linux-kernel - [PATCH 4.12 125/196] MIPS: Fix mips_atomic

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Date:   Tue, 25 Jul 2017 12:22:04 -0700
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, James Hogan <james.hogan@...tec.com>,
        linux-mips@...ux-mips.org, Ralf Baechle <ralf@...ux-mips.org>
Subject: [PATCH 4.12 125/196] MIPS: Fix mips_atomic_set() with EVA

4.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: James Hogan <james.hogan@...tec.com>

commit 4915e1b043d6286928207b1f6968197b50407294 upstream.

EVA linked loads (LLE) and conditional stores (SCE) should be used on
EVA kernels for the MIPS_ATOMIC_SET operation of the sysmips system
call, or else the atomic set will apply to the kernel view of the
virtual address space (potentially unmapped on EVA kernels) rather than
the user view (TLB mapped).

Signed-off-by: James Hogan <james.hogan@...tec.com>
Cc: linux-mips@...ux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/16151/
Signed-off-by: Ralf Baechle <ralf@...ux-mips.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 arch/mips/kernel/syscall.c |    7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

--- a/arch/mips/kernel/syscall.c
+++ b/arch/mips/kernel/syscall.c
@@ -29,6 +29,7 @@
 #include <linux/sched/task_stack.h>
 
 #include <asm/asm.h>
+#include <asm/asm-eva.h>
 #include <asm/branch.h>
 #include <asm/cachectl.h>
 #include <asm/cacheflush.h>
@@ -131,9 +132,11 @@ static inline int mips_atomic_set(unsign
 		__asm__ __volatile__ (
 		"	.set	"MIPS_ISA_ARCH_LEVEL"			\n"
 		"	li	%[err], 0				\n"
-		"1:	ll	%[old], (%[addr])			\n"
+		"1:							\n"
+		user_ll("%[old]", "(%[addr])")
 		"	move	%[tmp], %[new]				\n"
-		"2:	sc	%[tmp], (%[addr])			\n"
+		"2:							\n"
+		user_sc("%[tmp]", "(%[addr])")
 		"	beqz	%[tmp], 4f				\n"
 		"3:							\n"
 		"	.insn						\n"