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

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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: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Mark Rutland <mark.rutland@arm.com>
Link: https://lore.kernel.org/r/20210202123658.22308-2-joey.gouly@arm.com
Signed-off-by: Will Deacon <will@kernel.org>
This commit is contained in:
Joey Gouly 2021-02-02 12:36:57 +00:00 committed by Will Deacon
parent b9ba680969
commit 00ef543419
4 changed files with 12 additions and 3 deletions
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4
arch/arm64/include/asm/asm-uaccess.h
View File

@ -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

6
arch/arm64/include/asm/memory.h
View File

@ -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>

2
arch/arm64/include/asm/uaccess.h
View File

@ -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);

3
arch/arm64/kernel/vmlinux.lds.S
View File

@ -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!")