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arch: arc: fix the bug in _firq_enter

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* In ARC, pop reg ==> sp=sp-4; *sp= b; The original codes have bug that
  the save of ilink (st ilink [sp]) will crash the interruptted stack's
  content. This commit fixes this bug and makes the codes easier to
  understand

Signed-off-by: Wayne Ren <wei.ren@synopsys.com>
This commit is contained in:
Wayne Ren 2019-09-25 16:21:45 +08:00 • committed by Anas Nashif
commit c5c3fdd67b
2 changed files with 23 additions and 6 deletions
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17
arch/arc/core/fast_irq.S
View file

@ -101,20 +101,25 @@ firq_nest:
* save original value of _ARC_V2_USER_SP and ilink into
* the stack of interrupted context first, then restore them later
*/
st ilink, [sp]
lr ilink, [_ARC_V2_USER_SP]
st ilink, [sp, -4]
push ilink
PUSHAX ilink, _ARC_V2_USER_SP
/* sp here is the sp of interrupted context */
sr sp, [_ARC_V2_USER_SP]
/* here, bank 0 sp must go back to the value before push and
* PUSHAX as we will switch to bank1, the pop and POPAX later will
* change bank1's sp, not bank0's sp
*/
add sp, sp, 8
/* switch back to banked reg, only ilink can be used */
lr ilink, [_ARC_V2_STATUS32]
or ilink, ilink, _ARC_V2_STATUS32_RB(1)
kflag ilink
lr sp, [_ARC_V2_USER_SP]
ld ilink, [sp, -4]
sr ilink, [_ARC_V2_USER_SP]
ld ilink, [sp]
POPAX ilink, _ARC_V2_USER_SP
pop ilink
firq_nest_1:
#else
firq_nest:

12
arch/arc/include/swap_macros.h
View file

@ -365,6 +365,18 @@
#endif
.endm
/* macro to push aux reg through reg */
.macro PUSHAX reg aux
lr \reg, [\aux]
st.a \reg, [sp, -4]
.endm
/* macro to pop aux reg through reg */
.macro POPAX reg aux
ld.ab \reg, [sp, 4]
sr \reg, [\aux]
.endm
#endif /* _ASMLANGUAGE */
#endif /* ZEPHYR_ARCH_ARC_INCLUDE_SWAP_MACROS_H_ */