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alistair23-linux/include/linux/percpu.h
Thomas Gleixner 30106b8ce2 slub: Fix the lockless code on 32-bit platforms with no 64-bit cmpxchg 
The SLUB allocator use of the cmpxchg_double logic was wrong: it
actually needs the irq-safe one.

That happens automatically when we use the native unlocked 'cmpxchg8b'
instruction, but when compiling the kernel for older x86 CPUs that do
not support that instruction, we fall back to the generic emulation
code.

And if you don't specify that you want the irq-safe version, the generic
code ends up just open-coding the cmpxchg8b equivalent without any
protection against interrupts or preemption.  Which definitely doesn't
work for SLUB.

This was reported by Werner Landgraf <w.landgraf@ru.ru>, who saw
instability with his distro-kernel that was compiled to support pretty
much everything under the sun.  Most big Linux distributions tend to
compile for PPro and later, and would never have noticed this problem.

This also fixes the prototypes for the irqsafe cmpxchg_double functions
to use 'bool' like they should.

[ Btw, that whole "generic code defaults to no protection" design just
  sounds stupid - if the code needs no protection, there is no reason to
  use "cmpxchg_double" to begin with.  So we should probably just remove
  the unprotected version entirely as pointless.   - Linus ]

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reported-and-tested-by: werner <w.landgraf@ru.ru>
Acked-and-tested-by: Ingo Molnar <mingo@elte.hu>
Acked-by: Christoph Lameter <cl@linux.com>
Cc: Pekka Enberg <penberg@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Tejun Heo <tj@kernel.org>
Link: http://lkml.kernel.org/r/alpine.LFD.2.02.1105041539050.3005@ionos
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-05-04 14:20:20 -07:00

955 lines
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#ifndef __LINUX_PERCPU_H
#define __LINUX_PERCPU_H
#include <linux/preempt.h>
#include <linux/smp.h>
#include <linux/cpumask.h>
#include <linux/pfn.h>
#include <linux/init.h>
#include <asm/percpu.h>
/* enough to cover all DEFINE_PER_CPUs in modules */
#ifdef CONFIG_MODULES
#define PERCPU_MODULE_RESERVE (8 << 10)
#else
#define PERCPU_MODULE_RESERVE 0
#endif
#ifndef PERCPU_ENOUGH_ROOM
#define PERCPU_ENOUGH_ROOM \
(ALIGN(__per_cpu_end - __per_cpu_start, SMP_CACHE_BYTES) + \
PERCPU_MODULE_RESERVE)
#endif
/*
* Must be an lvalue. Since @var must be a simple identifier,
* we force a syntax error here if it isn't.
*/
#define get_cpu_var(var) (*({ \
preempt_disable(); \
&__get_cpu_var(var); }))
/*
* The weird & is necessary because sparse considers (void)(var) to be
* a direct dereference of percpu variable (var).
*/
#define put_cpu_var(var) do { \
(void)&(var); \
preempt_enable(); \
} while (0)
#define get_cpu_ptr(var) ({ \
preempt_disable(); \
this_cpu_ptr(var); })
#define put_cpu_ptr(var) do { \
(void)(var); \
preempt_enable(); \
} while (0)
/* minimum unit size, also is the maximum supported allocation size */
#define PCPU_MIN_UNIT_SIZE PFN_ALIGN(32 << 10)
/*
* Percpu allocator can serve percpu allocations before slab is
* initialized which allows slab to depend on the percpu allocator.
* The following two parameters decide how much resource to
* preallocate for this. Keep PERCPU_DYNAMIC_RESERVE equal to or
* larger than PERCPU_DYNAMIC_EARLY_SIZE.
*/
#define PERCPU_DYNAMIC_EARLY_SLOTS 128
#define PERCPU_DYNAMIC_EARLY_SIZE (12 << 10)
/*
* PERCPU_DYNAMIC_RESERVE indicates the amount of free area to piggy
* back on the first chunk for dynamic percpu allocation if arch is
* manually allocating and mapping it for faster access (as a part of
* large page mapping for example).
*
* The following values give between one and two pages of free space
* after typical minimal boot (2-way SMP, single disk and NIC) with
* both defconfig and a distro config on x86_64 and 32. More
* intelligent way to determine this would be nice.
