[PATCH] arm64/mm: Drop ARM64_KERNEL_USES_PMD_MAPS

[Will Deacon]

On Mon, Sep 26, 2022 at 08:48:22AM +0530, Anshuman Khandual wrote:
> On 9/23/22 19:08, Joey Gouly wrote:
> > On Fri, Sep 23, 2022 at 06:38:41PM +0530, Anshuman Khandual wrote:
> >> Currently ARM64_KERNEL_USES_PMD_MAPS is an unnecessary abstraction. Kernel
> >> mapping at PMD (aka huge page aka block) level, is only applicable with 4K
> >> base page, which makes it 2MB aligned, a necessary requirement for linear
> >> mapping and physical memory start address. This can be easily achieved by
> >> directly checking against base page size itself. This drops off the macro
> >> ARM64_KERNE_USES_PMD_MAPS which is redundant.
> >>
> >> Cc: Catalin Marinas <catalin.marinas at arm.com>
> >> Cc: Will Deacon <will at kernel.org>
> >> Cc: linux-arm-kernel at lists.infradead.org
> >> Signed-off-by: Anshuman Khandual <anshuman.khandual at arm.com>
> >> ---
> >> This applies on v6.0-rc6 after the following patch.
> >>
> >> https://lore.kernel.org/all/20220920014951.196191-1-wangkefeng.wang@huawei.com/
> >>
> >>  arch/arm64/include/asm/kernel-pgtable.h | 33 +++++++++----------------
> >>  arch/arm64/mm/mmu.c                     |  2 +-
> >>  2 files changed, 12 insertions(+), 23 deletions(-)

[...]

> >> @@ -96,15 +101,6 @@
> >>  #define INIT_IDMAP_DIR_PAGES	EARLY_PAGES(KIMAGE_VADDR, _end + MAX_FDT_SIZE + SWAPPER_BLOCK_SIZE, 1)
> >>  
> >>  /* Initial memory map size */
> >> -#if ARM64_KERNEL_USES_PMD_MAPS
> >> -#define SWAPPER_BLOCK_SHIFT	PMD_SHIFT
> >> -#define SWAPPER_BLOCK_SIZE	PMD_SIZE
> >> -#define SWAPPER_TABLE_SHIFT	PUD_SHIFT
> >> -#else
> >> -#define SWAPPER_BLOCK_SHIFT	PAGE_SHIFT
> >> -#define SWAPPER_BLOCK_SIZE	PAGE_SIZE
> >> -#define SWAPPER_TABLE_SHIFT	PMD_SHIFT
> >> -#endif
> > 
> > Also a dangling comment here.
> 
> These ? can be dropped off without much problem.
> 
> /* Initial memory map size */
> /*
>  * Initial memory map attributes.
>  */
> 
> Will try to re-arrange these comments next time around.

Did you post another version of this, or change your mind about it?

Will