[PATCH] mm: use correct section size macro to describe the FDT virtual address

[Ard Biesheuvel <ardb@kernel.org>]

Commit

  149a3ffe62b9dbc3 ("9012/1: move device tree mapping out of linear region")

created a permanent, read-only section mapping of the device tree blob
provided by the firmware, and added a set of macros to get the base and
size of the virtually mapped FDT based on the physical address. However,
while the mapping code uses the SECTION_SIZE macro correctly, the macros
use PMD_SIZE instead, which means something entirely different on ARM when
using short descriptors, and is therefore not the right quantity to use
here. So replace PMD_SIZE with SECTION_SIZE. While at it, change the names
of the macro and its parameter to clarify that it returns the virtual
address of the start of the FDT in memory, based on the physical address
in memory.

Tested-by: Joel Stanley <joel@jms.id.au>
Tested-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
Already submitted as 9020/1. Related discussion can be found at

https://lore.kernel.org/linux-arm-kernel/20201007083944.27910-3-ardb@kernel.org/

 arch/arm/include/asm/memory.h | 6 +++---
 arch/arm/kernel/setup.c       | 2 +-
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/arm/include/asm/memory.h b/arch/arm/include/asm/memory.h
index bb79e52aeb90..f717d7122d9d 100644
--- a/arch/arm/include/asm/memory.h
+++ b/arch/arm/include/asm/memory.h
@@ -68,8 +68,8 @@
 #define XIP_VIRT_ADDR(physaddr)  (MODULES_VADDR + ((physaddr) & 0x000fffff))
 
 #define FDT_FIXED_BASE		UL(0xff800000)
-#define FDT_FIXED_SIZE		(2 * PMD_SIZE)
-#define FDT_VIRT_ADDR(physaddr)	((void *)(FDT_FIXED_BASE | (physaddr) % PMD_SIZE))
+#define FDT_FIXED_SIZE		(2 * SECTION_SIZE)
+#define FDT_VIRT_BASE(physbase)	((void *)(FDT_FIXED_BASE | (physbase) % SECTION_SIZE))
 
 #if !defined(CONFIG_SMP) && !defined(CONFIG_ARM_LPAE)
 /*
@@ -111,7 +111,7 @@ extern unsigned long vectors_base;
 #define MODULES_VADDR		PAGE_OFFSET
 
 #define XIP_VIRT_ADDR(physaddr)  (physaddr)
-#define FDT_VIRT_ADDR(physaddr)  ((void *)(physaddr))
+#define FDT_VIRT_BASE(physbase)  ((void *)(physbase))
 
 #endif /* !CONFIG_MMU */
 
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 694aa6b4bd03..f90479d8b50c 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -1086,7 +1086,7 @@ void __init setup_arch(char **cmdline_p)
 	void *atags_vaddr = NULL;
 
 	if (__atags_pointer)
-		atags_vaddr = FDT_VIRT_ADDR(__atags_pointer);
+		atags_vaddr = FDT_VIRT_BASE(__atags_pointer);
 
 	setup_processor();
 	if (atags_vaddr) {
-- 
2.17.1


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