From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail.linuxfoundation.org ([140.211.169.12]:33316 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752564AbcLFUbZ (ORCPT ); Tue, 6 Dec 2016 15:31:25 -0500 Subject: Patch "arm64: suspend: Reconfigure PSTATE after resume from idle" has been added to the 4.8-stable tree To: james.morse@arm.com, gregkh@linuxfoundation.org, lorenzo.pieralisi@arm.com, will.deacon@arm.com Cc: , From: Date: Tue, 06 Dec 2016 21:23:52 +0100 Message-ID: <148105583223121@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ANSI_X3.4-1968 Content-Transfer-Encoding: 8bit Sender: stable-owner@vger.kernel.org List-ID: This is a note to let you know that I've just added the patch titled arm64: suspend: Reconfigure PSTATE after resume from idle to the 4.8-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: arm64-suspend-reconfigure-pstate-after-resume-from-idle.patch and it can be found in the queue-4.8 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >>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 From: James Morse commit d08544127d9fb4505635e3cb6871fd50a42947bd upstream. 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 Signed-off-by: Greg Kroah-Hartman --- arch/arm64/include/asm/exec.h | 3 +++ arch/arm64/kernel/process.c | 3 ++- arch/arm64/kernel/suspend.c | 11 +++++++++++ 3 files changed, 16 insertions(+), 1 deletion(-) --- a/arch/arm64/include/asm/exec.h +++ b/arch/arm64/include/asm/exec.h @@ -18,6 +18,9 @@ #ifndef __ASM_EXEC_H #define __ASM_EXEC_H +#include + extern unsigned long arch_align_stack(unsigned long sp); +void uao_thread_switch(struct task_struct *next); #endif /* __ASM_EXEC_H */ --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -49,6 +49,7 @@ #include #include #include +#include #include #include #include @@ -303,7 +304,7 @@ static void tls_thread_switch(struct tas } /* Restore the UAO state depending on next's addr_limit */ -static void uao_thread_switch(struct task_struct *next) +void uao_thread_switch(struct task_struct *next) { if (IS_ENABLED(CONFIG_ARM64_UAO)) { if (task_thread_info(next)->addr_limit == KERNEL_DS) --- 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 @@ -48,6 +51,14 @@ void notrace __cpu_suspend_exit(void) set_my_cpu_offset(per_cpu_offset(smp_processor_id())); /* + * 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 * through local_dbg_restore. Patches currently in stable-queue which might be from james.morse@arm.com are queue-4.8/arm64-mm-set-pstate.pan-from-the-cpu_enable_pan-call.patch queue-4.8/arm64-suspend-reconfigure-pstate-after-resume-from-idle.patch queue-4.8/arm64-cpufeature-schedule-enable-calls-instead-of-calling-them-via-ipi.patch