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xtensa: fix access to THREAD_RA/THREAD_SP/THREAD_DS 

With SMP and a lot of debug options enabled task_struct::thread gets out
of reach of s32i/l32i instructions with base pointing at task_struct,
breaking build with the following messages:

  arch/xtensa/kernel/entry.S: Assembler messages:
  arch/xtensa/kernel/entry.S:1002: Error: operand 3 of 'l32i.n' has invalid value '1048'
  arch/xtensa/kernel/entry.S:1831: Error: operand 3 of 's32i.n' has invalid value '1040'
  arch/xtensa/kernel/entry.S:1832: Error: operand 3 of 's32i.n' has invalid value '1044'

Change base to point to task_struct::thread in such cases.
Don't use a10 in _switch_to to save/restore prev pointer as a2 is not
clobbered.

Cc: stable@vger.kernel.org
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2014-07-27 07:23:41 +04:00
parent 89f77c6f5b
commit 5224712374
2 changed files with 13 additions and 4 deletions
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5
arch/xtensa/include/asm/uaccess.h
View File

@ -52,7 +52,12 @@
*/
.macro get_fs ad, sp
GET_CURRENT(\ad,\sp)
#if THREAD_CURRENT_DS > 1020
addi \ad, \ad, TASK_THREAD
l32i \ad, \ad, THREAD_CURRENT_DS - TASK_THREAD
#else
l32i \ad, \ad, THREAD_CURRENT_DS
#endif
.endm
/*

12
arch/xtensa/kernel/entry.S
View File

@ -1820,7 +1820,6 @@ ENTRY(_switch_to)
entry a1, 16
mov a10, a2 # preserve 'prev' (a2)
mov a11, a3 # and 'next' (a3)
l32i a4, a2, TASK_THREAD_INFO
@ -1828,8 +1827,14 @@ ENTRY(_switch_to)
save_xtregs_user a4 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
s32i a0, a10, THREAD_RA # save return address
s32i a1, a10, THREAD_SP # save stack pointer
#if THREAD_RA > 1020 || THREAD_SP > 1020
addi a10, a2, TASK_THREAD
s32i a0, a10, THREAD_RA - TASK_THREAD # save return address
s32i a1, a10, THREAD_SP - TASK_THREAD # save stack pointer
#else
s32i a0, a2, THREAD_RA # save return address
s32i a1, a2, THREAD_SP # save stack pointer
#endif
/* Disable ints while we manipulate the stack pointer. */
@ -1870,7 +1875,6 @@ ENTRY(_switch_to)
load_xtregs_user a5 a6 a8 a9 a12 a13 THREAD_XTREGS_USER
wsr a14, ps
mov a2, a10 # return 'prev'
rsync
retw