[Xen-changelog] [qemu-upstream-unstable] target-xtensa: fix translation for opcodes crossing page boundary

[patchbot@xxxxxxx]

commit 27ad3df73ef88476a288e3aebd5fbcd501ff7e7f
Author:     Max Filippov <jcmvbkbc@xxxxxxxxx>
AuthorDate: Sun Dec 14 07:50:55 2014 +0300
Commit:     Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun Feb 22 12:27:36 2015 -0600

    target-xtensa: fix translation for opcodes crossing page boundary
    
    If TB ends with an opcode that crosses page boundary and the following
    page is not executable then EPC1 for the code fetch exception wrongly
    points at the beginning of the TB. Always treat instruction that crosses
    page boundary as a separate TB.
    
    Cc: qemu-stable@xxxxxxxxxx
    Signed-off-by: Max Filippov <jcmvbkbc@xxxxxxxxx>
    (cherry picked from commit 01673a3401614b4199c9946ad47b97bedfc7a7c2)
    Signed-off-by: Michael Roth <mdroth@xxxxxxxxxxxxxxxxxx>
---
 target-xtensa/translate.c |   27 +++++++++++++++++++++++----
 1 files changed, 23 insertions(+), 4 deletions(-)

diff --git a/target-xtensa/translate.c b/target-xtensa/translate.c
index badca19..a81573d 100644
--- a/target-xtensa/translate.c
+++ b/target-xtensa/translate.c
@@ -887,6 +887,11 @@ static TCGv_i32 gen_mac16_m(TCGv_i32 v, bool hi, bool 
is_unsigned)
     return m;
 }
 
+static inline unsigned xtensa_op0_insn_len(unsigned op0)
+{
+    return op0 >= 8 ? 2 : 3;
+}
+
 static void disas_xtensa_insn(CPUXtensaState *env, DisasContext *dc)
 {
 #define HAS_OPTION_BITS(opt) do { \
@@ -989,6 +994,7 @@ static void disas_xtensa_insn(CPUXtensaState *env, 
DisasContext *dc)
     uint8_t b0 = cpu_ldub_code(env, dc->pc);
     uint8_t b1 = cpu_ldub_code(env, dc->pc + 1);
     uint8_t b2 = 0;
+    unsigned len = xtensa_op0_insn_len(OP0);
 
     static const uint32_t B4CONST[] = {
         0xffffffff, 1, 2, 3, 4, 5, 6, 7, 8, 10, 12, 16, 32, 64, 128, 256
@@ -998,13 +1004,19 @@ static void disas_xtensa_insn(CPUXtensaState *env, 
DisasContext *dc)
         32768, 65536, 2, 3, 4, 5, 6, 7, 8, 10, 12, 16, 32, 64, 128, 256
     };
 
-    if (OP0 >= 8) {
-        dc->next_pc = dc->pc + 2;
+    switch (len) {
+    case 2:
         HAS_OPTION(XTENSA_OPTION_CODE_DENSITY);
-    } else {
-        dc->next_pc = dc->pc + 3;
+        break;
+
+    case 3:
         b2 = cpu_ldub_code(env, dc->pc + 2);
+        break;
+
+    default:
+        RESERVED();
     }
+    dc->next_pc = dc->pc + len;
 
     switch (OP0) {
     case 0: /*QRST*/
@@ -2949,6 +2961,12 @@ invalid_opcode:
 #undef HAS_OPTION
 }
 
+static inline unsigned xtensa_insn_len(CPUXtensaState *env, DisasContext *dc)
+{
+    uint8_t b0 = cpu_ldub_code(env, dc->pc);
+    return xtensa_op0_insn_len(OP0);
+}
+
 static void check_breakpoint(CPUXtensaState *env, DisasContext *dc)
 {
     CPUState *cs = CPU(xtensa_env_get_cpu(env));
@@ -3081,6 +3099,7 @@ void gen_intermediate_code_internal(XtensaCPU *cpu,
     } while (dc.is_jmp == DISAS_NEXT &&
             insn_count < max_insns &&
             dc.pc < next_page_start &&
+            dc.pc + xtensa_insn_len(env, &dc) <= next_page_start &&
             tcg_ctx.gen_opc_ptr < gen_opc_end);
 
     reset_litbase(&dc);
--
generated by git-patchbot for /home/xen/git/qemu-upstream-unstable.git

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