*/
#if BITS_PER_LONG > 32
#define PERCPU_DYNAMIC_RESERVE (20 << 10)
#else
#define PERCPU_DYNAMIC_RESERVE (12 << 10)
#endif
extern void *pcpu_base_addr;
extern const unsigned long *pcpu_unit_offsets;
struct pcpu_group_info {
int nr_units; /* aligned # of units */
unsigned long base_offset; /* base address offset */
unsigned int *cpu_map; /* unit->cpu map, empty
* entries contain NR_CPUS */
};
struct pcpu_alloc_info {
size_t static_size;
size_t reserved_size;
size_t dyn_size;
size_t unit_size;
size_t atom_size;
size_t alloc_size;
size_t __ai_size; /* internal, don't use */
int nr_groups; /* 0 if grouping unnecessary */
struct pcpu_group_info groups[];
};
enum pcpu_fc {
PCPU_FC_AUTO,
PCPU_FC_EMBED,
PCPU_FC_PAGE,
PCPU_FC_NR,
};
extern const char *pcpu_fc_names[PCPU_FC_NR];
extern enum pcpu_fc pcpu_chosen_fc;
typedef void * (*pcpu_fc_alloc_fn_t)(unsigned int cpu, size_t size,
size_t align);
typedef void (*pcpu_fc_free_fn_t)(void *ptr, size_t size);
typedef void (*pcpu_fc_populate_pte_fn_t)(unsigned long addr);
typedef int (pcpu_fc_cpu_distance_fn_t)(unsigned int from, unsigned int to);
extern struct pcpu_alloc_info * __init pcpu_alloc_alloc_info(int nr_groups,
int nr_units);
extern void __init pcpu_free_alloc_info(struct pcpu_alloc_info *ai);
extern int __init pcpu_setup_first_chunk(const struct pcpu_alloc_info *ai,
void *base_addr);
#ifdef CONFIG_NEED_PER_CPU_EMBED_FIRST_CHUNK
extern int __init pcpu_embed_first_chunk(size_t reserved_size, size_t dyn_size,
size_t atom_size,
pcpu_fc_cpu_distance_fn_t cpu_distance_fn,
pcpu_fc_alloc_fn_t alloc_fn,
pcpu_fc_free_fn_t free_fn);
#endif
#ifdef CONFIG_NEED_PER_CPU_PAGE_FIRST_CHUNK
extern int __init pcpu_page_first_chunk(size_t reserved_size,
pcpu_fc_alloc_fn_t alloc_fn,
pcpu_fc_free_fn_t free_fn,
pcpu_fc_populate_pte_fn_t populate_pte_fn);
#endif
/*
* Use this to get to a cpu's version of the per-cpu object
* dynamically allocated. Non-atomic access to the current CPU's
* version should probably be combined with get_cpu()/put_cpu().
*/
#ifdef CONFIG_SMP
#define per_cpu_ptr(ptr, cpu) SHIFT_PERCPU_PTR((ptr), per_cpu_offset((cpu)))
#else
#define per_cpu_ptr(ptr, cpu) ({ (void)(cpu); VERIFY_PERCPU_PTR((ptr)); })
#endif
extern void __percpu *__alloc_reserved_percpu(size_t size, size_t align);
extern bool is_kernel_percpu_address(unsigned long addr);
#if !defined(CONFIG_SMP) || !defined(CONFIG_HAVE_SETUP_PER_CPU_AREA)
extern void __init setup_per_cpu_areas(void);
#endif
extern void __init percpu_init_late(void);
extern void __percpu *__alloc_percpu(size_t size, size_t align);
extern void free_percpu(void __percpu *__pdata);
extern phys_addr_t per_cpu_ptr_to_phys(void *addr);
#define alloc_percpu(type) \
(typeof(type) __percpu *)__alloc_percpu(sizeof(type), __alignof__(type))
/*
* Optional methods for optimized non-lvalue per-cpu variable access.
*
* @var can be a percpu variable or a field of it and its size should
* equal char, int or long. percpu_read() evaluates to a lvalue and
* all others to void.
*
* These operations are guaranteed to be atomic w.r.t. preemption.
* The generic versions use plain get/put_cpu_var(). Archs are
* encouraged to implement single-instruction alternatives which don't
* require preemption protection.
