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Groups > linux.kernel > #1537567
| From | Greg Kroah-Hartman <gregkh@linuxfoundation.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [PATCH 4.8 33/35] arm64: cpufeature: Schedule enable() calls instead of calling them via IPI |
| Date | 2016-12-07 08:20 +0100 |
| Message-ID | <sLEGe-5pa-43@gated-at.bofh.it> (permalink) |
| References | <sLEwx-5hv-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
4.8-stable review patch. If anyone has any objections, please let me know.
------------------
From: James Morse <james.morse@arm.com>
commit 2a6dcb2b5f3e21592ca8dfa198dcce7bec09b020 upstream.
The enable() call for a cpufeature/errata is called using on_each_cpu().
This issues a cross-call IPI to get the work done. Implicitly, this
stashes the running PSTATE in SPSR when the CPU receives the IPI, and
restores it when we return. This means an enable() call can never modify
PSTATE.
To allow PAN to do this, change the on_each_cpu() call to use
stop_machine(). This schedules the work on each CPU which allows
us to modify PSTATE.
This involves changing the protype of all the enable() functions.
enable_cpu_capabilities() is called during boot and enables the feature
on all online CPUs. This path now uses stop_machine(). CPU features for
hotplug'd CPUs are enabled by verify_local_cpu_features() which only
acts on the local CPU, and can already modify the running PSTATE as it
is called from secondary_start_kernel().
Reported-by: Tony Thompson <anthony.thompson@arm.com>
Reported-by: Vladimir Murzin <vladimir.murzin@arm.com>
Signed-off-by: James Morse <james.morse@arm.com>
Cc: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
[Removed enable() hunks for A53 workaround]
Signed-off-by: James Morse <james.morse@arm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
arch/arm64/include/asm/cpufeature.h | 2 +-
arch/arm64/include/asm/processor.h | 6 +++---
arch/arm64/kernel/cpufeature.c | 10 +++++++++-
arch/arm64/kernel/traps.c | 3 ++-
arch/arm64/mm/fault.c | 6 ++++--
5 files changed, 19 insertions(+), 8 deletions(-)
--- a/arch/arm64/include/asm/cpufeature.h
+++ b/arch/arm64/include/asm/cpufeature.h
@@ -90,7 +90,7 @@ struct arm64_cpu_capabilities {
u16 capability;
int def_scope; /* default scope */
bool (*matches)(const struct arm64_cpu_capabilities *caps, int scope);
- void (*enable)(void *); /* Called on all active CPUs */
+ int (*enable)(void *); /* Called on all active CPUs */
union {
struct { /* To be used for erratum handling only */
u32 midr_model;
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -190,8 +190,8 @@ static inline void spin_lock_prefetch(co
#endif
-void cpu_enable_pan(void *__unused);
-void cpu_enable_uao(void *__unused);
-void cpu_enable_cache_maint_trap(void *__unused);
+int cpu_enable_pan(void *__unused);
+int cpu_enable_uao(void *__unused);
+int cpu_enable_cache_maint_trap(void *__unused);
#endif /* __ASM_PROCESSOR_H */
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -19,7 +19,9 @@
#define pr_fmt(fmt) "CPU features: " fmt
#include <linux/bsearch.h>
+#include <linux/cpumask.h>
#include <linux/sort.h>
+#include <linux/stop_machine.h>
#include <linux/types.h>
#include <asm/cpu.h>
#include <asm/cpufeature.h>
@@ -936,7 +938,13 @@ void __init enable_cpu_capabilities(cons
{
for (; caps->matches; caps++)
if (caps->enable && cpus_have_cap(caps->capability))
- on_each_cpu(caps->enable, NULL, true);
+ /*
+ * Use stop_machine() as it schedules the work allowing
+ * us to modify PSTATE, instead of on_each_cpu() which
+ * uses an IPI, giving us a PSTATE that disappears when
+ * we return.
