[PATCH v2 09/28] ARM: mmu: Specify size in bytes in create_sections()

[Andrey Smirnov <andrew.smirnov@xxxxxxxxx>]

Seeing

        create_sections(ttb, 0, PAGE_SIZE, ...);

as the code the creates initial flat 4 GiB mapping is a bit less
intuitive then

        create_sections(ttb, 0, SZ_4G, ...);

so, for the sake of clarification, convert create_sections() to accept
size in bytes and do bytes -> MiB converstion as a part of the
function.

NOTE: To keep all of the arguments of create_sections() 32-bit:

    - Move all of the real code into a helper function accepting first
      and last addresses of the region (e.g passing 0 and U32_MAX
      means all 4GiB of address space)

    - Convert create_section() into a macro that does necessary size
      -> last addres conversion under the hood to preserve original API

Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
---
 arch/arm/cpu/mmu-early.c |  4 ++--
 arch/arm/cpu/mmu.c       |  4 ++--
 arch/arm/cpu/mmu.h       | 22 ++++++++++++++++------
 3 files changed, 20 insertions(+), 10 deletions(-)

diff --git a/arch/arm/cpu/mmu-early.c b/arch/arm/cpu/mmu-early.c
index 70ece0d2f..136b33c3a 100644
--- a/arch/arm/cpu/mmu-early.c
+++ b/arch/arm/cpu/mmu-early.c
@@ -16,7 +16,7 @@ static void map_cachable(unsigned long start, unsigned long size)
 	start = ALIGN_DOWN(start, SZ_1M);
 	size  = ALIGN(size, SZ_1M);
 
-	create_sections(ttb, start, size >> 20, PMD_SECT_AP_WRITE |
+	create_sections(ttb, start, size, PMD_SECT_AP_WRITE |
 			PMD_SECT_AP_READ | PMD_TYPE_SECT | PMD_SECT_WB);
 }
 
@@ -30,7 +30,7 @@ void mmu_early_enable(unsigned long membase, unsigned long memsize,
 	set_ttbr(ttb);
 	set_domain(DOMAIN_MANAGER);
 
-	create_sections(ttb, 0, 4096, PMD_SECT_AP_WRITE |
+	create_sections(ttb, 0, SZ_4G, PMD_SECT_AP_WRITE |
 			PMD_SECT_AP_READ | PMD_TYPE_SECT);
 
 	map_cachable(membase, memsize);
diff --git a/arch/arm/cpu/mmu.c b/arch/arm/cpu/mmu.c
index 0c367e47c..f02c99f65 100644
--- a/arch/arm/cpu/mmu.c
+++ b/arch/arm/cpu/mmu.c
@@ -460,7 +460,7 @@ static int mmu_init(void)
 	set_domain(DOMAIN_MANAGER);
 
 	/* create a flat mapping using 1MiB sections */
-	create_sections(ttb, 0, PAGE_SIZE, PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
+	create_sections(ttb, 0, SZ_4G, PMD_SECT_AP_WRITE | PMD_SECT_AP_READ |
 			PMD_TYPE_SECT);
 	__mmu_cache_flush();
 
@@ -472,7 +472,7 @@ static int mmu_init(void)
 	 * below
 	 */
 	for_each_memory_bank(bank) {
-		create_sections(ttb, bank->start, bank->size >> 20,
+		create_sections(ttb, bank->start, bank->size,
 				PMD_SECT_DEF_CACHED);
 		__mmu_cache_flush();
 	}
diff --git a/arch/arm/cpu/mmu.h b/arch/arm/cpu/mmu.h
index d71cd7e38..52689359a 100644
--- a/arch/arm/cpu/mmu.h
+++ b/arch/arm/cpu/mmu.h
@@ -27,16 +27,26 @@ static inline void set_domain(unsigned val)
 }
 
 static inline void
-create_sections(uint32_t *ttb, unsigned long addr,
-		int size_m, unsigned int flags)
+__create_sections(uint32_t *ttb, unsigned long first,
+		  unsigned long last, unsigned int flags)
 {
-	unsigned long ttb_start = addr >> 20;
-	unsigned long ttb_end   = ttb_start + size_m;
-	unsigned int i;
+	unsigned long ttb_start = first >> 20;
+	unsigned long ttb_end   = (last >> 20) + 1;
+	unsigned int i, addr;
 
-	for (i = ttb_start; i < ttb_end; i++, addr += SZ_1M)
+	for (i = ttb_start, addr = first; i < ttb_end; i++, addr += SZ_1M)
 		ttb[i] = addr | flags;
 }
 
+#define create_sections(ttb, addr, size, flags)				\
+	({								\
+		typeof(addr) __addr = addr;				\
+		typeof(size) __size = size;				\
+		/* Check for overflow */				\
+		BUG_ON(__addr > ULONG_MAX - __size + 1);		\
+		__create_sections(ttb, __addr, __addr + (size)  - 1,	\
+				  flags);				\
+	})
+
 
 #endif /* __ARM_MMU_H */
-- 
2.17.0


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