MIPS: genex: Add Loongson3 LL/SC workaround to ejtag_debug_handler

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 <[email protected]> Cc: [email protected] Cc: Huacai Chen <[email protected]> Cc: Jiaxun Yang <[email protected]> Cc: [email protected]
kmaincent · Oct 7, 2019 · 12dbb04 · 12dbb04
1 parent ae4cd0b
commit 12dbb04
Showing 1 changed file with 2 additions and 0 deletions.
diff --git 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