ARM: head-common.S: use PC-relative insn sequence for idmap creation (172c34c9) · Commits · 戴 / test

Replace the open coded PC relative offset calculations involving __turn_mmu_on and __turn_mmu_on_end with a pair of adr_l invocations. This removes some open coded arithmetic involving virtual addresses, avoids literal pools on v7+, and slightly reduces the footprint of the code. Reviewed-by:

Nicolas Pitre <nico@fluxnic.net> Signed-off-by:

Ard Biesheuvel <ardb@kernel.org>

arch/arm/kernel/head.S

+2 −10

Original line number	Diff line number	Diff line
		@@ -224,11 +224,8 @@ __create_page_tables:
		* Create identity mapping to cater for __enable_mmu.
		* This identity mapping will be removed by paging_init().
		*/
		adr r0, __turn_mmu_on_loc
		ldmia r0, {r3, r5, r6}
		sub r0, r0, r3 @ virt->phys offset
		add r5, r5, r0 @ phys __turn_mmu_on
		add r6, r6, r0 @ phys __turn_mmu_on_end
		adr_l r5, __turn_mmu_on @ _pa(__turn_mmu_on)
		adr_l r6, __turn_mmu_on_end @ _pa(__turn_mmu_on_end)
		mov r5, r5, lsr #SECTION_SHIFT
		mov r6, r6, lsr #SECTION_SHIFT

		@@ -351,11 +348,6 @@ __create_page_tables:
		ret lr
		ENDPROC(__create_page_tables)
		.ltorg
		.align
		__turn_mmu_on_loc:
		.long .
		.long __turn_mmu_on
		.long __turn_mmu_on_end

		#if defined(CONFIG_SMP)
		.text

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