On Wed, May 16, 2018 at 01:00:17PM -0700, Andrey Smirnov wrote:
> 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); \
> + })
Why do you preserve the original API of create_sections()? I would just
change it. We have only a few callers and they are easy to change.
Sascha
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