+ */
+ stop_machine(caps->enable, NULL, cpu_online_mask);
}
/*
--- a/arch/arm64/kernel/traps.c
+++ b/arch/arm64/kernel/traps.c
@@ -428,9 +428,10 @@ asmlinkage void __exception do_undefinst
force_signal_inject(SIGILL, ILL_ILLOPC, regs, 0);
}
-void cpu_enable_cache_maint_trap(void *__unused)
+int cpu_enable_cache_maint_trap(void *__unused)
{
config_sctlr_el1(SCTLR_EL1_UCI, 0);
+ return 0;
}
#define __user_cache_maint(insn, address, res) \
--- a/arch/arm64/mm/fault.c
+++ b/arch/arm64/mm/fault.c
@@ -671,9 +671,10 @@ asmlinkage int __exception do_debug_exce
NOKPROBE_SYMBOL(do_debug_exception);
#ifdef CONFIG_ARM64_PAN
-void cpu_enable_pan(void *__unused)
+int cpu_enable_pan(void *__unused)
{
config_sctlr_el1(SCTLR_EL1_SPAN, 0);
+ return 0;
}
#endif /* CONFIG_ARM64_PAN */
@@ -684,8 +685,9 @@ void cpu_enable_pan(void *__unused)
* We need to enable the feature at runtime (instead of adding it to
* PSR_MODE_EL1h) as the feature may not be implemented by the cpu.
*/
-void cpu_enable_uao(void *__unused)
+int cpu_enable_uao(void *__unused)
{
asm(SET_PSTATE_UAO(1));
+ return 0;
}
#endif /* CONFIG_ARM64_UAO */
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[PATCH 4.8 00/35] 4.8.13-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 16/35] PCI: Export pcie_find_root_port Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 11/35] ovl: fix d_real() for stacked fs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 01/35] libata-scsi: Fixup ata_gen_passthru_sense() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 25/35] drm/radeon: fix check for port PM availability Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 14/35] rcu: Fix soft lockup for rcu_nocb_kthread Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 21/35] drm/i915: drop the struct_mutex when wedged or trying to reset Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 02/35] scsi: hpsa: use bus 3 for legacy HBA devices Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 23/35] drm/radeon: fix power state when port pm is unavailable (v2) Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 26/35] arm64: dts: juno: fix cluster sleep state entry latency on all SoC versions Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:10 +0100
[PATCH 4.8 07/35] thp: fix corner case of munlock() of PTE-mapped THPs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 10/35] mm: fix false-positive WARN_ON() in truncate/invalidate for hugetlb Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 29/35] drm/mediatek: fix null pointer dereference Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 08/35] zram: fix unbalanced idr management at hot removal Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 35/35] arm64: suspend: Reconfigure PSTATE after resume from idle Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 34/35] arm64: mm: Set PSTATE.PAN from the cpu_enable_pan() call Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 04/35] ARC: mm: PAE40: Fix crash at munmap Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 24/35] drm/amdgpu: fix check for port PM availability Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 20/35] drm/i915: Dont touch NULL sg on i915_gem_object_get_pages_gtt() error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 05/35] ARC: Dont use "+l" inline asm constraint Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 12/35] Input: change KEY_DATA from 0x275 to 0x277 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 30/35] perf/x86: Restore TASK_SIZE check on frame pointer Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 28/35] pwm: Fix device reference leak Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 03/35] scsi: libfc: fix seconds_since_last_reset miscalculation Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 32/35] batman-adv: Detect missing primaryif during tp_send as error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 33/35] arm64: cpufeature: Schedule enable() calls instead of calling them via IPI Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
[PATCH 4.8 09/35] kasan: update kasan_global for gcc 7 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-07 08:20 +0100
Re: [PATCH 4.8 00/35] 4.8.13-stable review Guenter Roeck <linux@roeck-us.net> - 2016-12-07 17:10 +0100
Re: [PATCH 4.8 00/35] 4.8.13-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-08 17:30 +0100
Re: [PATCH 4.8 00/35] 4.8.13-stable review Shuah Khan <shuah.kh@samsung.com> - 2016-12-07 19:20 +0100
Re: [PATCH 4.8 00/35] 4.8.13-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-08 17:30 +0100
Re: [PATCH 4.8 00/35] 4.8.13-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-12-08 17:30 +0100
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