xtensa: add HIGHMEM support
Introduce fixmap area just below the vmalloc region. Use it for atomic
mapping of high memory pages.
High memory on cores with cache aliasing is not supported and is still
to be implemented. Fail build for such configurations for now.
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
diff --git a/arch/xtensa/mm/cache.c b/arch/xtensa/mm/cache.c
index ba4c47f..63cbb86 100644
--- a/arch/xtensa/mm/cache.c
+++ b/arch/xtensa/mm/cache.c
@@ -59,6 +59,10 @@
*
*/
+#if (DCACHE_WAY_SIZE > PAGE_SIZE) && defined(CONFIG_HIGHMEM)
+#error "HIGHMEM is not supported on cores with aliasing cache."
+#endif
+
#if (DCACHE_WAY_SIZE > PAGE_SIZE) && XCHAL_DCACHE_IS_WRITEBACK
/*
@@ -179,10 +183,11 @@
#else
if (!PageReserved(page) && !test_bit(PG_arch_1, &page->flags)
&& (vma->vm_flags & VM_EXEC) != 0) {
- unsigned long paddr = (unsigned long) page_address(page);
+ unsigned long paddr = (unsigned long)kmap_atomic(page);
__flush_dcache_page(paddr);
__invalidate_icache_page(paddr);
set_bit(PG_arch_1, &page->flags);
+ kunmap_atomic((void *)paddr);
}
#endif
}