[PATCH] arm64: allow late use of early_ioremap

[msalter@redhat.com (Mark Salter)]

Commit 0e63ea48b4d8 (arm64/efi: add missing call to early_ioremap_reset())
added a missing call to early_ioremap_reset(). This triggers a BUG if code
tries using early_ioremap() after the early_ioremap_reset(). This is a
problem for some ACPI code which needs short-lived temporary mappings
after paging_init() but before mm_init(). This patch adds definitions for
the __late_set_fixmap() and __late_clear_fixmap() which avoids the BUG
by allowing later use of early_ioremap().

Signed-off-by: Mark Salter <msalter@redhat.com>
CC: Leif Lindholm <leif.lindholm@linaro.org>
CC: Ard Biesheuvel <ard.biesheuvel@linaro.org>
---
 arch/arm64/include/asm/fixmap.h | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/include/asm/fixmap.h b/arch/arm64/include/asm/fixmap.h
index 9ef6eca..e629c70 100644
--- a/arch/arm64/include/asm/fixmap.h
+++ b/arch/arm64/include/asm/fixmap.h
@@ -61,6 +61,9 @@ void __init early_fixmap_init(void);
 
 #define __early_set_fixmap __set_fixmap
 
+#define __late_set_fixmap __set_fixmap
+#define __late_clear_fixmap(idx) __set_fixmap((idx), 0, FIXMAP_PAGE_CLEAR)
+
 extern void __set_fixmap(enum fixed_addresses idx, phys_addr_t phys, pgprot_t prot);
 
 #include <asm-generic/fixmap.h>
-- 
1.8.3.1