From: John David Anglin <dave.anglin@xxxxxxxx> 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.anglin@xxxxxxxx> Signed-off-by: Helge Deller <deller@xxxxxx> Cc: <stable@xxxxxxxxxxxxxxx> # v5.0+ Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- 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
