Commit c7e9ad7d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge branch 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull perf fixes from Ingo Molnar:

 - fix the perf build, by fixing the rbtree.c sharing bug between kernel
   and tools/perf by creating a local copy of rbtree.c (more will be
   done for v4.3)

 - fix an AUX buffer (Intel-PT support) refcounting bug

 - fix copy_from_user_nmi() return value"

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf/x86: Fix copy_from_user_nmi() return if range is not ok
  perf: Fix AUX buffer refcounting
  tools: Copy rbtree_augmented.h from the kernel
  tools: Move rbtree.h from tools/perf/
  tools: Copy lib/rbtree.c to tools/lib/
  perf tools: Copy rbtree.h from the kernel
  tools: Adopt {READ,WRITE_ONCE} from the kernel
parents 1c4c7159 ebf2d268

arch/x86/lib/usercopy.c

+1 −1
Original line number Diff line number Diff line
@@ -20,7 +20,7 @@ copy_from_user_nmi(void *to, const void __user *from, unsigned long n) 
	unsigned long ret;



	if (__range_not_ok(from, n, TASK_SIZE))

		return 0;

		return n;



	/*

	 * Even though this function is typically called from NMI/IRQ context

kernel/events/core.c

+0 −8
Original line number Diff line number Diff line
@@ -4358,14 +4358,6 @@ static void ring_buffer_wakeup(struct perf_event *event) 
	rcu_read_unlock();

}



static void rb_free_rcu(struct rcu_head *rcu_head)

{

	struct ring_buffer *rb;



	rb = container_of(rcu_head, struct ring_buffer, rcu_head);

	rb_free(rb);

}



struct ring_buffer *ring_buffer_get(struct perf_event *event)

{

	struct ring_buffer *rb;

kernel/events/internal.h

+10 −0
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 
struct ring_buffer {

	atomic_t			refcount;

	struct rcu_head			rcu_head;

	struct irq_work			irq_work;

#ifdef CONFIG_PERF_USE_VMALLOC

	struct work_struct		work;

	int				page_order;	/* allocation order  */
@@ -55,6 +56,15 @@ struct ring_buffer { 
};



extern void rb_free(struct ring_buffer *rb);



static inline void rb_free_rcu(struct rcu_head *rcu_head)

{

	struct ring_buffer *rb;



	rb = container_of(rcu_head, struct ring_buffer, rcu_head);

	rb_free(rb);

}



extern struct ring_buffer *

rb_alloc(int nr_pages, long watermark, int cpu, int flags);

extern void perf_event_wakeup(struct perf_event *event);

kernel/events/ring_buffer.c

+25 −2
Original line number Diff line number Diff line
@@ -221,6 +221,8 @@ void perf_output_end(struct perf_output_handle *handle) 
	rcu_read_unlock();

}



static void rb_irq_work(struct irq_work *work);



static void

ring_buffer_init(struct ring_buffer *rb, long watermark, int flags)

{
@@ -241,6 +243,16 @@ ring_buffer_init(struct ring_buffer *rb, long watermark, int flags) 


	INIT_LIST_HEAD(&rb->event_list);

	spin_lock_init(&rb->event_lock);

	init_irq_work(&rb->irq_work, rb_irq_work);

}



static void ring_buffer_put_async(struct ring_buffer *rb)

{

	if (!atomic_dec_and_test(&rb->refcount))

		return;



	rb->rcu_head.next = (void *)rb;

	irq_work_queue(&rb->irq_work);

}



/*
@@ -319,7 +331,7 @@ err_put: 
	rb_free_aux(rb);



err:

	ring_buffer_put(rb);

	ring_buffer_put_async(rb);

	handle->event = NULL;



	return NULL;
@@ -370,7 +382,7 @@ void perf_aux_output_end(struct perf_output_handle *handle, unsigned long size, 


	local_set(&rb->aux_nest, 0);

	rb_free_aux(rb);

	ring_buffer_put(rb);

	ring_buffer_put_async(rb);

}



/*
@@ -557,7 +569,18 @@ static void __rb_free_aux(struct ring_buffer *rb) 
void rb_free_aux(struct ring_buffer *rb)

{

	if (atomic_dec_and_test(&rb->aux_refcount))

		irq_work_queue(&rb->irq_work);

}



static void rb_irq_work(struct irq_work *work)

{

	struct ring_buffer *rb = container_of(work, struct ring_buffer, irq_work);



	if (!atomic_read(&rb->aux_refcount))

		__rb_free_aux(rb);



	if (rb->rcu_head.next == (void *)rb)

		call_rcu(&rb->rcu_head, rb_free_rcu);

}



#ifndef CONFIG_PERF_USE_VMALLOC

tools/include/linux/compiler.h

+58 −0
Original line number Diff line number Diff line
@@ -41,4 +41,62 @@ 


#define ACCESS_ONCE(x) (*(volatile typeof(x) *)&(x))



#include <linux/types.h>



static __always_inline void __read_once_size(const volatile void *p, void *res, int size)

{

	switch (size) {

	case 1: *(__u8 *)res = *(volatile __u8 *)p; break;

	case 2: *(__u16 *)res = *(volatile __u16 *)p; break;

	case 4: *(__u32 *)res = *(volatile __u32 *)p; break;

	case 8: *(__u64 *)res = *(volatile __u64 *)p; break;

	default:

		barrier();

		__builtin_memcpy((void *)res, (const void *)p, size);

		barrier();

	}

}



static __always_inline void __write_once_size(volatile void *p, void *res, int size)

{

	switch (size) {

	case 1: *(volatile __u8 *)p = *(__u8 *)res; break;

	case 2: *(volatile __u16 *)p = *(__u16 *)res; break;

	case 4: *(volatile __u32 *)p = *(__u32 *)res; break;

	case 8: *(volatile __u64 *)p = *(__u64 *)res; break;

	default:

		barrier();

		__builtin_memcpy((void *)p, (const void *)res, size);

		barrier();

	}

}



/*

 * Prevent the compiler from merging or refetching reads or writes. The

 * compiler is also forbidden from reordering successive instances of

 * READ_ONCE, WRITE_ONCE and ACCESS_ONCE (see below), but only when the

 * compiler is aware of some particular ordering.  One way to make the

 * compiler aware of ordering is to put the two invocations of READ_ONCE,

 * WRITE_ONCE or ACCESS_ONCE() in different C statements.

 *

 * In contrast to ACCESS_ONCE these two macros will also work on aggregate

 * data types like structs or unions. If the size of the accessed data

 * type exceeds the word size of the machine (e.g., 32 bits or 64 bits)

 * READ_ONCE() and WRITE_ONCE()  will fall back to memcpy and print a

 * compile-time warning.

 *

 * Their two major use cases are: (1) Mediating communication between

 * process-level code and irq/NMI handlers, all running on the same CPU,

 * and (2) Ensuring that the compiler does not  fold, spindle, or otherwise

 * mutilate accesses that either do not require ordering or that interact

 * with an explicit memory barrier or atomic instruction that provides the

 * required ordering.

 */



#define READ_ONCE(x) \

	({ union { typeof(x) __val; char __c[1]; } __u; __read_once_size(&(x), __u.__c, sizeof(x)); __u.__val; })



#define WRITE_ONCE(x, val) \

	({ union { typeof(x) __val; char __c[1]; } __u = { .__val = (val) }; __write_once_size(&(x), __u.__c, sizeof(x)); __u.__val; })



#endif /* _TOOLS_LINUX_COMPILER_H */

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