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 5.4 075/350] MIPS: futex: Emit Loongson3 sync workarounds within asm
Date: Tue, 10 Dec 2019 16:03:00 -0500 [thread overview]
Message-ID: <20191210210735.9077-36-sashal@kernel.org> (raw)
In-Reply-To: <20191210210735.9077-1-sashal@kernel.org>
From: Paul Burton <paul.burton@mips.com>
[ Upstream commit 3c1d3f0979721a39dd2980c97466127ce65aa130 ]
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/include/asm/barrier.h | 13 +++++++------
arch/mips/include/asm/futex.h | 15 +++++++--------
2 files changed, 14 insertions(+), 14 deletions(-)
diff --git a/arch/mips/include/asm/barrier.h b/arch/mips/include/asm/barrier.h
index 9228f73862205..fb842965d541d 100644
--- a/arch/mips/include/asm/barrier.h
+++ b/arch/mips/include/asm/barrier.h
@@ -218,13 +218,14 @@
* ordering will be done by smp_llsc_mb() and friends.
*/
#if defined(CONFIG_WEAK_REORDERING_BEYOND_LLSC) && defined(CONFIG_SMP)
-#define __WEAK_LLSC_MB " sync \n"
-#define smp_llsc_mb() __asm__ __volatile__(__WEAK_LLSC_MB : : :"memory")
-#define __LLSC_CLOBBER
+# define __WEAK_LLSC_MB sync
+# define smp_llsc_mb() \
+ __asm__ __volatile__(__stringify(__WEAK_LLSC_MB) : : :"memory")
+# define __LLSC_CLOBBER
#else
-#define __WEAK_LLSC_MB " \n"
-#define smp_llsc_mb() do { } while (0)
-#define __LLSC_CLOBBER "memory"
+# define __WEAK_LLSC_MB
+# define smp_llsc_mb() do { } while (0)
+# define __LLSC_CLOBBER "memory"
#endif
#ifdef CONFIG_CPU_CAVIUM_OCTEON
diff --git a/arch/mips/include/asm/futex.h b/arch/mips/include/asm/futex.h
index b83b0397462d9..54cf205309316 100644
--- a/arch/mips/include/asm/futex.h
+++ b/arch/mips/include/asm/futex.h
@@ -16,6 +16,7 @@
#include <asm/barrier.h>
#include <asm/compiler.h>
#include <asm/errno.h>
+#include <asm/sync.h>
#include <asm/war.h>
#define __futex_atomic_op(insn, ret, oldval, uaddr, oparg) \
@@ -32,7 +33,7 @@
" .set arch=r4000 \n" \
"2: sc $1, %2 \n" \
" beqzl $1, 1b \n" \
- __WEAK_LLSC_MB \
+ __stringify(__WEAK_LLSC_MB) \
"3: \n" \
" .insn \n" \
" .set pop \n" \
@@ -50,19 +51,19 @@
"i" (-EFAULT) \
: "memory"); \
} else if (cpu_has_llsc) { \
- loongson_llsc_mb(); \
__asm__ __volatile__( \
" .set push \n" \
" .set noat \n" \
" .set push \n" \
" .set "MIPS_ISA_ARCH_LEVEL" \n" \
+ " " __SYNC(full, loongson3_war) " \n" \
"1: "user_ll("%1", "%4")" # __futex_atomic_op\n" \
" .set pop \n" \
" " insn " \n" \
" .set "MIPS_ISA_ARCH_LEVEL" \n" \
"2: "user_sc("$1", "%2")" \n" \
" beqz $1, 1b \n" \
- __WEAK_LLSC_MB \
+ __stringify(__WEAK_LLSC_MB) \
"3: \n" \
" .insn \n" \
" .set pop \n" \
@@ -147,7 +148,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
" .set arch=r4000 \n"
"2: sc $1, %2 \n"
" beqzl $1, 1b \n"
- __WEAK_LLSC_MB
+ __stringify(__WEAK_LLSC_MB)
"3: \n"
" .insn \n"
" .set pop \n"
@@ -164,13 +165,13 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
"i" (-EFAULT)
: "memory");
} else if (cpu_has_llsc) {
- loongson_llsc_mb();
__asm__ __volatile__(
"# futex_atomic_cmpxchg_inatomic \n"
" .set push \n"
" .set noat \n"
" .set push \n"
" .set "MIPS_ISA_ARCH_LEVEL" \n"
+ " " __SYNC(full, loongson3_war) " \n"
"1: "user_ll("%1", "%3")" \n"
" bne %1, %z4, 3f \n"
" .set pop \n"
@@ -178,8 +179,7 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
" .set "MIPS_ISA_ARCH_LEVEL" \n"
"2: "user_sc("$1", "%2")" \n"
" beqz $1, 1b \n"
- __WEAK_LLSC_MB
- "3: \n"
+ "3: " __SYNC_ELSE(full, loongson3_war, __WEAK_LLSC_MB) "\n"
" .insn \n"
" .set pop \n"
" .section .fixup,\"ax\" \n"
@@ -194,7 +194,6 @@ futex_atomic_cmpxchg_inatomic(u32 *uval, u32 __user *uaddr,
: GCC_OFF_SMALL_ASM() (*uaddr), "Jr" (oldval), "Jr" (newval),
"i" (-EFAULT)
: "memory");
- loongson_llsc_mb();
} else
return -ENOSYS;
--
2.20.1
next prev parent 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 ` [PATCH AUTOSEL 5.4 072/350] MIPS: syscall: Emit Loongson3 sync workarounds within asm Sasha Levin
2019-12-10 21:03 ` Sasha Levin [this message]
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
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20191210210735.9077-36-sashal@kernel.org \
--to=sashal@kernel.org \
--cc=chenhc@lemote.com \
--cc=jiaxun.yang@flygoat.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mips@vger.kernel.org \
--cc=paul.burton@mips.com \
--cc=stable@vger.kernel.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).