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From: John David Anglin <dave.anglin@bell.net>
To: linux-parisc <linux-parisc@vger.kernel.org>
Cc: Helge Deller <deller@gmx.de>,
	James Bottomley <James.Bottomley@HansenPartnership.com>
Subject: [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S
Date: Fri, 12 Apr 2019 19:12:04 -0400	[thread overview]
Message-ID: <bd9ad9ce-8e83-6653-00d9-68b8504efc11@bell.net> (raw)

TLB operations only need to be serialized on machines with the Merced (Stretch) bus.
The only machines in this category are L and N class, and they require a 64-bit PA 2.0
kernel.  On these machines, we use local TLB purges in the tmpalias routines.  We don't
need to serialize TLB purges on all other machines.  Thus, the lock/unlock code can be
removed when CONFIG_PA20 is not defined.  Further, when CONFIG_PA20 is not defined,
alternative patching converts the TLB purges to local purges when PA 2.0 hardware has
been detected.

Signed-off-by: John David Anglin <dave.anglin@bell.net>

diff --git a/arch/parisc/kernel/pacache.S b/arch/parisc/kernel/pacache.S
index 187f032c9dd8..4e4e8eb25874 100644
--- a/arch/parisc/kernel/pacache.S
+++ b/arch/parisc/kernel/pacache.S
@@ -311,39 +311,6 @@ fdsync:
 	nop
 ENDPROC_CFI(flush_data_cache_local)

-/* Macros to serialize TLB purge operations on SMP.  */
-
-	.macro	tlb_lock	la,flags,tmp
-#ifdef CONFIG_SMP
-98:
-#if __PA_LDCW_ALIGNMENT > 4
-	load32		pa_tlb_lock + __PA_LDCW_ALIGNMENT-1, \la
-	depi		0,31,__PA_LDCW_ALIGN_ORDER, \la
-#else
-	load32		pa_tlb_lock, \la
-#endif
-	rsm		PSW_SM_I,\flags
-1:	LDCW		0(\la),\tmp
-	cmpib,<>,n	0,\tmp,3f
-2:	ldw		0(\la),\tmp
-	cmpb,<>		%r0,\tmp,1b
-	nop
-	b,n		2b
-3:
-99:	ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
-#endif
-	.endm
-
-	.macro	tlb_unlock	la,flags,tmp
-#ifdef CONFIG_SMP
-98:	ldi		1,\tmp
-	sync
-	stw		\tmp,0(\la)
-	mtsm		\flags
-99:	ALTERNATIVE(98b, 99b, ALT_COND_NO_SMP, INSN_NOP)
-#endif
-	.endm
-
 /* Clear page using kernel mapping.  */

 ENTRY_CFI(clear_page_asm)
@@ -601,10 +568,8 @@ ENTRY_CFI(copy_user_page_asm)
 	pdtlb,l		%r0(%r28)
 	pdtlb,l		%r0(%r29)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
 1:	pdtlb		%r0(%r29)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif
@@ -743,9 +708,7 @@ ENTRY_CFI(clear_user_page_asm)
 #ifdef CONFIG_PA20
 	pdtlb,l		%r0(%r28)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif

@@ -821,9 +784,7 @@ ENTRY_CFI(flush_dcache_page_asm)
 #ifdef CONFIG_PA20
 	pdtlb,l		%r0(%r28)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif

@@ -882,9 +843,7 @@ ENTRY_CFI(purge_dcache_page_asm)
 #ifdef CONFIG_PA20
 	pdtlb,l		%r0(%r28)
 #else
-	tlb_lock	%r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
-	tlb_unlock	%r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 #endif

@@ -948,10 +907,8 @@ ENTRY_CFI(flush_icache_page_asm)
 1:	pitlb,l         %r0(%sr4,%r28)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SPLIT_TLB, INSN_NOP)
 #else
-	tlb_lock        %r20,%r21,%r22
 0:	pdtlb		%r0(%r28)
 1:	pitlb           %r0(%sr4,%r28)
-	tlb_unlock      %r20,%r21,%r22
 	ALTERNATIVE(0b, 0b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SMP, INSN_PxTLB)
 	ALTERNATIVE(1b, 1b+4, ALT_COND_NO_SPLIT_TLB, INSN_NOP)

             reply	other threads:[~2019-04-12 23:12 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-12 23:12 John David Anglin [this message]
2019-04-17 20:55 ` [PATCH] parisc: Remove lock code to serialize TLB operations in pacache.S Sven Schnelle
2019-04-17 20:58   ` Helge Deller
2019-04-17 21:01     ` Helge Deller
2019-04-17 21:09       ` John David Anglin
2019-04-17 23:21         ` John David Anglin
2019-04-17 21:04     ` John David Anglin
2019-04-21 23:37     ` John David Anglin

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