commit b5b13eb712e73545c4323d497ef1fabf7e63c360
author Bibo Mao <maobibo@loongson.cn> Thu Jan 16 19:09:25 2025 +0800
committer Bibo Mao <maobibo@loongson.cn> Fri Jan 24 14:49:24 2025 +0800
tree 551c725bd4aeabdc43e1f3d5f9b9ec59d76251ae
parent cb6fa4142f883684c7689944020aa95e422e0578

target/loongarch: Set unused flag with CSR registers

On LA464, some CSR registers are not used such as CSR_SAVE8 -
CSR_SAVE15, also CSR registers relative with MCE is not used now.

Flag CSRFL_UNUSED is added for these registers, so that it will
not dumped. In order to keep compatiblity, these CSR registers are
not removed since it is used in vmstate already.

Signed-off-by: Bibo Mao <maobibo@loongson.cn>

target/loongarch/cpu.c

diff --git a/target/loongarch/cpu.c b/target/loongarch/cpu.c
index d611a60..a744010 100644
--- a/target/loongarch/cpu.c
+++ b/target/loongarch/cpu.c
@@ -19,7 +19,7 @@
 #include "cpu.h"
 #include "internals.h"
 #include "fpu/softfloat-helpers.h"
-#include "cpu-csr.h"
+#include "csr.h"
 #ifndef CONFIG_USER_ONLY
 #include "system/reset.h"
 #endif
@@ -375,6 +375,33 @@
     return MMU_DA_IDX;
 }
 
+static void loongarch_la464_init_csr(Object *obj)
+{
+#ifndef CONFIG_USER_ONLY
+    static bool initialized;
+    LoongArchCPU *cpu = LOONGARCH_CPU(obj);
+    CPULoongArchState *env = &cpu->env;
+    int i, num;
+
+    if (!initialized) {
+        initialized = true;
+        num = FIELD_EX64(env->CSR_PRCFG1, CSR_PRCFG1, SAVE_NUM);
+        for (i = num; i < 16; i++) {
+            set_csr_flag(LOONGARCH_CSR_SAVE(i), CSRFL_UNUSED);
+        }
+        set_csr_flag(LOONGARCH_CSR_IMPCTL1, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_IMPCTL2, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_MERRCTL, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_MERRINFO1, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_MERRINFO2, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_MERRENTRY, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_MERRERA, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_MERRSAVE, CSRFL_UNUSED);
+        set_csr_flag(LOONGARCH_CSR_CTAG, CSRFL_UNUSED);
+    }
+#endif
+}
+
 static void loongarch_la464_initfn(Object *obj)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(obj);
@@ -470,6 +497,7 @@
     env->CSR_PRCFG3 = FIELD_DP64(env->CSR_PRCFG3, CSR_PRCFG3, STLB_WAYS, 7);
     env->CSR_PRCFG3 = FIELD_DP64(env->CSR_PRCFG3, CSR_PRCFG3, STLB_SETS, 8);
 
+    loongarch_la464_init_csr(obj);
     loongarch_cpu_post_init(obj);
 }
 

target/loongarch/csr.c

diff --git a/target/loongarch/csr.c b/target/loongarch/csr.c
index 62c1815..87bd24e 100644
--- a/target/loongarch/csr.c
+++ b/target/loongarch/csr.c
@@ -112,3 +112,16 @@
 
     return csr;
 }
+
+bool set_csr_flag(unsigned int csr_num, int flag)
+{
+    CSRInfo *csr;
+
+    csr = get_csr(csr_num);
+    if (!csr) {
+        return false;
+    }
+
+    csr->flags |= flag;
+    return true;
+}

target/loongarch/csr.h

diff --git a/target/loongarch/csr.h b/target/loongarch/csr.h
index caad832..deb1aac 100644
--- a/target/loongarch/csr.h
+++ b/target/loongarch/csr.h
@@ -13,6 +13,7 @@
     CSRFL_READONLY = (1 << 0),
     CSRFL_EXITTB   = (1 << 1),
     CSRFL_IO       = (1 << 2),
+    CSRFL_UNUSED   = (1 << 3),
 };
 
 typedef struct {
@@ -23,4 +24,5 @@
 } CSRInfo;
 
 CSRInfo *get_csr(unsigned int csr_num);
+bool set_csr_flag(unsigned int csr_num, int flag);
 #endif /* TARGET_LOONGARCH_CSR_H */