*/
#ifndef percpu_read
# define percpu_read(var) \
({ \
typeof(var) *pr_ptr__ = &(var); \
typeof(var) pr_ret__; \
pr_ret__ = get_cpu_var(*pr_ptr__); \
put_cpu_var(*pr_ptr__); \
pr_ret__; \
})
#endif
#define __percpu_generic_to_op(var, val, op) \
do { \
typeof(var) *pgto_ptr__ = &(var); \
get_cpu_var(*pgto_ptr__) op val; \
put_cpu_var(*pgto_ptr__); \
} while (0)
#ifndef percpu_write
# define percpu_write(var, val) __percpu_generic_to_op(var, (val), =)
#endif
#ifndef percpu_add
# define percpu_add(var, val) __percpu_generic_to_op(var, (val), +=)
#endif
#ifndef percpu_sub
# define percpu_sub(var, val) __percpu_generic_to_op(var, (val), -=)
#endif
#ifndef percpu_and
# define percpu_and(var, val) __percpu_generic_to_op(var, (val), &=)
#endif
#ifndef percpu_or
# define percpu_or(var, val) __percpu_generic_to_op(var, (val), |=)
#endif
#ifndef percpu_xor
# define percpu_xor(var, val) __percpu_generic_to_op(var, (val), ^=)
#endif
/*
* Branching function to split up a function into a set of functions that
* are called for different scalar sizes of the objects handled.
*/
extern void __bad_size_call_parameter(void);
#define __pcpu_size_call_return(stem, variable) \
({ typeof(variable) pscr_ret__; \
__verify_pcpu_ptr(&(variable)); \
switch(sizeof(variable)) { \
case 1: pscr_ret__ = stem##1(variable);break; \
case 2: pscr_ret__ = stem##2(variable);break; \
case 4: pscr_ret__ = stem##4(variable);break; \
case 8: pscr_ret__ = stem##8(variable);break; \
default: \
__bad_size_call_parameter();break; \
} \
pscr_ret__; \
})
#define __pcpu_size_call_return2(stem, variable, ...) \
({ \
typeof(variable) pscr2_ret__; \
__verify_pcpu_ptr(&(variable)); \
switch(sizeof(variable)) { \
case 1: pscr2_ret__ = stem##1(variable, __VA_ARGS__); break; \
case 2: pscr2_ret__ = stem##2(variable, __VA_ARGS__); break; \
case 4: pscr2_ret__ = stem##4(variable, __VA_ARGS__); break; \
case 8: pscr2_ret__ = stem##8(variable, __VA_ARGS__); break; \
default: \
__bad_size_call_parameter(); break; \
} \
pscr2_ret__; \
})
/*
* Special handling for cmpxchg_double. cmpxchg_double is passed two
* percpu variables. The first has to be aligned to a double word
* boundary and the second has to follow directly thereafter.
*/
#define __pcpu_double_call_return_bool(stem, pcp1, pcp2, ...) \
({ \
bool pdcrb_ret__; \
__verify_pcpu_ptr(&pcp1); \
BUILD_BUG_ON(sizeof(pcp1) != sizeof(pcp2)); \
VM_BUG_ON((unsigned long)(&pcp1) % (2 * sizeof(pcp1))); \
VM_BUG_ON((unsigned long)(&pcp2) != \
(unsigned long)(&pcp1) + sizeof(pcp1)); \
switch(sizeof(pcp1)) { \
case 1: pdcrb_ret__ = stem##1(pcp1, pcp2, __VA_ARGS__); break; \
case 2: pdcrb_ret__ = stem##2(pcp1, pcp2, __VA_ARGS__); break; \
case 4: pdcrb_ret__ = stem##4(pcp1, pcp2, __VA_ARGS__); break; \
case 8: pdcrb_ret__ = stem##8(pcp1, pcp2, __VA_ARGS__); break; \
default: \
__bad_size_call_parameter(); break; \
} \
pdcrb_ret__; \
})
#define __pcpu_size_call(stem, variable, ...) \
do { \
__verify_pcpu_ptr(&(variable)); \
switch(sizeof(variable)) { \
case 1: stem##1(variable, __VA_ARGS__);break; \
case 2: stem##2(variable, __VA_ARGS__);break; \
case 4: stem##4(variable, __VA_ARGS__);break; \
case 8: stem##8(variable, __VA_ARGS__);break; \
default: \
__bad_size_call_parameter();break; \
} \
} while (0)
/*
* Optimized manipulation for memory allocated through the per cpu
* allocator or for addresses of per cpu variables.
*
* These operation guarantee exclusivity of access for other operations
* on the *same* processor. The assumption is that per cpu data is only
* accessed by a single processor instance (the current one).
*
* The first group is used for accesses that must be done in a
* preemption safe way since we know that the context is not preempt
* safe. Interrupts may occur. If the interrupt modifies the variable
* too then RMW actions will not be reliable.
*
* The arch code can provide optimized functions in two ways:
*
* 1. Override the function completely. F.e. define this_cpu_add().
