From 1b2d3451ee50a0968cb9933f726e50b368ba5073 Mon Sep 17 00:00:00 2001
From: Mark Rutland <mark.rutland@arm.com>
Date: Mon, 14 Feb 2022 16:52:16 +0000
Subject: arm64: Support PREEMPT_DYNAMIC

This patch enables support for PREEMPT_DYNAMIC on arm64, allowing the
preemption model to be chosen at boot time.

Specifically, this patch selects HAVE_PREEMPT_DYNAMIC_KEY, so that each
preemption function is an out-of-line call with an early return
depending upon a static key. This leaves almost all the codegen up to
the compiler, and side-steps a number of pain points with static calls
(e.g. interaction with CFI schemes). This should have no worse overhead
than using non-inline static calls, as those use out-of-line trampolines
with early returns.

For example, the dynamic_cond_resched() wrapper looks as follows when
enabled. When disabled, the first `B` is replaced with a `NOP`,
resulting in an early return.

| <dynamic_cond_resched>:
|        bti     c
|        b       <dynamic_cond_resched+0x10>     // or `nop`
|        mov     w0, #0x0
|        ret
|        mrs     x0, sp_el0
|        ldr     x0, [x0, #8]
|        cbnz    x0, <dynamic_cond_resched+0x8>
|        paciasp
|        stp     x29, x30, [sp, #-16]!
|        mov     x29, sp
|        bl      <preempt_schedule_common>
|        mov     w0, #0x1
|        ldp     x29, x30, [sp], #16
|        autiasp
|        ret

... compared to the regular form of the function:

| <__cond_resched>:
|        bti     c
|        mrs     x0, sp_el0
|        ldr     x1, [x0, #8]
|        cbz     x1, <__cond_resched+0x18>
|        mov     w0, #0x0
|        ret
|        paciasp
|        stp     x29, x30, [sp, #-16]!
|        mov     x29, sp
|        bl      <preempt_schedule_common>
|        mov     w0, #0x1
|        ldp     x29, x30, [sp], #16
|        autiasp
|        ret

Since arm64 does not yet use the generic entry code, we must define our
own `sk_dynamic_irqentry_exit_cond_resched`, which will be
enabled/disabled by the common code in kernel/sched/core.c. All other
preemption functions and associated static keys are defined there.

Signed-off-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20220214165216.2231574-8-mark.rutland@arm.com
---
 arch/arm64/include/asm/preempt.h | 19 +++++++++++++++++--
 1 file changed, 17 insertions(+), 2 deletions(-)

(limited to 'arch/arm64/include')

diff --git a/arch/arm64/include/asm/preempt.h b/arch/arm64/include/asm/preempt.h
index e83f0982b99c..0159b625cc7f 100644
--- a/arch/arm64/include/asm/preempt.h
+++ b/arch/arm64/include/asm/preempt.h
@@ -2,6 +2,7 @@
 #ifndef __ASM_PREEMPT_H
 #define __ASM_PREEMPT_H
 
+#include <linux/jump_label.h>
 #include <linux/thread_info.h>
 
 #define PREEMPT_NEED_RESCHED	BIT(32)
@@ -80,10 +81,24 @@ static inline bool should_resched(int preempt_offset)
 }
 
 #ifdef CONFIG_PREEMPTION
+
 void preempt_schedule(void);
-#define __preempt_schedule() preempt_schedule()
 void preempt_schedule_notrace(void);
-#define __preempt_schedule_notrace() preempt_schedule_notrace()
+
+#ifdef CONFIG_PREEMPT_DYNAMIC
+
+DECLARE_STATIC_KEY_TRUE(sk_dynamic_irqentry_exit_cond_resched);
+void dynamic_preempt_schedule(void);
+#define __preempt_schedule()		dynamic_preempt_schedule()
+void dynamic_preempt_schedule_notrace(void);
+#define __preempt_schedule_notrace()	dynamic_preempt_schedule_notrace()
+
+#else /* CONFIG_PREEMPT_DYNAMIC */
+
+#define __preempt_schedule()		preempt_schedule()
+#define __preempt_schedule_notrace()	preempt_schedule_notrace()
+
+#endif /* CONFIG_PREEMPT_DYNAMIC */
 #endif /* CONFIG_PREEMPTION */
 
 #endif /* __ASM_PREEMPT_H */
-- 
cgit 1.4.1


From 669f45f19cf7feea7066dce86a0ce89dfc8a2065 Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@kernel.org>
Date: Tue, 22 Feb 2022 13:23:59 +0100
Subject: sched/headers: Add initial new headers as identity mappings

