[Qemu-devel] [PATCH 0/2] target-xtensa: fix translation for cross-page opcodes

[Qemu-devel] [PATCH 0/2] target-xtensa: fix translation for cross-page opcodes

[Max Filippov]

Hi,

this series fixes translation for opcodes crossing page boundary and adds a
testcase.

Max Filippov (2):
  target-xtensa: fix translation for opcodes crossing page boundary
  target-xtensa: test cross-page opcode

 target-xtensa/translate.c   | 27 +++++++++++++++++++++++----
 tests/tcg/xtensa/test_mmu.S | 26 +++++++++++++-------------
 2 files changed, 36 insertions(+), 17 deletions(-)

-- 
1.8.1.4

[Qemu-devel] [PATCH 1/2] target-xtensa: fix translation for opcodes crossing page boundary

[Max Filippov]

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@nongnu.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 target-xtensa/translate.c | 27 +++++++++++++++++++++++----
 1 file 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);
-- 
1.8.1.4

[Qemu-devel] [PATCH 2/2] target-xtensa: test cross-page opcode

[Max Filippov]

Alter cross-page TB test to also test cross-page opcode.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
---
 tests/tcg/xtensa/test_mmu.S | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/tests/tcg/xtensa/test_mmu.S b/tests/tcg/xtensa/test_mmu.S
index 58c5bca..a15316f 100644
--- a/tests/tcg/xtensa/test_mmu.S
+++ b/tests/tcg/xtensa/test_mmu.S
@@ -641,7 +641,7 @@ test cross_page_tb
     witlb   a2, a3
     wdtlb   a2, a3
 
-    movi    a2, 0x00007ffd
+    movi    a2, 0x00007ffc
     movi    a3, 20f
     movi    a4, 21f
     sub     a4, a4, a3
@@ -651,7 +651,7 @@ test cross_page_tb
     addi    a2, a2, 1
     addi    a3, a3, 1
 1:
-    movi    a2, 0x00007ffd
+    movi    a2, 0x00007ffc
     movi    a3, 0x00008000
     /* DTLB: OK, ITLB: OK */
     jx      a2
@@ -668,10 +668,10 @@ test cross_page_tb
     movi    a3, 1
     assert  eq, a2, a3
     rsr     a2, epc1
-    movi    a3, 0x8000
+    movi    a3, 0x7fff
     assert  eq, a2, a3
     rsr     a2, excsave1
-    movi    a3, 0x00007ffd
+    movi    a3, 0x00007ffc
     assert  ne, a2, a3
 
     reset_ps
@@ -680,7 +680,7 @@ test cross_page_tb
     movi    a2, 0x0400000c /* PPN */
     movi    a3, 0x00008000 /* VPN */
     wdtlb   a2, a3
-    movi    a2, 0x00007ffd
+    movi    a2, 0x00007ffc
     movi    a3, 0x00008000
     /* DTLB: FAIL, ITLB: OK */
     jx      a2
@@ -689,10 +689,10 @@ test cross_page_tb
     movi    a3, 28
     assert  eq, a2, a3
     rsr     a2, epc1
-    movi    a3, 0x7ffd
+    movi    a3, 0x7ffc
     assert  eq, a2, a3
     rsr     a2, excsave1
-    movi    a3, 0x00007ffd
+    movi    a3, 0x00007ffc
     assert  eq, a2, a3
 
     reset_ps
@@ -703,7 +703,7 @@ test cross_page_tb
     witlb   a2, a3
     movi    a2, 0x04000003 /* PPN */
     wdtlb   a2, a3
-    movi    a2, 0x00007ffd
+    movi    a2, 0x00007ffc
     movi    a3, 0x00008000
     /* DTLB: OK, ITLB: FAIL */
     jx      a2
@@ -712,10 +712,10 @@ test cross_page_tb
     movi    a3, 20
     assert  eq, a2, a3
     rsr     a2, epc1
-    movi    a3, 0x8000
+    movi    a3, 0x7fff
     assert  eq, a2, a3
     rsr     a2, excsave1
-    movi    a3, 0x00007ffd
+    movi    a3, 0x00007ffc
     assert  ne, a2, a3
 
     reset_ps
@@ -724,7 +724,7 @@ test cross_page_tb
     movi    a2, 0x0400000c /* PPN */
     movi    a3, 0x00008000 /* VPN */
     wdtlb   a2, a3
-    movi    a2, 0x00007ffd
+    movi    a2, 0x00007ffc
     movi    a3, 0x00008000
     /* DTLB: FAIL, ITLB: FAIL */
     jx      a2
@@ -733,10 +733,10 @@ test cross_page_tb
     movi    a3, 28
     assert  eq, a2, a3
     rsr     a2, epc1
-    movi    a3, 0x7ffd
+    movi    a3, 0x7ffc
     assert  eq, a2, a3
     rsr     a2, excsave1
-    movi    a3, 0x00007ffd
+    movi    a3, 0x00007ffc
     assert  eq, a2, a3
 test_end
 
-- 
1.8.1.4