From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: linux-kernel@vger.kernel.org
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
stable@vger.kernel.org, James Morse <james.morse@arm.com>,
Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>,
Will Deacon <will.deacon@arm.com>
Subject: [PATCH 4.4 13/13] arm64: suspend: Reconfigure PSTATE after resume from idle
Date: Wed, 7 Dec 2016 08:07:52 +0100 [thread overview]
Message-ID: <20161207070717.199713933@linuxfoundation.org> (raw)
In-Reply-To: <20161207070716.317145973@linuxfoundation.org>
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: James Morse <james.morse@arm.com>
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 <james.morse@arm.com>
Cc: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[Removed UAO hooks and commit-message references: this feature is not
present in v4.4]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/kernel/suspend.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/arch/arm64/kernel/suspend.c
+++ b/arch/arm64/kernel/suspend.c
@@ -1,7 +1,9 @@
#include <linux/ftrace.h>
#include <linux/percpu.h>
#include <linux/slab.h>
+#include <asm/alternative.h>
#include <asm/cacheflush.h>
+#include <asm/cpufeature.h>
#include <asm/debug-monitors.h>
#include <asm/pgtable.h>
#include <asm/memory.h>
@@ -111,6 +113,13 @@ int cpu_suspend(unsigned long arg, int (
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));
+
+ /*
* Restore HW breakpoint registers to sane values
* before debug exceptions are possibly reenabled
* through local_dbg_restore.
next prev parent reply other threads:[~2016-12-07 7:08 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <CGME20161207070805epcas3p1487b13063215635759cae58441ad906a@epcas3p1.samsung.com>
2016-12-07 7:07 ` [PATCH 4.4 00/13] 4.4.37-stable review Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 01/13] ARC: Dont use "+l" inline asm constraint Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 02/13] zram: fix unbalanced idr management at hot removal Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 03/13] kasan: update kasan_global for gcc 7 Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 04/13] x86/traps: Ignore high word of regs->cs in early_fixup_exception() Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 05/13] ALSA: pcm : Call kill_fasync() in stream lock Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 06/13] rcu: Fix soft lockup for rcu_nocb_kthread Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 07/13] PCI: Export pcie_find_root_port Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 09/13] mwifiex: printk() overflow with 32-byte SSIDs Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 10/13] pwm: Fix device reference leak Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 11/13] arm64: cpufeature: Schedule enable() calls instead of calling them via IPI Greg Kroah-Hartman
2016-12-07 7:07 ` [PATCH 4.4 12/13] arm64: mm: Set PSTATE.PAN from the cpu_enable_pan() call Greg Kroah-Hartman
2016-12-07 7:07 ` Greg Kroah-Hartman [this message]
2016-12-07 16:07 ` [PATCH 4.4 00/13] 4.4.37-stable review Guenter Roeck
2016-12-07 18:17 ` Shuah Khan
[not found] ` <5847f96a.45f6c20a.fab5.7b38@mx.google.com>
[not found] ` <m2inqvekqu.fsf@baylibre.com>
2016-12-08 16:25 ` Greg Kroah-Hartman
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