From mboxrd@z Thu Jan 1 00:00:00 1970 From: ard.biesheuvel@linaro.org (Ard Biesheuvel) Date: Wed, 30 Mar 2016 17:43:05 +0200 Subject: [PATCH v2 0/4] arm64: simplify and optimize kernel mapping Message-ID: <1459352589-28721-1-git-send-email-ard.biesheuvel@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org This series makes a couple of minor changes that should result in the kernel being mapped in a more efficient manner. First of all, it introduces 'segment' to describe the various chunks that make up the kernel runtime mapping, and replaces some instances of chunk with segment (#1) Then, it merges the .head.text with the .text section (patch #3) after moving everything except the kernel and EFI header into the __init section (patch #2) Then, it standardizes the segment alignment to 64 KB for all page sizes. (patch #4). In the example below (4 KB granule, with Jeremy's PTE_CONT patch applied), we lose 80 KB in total to padding (some of which is covered by .init), but the resulting mappings do look somewhat better. Before: 0xffff000008082000-0xffff000008090000 56K ro x SHD AF UXN MEM 0xffff000008090000-0xffff000008200000 1472K ro x SHD AF CON UXN MEM 0xffff000008200000-0xffff000008600000 4M ro x SHD AF BLK UXN MEM 0xffff000008600000-0xffff000008660000 384K ro x SHD AF CON UXN MEM 0xffff000008660000-0xffff00000866c000 48K ro x SHD AF UXN MEM 0xffff00000866c000-0xffff000008670000 16K ro NX SHD AF UXN MEM 0xffff000008670000-0xffff000008900000 2624K ro NX SHD AF CON UXN MEM 0xffff000008900000-0xffff000008909000 36K ro NX SHD AF UXN MEM 0xffff000008c39000-0xffff000008c40000 28K RW NX SHD AF UXN MEM 0xffff000008c40000-0xffff000008d50000 1088K RW NX SHD AF CON UXN MEM 0xffff000008d50000-0xffff000008d57000 28K RW NX SHD AF UXN MEM After: 0xffff000008080000-0xffff000008200000 1536K ro x SHD AF CON UXN MEM 0xffff000008200000-0xffff000008600000 4M ro x SHD AF BLK UXN MEM 0xffff000008600000-0xffff000008670000 448K ro x SHD AF CON UXN MEM 0xffff000008670000-0xffff000008910000 2688K ro NX SHD AF CON UXN MEM 0xffff000008c50000-0xffff000008d60000 1088K RW NX SHD AF CON UXN MEM 0xffff000008d60000-0xffff000008d6b000 44K RW NX SHD AF UXN MEM Changes since v2: - add patch #1 to introduce 'segment' to describe the parts of the static kernel Image that are mapped with different permissions and/or lifetimes - drop dependency on 4 KB pages for CONFIG_DEBUG_ALIGN_RODATA (#4) Ard Biesheuvel (4): arm64: use 'segment' rather than 'chunk' to describe mapped kernel regions arm64: move early boot code to the .init segment arm64: cover the .head.text section in the .text segment mapping arm64: simplify kernel segment mapping granularity arch/arm64/Kconfig.debug | 2 +- arch/arm64/kernel/efi-entry.S | 2 +- arch/arm64/kernel/head.S | 32 +++++++++----------- arch/arm64/kernel/image.h | 4 +++ arch/arm64/kernel/vmlinux.lds.S | 26 +++++++++------- arch/arm64/mm/mmu.c | 22 +++++++------- 6 files changed, 47 insertions(+), 41 deletions(-) -- 2.5.0