parisc: Add memory barrier to asm pdc and sync instructions

commit 2d94a832e246ac00fd32eec241e6f1aa6fbc5700 upstream.

Add compiler memory barriers to ensure the compiler doesn't reorder memory
operations around these instructions.

Cc: stable@vger.kernel.org # v4.20+
Fixes: 3847dab77421 ("parisc: Add alternative coding infrastructure")
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/parisc/include/asm/cache.h b/arch/parisc/include/asm/cache.h
index c18351cf58762d4a416be433c435464e1cbccb0c..4016fe1c65a9c31148d677d6678c6dbe0d2c3871 100644 (file)
--- a/arch/parisc/include/asm/cache.h
+++ b/arch/parisc/include/asm/cache.h
@@ -56,10 +56,10 @@ void parisc_setup_cache_timing(void);
 #define asm_io_fdc(addr) asm volatile("fdc %%r0(%0)" \
                        ALTERNATIVE(ALT_COND_NO_DCACHE, INSN_NOP) \
                        ALTERNATIVE(ALT_COND_NO_IOC_FDC, INSN_NOP) \
-                       : : "r" (addr))
+                       : : "r" (addr) : "memory")
 #define asm_io_sync()  asm volatile("sync" \
                        ALTERNATIVE(ALT_COND_NO_DCACHE, INSN_NOP) \
-                       ALTERNATIVE(ALT_COND_NO_IOC_FDC, INSN_NOP) :: )
+                       ALTERNATIVE(ALT_COND_NO_IOC_FDC, INSN_NOP) :::"memory")
 
 #endif /* ! __ASSEMBLY__ */