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parisc: Do not use an ordered store in pa_tlb_lock() 

No need to use an ordered store in pa_tlb_lock() and update the comment
regarng usage of the sid register to unlocak a spinlock in
tlb_unlock0().

Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: <stable@vger.kernel.org> # v5.0+
This commit is contained in:
John David Anglin 2020-07-28 19:13:20 +02:00 committed by Helge Deller
parent 157e9afcc4
commit e72b23dec1
1 changed files with 7 additions and 2 deletions
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9
arch/parisc/kernel/entry.S
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@ -455,7 +455,7 @@
LDREG 0(\ptp),\pte LDREG 0(\ptp),\pte
bb,<,n \pte,_PAGE_PRESENT_BIT,3f bb,<,n \pte,_PAGE_PRESENT_BIT,3f
b \fault b \fault
stw,ma \spc,0(\tmp) stw \spc,0(\tmp)
99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP) 99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
#endif #endif
2: LDREG 0(\ptp),\pte 2: LDREG 0(\ptp),\pte
@ -463,7 +463,12 @@
3: 3:
.endm .endm
/* Release pa_tlb_lock lock without reloading lock address. */ /* Release pa_tlb_lock lock without reloading lock address.
Note that the values in the register spc are limited to
NR_SPACE_IDS (262144). Thus, the stw instruction always
stores a nonzero value even when register spc is 64 bits.
We use an ordered store to ensure all prior accesses are
performed prior to releasing the lock. */
.macro tlb_unlock0 spc,tmp .macro tlb_unlock0 spc,tmp
#ifdef CONFIG_SMP #ifdef CONFIG_SMP
98: or,COND(=) %r0,\spc,%r0 98: or,COND(=) %r0,\spc,%r0