This allows code sharing between fast-headers tree and the vanilla
scheduler tree.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Peter Zijlstra <peterz@infradead.org>
---
 arch/arm64/include/asm/paravirt_api_clock.h | 1 +
 arch/x86/include/asm/paravirt_api_clock.h   | 1 +
 include/linux/cgroup_api.h                  | 1 +
 include/linux/cpumask_api.h                 | 1 +
 include/linux/fs_api.h                      | 1 +
 include/linux/gfp_api.h                     | 1 +
 include/linux/hashtable_api.h               | 1 +
 include/linux/hrtimer_api.h                 | 1 +
 include/linux/kobject_api.h                 | 1 +
 include/linux/kref_api.h                    | 1 +
 include/linux/ktime_api.h                   | 1 +
 include/linux/llist_api.h                   | 1 +
 include/linux/lockdep_api.h                 | 1 +
 include/linux/mm_api.h                      | 1 +
 include/linux/mutex_api.h                   | 1 +
 include/linux/perf_event_api.h              | 1 +
 include/linux/pgtable_api.h                 | 1 +
 include/linux/ptrace_api.h                  | 1 +
 include/linux/rcuwait_api.h                 | 1 +
 include/linux/refcount_api.h                | 1 +
 include/linux/sched/affinity.h              | 1 +
 include/linux/sched/cond_resched.h          | 1 +
 include/linux/sched/posix-timers.h          | 1 +
 include/linux/sched/rseq_api.h              | 1 +
 include/linux/sched/task_flags.h            | 1 +
 include/linux/sched/thread_info_api.h       | 1 +
 include/linux/seqlock_api.h                 | 1 +
 include/linux/softirq.h                     | 1 +
 include/linux/spinlock_api.h                | 1 +
 include/linux/swait_api.h                   | 1 +
 include/linux/syscalls_api.h                | 1 +
 include/linux/u64_stats_sync_api.h          | 1 +
 include/linux/wait_api.h                    | 1 +
 include/linux/workqueue_api.h               | 1 +
 34 files changed, 34 insertions(+)
 create mode 100644 arch/arm64/include/asm/paravirt_api_clock.h
 create mode 100644 arch/x86/include/asm/paravirt_api_clock.h
 create mode 100644 include/linux/cgroup_api.h
 create mode 100644 include/linux/cpumask_api.h
 create mode 100644 include/linux/fs_api.h
 create mode 100644 include/linux/gfp_api.h
 create mode 100644 include/linux/hashtable_api.h
 create mode 100644 include/linux/hrtimer_api.h
 create mode 100644 include/linux/kobject_api.h
 create mode 100644 include/linux/kref_api.h
 create mode 100644 include/linux/ktime_api.h
 create mode 100644 include/linux/llist_api.h
 create mode 100644 include/linux/lockdep_api.h
 create mode 100644 include/linux/mm_api.h
 create mode 100644 include/linux/mutex_api.h
 create mode 100644 include/linux/perf_event_api.h
 create mode 100644 include/linux/pgtable_api.h
 create mode 100644 include/linux/ptrace_api.h
 create mode 100644 include/linux/rcuwait_api.h
 create mode 100644 include/linux/refcount_api.h
 create mode 100644 include/linux/sched/affinity.h
 create mode 100644 include/linux/sched/cond_resched.h
 create mode 100644 include/linux/sched/posix-timers.h
 create mode 100644 include/linux/sched/rseq_api.h
 create mode 100644 include/linux/sched/task_flags.h
 create mode 100644 include/linux/sched/thread_info_api.h
 create mode 100644 include/linux/seqlock_api.h
 create mode 100644 include/linux/softirq.h
 create mode 100644 include/linux/spinlock_api.h
 create mode 100644 include/linux/swait_api.h
 create mode 100644 include/linux/syscalls_api.h
 create mode 100644 include/linux/u64_stats_sync_api.h
 create mode 100644 include/linux/wait_api.h
 create mode 100644 include/linux/workqueue_api.h

(limited to 'arch/arm64/include')

