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xtensa: userspace: Fixes in xtensa_userspace_enter

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- spill windows in the current context (before switching task) since
  it will be erased.
- Remove unnucessary load/mov

Signed-off-by: Flavio Ceolin <flavio.ceolin@intel.com>
This commit is contained in:
Flavio Ceolin 2024-02-06 19:52:19 -08:00 • committed by David Leach
commit dbbe9d07b5
1 changed files with 4 additions and 7 deletions
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11
arch/xtensa/core/userspace.S
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@ -276,13 +276,12 @@ xtensa_userspace_enter:
*/ */
entry a1, 16 entry a1, 16
SPILL_ALL_WINDOWS
/* We have to switch to kernel stack before spill kernel data and /* We have to switch to kernel stack before spill kernel data and
* erase user stack to avoid leak from previous context. * erase user stack to avoid leak from previous context.
*/ */
mov a1, a7 /* stack start (low address) */ mov a1, a7 /* stack start (low address) */
addi a1, a1, -16
SPILL_ALL_WINDOWS
rsr a0, ZSR_CPU rsr a0, ZSR_CPU
l32i a0, a0, ___cpu_t_current_OFFSET l32i a0, a0, ___cpu_t_current_OFFSET
@ -329,11 +328,8 @@ xtensa_userspace_enter:
l32i a8, a1, 12 l32i a8, a1, 12
l32i a9, a1, 8 l32i a9, a1, 8
/* stash user stack */
l32i a0, a1, 4
/* Go back to user stack */ /* Go back to user stack */
mov a1, a0 l32i a1, a1, 4
movi a0, z_thread_entry movi a0, z_thread_entry
wsr.epc2 a0 wsr.epc2 a0
@ -352,6 +348,7 @@ xtensa_userspace_enter:
wsr a0, EPS2 wsr a0, EPS2
/* Wipe out a0 (thre is no return from this function */
movi a0, 0 movi a0, 0
rfi 2 rfi 2