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From: Sasha Levin <sashal@kernel.org>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: Paul Burton <paul.burton@mips.com>,
	linux-mips@vger.kernel.org, Huacai Chen <chenhc@lemote.com>,
	Jiaxun Yang <jiaxun.yang@flygoat.com>,
	Sasha Levin <sashal@kernel.org>
Subject: [PATCH AUTOSEL 5.4 072/350] MIPS: syscall: Emit Loongson3 sync workarounds within asm
Date: Tue, 10 Dec 2019 16:02:57 -0500	[thread overview]
Message-ID: <20191210210735.9077-33-sashal@kernel.org> (raw)
In-Reply-To: <20191210210735.9077-1-sashal@kernel.org>

From: Paul Burton <paul.burton@mips.com>

[ Upstream commit e84957e6ae043bb83ad6ae7e949a1ce97b6bbfef ]

Generate the sync instructions required to workaround Loongson3 LL/SC
errata within inline asm blocks, which feels a little safer than doing
it from C where strictly speaking the compiler would be well within its
rights to insert a memory access between the separate asm statements we
previously had, containing sync & ll instructions respectively.

Signed-off-by: Paul Burton <paul.burton@mips.com>
Cc: linux-mips@vger.kernel.org
Cc: Huacai Chen <chenhc@lemote.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/mips/kernel/syscall.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
index 3f16f38230310..c333e57886642 100644
--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -37,6 +37,7 @@
 #include <asm/signal.h>
 #include <asm/sim.h>
 #include <asm/shmparam.h>
+#include <asm/sync.h>
 #include <asm/sysmips.h>
 #include <asm/switch_to.h>
 
@@ -133,12 +134,12 @@ static inline int mips_atomic_set(unsigned long addr, unsigned long new)
 		  [efault] "i" (-EFAULT)
 		: "memory");
 	} else if (cpu_has_llsc) {
-		loongson_llsc_mb();
 		__asm__ __volatile__ (
 		"	.set	push					\n"
 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
 		"	li	%[err], 0				\n"
 		"1:							\n"
+		"	" __SYNC(full, loongson3_war) "			\n"
 		user_ll("%[old]", "(%[addr])")
 		"	move	%[tmp], %[new]				\n"
 		"2:							\n"
-- 
2.20.1


       reply	other threads:[~2019-12-10 21:50 UTC|newest]

Thread overview: 5+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <20191210210735.9077-1-sashal@kernel.org>
2019-12-10 21:02 ` Sasha Levin [this message]
2019-12-10 21:03 ` [PATCH AUTOSEL 5.4 075/350] MIPS: futex: " Sasha Levin
2019-12-10 21:06 ` [PATCH AUTOSEL 5.4 288/350] MIPS: ralink: enable PCI support only if driver for mt7621 SoC is selected Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 336/350] mips: fix build when "48 bits virtual memory" is enabled Sasha Levin
2019-12-10 21:07 ` [PATCH AUTOSEL 5.4 350/350] MIPS: futex: Restore \n after sync instructions Sasha Levin

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