* The arch must then ensure that the various scalar format passed
* are handled correctly.
*
* 2. Provide functions for certain scalar sizes. F.e. provide
* this_cpu_add_2() to provide per cpu atomic operations for 2 byte
* sized RMW actions. If arch code does not provide operations for
* a scalar size then the fallback in the generic code will be
* used.
*/
#define _this_cpu_generic_read(pcp) \
({ typeof(pcp) ret__; \
preempt_disable(); \
ret__ = *this_cpu_ptr(&(pcp)); \
preempt_enable(); \
ret__; \
})
#ifndef this_cpu_read
# ifndef this_cpu_read_1
# define this_cpu_read_1(pcp) _this_cpu_generic_read(pcp)
# endif
# ifndef this_cpu_read_2
# define this_cpu_read_2(pcp) _this_cpu_generic_read(pcp)
# endif
# ifndef this_cpu_read_4
# define this_cpu_read_4(pcp) _this_cpu_generic_read(pcp)
# endif
# ifndef this_cpu_read_8
# define this_cpu_read_8(pcp) _this_cpu_generic_read(pcp)
# endif
# define this_cpu_read(pcp) __pcpu_size_call_return(this_cpu_read_, (pcp))
#endif
#define _this_cpu_generic_to_op(pcp, val, op) \
do { \
preempt_disable(); \
*__this_cpu_ptr(&(pcp)) op val; \
preempt_enable(); \
} while (0)
#ifndef this_cpu_write
# ifndef this_cpu_write_1
# define this_cpu_write_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef this_cpu_write_2
# define this_cpu_write_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef this_cpu_write_4
# define this_cpu_write_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef this_cpu_write_8
# define this_cpu_write_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), =)
# endif
# define this_cpu_write(pcp, val) __pcpu_size_call(this_cpu_write_, (pcp), (val))
#endif
#ifndef this_cpu_add
# ifndef this_cpu_add_1
# define this_cpu_add_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef this_cpu_add_2
# define this_cpu_add_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef this_cpu_add_4
# define this_cpu_add_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef this_cpu_add_8
# define this_cpu_add_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), +=)
# endif
# define this_cpu_add(pcp, val) __pcpu_size_call(this_cpu_add_, (pcp), (val))
#endif
#ifndef this_cpu_sub
# define this_cpu_sub(pcp, val) this_cpu_add((pcp), -(val))
#endif
#ifndef this_cpu_inc
# define this_cpu_inc(pcp) this_cpu_add((pcp), 1)
#endif
#ifndef this_cpu_dec
# define this_cpu_dec(pcp) this_cpu_sub((pcp), 1)
#endif
#ifndef this_cpu_and
# ifndef this_cpu_and_1
# define this_cpu_and_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef this_cpu_and_2
# define this_cpu_and_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef this_cpu_and_4
# define this_cpu_and_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef this_cpu_and_8
# define this_cpu_and_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), &=)
# endif
# define this_cpu_and(pcp, val) __pcpu_size_call(this_cpu_and_, (pcp), (val))
#endif
#ifndef this_cpu_or
# ifndef this_cpu_or_1
# define this_cpu_or_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef this_cpu_or_2
# define this_cpu_or_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef this_cpu_or_4
# define this_cpu_or_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef this_cpu_or_8
# define this_cpu_or_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), |=)
# endif
# define this_cpu_or(pcp, val) __pcpu_size_call(this_cpu_or_, (pcp), (val))
#endif
#ifndef this_cpu_xor
# ifndef this_cpu_xor_1
# define this_cpu_xor_1(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef this_cpu_xor_2
# define this_cpu_xor_2(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef this_cpu_xor_4
# define this_cpu_xor_4(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef this_cpu_xor_8
# define this_cpu_xor_8(pcp, val) _this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# define this_cpu_xor(pcp, val) __pcpu_size_call(this_cpu_or_, (pcp), (val))
#endif
#define _this_cpu_generic_add_return(pcp, val) \
({ \
typeof(pcp) ret__; \
preempt_disable(); \
__this_cpu_add(pcp, val); \
ret__ = __this_cpu_read(pcp); \
preempt_enable(); \
ret__; \
})
#ifndef this_cpu_add_return
