From d08544127d9fb4505635e3cb6871fd50a42947bd Mon Sep 17 00:00:00 2001 From: James Morse Date: Tue, 18 Oct 2016 11:27:48 +0100 Subject: arm64: suspend: Reconfigure PSTATE after resume from idle The suspend/resume path in kernel/sleep.S, as used by cpu-idle, does not save/restore PSTATE. As a result of this cpufeatures that were detected and have bits in PSTATE get lost when we resume from idle. UAO gets set appropriately on the next context switch. PAN will be re-enabled next time we return from user-space, but on a preemptible kernel we may run work accessing user space before this point. Add code to re-enable theses two features in __cpu_suspend_exit(). We re-use uao_thread_switch() passing current. Signed-off-by: James Morse Cc: Lorenzo Pieralisi Signed-off-by: Will Deacon --- arch/arm64/kernel/suspend.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'arch/arm64/kernel/suspend.c') diff --git a/arch/arm64/kernel/suspend.c b/arch/arm64/kernel/suspend.c index ad734142070d..bb0cd787a9d3 100644 --- a/arch/arm64/kernel/suspend.c +++ b/arch/arm64/kernel/suspend.c @@ -1,8 +1,11 @@ #include #include #include +#include #include +#include #include +#include #include #include #include @@ -49,6 +52,14 @@ void notrace __cpu_suspend_exit(void) */ set_my_cpu_offset(per_cpu_offset(cpu)); + /* + * PSTATE was not saved over suspend/resume, re-enable any detected + * features that might not have been set correctly. + */ + asm(ALTERNATIVE("nop", SET_PSTATE_PAN(1), ARM64_HAS_PAN, + CONFIG_ARM64_PAN)); + uao_thread_switch(current); + /* * Restore HW breakpoint registers to sane values * before debug exceptions are possibly reenabled -- cgit v1.2.3