[PATCH 07/10] target/sparc64: expose system registers via GDB

["Marc-André Lureau" <marcandre.lureau@redhat.com>]

Add a sparc64-system.xml GDB feature that exposes asi, pstate,
cansave, canrestore, otherwin, wstate, and cleanwin as read-only
system registers through the GDB coprocessor interface.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
---
 configs/targets/sparc64-softmmu.mak |  2 +-
 gdbstub/gdb-xml/sparc64-system.xml  | 22 +++++++++++++++++++++
 target/sparc/gdbstub.c              | 38 +++++++++++++++++++++++++++++++++++++
 3 files changed, 61 insertions(+), 1 deletion(-)

diff --git a/configs/targets/sparc64-softmmu.mak b/configs/targets/sparc64-softmmu.mak
index 4e621fb8e39e..7f2789136653 100644
--- a/configs/targets/sparc64-softmmu.mak
+++ b/configs/targets/sparc64-softmmu.mak
@@ -1,7 +1,7 @@
 TARGET_ARCH=sparc64
 TARGET_BASE_ARCH=sparc
 TARGET_BIG_ENDIAN=y
-TARGET_XML_FILES=sparc64-cpu.xml sparc64-fpu.xml sparc64-cp0.xml
+TARGET_XML_FILES=sparc64-cpu.xml sparc64-fpu.xml sparc64-cp0.xml sparc64-system.xml
 TARGET_LONG_BITS=64
 TARGET_NOT_USING_LEGACY_LDST_PHYS_API=y
 TARGET_NOT_USING_LEGACY_NATIVE_ENDIAN_API=y
diff --git a/gdbstub/gdb-xml/sparc64-system.xml b/gdbstub/gdb-xml/sparc64-system.xml
new file mode 100644
index 000000000000..e00baedb467e
--- /dev/null
+++ b/gdbstub/gdb-xml/sparc64-system.xml
@@ -0,0 +1,22 @@
+<?xml version="1.0"?>
+<!--
+  SPDX-License-Identifier: GPL-2.0-or-later
+-->
+<!DOCTYPE feature SYSTEM "gdb-target.dtd">
+<!-- System-register values are read-only; writes are ignored. -->
+<feature name="org.qemu.gdb.sparc.system">
+  <reg name="asi" bitsize="32" type="uint32"
+       group="qemu-debug" save-restore="no"/>
+  <reg name="pstate" bitsize="32" type="uint32"
+       group="qemu-debug" save-restore="no"/>
+  <reg name="cansave" bitsize="32" type="uint32"
+       group="qemu-debug" save-restore="no"/>
+  <reg name="canrestore" bitsize="32" type="uint32"
+       group="qemu-debug" save-restore="no"/>
+  <reg name="otherwin" bitsize="32" type="uint32"
+       group="qemu-debug" save-restore="no"/>
+  <reg name="wstate" bitsize="32" type="uint32"
+       group="qemu-debug" save-restore="no"/>
+  <reg name="cleanwin" bitsize="32" type="uint32"
+       group="qemu-debug" save-restore="no"/>
+</feature>
diff --git a/target/sparc/gdbstub.c b/target/sparc/gdbstub.c
index 2874ce1b3501..ca23a4a94532 100644
--- a/target/sparc/gdbstub.c
+++ b/target/sparc/gdbstub.c
@@ -266,6 +266,39 @@ static int sparc_cp0_gdb_write_register(CPUState *cs, uint8_t *mem_buf, int n)
 #endif
 }
 
+#if defined(TARGET_SPARC64) && !defined(CONFIG_USER_ONLY)
+static int sparc64_gdb_read_system_register(CPUState *cs, GByteArray *buf,
+                                           int n)
+{
+    CPUSPARCState *env = cpu_env(cs);
+
+    switch (n) {
+    case 0:
+        return gdb_get_reg32(buf, env->asi);
+    case 1:
+        return gdb_get_reg32(buf, env->pstate);
+    case 2:
+        return gdb_get_reg32(buf, env->cansave);
+    case 3:
+        return gdb_get_reg32(buf, env->canrestore);
+    case 4:
+        return gdb_get_reg32(buf, env->otherwin);
+    case 5:
+        return gdb_get_reg32(buf, env->wstate);
+    case 6:
+        return gdb_get_reg32(buf, env->cleanwin);
+    default:
+        return 0;
+    }
+}
+
+static int sparc64_gdb_write_system_register(CPUState *cs, uint8_t *buf, int n)
+{
+    /* These registers are exposed for inspection only. Ignore writes. */
+    return 4;
+}
+#endif
+
 void sparc_cpu_register_gdb_regs(CPUState *cs)
 {
 #if defined(TARGET_ABI32) || !defined(TARGET_SPARC64)
@@ -282,5 +315,10 @@ void sparc_cpu_register_gdb_regs(CPUState *cs)
     gdb_register_coprocessor(cs, sparc_cp0_gdb_read_register,
                              sparc_cp0_gdb_write_register,
                              gdb_find_static_feature("sparc64-cp0.xml"));
+#ifndef CONFIG_USER_ONLY
+    gdb_register_coprocessor(cs, sparc64_gdb_read_system_register,
+                             sparc64_gdb_write_system_register,
+                             gdb_find_static_feature("sparc64-system.xml"));
+#endif
 #endif
 }

-- 
2.55.0.543.g5ebe2ebe4ea8