# ifndef this_cpu_add_return_1
# define this_cpu_add_return_1(pcp, val) _this_cpu_generic_add_return(pcp, val)
# endif
# ifndef this_cpu_add_return_2
# define this_cpu_add_return_2(pcp, val) _this_cpu_generic_add_return(pcp, val)
# endif
# ifndef this_cpu_add_return_4
# define this_cpu_add_return_4(pcp, val) _this_cpu_generic_add_return(pcp, val)
# endif
# ifndef this_cpu_add_return_8
# define this_cpu_add_return_8(pcp, val) _this_cpu_generic_add_return(pcp, val)
# endif
# define this_cpu_add_return(pcp, val) __pcpu_size_call_return2(this_cpu_add_return_, pcp, val)
#endif
#define this_cpu_sub_return(pcp, val) this_cpu_add_return(pcp, -(val))
#define this_cpu_inc_return(pcp) this_cpu_add_return(pcp, 1)
#define this_cpu_dec_return(pcp) this_cpu_add_return(pcp, -1)
#define _this_cpu_generic_xchg(pcp, nval) \
({ typeof(pcp) ret__; \
preempt_disable(); \
ret__ = __this_cpu_read(pcp); \
__this_cpu_write(pcp, nval); \
preempt_enable(); \
ret__; \
})
#ifndef this_cpu_xchg
# ifndef this_cpu_xchg_1
# define this_cpu_xchg_1(pcp, nval) _this_cpu_generic_xchg(pcp, nval)
# endif
# ifndef this_cpu_xchg_2
# define this_cpu_xchg_2(pcp, nval) _this_cpu_generic_xchg(pcp, nval)
# endif
# ifndef this_cpu_xchg_4
# define this_cpu_xchg_4(pcp, nval) _this_cpu_generic_xchg(pcp, nval)
# endif
# ifndef this_cpu_xchg_8
# define this_cpu_xchg_8(pcp, nval) _this_cpu_generic_xchg(pcp, nval)
# endif
# define this_cpu_xchg(pcp, nval) \
__pcpu_size_call_return2(this_cpu_xchg_, (pcp), nval)
#endif
#define _this_cpu_generic_cmpxchg(pcp, oval, nval) \
({ typeof(pcp) ret__; \
preempt_disable(); \
ret__ = __this_cpu_read(pcp); \
if (ret__ == (oval)) \
__this_cpu_write(pcp, nval); \
preempt_enable(); \
ret__; \
})
#ifndef this_cpu_cmpxchg
# ifndef this_cpu_cmpxchg_1
# define this_cpu_cmpxchg_1(pcp, oval, nval) _this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef this_cpu_cmpxchg_2
# define this_cpu_cmpxchg_2(pcp, oval, nval) _this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef this_cpu_cmpxchg_4
# define this_cpu_cmpxchg_4(pcp, oval, nval) _this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef this_cpu_cmpxchg_8
# define this_cpu_cmpxchg_8(pcp, oval, nval) _this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# define this_cpu_cmpxchg(pcp, oval, nval) \
__pcpu_size_call_return2(this_cpu_cmpxchg_, pcp, oval, nval)
#endif
/*
* cmpxchg_double replaces two adjacent scalars at once. The first
* two parameters are per cpu variables which have to be of the same
* size. A truth value is returned to indicate success or failure
* (since a double register result is difficult to handle). There is
* very limited hardware support for these operations, so only certain
* sizes may work.
*/
#define _this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
({ \
int ret__; \
preempt_disable(); \
ret__ = __this_cpu_generic_cmpxchg_double(pcp1, pcp2, \
oval1, oval2, nval1, nval2); \
preempt_enable(); \
ret__; \
})
#ifndef this_cpu_cmpxchg_double
# ifndef this_cpu_cmpxchg_double_1
# define this_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \
_this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef this_cpu_cmpxchg_double_2
# define this_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2) \
_this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef this_cpu_cmpxchg_double_4
# define this_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2) \
_this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef this_cpu_cmpxchg_double_8
# define this_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2) \
_this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# define this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
__pcpu_double_call_return_bool(this_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
#endif
/*
* Generic percpu operations that do not require preemption handling.
* Either we do not care about races or the caller has the
* responsibility of handling preemptions issues. Arch code can still
* override these instructions since the arch per cpu code may be more
* efficient and may actually get race freeness for free (that is the
* case for x86 for example).
*
* If there is no other protection through preempt disable and/or
* disabling interupts then one of these RMW operations can show unexpected
* behavior because the execution thread was rescheduled on another processor
* or an interrupt occurred and the same percpu variable was modified from
* the interrupt context.
