diff mbox

[09/11] linux-user: Check type of microMIPS break instruction

Message ID 1308c464a8414ce3c6f79e172255fb90b5aa313d.1380283598.git.riku.voipio@linaro.org
State New
Headers show

Commit Message

Riku Voipio Sept. 27, 2013, 12:10 p.m. UTC 
From: Kwok Cheung Yeung <kcy@codesourcery.com>

microMIPS instructions that cause breakpoint exceptions come in
16-bit and 32-bit variants.  When handling exceptions caused by
such instructions, the instruction type needs to be taken into
account when extracting the break code.

The code has also been restructured for better clarity.

Signed-off-by: Kwok Cheung Yeung <kcy@codesourcery.com>
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
---
 linux-user/main.c | 56 ++++++++++++++++++++++++++++++++++---------------------
 1 file changed, 35 insertions(+), 21 deletions(-)
diff mbox

Patch

diff --git a/linux-user/main.c b/linux-user/main.c
index 016e2e1..1561950 100644
--- a/linux-user/main.c
+++ b/linux-user/main.c
@@ -2400,12 +2400,31 @@  done_syscall:
                 if (env->hflags & MIPS_HFLAG_M16) {
                     if (env->insn_flags & ASE_MICROMIPS) {
                         /* microMIPS mode */
-                        abi_ulong instr[2];
-
-                        ret = get_user_u16(instr[0], env->active_tc.PC) ||
-                              get_user_u16(instr[1], env->active_tc.PC + 2);
+                        ret = get_user_u16(trap_instr, env->active_tc.PC);
+                        if (ret != 0) {
+                            goto error;
+                        }
 
-                        trap_instr = (instr[0] << 16) | instr[1];
+                        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);
@@ -2413,26 +2432,21 @@  done_syscall:
                             goto error;
                         }
                         code = (trap_instr >> 6) & 0x3f;
-                        if (do_break(env, &info, code) != 0) {
-                            goto error;
-                        }
-                        break;
                     }
                 } else {
                     ret = get_user_ual(trap_instr, env->active_tc.PC);
-                }
-
-                if (ret != 0) {
-                    goto error;
-                }
+                    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;
+                    /* 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;
+                    }
                 }
 
                 if (do_break(env, &info, code) != 0) {