diff --git a/arch/arm64/include/asm/paravirt_api_clock.h b/arch/arm64/include/asm/paravirt_api_clock.h
new file mode 100644
index 000000000000..65ac7cee0dad
--- /dev/null
+++ b/arch/arm64/include/asm/paravirt_api_clock.h
@@ -0,0 +1 @@
+#include <asm/paravirt.h>
diff --git a/arch/x86/include/asm/paravirt_api_clock.h b/arch/x86/include/asm/paravirt_api_clock.h
new file mode 100644
index 000000000000..65ac7cee0dad
--- /dev/null
+++ b/arch/x86/include/asm/paravirt_api_clock.h
@@ -0,0 +1 @@
+#include <asm/paravirt.h>
diff --git a/include/linux/cgroup_api.h b/include/linux/cgroup_api.h
new file mode 100644
index 000000000000..d0cfe8025111
--- /dev/null
+++ b/include/linux/cgroup_api.h
@@ -0,0 +1 @@
+#include <linux/cgroup.h>
diff --git a/include/linux/cpumask_api.h b/include/linux/cpumask_api.h
new file mode 100644
index 000000000000..83bd3ebe82b0
--- /dev/null
+++ b/include/linux/cpumask_api.h
@@ -0,0 +1 @@
+#include <linux/cpumask.h>
diff --git a/include/linux/fs_api.h b/include/linux/fs_api.h
new file mode 100644
index 000000000000..83be38d6d413
--- /dev/null
+++ b/include/linux/fs_api.h
@@ -0,0 +1 @@
+#include <linux/fs.h>
diff --git a/include/linux/gfp_api.h b/include/linux/gfp_api.h
new file mode 100644
index 000000000000..5a05a2764a86
--- /dev/null
+++ b/include/linux/gfp_api.h
@@ -0,0 +1 @@
+#include <linux/gfp.h>
diff --git a/include/linux/hashtable_api.h b/include/linux/hashtable_api.h
new file mode 100644
index 000000000000..c268ac2c5c0e
--- /dev/null
+++ b/include/linux/hashtable_api.h
@@ -0,0 +1 @@
+#include <linux/hashtable.h>
diff --git a/include/linux/hrtimer_api.h b/include/linux/hrtimer_api.h
new file mode 100644
index 000000000000..8d9700894468
--- /dev/null
+++ b/include/linux/hrtimer_api.h
@@ -0,0 +1 @@
+#include <linux/hrtimer.h>
diff --git a/include/linux/kobject_api.h b/include/linux/kobject_api.h
new file mode 100644
index 000000000000..6e36a054c2d6
--- /dev/null
+++ b/include/linux/kobject_api.h
@@ -0,0 +1 @@
+#include <linux/kobject.h>
diff --git a/include/linux/kref_api.h b/include/linux/kref_api.h
new file mode 100644
index 000000000000..d67e554721d2
--- /dev/null
+++ b/include/linux/kref_api.h
@@ -0,0 +1 @@
+#include <linux/kref.h>
diff --git a/include/linux/ktime_api.h b/include/linux/ktime_api.h
new file mode 100644
index 000000000000..f697d493960f
--- /dev/null
+++ b/include/linux/ktime_api.h
@@ -0,0 +1 @@
+#include <linux/ktime.h>
diff --git a/include/linux/llist_api.h b/include/linux/llist_api.h
new file mode 100644
index 000000000000..625bec0393a1
--- /dev/null
+++ b/include/linux/llist_api.h
@@ -0,0 +1 @@
+#include <linux/llist.h>
diff --git a/include/linux/lockdep_api.h b/include/linux/lockdep_api.h
new file mode 100644
index 000000000000..907e66979ab2
--- /dev/null
+++ b/include/linux/lockdep_api.h
@@ -0,0 +1 @@
+#include <linux/lockdep.h>
diff --git a/include/linux/mm_api.h b/include/linux/mm_api.h
new file mode 100644
index 000000000000..a5ace2b198b8
--- /dev/null
+++ b/include/linux/mm_api.h
@@ -0,0 +1 @@
+#include <linux/mm.h>
diff --git a/include/linux/mutex_api.h b/include/linux/mutex_api.h
new file mode 100644
index 000000000000..85ab9491e13e
--- /dev/null
+++ b/include/linux/mutex_api.h
@@ -0,0 +1 @@
+#include <linux/mutex.h>
diff --git a/include/linux/perf_event_api.h b/include/linux/perf_event_api.h
new file mode 100644
index 000000000000..c2fd6048b790
--- /dev/null
+++ b/include/linux/perf_event_api.h
@@ -0,0 +1 @@
+#include <linux/perf_event.h>
diff --git a/include/linux/pgtable_api.h b/include/linux/pgtable_api.h
new file mode 100644
index 000000000000..ff367a4ba8c4
--- /dev/null
+++ b/include/linux/pgtable_api.h
@@ -0,0 +1 @@
+#include <linux/pgtable.h>
diff --git a/include/linux/ptrace_api.h b/include/linux/ptrace_api.h
