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Commit 52247123 authored by Max Filippov's avatar Max Filippov
Browse files

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: default avatarMax Filippov <jcmvbkbc@gmail.com>
parent 89f77c6f

arch/xtensa/include/asm/uaccess.h

+5 −0
Original line number Original line Diff line number Diff line
@@ -52,7 +52,12 @@ 
 */

 */

	.macro	get_fs	ad, sp

	.macro	get_fs	ad, sp

	GET_CURRENT(\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

	l32i	\ad, \ad, THREAD_CURRENT_DS

#endif

	.endm

	.endm





/*

/*

arch/xtensa/kernel/entry.S

+8 −4
Original line number Original line Diff line number Diff line
@@ -1820,7 +1820,6 @@ ENTRY(_switch_to) 




	entry	a1, 16

	entry	a1, 16





	mov	a10, a2			# preserve 'prev' (a2)

	mov	a11, a3			# and 'next' (a3)

	mov	a11, a3			# and 'next' (a3)





	l32i	a4, a2, TASK_THREAD_INFO

	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

	save_xtregs_user a4 a6 a8 a9 a12 a13 THREAD_XTREGS_USER





	s32i	a0, a10, THREAD_RA	# save return address

#if THREAD_RA > 1020 || THREAD_SP > 1020

	s32i	a1, a10, THREAD_SP	# save stack pointer

	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. */

	/* 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

	load_xtregs_user a5 a6 a8 a9 a12 a13 THREAD_XTREGS_USER





	wsr	a14, ps

	wsr	a14, ps

	mov	a2, a10			# return 'prev'

	rsync

	rsync





	retw

	retw