parisc: Avoid flushing cache on cache-less machines

Avoid flushing caches in __flush_cache_page() and __purge_cache_page()
if the machine hasn't data or instruction caches - as e.g. in qemu.

Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c
index 231cebb..d41fee3 100644 (file)
--- a/arch/parisc/kernel/cache.c
+++ b/arch/parisc/kernel/cache.c
@@ -315,6 +315,8 @@ static inline void
 __flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,
                   unsigned long physaddr)
 {
+       if (!static_branch_likely(&parisc_has_cache))
+               return;
        preempt_disable();
        flush_dcache_page_asm(physaddr, vmaddr);
        if (vma->vm_flags & VM_EXEC)
@@ -326,6 +328,8 @@ static inline void
 __purge_cache_page(struct vm_area_struct *vma, unsigned long vmaddr,
                   unsigned long physaddr)
 {
+       if (!static_branch_likely(&parisc_has_cache))
+               return;
        preempt_disable();
        purge_dcache_page_asm(physaddr, vmaddr);
        if (vma->vm_flags & VM_EXEC)