kpriv/linux-hardened
1
0
Fork 0
Code Issues Pull requests Projects Releases Packages Wiki Activity

arm64: Re-order reserved_ttbr0 in linker script

Browse source 
Currently one resolves the location of the reserved_ttbr0 for PAN by
taking a positive offset from swapper_pg_dir. In a future patch we wish
to extend the swapper s.t. its size is determined at link time rather
than comile time, rendering SWAPPER_DIR_SIZE unsuitable for such a low
level calculation.

In this patch we re-arrange the order of the linker script s.t. instead
one computes reserved_ttbr0 by subtracting RESERVED_TTBR0_SIZE from
swapper_pg_dir.

Tested-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Reviewed-by: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
This commit is contained in:
Steve Capper 2018-01-11 10:11:57 +00:00 committed by Catalin Marinas
parent 79e9aa59dc
commit 9dfe4828aa
3 changed files with 8 additions and 9 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
arch/arm64/include/asm/asm-uaccess.h
View file

@ -13,11 +13,11 @@
*/ */
#ifdef CONFIG_ARM64_SW_TTBR0_PAN #ifdef CONFIG_ARM64_SW_TTBR0_PAN
.macro __uaccess_ttbr0_disable, tmp1 .macro __uaccess_ttbr0_disable, tmp1
mrs \tmp1, ttbr1_el1 // swapper_pg_dir mrs \tmp1, ttbr1_el1 // swapper_pg_dir
add \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir sub \tmp1, \tmp1, #RESERVED_TTBR0_SIZE // reserved_ttbr0 just before swapper_pg_dir
msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1 msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1
isb isb
sub \tmp1, \tmp1, #SWAPPER_DIR_SIZE add \tmp1, \tmp1, #RESERVED_TTBR0_SIZE
bic \tmp1, \tmp1, #TTBR_ASID_MASK bic \tmp1, \tmp1, #TTBR_ASID_MASK
msr ttbr1_el1, \tmp1 // set reserved ASID msr ttbr1_el1, \tmp1 // set reserved ASID
isb isb

4
arch/arm64/include/asm/uaccess.h
View file

@ -108,8 +108,8 @@ static inline void __uaccess_ttbr0_disable(void)
unsigned long ttbr; unsigned long ttbr;
ttbr = read_sysreg(ttbr1_el1); ttbr = read_sysreg(ttbr1_el1);
/* reserved_ttbr0 placed at the end of swapper_pg_dir */ /* reserved_ttbr0 placed before swapper_pg_dir */
write_sysreg(ttbr + SWAPPER_DIR_SIZE, ttbr0_el1); write_sysreg(ttbr - RESERVED_TTBR0_SIZE, ttbr0_el1);
isb(); isb();
/* Set reserved ASID */ /* Set reserved ASID */
ttbr &= ~TTBR_ASID_MASK; ttbr &= ~TTBR_ASID_MASK;

5
arch/arm64/kernel/vmlinux.lds.S
View file

@ -218,13 +218,12 @@ SECTIONS
. = ALIGN(PAGE_SIZE); . = ALIGN(PAGE_SIZE);
idmap_pg_dir = .; idmap_pg_dir = .;
. += IDMAP_DIR_SIZE; . += IDMAP_DIR_SIZE;
swapper_pg_dir = .;
. += SWAPPER_DIR_SIZE;
#ifdef CONFIG_ARM64_SW_TTBR0_PAN #ifdef CONFIG_ARM64_SW_TTBR0_PAN
reserved_ttbr0 = .; reserved_ttbr0 = .;
. += RESERVED_TTBR0_SIZE; . += RESERVED_TTBR0_SIZE;
#endif #endif
swapper_pg_dir = .;
. += SWAPPER_DIR_SIZE;
#ifdef CONFIG_UNMAP_KERNEL_AT_EL0 #ifdef CONFIG_UNMAP_KERNEL_AT_EL0
tramp_pg_dir = .; tramp_pg_dir = .;