espressif/binutils-gdb
1
0
Fork 0
mirror of https://github.com/espressif/binutils-gdb.git synced 2025-10-14 03:15:06 +08:00
Code Issues Packages Projects Releases Wiki Activity

x86: never set i386_cpu_flags' "unused" field

Browse Source 
Setting this field risks cpu_flags_all_zero() mistakenly returning
"false" when the object passed in was e.g. the result of ANDing together
two objects which had the bit set, or ANDNing together an object with
the field set and one with the field clear.

While there also avoid setting CpuNo64: Like Cpu64 this is driven
differently anyway and hence shouldn't be set anywhere by default.

Note that the moving of the two items in i386-gen.c's cpu_flags[] is
only for documentation purposes (and slight reducing of overhead), as
the fields are sorted anyway upon program start.
This commit is contained in:
Jan Beulich
2022-03-17 11:05:11 +01:00
parent ad9de929c3
commit 13ed231a0f
3 changed files with 10 additions and 5 deletions
Download Patch File Download Diff File Expand all files Collapse all files

9
opcodes/i386-gen.c
View File

@ -628,8 +628,6 @@ static bitfield cpu_flags[] =
BITFIELD (CpuPREFETCHWT1),
BITFIELD (CpuSE1),
BITFIELD (CpuCLWB),
BITFIELD (Cpu64),
BITFIELD (CpuNo64),
BITFIELD (CpuMPX),
BITFIELD (CpuAVX512IFMA),
BITFIELD (CpuAVX512VBMI),
@ -676,6 +674,8 @@ static bitfield cpu_flags[] =
BITFIELD (CpuINVLPGB),
BITFIELD (CpuTLBSYNC),
BITFIELD (CpuSNP),
BITFIELD (Cpu64),
BITFIELD (CpuNo64),
#ifdef CpuUnused
BITFIELD (CpuUnused),
#endif
@ -1068,9 +1068,10 @@ process_i386_cpu_flag (FILE *table, char *flag, int macro,
else
next = flag + 1;
/* First we turn on everything except for cpu64. */
/* First we turn on everything except for cpu64, cpuno64, and - if
present - the padding field. */
for (i = 0; i < ARRAY_SIZE (flags); i++)
if (flags[i].position != Cpu64)
if (flags[i].position < Cpu64)
flags[i].value = 1;
/* Turn off selective bits. */

2
opcodes/i386-init.h
View File

@ -25,7 +25,7 @@
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, \
1, 1, 0, 1, 1 } }
1, 1, 0, 0, 0 } }
#define CPU_GENERIC32_FLAGS \
{ { 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, \

4
opcodes/i386-opc.h
View File

@ -272,6 +272,9 @@ enum
CpuTLBSYNC,
/* SNP instructions required */
CpuSNP,
/* NOTE: These last three items need to remain last and in this order. */
/* 64bit support required */
Cpu64,
/* Not supported in the 64bit mode */
@ -417,6 +420,7 @@ typedef union i386_cpu_flags
unsigned int cpuinvlpgb:1;
unsigned int cputlbsync:1;
unsigned int cpusnp:1;
/* NOTE: These last three fields need to remain last and in this order. */
unsigned int cpu64:1;
unsigned int cpuno64:1;
#ifdef CpuUnused