*/
#ifndef __this_cpu_read
# ifndef __this_cpu_read_1
# define __this_cpu_read_1(pcp) (*__this_cpu_ptr(&(pcp)))
# endif
# ifndef __this_cpu_read_2
# define __this_cpu_read_2(pcp) (*__this_cpu_ptr(&(pcp)))
# endif
# ifndef __this_cpu_read_4
# define __this_cpu_read_4(pcp) (*__this_cpu_ptr(&(pcp)))
# endif
# ifndef __this_cpu_read_8
# define __this_cpu_read_8(pcp) (*__this_cpu_ptr(&(pcp)))
# endif
# define __this_cpu_read(pcp) __pcpu_size_call_return(__this_cpu_read_, (pcp))
#endif
#define __this_cpu_generic_to_op(pcp, val, op) \
do { \
*__this_cpu_ptr(&(pcp)) op val; \
} while (0)
#ifndef __this_cpu_write
# ifndef __this_cpu_write_1
# define __this_cpu_write_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef __this_cpu_write_2
# define __this_cpu_write_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef __this_cpu_write_4
# define __this_cpu_write_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
# endif
# ifndef __this_cpu_write_8
# define __this_cpu_write_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), =)
# endif
# define __this_cpu_write(pcp, val) __pcpu_size_call(__this_cpu_write_, (pcp), (val))
#endif
#ifndef __this_cpu_add
# ifndef __this_cpu_add_1
# define __this_cpu_add_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef __this_cpu_add_2
# define __this_cpu_add_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef __this_cpu_add_4
# define __this_cpu_add_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef __this_cpu_add_8
# define __this_cpu_add_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), +=)
# endif
# define __this_cpu_add(pcp, val) __pcpu_size_call(__this_cpu_add_, (pcp), (val))
#endif
#ifndef __this_cpu_sub
# define __this_cpu_sub(pcp, val) __this_cpu_add((pcp), -(val))
#endif
#ifndef __this_cpu_inc
# define __this_cpu_inc(pcp) __this_cpu_add((pcp), 1)
#endif
#ifndef __this_cpu_dec
# define __this_cpu_dec(pcp) __this_cpu_sub((pcp), 1)
#endif
#ifndef __this_cpu_and
# ifndef __this_cpu_and_1
# define __this_cpu_and_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef __this_cpu_and_2
# define __this_cpu_and_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef __this_cpu_and_4
# define __this_cpu_and_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef __this_cpu_and_8
# define __this_cpu_and_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), &=)
# endif
# define __this_cpu_and(pcp, val) __pcpu_size_call(__this_cpu_and_, (pcp), (val))
#endif
#ifndef __this_cpu_or
# ifndef __this_cpu_or_1
# define __this_cpu_or_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef __this_cpu_or_2
# define __this_cpu_or_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef __this_cpu_or_4
# define __this_cpu_or_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef __this_cpu_or_8
# define __this_cpu_or_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), |=)
# endif
# define __this_cpu_or(pcp, val) __pcpu_size_call(__this_cpu_or_, (pcp), (val))
#endif
#ifndef __this_cpu_xor
# ifndef __this_cpu_xor_1
# define __this_cpu_xor_1(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef __this_cpu_xor_2
# define __this_cpu_xor_2(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef __this_cpu_xor_4
# define __this_cpu_xor_4(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef __this_cpu_xor_8
# define __this_cpu_xor_8(pcp, val) __this_cpu_generic_to_op((pcp), (val), ^=)
# endif
# define __this_cpu_xor(pcp, val) __pcpu_size_call(__this_cpu_xor_, (pcp), (val))
#endif
#define __this_cpu_generic_add_return(pcp, val) \
({ \
__this_cpu_add(pcp, val); \
__this_cpu_read(pcp); \
})
#ifndef __this_cpu_add_return