new file mode 100644
index 000000000000..26e7d275ad8d
--- /dev/null
+++ b/include/linux/ptrace_api.h
@@ -0,0 +1 @@
+#include <linux/ptrace.h>
diff --git a/include/linux/rcuwait_api.h b/include/linux/rcuwait_api.h
new file mode 100644
index 000000000000..f962e28544dd
--- /dev/null
+++ b/include/linux/rcuwait_api.h
@@ -0,0 +1 @@
+#include <linux/rcuwait.h>
diff --git a/include/linux/refcount_api.h b/include/linux/refcount_api.h
new file mode 100644
index 000000000000..5f032589f568
--- /dev/null
+++ b/include/linux/refcount_api.h
@@ -0,0 +1 @@
+#include <linux/refcount.h>
diff --git a/include/linux/sched/affinity.h b/include/linux/sched/affinity.h
new file mode 100644
index 000000000000..227f5be81bcd
--- /dev/null
+++ b/include/linux/sched/affinity.h
@@ -0,0 +1 @@
+#include <linux/sched.h>
diff --git a/include/linux/sched/cond_resched.h b/include/linux/sched/cond_resched.h
new file mode 100644
index 000000000000..227f5be81bcd
--- /dev/null
+++ b/include/linux/sched/cond_resched.h
@@ -0,0 +1 @@
+#include <linux/sched.h>
diff --git a/include/linux/sched/posix-timers.h b/include/linux/sched/posix-timers.h
new file mode 100644
index 000000000000..523a381d6c88
--- /dev/null
+++ b/include/linux/sched/posix-timers.h
@@ -0,0 +1 @@
+#include <linux/posix-timers.h>
diff --git a/include/linux/sched/rseq_api.h b/include/linux/sched/rseq_api.h
new file mode 100644
index 000000000000..cf2af72693e1
--- /dev/null
+++ b/include/linux/sched/rseq_api.h
@@ -0,0 +1 @@
+#include <linux/rseq.h>
diff --git a/include/linux/sched/task_flags.h b/include/linux/sched/task_flags.h
new file mode 100644
index 000000000000..227f5be81bcd
--- /dev/null
+++ b/include/linux/sched/task_flags.h
@@ -0,0 +1 @@
+#include <linux/sched.h>
diff --git a/include/linux/sched/thread_info_api.h b/include/linux/sched/thread_info_api.h
new file mode 100644
index 000000000000..2c60fbc16c08
--- /dev/null
+++ b/include/linux/sched/thread_info_api.h
@@ -0,0 +1 @@
+#include <linux/thread_info.h>
diff --git a/include/linux/seqlock_api.h b/include/linux/seqlock_api.h
new file mode 100644
index 000000000000..be91e7d3b826
--- /dev/null
+++ b/include/linux/seqlock_api.h
@@ -0,0 +1 @@
+#include <linux/seqlock.h>
diff --git a/include/linux/softirq.h b/include/linux/softirq.h
new file mode 100644
index 000000000000..c73d7dcb4cb5
--- /dev/null
+++ b/include/linux/softirq.h
@@ -0,0 +1 @@
+#include <linux/interrupt.h>
diff --git a/include/linux/spinlock_api.h b/include/linux/spinlock_api.h
new file mode 100644
index 000000000000..6338b27f98df
--- /dev/null
+++ b/include/linux/spinlock_api.h
@@ -0,0 +1 @@
+#include <linux/spinlock.h>
diff --git a/include/linux/swait_api.h b/include/linux/swait_api.h
new file mode 100644
index 000000000000..1eeaaaaa5ea7
--- /dev/null
+++ b/include/linux/swait_api.h
@@ -0,0 +1 @@
+#include <linux/swait.h>
diff --git a/include/linux/syscalls_api.h b/include/linux/syscalls_api.h
new file mode 100644
index 000000000000..23e012b04db4
--- /dev/null
+++ b/include/linux/syscalls_api.h
@@ -0,0 +1 @@
+#include <linux/syscalls.h>
diff --git a/include/linux/u64_stats_sync_api.h b/include/linux/u64_stats_sync_api.h
new file mode 100644
index 000000000000..c72ca63da44b
--- /dev/null
+++ b/include/linux/u64_stats_sync_api.h
@@ -0,0 +1 @@
+#include <linux/u64_stats_sync.h>
diff --git a/include/linux/wait_api.h b/include/linux/wait_api.h
new file mode 100644
index 000000000000..4e930548935a
--- /dev/null
+++ b/include/linux/wait_api.h
@@ -0,0 +1 @@
+#include <linux/wait.h>
diff --git a/include/linux/workqueue_api.h b/include/linux/workqueue_api.h
new file mode 100644
index 000000000000..77debb5d2760
--- /dev/null
+++ b/include/linux/workqueue_api.h
@@ -0,0 +1 @@
+#include <linux/workqueue.h>
-- 
cgit 1.4.1