++ b/target/loongarch/gdbstub.c
@@ -0,0 +1,81 @@
+/*
+ * LOONGARCH gdb server stub
+ *
+ * Copyright (c) 2021 Loongson Technology Corporation Limited
+ *
+ * SPDX-License-Identifier: LGPL-2.1+
+ */
+
+#include "qemu/osdep.h"
+#include "cpu.h"
+#include "internals.h"
+#include "exec/gdbstub.h"
+
+int loongarch_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(cs);
+    CPULoongArchState *env = &cpu->env;
+
+    if (0 <= n && 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 == 33) {
+        return gdb_get_regl(mem_buf, env->badaddr);
+    }
+    return 0;
+}
+
+int loongarch_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
+{
+    LoongArchCPU *cpu = LOONGARCH_CPU(cs);
+    CPULoongArchState *env = &cpu->env;
+    target_ulong tmp = ldtul_p(mem_buf);
+    int length = 0;
+
+    if (0 <= n && n < 32) {
+        env->gpr[n] = tmp;
+        length = sizeof(target_ulong);
+    } else if (n == 32) {
+        env->pc = tmp;
+        length = sizeof(target_ulong);
+    }
+    return length;
+}
+
+static int loongarch_gdb_get_fpu(CPULoongArchState *env,
+                                 GByteArray *mem_buf, int n)
+{
+    if (0 <= n && n < 32) {
+        return gdb_get_reg64(mem_buf, env->fpr[n]);
+    } else if (32 <= n && n < 40) {
+        return gdb_get_reg8(mem_buf, env->cf[n - 32]);
+    } else if (n == 40) {
+        return gdb_get_reg32(mem_buf, env->fcsr0);
+    }
+    return 0;
+}
+
+static int loongarch_gdb_set_fpu(CPULoongArchState *env,
+                                 uint8_t *mem_buf, int n)
+{
+    int length = 0;
+
+    if (0 <= n && n < 32) {
+        env->fpr[n] = ldq_p(mem_buf);
+        length = 8;
+    } else if (32 <= n && n < 40) {
+        env->cf[n - 32] = ldub_p(mem_buf);
+        length = 1;
+    } else if (n == 40) {
+        env->fcsr0 = ldl_p(mem_buf);
+        length = 4;
+    }
+    return length;
+}
+
+void loongarch_cpu_register_gdb_regs_for_features(CPUState *cs)
+{
+    gdb_register_coprocessor(cs, loongarch_gdb_get_fpu, loongarch_gdb_set_fpu,
+                             41, "loongarch-fpu64.xml", 0);
+}
diff --git a/target/loongarch/internals.h b/target/loongarch/internals.h
index a410c41c37..9d50fbdd81 100644
--- a/target/loongarch/internals.h
+++ b/target/loongarch/internals.h
@@ -49,4 +49,8 @@ bool loongarch_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
 
 hwaddr loongarch_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 
+int loongarch_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n);
+int loongarch_cpu_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n);
+void loongarch_cpu_register_gdb_regs_for_features(CPUState *cs);
+
 #endif
diff --git a/target/loongarch/meson.build b/target/loongarch/meson.build
index 74e5f3b2a7..6376f9e84b 100644
--- a/target/loongarch/meson.build
+++ b/target/loongarch/meson.build
@@ -11,6 +11,7 @@ loongarch_tcg_ss.add(files(
   'fpu_helper.c',
   'op_helper.c',
   'translate.c',
+  'gdbstub.c',
 ))
 loongarch_tcg_ss.add(zlib)