# ifndef __this_cpu_add_return_1
# define __this_cpu_add_return_1(pcp, val) __this_cpu_generic_add_return(pcp, val)
# endif
# ifndef __this_cpu_add_return_2
# define __this_cpu_add_return_2(pcp, val) __this_cpu_generic_add_return(pcp, val)
# endif
# ifndef __this_cpu_add_return_4
# define __this_cpu_add_return_4(pcp, val) __this_cpu_generic_add_return(pcp, val)
# endif
# ifndef __this_cpu_add_return_8
# define __this_cpu_add_return_8(pcp, val) __this_cpu_generic_add_return(pcp, val)
# endif
# define __this_cpu_add_return(pcp, val) __pcpu_size_call_return2(this_cpu_add_return_, pcp, val)
#endif
#define __this_cpu_sub_return(pcp, val) this_cpu_add_return(pcp, -(val))
#define __this_cpu_inc_return(pcp) this_cpu_add_return(pcp, 1)
#define __this_cpu_dec_return(pcp) this_cpu_add_return(pcp, -1)
#define __this_cpu_generic_xchg(pcp, nval) \
({ typeof(pcp) ret__; \
ret__ = __this_cpu_read(pcp); \
__this_cpu_write(pcp, nval); \
ret__; \
})
#ifndef __this_cpu_xchg
# ifndef __this_cpu_xchg_1
# define __this_cpu_xchg_1(pcp, nval) __this_cpu_generic_xchg(pcp, nval)
# endif
# ifndef __this_cpu_xchg_2
# define __this_cpu_xchg_2(pcp, nval) __this_cpu_generic_xchg(pcp, nval)
# endif
# ifndef __this_cpu_xchg_4
# define __this_cpu_xchg_4(pcp, nval) __this_cpu_generic_xchg(pcp, nval)
# endif
# ifndef __this_cpu_xchg_8
# define __this_cpu_xchg_8(pcp, nval) __this_cpu_generic_xchg(pcp, nval)
# endif
# define __this_cpu_xchg(pcp, nval) \
__pcpu_size_call_return2(__this_cpu_xchg_, (pcp), nval)
#endif
#define __this_cpu_generic_cmpxchg(pcp, oval, nval) \
({ \
typeof(pcp) ret__; \
ret__ = __this_cpu_read(pcp); \
if (ret__ == (oval)) \
__this_cpu_write(pcp, nval); \
ret__; \
})
#ifndef __this_cpu_cmpxchg
# ifndef __this_cpu_cmpxchg_1
# define __this_cpu_cmpxchg_1(pcp, oval, nval) __this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef __this_cpu_cmpxchg_2
# define __this_cpu_cmpxchg_2(pcp, oval, nval) __this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef __this_cpu_cmpxchg_4
# define __this_cpu_cmpxchg_4(pcp, oval, nval) __this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef __this_cpu_cmpxchg_8
# define __this_cpu_cmpxchg_8(pcp, oval, nval) __this_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# define __this_cpu_cmpxchg(pcp, oval, nval) \
__pcpu_size_call_return2(__this_cpu_cmpxchg_, pcp, oval, nval)
#endif
#define __this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
({ \
int __ret = 0; \
if (__this_cpu_read(pcp1) == (oval1) && \
__this_cpu_read(pcp2) == (oval2)) { \
__this_cpu_write(pcp1, (nval1)); \
__this_cpu_write(pcp2, (nval2)); \
__ret = 1; \
} \
(__ret); \
})
#ifndef __this_cpu_cmpxchg_double
# ifndef __this_cpu_cmpxchg_double_1
# define __this_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \
__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef __this_cpu_cmpxchg_double_2
# define __this_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2) \
__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef __this_cpu_cmpxchg_double_4
# define __this_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2) \
__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef __this_cpu_cmpxchg_double_8
# define __this_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2) \
__this_cpu_generic_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# define __this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
__pcpu_double_call_return_bool(__this_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
#endif
/*
* IRQ safe versions of the per cpu RMW operations. Note that these operations
* are *not* safe against modification of the same variable from another
* processors (which one gets when using regular atomic operations)
* They are guaranteed to be atomic vs. local interrupts and
* preemption only.
