Commit 00ef5434 authored by Joey Gouly's avatar Joey Gouly Committed by Will Deacon
Browse files

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



Add RESERVED_SWAPPER_OFFSET and use that instead of hardcoding
the offset between swapper_pg_dir and reserved_pg_dir.

Then use RESERVED_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/20210202123658.22308-2-joey.gouly@arm.com


Signed-off-by: default avatarWill Deacon <will@kernel.org>
parent b9ba6809

arch/arm64/include/asm/asm-uaccess.h

+2 −2
Original line number Diff line number Diff line
@@ -15,10 +15,10 @@ 
	.macro	__uaccess_ttbr0_disable, tmp1

	mrs	\tmp1, ttbr1_el1			// swapper_pg_dir

	bic	\tmp1, \tmp1, #TTBR_ASID_MASK

	sub	\tmp1, \tmp1, #PAGE_SIZE		// reserved_pg_dir just before swapper_pg_dir

	sub	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET	// reserved_pg_dir

	msr	ttbr0_el1, \tmp1			// set reserved TTBR0_EL1

	isb

	add	\tmp1, \tmp1, #PAGE_SIZE

	add	\tmp1, \tmp1, #RESERVED_SWAPPER_OFFSET

	msr	ttbr1_el1, \tmp1		// set reserved ASID

	isb

	.endm

arch/arm64/include/asm/memory.h

+6 −0
Original line number Diff line number Diff line
@@ -159,6 +159,12 @@ 
#define IOREMAP_MAX_ORDER	(PMD_SHIFT)

#endif



/*

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

 *  until link time.

 */

#define RESERVED_SWAPPER_OFFSET	(PAGE_SIZE)



#ifndef __ASSEMBLY__



#include <linux/bitops.h>

arch/arm64/include/asm/uaccess.h

+1 −1
Original line number Diff line number Diff line
@@ -87,7 +87,7 @@ static inline void __uaccess_ttbr0_disable(void) 
	ttbr = read_sysreg(ttbr1_el1);

	ttbr &= ~TTBR_ASID_MASK;

	/* reserved_pg_dir placed before swapper_pg_dir */

	write_sysreg(ttbr - PAGE_SIZE, ttbr0_el1);

	write_sysreg(ttbr - RESERVED_SWAPPER_OFFSET, ttbr0_el1);

	isb();

	/* Set reserved ASID */

	write_sysreg(ttbr, ttbr1_el1);

arch/arm64/kernel/vmlinux.lds.S

+3 −0
Original line number Diff line number Diff line
@@ -316,3 +316,6 @@ ASSERT((__entry_tramp_text_end - __entry_tramp_text_start) == PAGE_SIZE, 
 * If padding is applied before .head.text, virt<->phys conversions will fail.

 */

ASSERT(_text == KIMAGE_VADDR, "HEAD is misaligned")



ASSERT(swapper_pg_dir - reserved_pg_dir == RESERVED_SWAPPER_OFFSET,

       "RESERVED_SWAPPER_OFFSET is wrong!")