target/loongarch: Add GDB support for loongarch32 mode

GPRs and PC are 32-bit wide in loongarch32 mode.

Signed-off-by: Jiajie Chen <[email protected]>
Reviewed-by: Richard Henderson <[email protected]>
Signed-off-by: Song Gao <[email protected]>
Message-ID: <[email protected]>
[PMD: Rebased, set gdb_num_core_regs]
Signed-off-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <[email protected]>

Author: jiegec

configs/targets/loongarch64-softmmu.mak

@@ -1,5 +1,5 @@
 TARGET_ARCH=loongarch64
 TARGET_BASE_ARCH=loongarch
 TARGET_SUPPORTS_MTTCG=y
-TARGET_XML_FILES= gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml
+TARGET_XML_FILES= gdb-xml/loongarch-base32.xml gdb-xml/loongarch-base64.xml gdb-xml/loongarch-fpu.xml
 TARGET_NEED_FDT=y

gdb-xml/loongarch-base32.xml

@@ -0,0 +1,45 @@
+<?xml version="1.0"?>
+<!-- Copyright (C) 2022 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="32" type="uint32" group="general"/>
+  <reg name="r1" bitsize="32" type="code_ptr" group="general"/>
+  <reg name="r2" bitsize="32" type="data_ptr" group="general"/>
+  <reg name="r3" bitsize="32" type="data_ptr" group="general"/>
+  <reg name="r4" bitsize="32" type="uint32" group="general"/>
+  <reg name="r5" bitsize="32" type="uint32" group="general"/>
+  <reg name="r6" bitsize="32" type="uint32" group="general"/>
+  <reg name="r7" bitsize="32" type="uint32" group="general"/>
+  <reg name="r8" bitsize="32" type="uint32" group="general"/>
+  <reg name="r9" bitsize="32" type="uint32" group="general"/>
+  <reg name="r10" bitsize="32" type="uint32" group="general"/>
+  <reg name="r11" bitsize="32" type="uint32" group="general"/>
+  <reg name="r12" bitsize="32" type="uint32" group="general"/>
+  <reg name="r13" bitsize="32" type="uint32" group="general"/>
+  <reg name="r14" bitsize="32" type="uint32" group="general"/>
+  <reg name="r15" bitsize="32" type="uint32" group="general"/>
+  <reg name="r16" bitsize="32" type="uint32" group="general"/>
+  <reg name="r17" bitsize="32" type="uint32" group="general"/>
+  <reg name="r18" bitsize="32" type="uint32" group="general"/>
+  <reg name="r19" bitsize="32" type="uint32" group="general"/>
+  <reg name="r20" bitsize="32" type="uint32" group="general"/>
+  <reg name="r21" bitsize="32" type="uint32" group="general"/>
+  <reg name="r22" bitsize="32" type="data_ptr" group="general"/>
+  <reg name="r23" bitsize="32" type="uint32" group="general"/>
+  <reg name="r24" bitsize="32" type="uint32" group="general"/>
+  <reg name="r25" bitsize="32" type="uint32" group="general"/>
+  <reg name="r26" bitsize="32" type="uint32" group="general"/>
+  <reg name="r27" bitsize="32" type="uint32" group="general"/>
+  <reg name="r28" bitsize="32" type="uint32" group="general"/>
+  <reg name="r29" bitsize="32" type="uint32" group="general"/>
+  <reg name="r30" bitsize="32" type="uint32" group="general"/>
+  <reg name="r31" bitsize="32" type="uint32" group="general"/>
+  <reg name="orig_a0" bitsize="32" type="uint32" group="general"/>
+  <reg name="pc" bitsize="32" type="code_ptr" group="general"/>
+  <reg name="badv" bitsize="32" type="code_ptr" group="general"/>
+</feature>

target/loongarch/cpu.c

@@ -726,8 +726,18 @@ static void loongarch_cpu_class_init(ObjectClass *c, void *data)
 #endif
 }
 
+static gchar *loongarch32_gdb_arch_name(CPUState *cs)
+{
+    return g_strdup("loongarch32");
+}
+
 static void loongarch32_cpu_class_init(ObjectClass *c, void *data)
 {
+    CPUClass *cc = CPU_CLASS(c);
+
+    cc->gdb_num_core_regs = 35;
+    cc->gdb_core_xml_file = "loongarch-base32.xml";
+    cc->gdb_arch_name = loongarch32_gdb_arch_name;
 }
 
 static gchar *loongarch64_gdb_arch_name(CPUState *cs)

target/loongarch/gdbstub.c

@@ -34,16 +34,25 @@ int loongarch_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(cs);
     CPULoongArchState *env = &cpu->env;
+    uint64_t val;
 
     if (0 <= n && n < 32) {
-        return gdb_get_regl(mem_buf, env->gpr[n]);
+        val = env->gpr[n];
     } else if (n == 32) {
         /* orig_a0 */
-        return gdb_get_regl(mem_buf, 0);
+        val = 0;
     } else if (n == 33) {
-        return gdb_get_regl(mem_buf, env->pc);
+        val = env->pc;
     } else if (n == 34) {
-        return gdb_get_regl(mem_buf, env->CSR_BADV);
+        val = env->CSR_BADV;
+    }
+
+    if (0 <= n && n <= 34) {
+        if (is_la64(env)) {
+            return gdb_get_reg64(mem_buf, val);
+        } else {
+            return gdb_get_reg32(mem_buf, val);
+        }
     }
     return 0;
 }
@@ -52,15 +61,24 @@ 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);
+    target_ulong tmp;
+    int read_length;
     int length = 0;
 
+    if (is_la64(env)) {
+        tmp = ldq_p(mem_buf);
+        read_length = 8;
+    } else {
+        tmp = ldl_p(mem_buf);
+        read_length = 4;
+    }
+
     if (0 <= n && n < 32) {
         env->gpr[n] = tmp;
-        length = sizeof(target_ulong);
+        length = read_length;
     } else if (n == 33) {
         env->pc = tmp;
-        length = sizeof(target_ulong);
+        length = read_length;
     }
     return length;
 }