From: John David Anglin Date: Tue, 28 Jul 2020 17:13:20 +0000 (+0200) Subject: parisc: Do not use an ordered store in pa_tlb_lock() X-Git-Tag: v5.7.16~21 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=953dcf9b548cbca127f9bdea51697a9a787b9594;p=thirdparty%2Fkernel%2Fstable.git parisc: Do not use an ordered store in pa_tlb_lock() 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 Signed-off-by: Helge Deller Cc: # v5.0+ Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/parisc/kernel/entry.S b/arch/parisc/kernel/entry.S index aa042112c5b15..755240ce671eb 100644 --- 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