Commit 0188a894 authored by Joey Gouly's avatar Joey Gouly Committed by Will Deacon
Browse files

arm64: vmlinux.ld.S: add assertion for tramp_pg_dir offset 



Add TRAMP_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and tramp_pg_dir.

Then use TRAMP_SWAPPER_OFFSET to assert that the offset is
correct at link time.

Signed-off-by: default avatarJoey Gouly <joey.gouly@arm.com>
Reviewed-by: default avatarMark Rutland <mark.rutland@arm.com>
Tested-by: default avatarMark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210202123658.22308-3-joey.gouly@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent 00ef5434

arch/arm64/include/asm/memory.h

+6 −0
Original line number Diff line number Diff line
@@ -165,6 +165,12 @@ 
 */

#define RESERVED_SWAPPER_OFFSET	(PAGE_SIZE)



/*

 *  Open-coded (swapper_pg_dir - tramp_pg_dir) as this cannot be calculated

 *  until link time.

 */

#define TRAMP_SWAPPER_OFFSET	(2 * PAGE_SIZE)



#ifndef __ASSEMBLY__



#include <linux/bitops.h>

arch/arm64/kernel/entry.S

+2 −2
Original line number Diff line number Diff line
@@ -805,7 +805,7 @@ SYM_CODE_END(ret_to_user) 
	// Move from tramp_pg_dir to swapper_pg_dir

	.macro tramp_map_kernel, tmp

	mrs	\tmp, ttbr1_el1

	add	\tmp, \tmp, #(2 * PAGE_SIZE)

	add	\tmp, \tmp, #TRAMP_SWAPPER_OFFSET

	bic	\tmp, \tmp, #USER_ASID_FLAG

	msr	ttbr1_el1, \tmp

#ifdef CONFIG_QCOM_FALKOR_ERRATUM_1003
@@ -825,7 +825,7 @@ alternative_else_nop_endif 
	// Move from swapper_pg_dir to tramp_pg_dir

	.macro tramp_unmap_kernel, tmp

	mrs	\tmp, ttbr1_el1

	sub	\tmp, \tmp, #(2 * PAGE_SIZE)

	sub	\tmp, \tmp, #TRAMP_SWAPPER_OFFSET

	orr	\tmp, \tmp, #USER_ASID_FLAG

	msr	ttbr1_el1, \tmp

	/*

arch/arm64/kernel/vmlinux.lds.S

+5 −0
Original line number Diff line number Diff line
@@ -319,3 +319,8 @@ ASSERT(_text == KIMAGE_VADDR, "HEAD is misaligned") 


ASSERT(swapper_pg_dir - reserved_pg_dir == RESERVED_SWAPPER_OFFSET,

       "RESERVED_SWAPPER_OFFSET is wrong!")



#ifdef CONFIG_UNMAP_KERNEL_AT_EL0

ASSERT(swapper_pg_dir - tramp_pg_dir == TRAMP_SWAPPER_OFFSET,

       "TRAMP_SWAPPER_OFFSET is wrong!")

#endif