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| author | Linus Walleij <linus.walleij@linaro.org> | 2021-06-03 10:51:21 +0200 |
|---|---|---|
| committer | Russell King (Oracle) <rmk+kernel@armlinux.org.uk> | 2021-06-13 19:16:41 +0200 |
| commit | a91da54570856e3d3af4ba2884db71fbce06f70b (patch) | |
| tree | 6a7cfbf300f11676e139292794744a472cef7e1b /arch/arm/kernel/head.S | |
| parent | ARM: 9088/1: Split KERNEL_OFFSET from PAGE_OFFSET (diff) | |
| download | linux-a91da54570856e3d3af4ba2884db71fbce06f70b.tar.xz linux-a91da54570856e3d3af4ba2884db71fbce06f70b.zip | |
ARM: 9089/1: Define kernel physical section start and end
When we are mapping the initial sections in head.S we
know very well where the start and end of the kernel image
in physical memory is placed. Later on it gets hard
to determine this.
Save the information into two variables named
kernel_sec_start and kernel_sec_end for convenience
for later work involving the physical start and end
of the kernel. These variables are section-aligned
corresponding to the early section mappings set up
in head.S.
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
Diffstat (limited to 'arch/arm/kernel/head.S')
| -rw-r--r-- | arch/arm/kernel/head.S | 27 |
1 files changed, 24 insertions, 3 deletions
diff --git a/arch/arm/kernel/head.S b/arch/arm/kernel/head.S index 4e2daaa7636a..9eb0b4dbcc12 100644 --- a/arch/arm/kernel/head.S +++ b/arch/arm/kernel/head.S @@ -47,6 +47,20 @@ .globl swapper_pg_dir .equ swapper_pg_dir, KERNEL_RAM_VADDR - PG_DIR_SIZE + /* + * This needs to be assigned at runtime when the linker symbols are + * resolved. + */ + .pushsection .data + .align 2 + .globl kernel_sec_start + .globl kernel_sec_end +kernel_sec_start: + .long 0 +kernel_sec_end: + .long 0 + .popsection + .macro pgtbl, rd, phys add \rd, \phys, #TEXT_OFFSET sub \rd, \rd, #PG_DIR_SIZE @@ -229,16 +243,23 @@ __create_page_tables: blo 1b /* - * Map our RAM from the start to the end of the kernel .bss section. + * The main matter: map in the kernel using section mappings, and + * set two variables to indicate the physical start and end of the + * kernel. */ - add r0, r4, #PAGE_OFFSET >> (SECTION_SHIFT - PMD_ORDER) + add r0, r4, #KERNEL_OFFSET >> (SECTION_SHIFT - PMD_ORDER) ldr r6, =(_end - 1) - orr r3, r8, r7 + adr_l r5, kernel_sec_start @ _pa(kernel_sec_start) + str r8, [r5] @ Save physical start of kernel + orr r3, r8, r7 @ Add the MMU flags add r6, r4, r6, lsr #(SECTION_SHIFT - PMD_ORDER) 1: str r3, [r0], #1 << PMD_ORDER add r3, r3, #1 << SECTION_SHIFT cmp r0, r6 bls 1b + eor r3, r3, r7 @ Remove the MMU flags + adr_l r5, kernel_sec_end @ _pa(kernel_sec_end) + str r3, [r5] @ Save physical end of kernel #ifdef CONFIG_XIP_KERNEL /* |