*/
#define irqsafe_cpu_generic_to_op(pcp, val, op) \
do { \
unsigned long flags; \
local_irq_save(flags); \
*__this_cpu_ptr(&(pcp)) op val; \
local_irq_restore(flags); \
} while (0)
#ifndef irqsafe_cpu_add
# ifndef irqsafe_cpu_add_1
# define irqsafe_cpu_add_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef irqsafe_cpu_add_2
# define irqsafe_cpu_add_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef irqsafe_cpu_add_4
# define irqsafe_cpu_add_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# ifndef irqsafe_cpu_add_8
# define irqsafe_cpu_add_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), +=)
# endif
# define irqsafe_cpu_add(pcp, val) __pcpu_size_call(irqsafe_cpu_add_, (pcp), (val))
#endif
#ifndef irqsafe_cpu_sub
# define irqsafe_cpu_sub(pcp, val) irqsafe_cpu_add((pcp), -(val))
#endif
#ifndef irqsafe_cpu_inc
# define irqsafe_cpu_inc(pcp) irqsafe_cpu_add((pcp), 1)
#endif
#ifndef irqsafe_cpu_dec
# define irqsafe_cpu_dec(pcp) irqsafe_cpu_sub((pcp), 1)
#endif
#ifndef irqsafe_cpu_and
# ifndef irqsafe_cpu_and_1
# define irqsafe_cpu_and_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef irqsafe_cpu_and_2
# define irqsafe_cpu_and_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef irqsafe_cpu_and_4
# define irqsafe_cpu_and_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# ifndef irqsafe_cpu_and_8
# define irqsafe_cpu_and_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), &=)
# endif
# define irqsafe_cpu_and(pcp, val) __pcpu_size_call(irqsafe_cpu_and_, (val))
#endif
#ifndef irqsafe_cpu_or
# ifndef irqsafe_cpu_or_1
# define irqsafe_cpu_or_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef irqsafe_cpu_or_2
# define irqsafe_cpu_or_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef irqsafe_cpu_or_4
# define irqsafe_cpu_or_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# ifndef irqsafe_cpu_or_8
# define irqsafe_cpu_or_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), |=)
# endif
# define irqsafe_cpu_or(pcp, val) __pcpu_size_call(irqsafe_cpu_or_, (val))
#endif
#ifndef irqsafe_cpu_xor
# ifndef irqsafe_cpu_xor_1
# define irqsafe_cpu_xor_1(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef irqsafe_cpu_xor_2
# define irqsafe_cpu_xor_2(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef irqsafe_cpu_xor_4
# define irqsafe_cpu_xor_4(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# ifndef irqsafe_cpu_xor_8
# define irqsafe_cpu_xor_8(pcp, val) irqsafe_cpu_generic_to_op((pcp), (val), ^=)
# endif
# define irqsafe_cpu_xor(pcp, val) __pcpu_size_call(irqsafe_cpu_xor_, (val))
#endif
#define irqsafe_cpu_generic_cmpxchg(pcp, oval, nval) \
({ \
typeof(pcp) ret__; \
unsigned long flags; \
local_irq_save(flags); \
ret__ = __this_cpu_read(pcp); \
if (ret__ == (oval)) \
__this_cpu_write(pcp, nval); \
local_irq_restore(flags); \
ret__; \
})
#ifndef irqsafe_cpu_cmpxchg
# ifndef irqsafe_cpu_cmpxchg_1
# define irqsafe_cpu_cmpxchg_1(pcp, oval, nval) irqsafe_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef irqsafe_cpu_cmpxchg_2
# define irqsafe_cpu_cmpxchg_2(pcp, oval, nval) irqsafe_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef irqsafe_cpu_cmpxchg_4
# define irqsafe_cpu_cmpxchg_4(pcp, oval, nval) irqsafe_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# ifndef irqsafe_cpu_cmpxchg_8
# define irqsafe_cpu_cmpxchg_8(pcp, oval, nval) irqsafe_cpu_generic_cmpxchg(pcp, oval, nval)
# endif
# define irqsafe_cpu_cmpxchg(pcp, oval, nval) \
__pcpu_size_call_return2(irqsafe_cpu_cmpxchg_, (pcp), oval, nval)
#endif
#define irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
({ \
int ret__; \
unsigned long flags; \
local_irq_save(flags); \
ret__ = __this_cpu_generic_cmpxchg_double(pcp1, pcp2, \
oval1, oval2, nval1, nval2); \
local_irq_restore(flags); \
ret__; \
})
#ifndef irqsafe_cpu_cmpxchg_double
# ifndef irqsafe_cpu_cmpxchg_double_1
# define irqsafe_cpu_cmpxchg_double_1(pcp1, pcp2, oval1, oval2, nval1, nval2) \
irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef irqsafe_cpu_cmpxchg_double_2
# define irqsafe_cpu_cmpxchg_double_2(pcp1, pcp2, oval1, oval2, nval1, nval2) \
irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef irqsafe_cpu_cmpxchg_double_4
# define irqsafe_cpu_cmpxchg_double_4(pcp1, pcp2, oval1, oval2, nval1, nval2) \
irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# ifndef irqsafe_cpu_cmpxchg_double_8
# define irqsafe_cpu_cmpxchg_double_8(pcp1, pcp2, oval1, oval2, nval1, nval2) \
irqsafe_generic_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)
# endif
# define irqsafe_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2) \
__pcpu_double_call_return_bool(irqsafe_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))
#endif
#endif /* __LINUX_PERCPU_H */
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