target/mips: Extract break code into env->error_code

Simplify cpu_loop by doing all of the decode in translate.

This fixes a bug in that cpu_loop was not handling the
different layout of the R6 version of break16.  This fixes
a bug in that cpu_loop extracted the wrong bits for the
mips16e break16 instruction.

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220107213243.212806-17-richard.henderson@linaro.org>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>

1 files changed, 9 insertions, 64 deletions

diff --git a/linux-user/mips/cpu_loop.c b/linux-user/mips/cpu_loop.c
index 1286fbc2e0..9a6ab2dd98 100644
--- a/linux-user/mips/cpu_loop.c
+++ b/linux-user/mips/cpu_loop.c
@@ -65,6 +65,7 @@ void cpu_loop(CPUMIPSState *env)
 {
     CPUState *cs = env_cpu(env);
     int trapnr, si_code;
+    unsigned int code;
     abi_long ret;
 # ifdef TARGET_ABI_MIPSO32
     unsigned int syscall_num;
@@ -185,71 +186,15 @@ done_syscall:
          * handling code in arch/mips/kernel/traps.c.
          */
         case EXCP_BREAK:
-            {
-                abi_ulong trap_instr;
-                unsigned int code;
-
-                /*
-                 * FIXME: It would be better to decode the trap number
-                 * during translate, and store it in error_code while
-                 * raising the exception.  We should not be re-reading
-                 * the opcode here.
-                 */
-
-                if (env->hflags & MIPS_HFLAG_M16) {
-                    if (env->insn_flags & ASE_MICROMIPS) {
-                        /* microMIPS mode */
-                        ret = get_user_u16(trap_instr, env->active_tc.PC);
-                        if (ret != 0) {
-                            goto error;
-                        }
-
-                        if ((trap_instr >> 10) == 0x11) {
-                            /* 16-bit instruction */
-                            code = trap_instr & 0xf;
-                        } else {
-                            /* 32-bit instruction */
-                            abi_ulong instr_lo;
-
-                            ret = get_user_u16(instr_lo,
-                                               env->active_tc.PC + 2);
-                            if (ret != 0) {
-                                goto error;
-                            }
-                            trap_instr = (trap_instr << 16) | instr_lo;
-                            code = ((trap_instr >> 6) & ((1 << 20) - 1));
-                            /* Unfortunately, microMIPS also suffers from
-                               the old assembler bug...  */
-                            if (code >= (1 << 10)) {
-                                code >>= 10;
-                            }
-                        }
-                    } else {
-                        /* MIPS16e mode */
-                        ret = get_user_u16(trap_instr, env->active_tc.PC);
-                        if (ret != 0) {
-                            goto error;
-                        }
-                        code = (trap_instr >> 6) & 0x3f;
-                    }
-                } else {
-                    ret = get_user_u32(trap_instr, env->active_tc.PC);
-                    if (ret != 0) {
-                        goto error;
-                    }
-
-                    /* As described in the original Linux kernel code, the
-                     * below checks on 'code' are to work around an old
-                     * assembly bug.
-                     */
-                    code = ((trap_instr >> 6) & ((1 << 20) - 1));
-                    if (code >= (1 << 10)) {
-                        code >>= 10;
-                    }
-                }
-
-                do_tr_or_bp(env, code, false);
+            /*
+             * As described in the original Linux kernel code, the below
+             * checks on 'code' are to work around an old assembly bug.
+             */
+            code = env->error_code;
+            if (code >= (1 << 10)) {
+                code >>= 10;
             }
+            do_tr_or_bp(env, code, false);
             break;
         case EXCP_TRAP:
             {