From: Mark Salter <redacted>

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 acpi_early_init() in start_kernel(). This
patch adds definitions for the __late_set_fixmap() and __late_clear_fixmap()
which avoids the BUG by allowing later use of early_ioremap().

CC: Leif Lindholm <redacted>
CC: Ard Biesheuvel <redacted>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Tested-by: Mark Langsdorf <redacted>
Tested-by: Jon Masters <redacted>
Signed-off-by: Mark Salter <redacted>
Signed-off-by: Hanjun Guo <redacted>
---
 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>

-- 
1.9.1