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arm64: mm: Fix and re-enable ARM64_SW_TTBR0_PAN

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With the ASID now installed in TTBR1, we can re-enable ARM64_SW_TTBR0_PAN
by ensuring that we switch to a reserved ASID of zero when disabling
user access and restore the active user ASID on the uaccess enable path.

Reviewed-by: Mark Rutland <mark.rutland@arm.com>
Tested-by: Laura Abbott <labbott@redhat.com>
Tested-by: Shanker Donthineni <shankerd@codeaurora.org>
Signed-off-by: Will Deacon <will.deacon@arm.com>
This commit is contained in:
Will Deacon
2017-08-10 13:58:16 +01:00
parent 158d495899
commit 27a921e757
10 changed files with 42 additions and 21 deletions
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25
arch/arm64/include/asm/asm-uaccess.h
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@@ -16,11 +16,20 @@
add \tmp1, \tmp1, #SWAPPER_DIR_SIZE // reserved_ttbr0 at the end of swapper_pg_dir
msr ttbr0_el1, \tmp1 // set reserved TTBR0_EL1
isb
sub \tmp1, \tmp1, #SWAPPER_DIR_SIZE
bic \tmp1, \tmp1, #(0xffff << 48)
msr ttbr1_el1, \tmp1 // set reserved ASID
isb
.endm
.macro __uaccess_ttbr0_enable, tmp1
.macro __uaccess_ttbr0_enable, tmp1, tmp2
get_thread_info \tmp1
ldr \tmp1, [\tmp1, #TSK_TI_TTBR0] // load saved TTBR0_EL1
mrs \tmp2, ttbr1_el1
extr \tmp2, \tmp2, \tmp1, #48
ror \tmp2, \tmp2, #16
msr ttbr1_el1, \tmp2 // set the active ASID
isb
msr ttbr0_el1, \tmp1 // set the non-PAN TTBR0_EL1
isb
.endm
@@ -31,18 +40,18 @@ alternative_if_not ARM64_HAS_PAN
alternative_else_nop_endif
.endm
.macro uaccess_ttbr0_enable, tmp1, tmp2
.macro uaccess_ttbr0_enable, tmp1, tmp2, tmp3
alternative_if_not ARM64_HAS_PAN
save_and_disable_irq \tmp2 // avoid preemption
__uaccess_ttbr0_enable \tmp1
restore_irq \tmp2
save_and_disable_irq \tmp3 // avoid preemption
__uaccess_ttbr0_enable \tmp1, \tmp2
restore_irq \tmp3
alternative_else_nop_endif
.endm
#else
.macro uaccess_ttbr0_disable, tmp1
.endm
.macro uaccess_ttbr0_enable, tmp1, tmp2
.macro uaccess_ttbr0_enable, tmp1, tmp2, tmp3
.endm
#endif
@@ -56,8 +65,8 @@ alternative_if ARM64_ALT_PAN_NOT_UAO
alternative_else_nop_endif
.endm
.macro uaccess_enable_not_uao, tmp1, tmp2
uaccess_ttbr0_enable \tmp1, \tmp2
.macro uaccess_enable_not_uao, tmp1, tmp2, tmp3
uaccess_ttbr0_enable \tmp1, \tmp2, \tmp3
alternative_if ARM64_ALT_PAN_NOT_UAO
SET_PSTATE_PAN(0)
alternative_else_nop_endif