arm64: mm: Fix and re-enable ARM64_SW_TTBR0_PAN
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>
diff --git a/arch/arm64/include/asm/asm-uaccess.h b/arch/arm64/include/asm/asm-uaccess.h
index b3da6c8..21b8cf3 100644
--- a/arch/arm64/include/asm/asm-uaccess.h
+++ b/arch/arm64/include/asm/asm-uaccess.h
@@ -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_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_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