From: John David Anglin <dave.ang...@bell.net>
commit e72b23dec1da5e62a0090c5da1d926778284e230 upstream.
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.ang...@bell.net>
Signed-off-by: Helge Deller <del...@gmx.de>
Cc: <sta...@vger.kernel.org> # v5.0+
Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org>
---
arch/parisc/kernel/entry.S | 9 +++++++--
1 file changed, 7 insertions(+), 2 deletions(-)
--- a/arch/parisc/kernel/entry.S
+++ b/arch/parisc/kernel/entry.S
@@ -455,7 +455,7 @@
LDREG 0(\ptp),\pte
bb,<,n \pte,_PAGE_PRESENT_BIT,3f
b \fault
- stw,ma \spc,0(\tmp)
+ stw \spc,0(\tmp)
99: ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
#endif
2: LDREG 0(\ptp),\pte
@@ -463,7 +463,12 @@
3:
.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
#ifdef CONFIG_SMP
98: or,COND(=) %r0,\spc,%r0
