diff mbox series

[35/37] MIPS: genex: Add Loongson3 LL/SC workaround to ejtag_debug_handler

Message ID 20190930230806.2940505-36-paul.burton@mips.com (mailing list archive)
State Superseded
Headers show
Series MIPS: barriers & atomics cleanups | expand

Commit Message

Paul Burton Sept. 30, 2019, 11:08 p.m. UTC 
In ejtag_debug_handler we use LL & SC instructions to acquire & release
an open-coded spinlock. For Loongson3 systems affected by LL/SC errata
this requires that we insert a sync instruction prior to the LL in order
to ensure correct behavior of the LL/SC loop.

Signed-off-by: Paul Burton <paul.burton@mips.com>
---

 arch/mips/kernel/genex.S | 2 ++
 1 file changed, 2 insertions(+)
diff mbox series

Patch

diff --git a/arch/mips/kernel/genex.S b/arch/mips/kernel/genex.S
index efde27c99414..ac4f2b835165 100644
--- a/arch/mips/kernel/genex.S
+++ b/arch/mips/kernel/genex.S
@@ -18,6 +18,7 @@ 
 #include <asm/fpregdef.h>
 #include <asm/mipsregs.h>
 #include <asm/stackframe.h>
+#include <asm/sync.h>
 #include <asm/war.h>
 #include <asm/thread_info.h>
 
@@ -353,6 +354,7 @@  NESTED(ejtag_debug_handler, PT_SIZE, sp)
 
 #ifdef CONFIG_SMP
 1:	PTR_LA	k0, ejtag_debug_buffer_spinlock
+	__SYNC(full, loongson3_war)
 	ll	k0, 0(k0)
 	bnez	k0, 1b
 	PTR_LA	k0, ejtag_debug_buffer_spinlock