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xtensa: fixes for configs without loop option

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Build-time fixes:
- make lbeg/lend/lcount save/restore conditional on kernel entry;
- don't clear lcount in platform_restart functions unconditionally.

Run-time fixes:
- use correct end of range register in __endla paired with __loopt, not
  the unused temporary register. This fixes .bss zero-initialization.
  Update comments in asmmacro.h;
- don't clobber a10 in the usercopy that leads to access to unmapped
  memory.

Cc: <stable@vger.kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2015-09-24 23:11:53 +03:00
parent 6a13feb9c8
commit 5029615e25
7 changed files with 20 additions and 9 deletions
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7
arch/xtensa/include/asm/asmmacro.h
View File

@ -35,9 +35,10 @@
* __loop as
* restart loop. 'as' register must not have been modified!
*
* __endla ar, at, incr
* __endla ar, as, incr
* ar start address (modified)
* as scratch register used by macro
* as scratch register used by __loops/__loopi macros or
* end address used by __loopt macro
* inc increment
*/
@ -97,7 +98,7 @@
.endm
/*
* loop from ar to ax
* loop from ar to as
*/
.macro __loopt ar, as, at, incr_log2

8
arch/xtensa/kernel/entry.S
View File

@ -367,8 +367,10 @@ common_exception:
s32i a2, a1, PT_SYSCALL
movi a2, 0
s32i a3, a1, PT_EXCVADDR
#if XCHAL_HAVE_LOOPS
xsr a2, lcount
s32i a2, a1, PT_LCOUNT
#endif
/* It is now save to restore the EXC_TABLE_FIXUP variable. */
@ -429,11 +431,12 @@ common_exception:
rsync # PS.WOE => rsync => overflow
/* Save lbeg, lend */
#if XCHAL_HAVE_LOOPS
rsr a4, lbeg
rsr a3, lend
s32i a4, a1, PT_LBEG
s32i a3, a1, PT_LEND
#endif
/* Save SCOMPARE1 */
@ -724,13 +727,14 @@ common_exception_exit:
wsr a3, sar
/* Restore LBEG, LEND, LCOUNT */
#if XCHAL_HAVE_LOOPS
l32i a2, a1, PT_LBEG
l32i a3, a1, PT_LEND
wsr a2, lbeg
l32i a2, a1, PT_LCOUNT
wsr a3, lend
wsr a2, lcount
#endif
/* We control single stepping through the ICOUNTLEVEL register. */

2
arch/xtensa/kernel/head.S
View File

@ -249,7 +249,7 @@ ENTRY(_startup)
__loopt a2, a3, a4, 2
s32i a0, a2, 0
__endla a2, a4, 4
__endla a2, a3, 4
#if XCHAL_DCACHE_IS_WRITEBACK

6
arch/xtensa/lib/usercopy.S
View File

@ -222,8 +222,8 @@ __xtensa_copy_user:
loopnez a7, .Loop2done
#else /* !XCHAL_HAVE_LOOPS */
beqz a7, .Loop2done
slli a10, a7, 4
add a10, a10, a3 # a10 = end of last 16B source chunk
slli a12, a7, 4
add a12, a12, a3 # a12 = end of last 16B source chunk
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2:
EX(l32i, a7, a3, 4, l_fixup)
@ -241,7 +241,7 @@ __xtensa_copy_user:
EX(s32i, a9, a5, 12, s_fixup)
addi a5, a5, 16
#if !XCHAL_HAVE_LOOPS
blt a3, a10, .Loop2
blt a3, a12, .Loop2
#endif /* !XCHAL_HAVE_LOOPS */
.Loop2done:
bbci.l a4, 3, .L12

2
arch/xtensa/platforms/iss/setup.c
View File

@ -61,7 +61,9 @@ void platform_restart(void)
#if XCHAL_NUM_IBREAK > 0
"wsr a2, ibreakenable\n\t"
#endif
#if XCHAL_HAVE_LOOPS
"wsr a2, lcount\n\t"
#endif
"movi a2, 0x1f\n\t"
"wsr a2, ps\n\t"
"isync\n\t"

2
arch/xtensa/platforms/xt2000/setup.c
View File

@ -72,7 +72,9 @@ void platform_restart(void)
#if XCHAL_NUM_IBREAK > 0
"wsr a2, ibreakenable\n\t"
#endif
#if XCHAL_HAVE_LOOPS
"wsr a2, lcount\n\t"
#endif
"movi a2, 0x1f\n\t"
"wsr a2, ps\n\t"
"isync\n\t"

2
arch/xtensa/platforms/xtfpga/setup.c
View File

@ -63,7 +63,9 @@ void platform_restart(void)
#if XCHAL_NUM_IBREAK > 0
"wsr a2, ibreakenable\n\t"
#endif
#if XCHAL_HAVE_LOOPS
"wsr a2, lcount\n\t"
#endif
"movi a2, 0x1f\n\t"
"wsr a2, ps\n\t"
"isync\n\t"