target/loongarch: Update gdb_set_fpu() and gdb_get_fpu()

GDB LoongArch fpu use fcc register, update gdb_set_fpu()
and gdb_get_fpu() to match it.

Signed-off-by: Song Gao <gaosong@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Acked-by: Alex Bennée <alex.bennee@linaro.org>
Message-Id: <20220805033523.1416837-6-gaosong@loongson.cn>

linux-user/loongarch64/signal.c

@@ -71,26 +71,6 @@ struct extctx_layout {
     struct ctx_layout end;
 };
 
-/* The kernel's sc_save_fcc macro is a sequence of MOVCF2GR+BSTRINS. */
-static uint64_t read_all_fcc(CPULoongArchState *env)
-{
-    uint64_t ret = 0;
-
-    for (int i = 0; i < 8; ++i) {
-        ret |= (uint64_t)env->cf[i] << (i * 8);
-    }
-
-    return ret;
-}
-
-/* The kernel's sc_restore_fcc macro is a sequence of BSTRPICK+MOVGR2CF. */
-static void write_all_fcc(CPULoongArchState *env, uint64_t val)
-{
-    for (int i = 0; i < 8; ++i) {
-        env->cf[i] = (val >> (i * 8)) & 1;
-    }
-}
-
 static abi_ptr extframe_alloc(struct extctx_layout *extctx,
                               struct ctx_layout *sctx, unsigned size,
                               unsigned align, abi_ptr orig_sp)
@@ -150,7 +130,7 @@ static void setup_sigframe(CPULoongArchState *env,
     for (i = 0; i < 32; ++i) {
         __put_user(env->fpr[i], &fpu_ctx->regs[i]);
     }
-    __put_user(read_all_fcc(env), &fpu_ctx->fcc);
+    __put_user(read_fcc(env), &fpu_ctx->fcc);
     __put_user(env->fcsr0, &fpu_ctx->fcsr);
 
     /*
@@ -216,7 +196,7 @@ static void restore_sigframe(CPULoongArchState *env,
             __get_user(env->fpr[i], &fpu_ctx->regs[i]);
         }
         __get_user(fcc, &fpu_ctx->fcc);
-        write_all_fcc(env, fcc);
+        write_fcc(env, fcc);
         __get_user(env->fcsr0, &fpu_ctx->fcsr);
         restore_fp_status(env);
     }

target/loongarch/gdbstub.c

@@ -11,6 +11,24 @@
 #include "internals.h"
 #include "exec/gdbstub.h"
 
+uint64_t read_fcc(CPULoongArchState *env)
+{
+    uint64_t ret = 0;
+
+    for (int i = 0; i < 8; ++i) {
+        ret |= (uint64_t)env->cf[i] << (i * 8);
+    }
+
+    return ret;
+}
+
+void write_fcc(CPULoongArchState *env, uint64_t val)
+{
+    for (int i = 0; i < 8; ++i) {
+        env->cf[i] = (val >> (i * 8)) & 1;
+    }
+}
+
 int loongarch_cpu_gdb_read_register(CPUState *cs, GByteArray *mem_buf, int n)
 {
     LoongArchCPU *cpu = LOONGARCH_CPU(cs);
@@ -51,9 +69,10 @@ static int loongarch_gdb_get_fpu(CPULoongArchState *env,
 {
     if (0 <= n && n < 32) {
         return gdb_get_reg64(mem_buf, env->fpr[n]);
-    } else if (32 <= n && n < 40) {
+    } else if (n == 32) {
-        return gdb_get_reg8(mem_buf, env->cf[n - 32]);
+        uint64_t val = read_fcc(env);
-    } else if (n == 40) {
+        return gdb_get_reg64(mem_buf, val);
+    } else if (n == 33) {
         return gdb_get_reg32(mem_buf, env->fcsr0);
     }
     return 0;
@@ -67,10 +86,11 @@ static int loongarch_gdb_set_fpu(CPULoongArchState *env,
     if (0 <= n && n < 32) {
         env->fpr[n] = ldq_p(mem_buf);
         length = 8;
-    } else if (32 <= n && n < 40) {
+    } else if (n == 32) {
-        env->cf[n - 32] = ldub_p(mem_buf);
+        uint64_t val = ldq_p(mem_buf);
-        length = 1;
+        write_fcc(env, val);
-    } else if (n == 40) {
+        length = 8;
+    } else if (n == 33) {
         env->fcsr0 = ldl_p(mem_buf);
         length = 4;
     }

target/loongarch/internals.h

@@ -51,6 +51,9 @@ bool loongarch_cpu_tlb_fill(CPUState *cs, vaddr address, int size,
 hwaddr loongarch_cpu_get_phys_page_debug(CPUState *cpu, vaddr addr);
 #endif /* !CONFIG_USER_ONLY */
 
+uint64_t read_fcc(CPULoongArchState *env);
+void write_fcc(CPULoongArchState *env, uint64_t val);
+
 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);