Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 1e1b8c04 authored by Steve Capper's avatar Steve Capper Committed by Catalin Marinas
Browse files

arm64: entry: Move the trampoline to be before PAN 



The trampoline page tables are positioned after the early page tables in
the kernel linker script.

As we are about to change the early page table logic to resolve the
swapper size at link time as opposed to compile time, the
SWAPPER_DIR_SIZE variable (currently used to locate the trampline)
will be rendered unsuitable for low level assembler.

This patch solves this issue by moving the trampoline before the PAN
page tables. The offset to the trampoline from ttbr1 can then be
expressed by: PAGE_SIZE + RESERVED_TTBR0_SIZE, which is available to the
entry assembler.

Tested-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: default avatarArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: default avatarSteve Capper <steve.capper@arm.com>
Signed-off-by: default avatarCatalin Marinas <catalin.marinas@arm.com>
parent 9dfe4828

arch/arm64/kernel/entry.S

+2 −2
Original line number Diff line number Diff line
@@ -990,7 +990,7 @@ __ni_sys_trace: 


	.macro tramp_map_kernel, tmp

	mrs	\tmp, ttbr1_el1

	sub	\tmp, \tmp, #(SWAPPER_DIR_SIZE + RESERVED_TTBR0_SIZE)

	add	\tmp, \tmp, #(PAGE_SIZE + RESERVED_TTBR0_SIZE)

	bic	\tmp, \tmp, #USER_ASID_FLAG

	msr	ttbr1_el1, \tmp

#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003
@@ -1009,7 +1009,7 @@ alternative_else_nop_endif 


	.macro tramp_unmap_kernel, tmp

	mrs	\tmp, ttbr1_el1

	add	\tmp, \tmp, #(SWAPPER_DIR_SIZE + RESERVED_TTBR0_SIZE)

	sub	\tmp, \tmp, #(PAGE_SIZE + RESERVED_TTBR0_SIZE)

	orr	\tmp, \tmp, #USER_ASID_FLAG

	msr	ttbr1_el1, \tmp

	/*

arch/arm64/kernel/vmlinux.lds.S

+6 −5
Original line number Diff line number Diff line
@@ -218,6 +218,12 @@ SECTIONS 
	. = ALIGN(PAGE_SIZE);

	idmap_pg_dir = .;

	. += IDMAP_DIR_SIZE;



#ifdef CONFIG_UNMAP_KERNEL_AT_EL0

	tramp_pg_dir = .;

	. += PAGE_SIZE;

#endif



#ifdef CONFIG_ARM64_SW_TTBR0_PAN

	reserved_ttbr0 = .;

	. += RESERVED_TTBR0_SIZE;
@@ -225,11 +231,6 @@ SECTIONS 
	swapper_pg_dir = .;

	. += SWAPPER_DIR_SIZE;



#ifdef CONFIG_UNMAP_KERNEL_AT_EL0

	tramp_pg_dir = .;

	. += PAGE_SIZE;

#endif



	__pecoff_data_size = ABSOLUTE(. - __initdata_begin);

	_end = .;