Commit a9d3d1dff6 for qemu.org

commit a9d3d1dff6f9e1544e8a84e74645b8e4fe08c0ad
Author: WANG Rui <wangrui@loongson.cn>
Date:   Mon Apr 14 15:49:52 2025 +0800

    linux-user/loongarch64: Decode BRK break codes for FPE signals

    Handle specific LoongArch BRK break codes in user-mode emulation
    to deliver accurate floating-point exception signals. Specifically,
    BRK_OVERFLOW (6) triggers TARGET_FPE_INTOVF, and BRK_DIVZERO (7)
    triggers TARGET_FPE_INTDIV. Other BRK codes fall back to a generic
    SIGTRAP.

    This improves correctness for programs that rely on BRK to signal
    overflow or divide-by-zero conditions.

    Signed-off-by: WANG Rui <wangrui@loongson.cn>
    Acked-by: Song Gao <gaosong@loongson.cn>
    Message-Id: <20250414074952.6253-1-wangrui@loongson.cn>
    Signed-off-by: Song Gao <gaosong@loongson.cn>

diff --git a/linux-user/loongarch64/cpu_loop.c b/linux-user/loongarch64/cpu_loop.c
index 0614d3de22..ec8a06c88c 100644
--- a/linux-user/loongarch64/cpu_loop.c
+++ b/linux-user/loongarch64/cpu_loop.c
@@ -11,6 +11,12 @@
 #include "user/cpu_loop.h"
 #include "signal-common.h"

+/* Break codes */
+enum {
+    BRK_OVERFLOW = 6,
+    BRK_DIVZERO = 7
+};
+
 void cpu_loop(CPULoongArchState *env)
 {
     CPUState *cs = env_cpu(env);
@@ -66,9 +72,26 @@ void cpu_loop(CPULoongArchState *env)
             force_sig_fault(TARGET_SIGFPE, si_code, env->pc);
             break;
         case EXCP_DEBUG:
-        case EXCCODE_BRK:
             force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
             break;
+        case EXCCODE_BRK:
+            {
+                unsigned int opcode;
+
+                get_user_u32(opcode, env->pc);
+
+                switch (opcode & 0x7fff) {
+                case BRK_OVERFLOW:
+                    force_sig_fault(TARGET_SIGFPE, TARGET_FPE_INTOVF, env->pc);
+                    break;
+                case BRK_DIVZERO:
+                    force_sig_fault(TARGET_SIGFPE, TARGET_FPE_INTDIV, env->pc);
+                    break;
+                default:
+                    force_sig_fault(TARGET_SIGTRAP, TARGET_TRAP_BRKPT, env->pc);
+                }
+            }
+            break;
         case EXCCODE_BCE:
             force_sig_fault(TARGET_SIGSYS, TARGET_SI_KERNEL, env->pc);
             break;