Mesa (master): intel: decoder: don't read qword outside instruction/ struct limit

[Lionel Landwerlin]

Module: Mesa
Branch: master
Commit: 68e1853ea3a6feabf14cbe42e8e003647fdc82f3
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=68e1853ea3a6feabf14cbe42e8e003647fdc82f3

Author: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Date:   Thu Aug  3 14:50:35 2017 +0100

intel: decoder: don't read qword outside instruction/struct limit

We used to print invalid data when the last field was being clamped to
32bits due to Dword Length of the whole instruction. Here is an
example where the decoder read part of the next instruction instead of
stopping at the 32bit limit:

0x000ce0b4:  0x10000002:  MI_STORE_DATA_IMM
0x000ce0b4:  0x10000002 : Dword 0
    DWord Length: 2
    Store Qword: 0
    Use Global GTT: false
0x000ce0b8:  0x00045010 : Dword 1
    Core Mode Enable: 0
    Address: 0x00045010
0x000ce0bc:  0x00000000 : Dword 2
0x000ce0c0:  0x00000000 : Dword 3
    Immediate Data: 8791026489807077376

With this change we have the proper value :

0x000ce0b4:  0x10000002:  MI_STORE_DATA_IMM (4 Dwords)
0x000ce0b4:  0x10000002 : Dword 0
    DWord Length: 2
    Store Qword: 0
    Use Global GTT: false
0x000ce0b8:  0x00045010 : Dword 1
    Core Mode Enable: 0
    Address: 0x00045010
0x000ce0bc:  0x00000000 : Dword 2
0x000ce0c0:  0x00000000 : Dword 3
    Immediate Data: 0

Signed-off-by: Lionel Landwerlin <lionel.g.landwerlin at intel.com>
Reviewed-by: Scott D Phillips <scott.d.phillips at intel.com>

---

 src/intel/common/gen_decoder.c | 11 ++++++++---
 src/intel/common/gen_decoder.h |  1 +
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/src/intel/common/gen_decoder.c b/src/intel/common/gen_decoder.c
index ac7c94f41e..d2190cb8b1 100644
--- a/src/intel/common/gen_decoder.c
+++ b/src/intel/common/gen_decoder.c
@@ -850,9 +850,13 @@ gen_field_decode(struct gen_field_iterator *iter)
    else
       memset(iter->name, 0, sizeof(iter->name));
 
-   if ((iter->field->end - iter->field->start) > 32)
-      v.qw = ((uint64_t) iter->p[iter->dword+1] << 32) | iter->p[iter->dword];
-   else
+   memset(&v, 0, sizeof(v));
+
+   if ((iter->field->end - iter->field->start) > 32) {
+      if (&iter->p[iter->dword + 1] < iter->p_end)
+         v.qw = ((uint64_t) iter->p[iter->dword+1] << 32);
+      v.qw |= iter->p[iter->dword];
+   } else
       v.qw = iter->p[iter->dword];
 
    const char *enum_name = NULL;
@@ -941,6 +945,7 @@ gen_field_iterator_init(struct gen_field_iterator *iter,
    else
       iter->field = group->next->fields;
    iter->p = p;
+   iter->p_end = &p[gen_group_get_length(iter->group, iter->p)];
    iter->print_colors = print_colors;
 
    gen_field_decode(iter);
diff --git a/src/intel/common/gen_decoder.h b/src/intel/common/gen_decoder.h
index b8666ca304..88375c8223 100644
--- a/src/intel/common/gen_decoder.h
+++ b/src/intel/common/gen_decoder.h
@@ -57,6 +57,7 @@ struct gen_field_iterator {
    char value[128];
    struct gen_group *struct_desc;
    const uint32_t *p;
+   const uint32_t *p_end;
    int dword; /**< current field starts at &p[dword] */
    int start; /**< current field starts at this bit number */
    int end;   /**< current field ends at this bit number */