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Commit 188a8140 authored by Christoph Lameter's avatar Christoph Lameter Committed by Linus Torvalds
Browse files

percpu: add preemption checks to __this_cpu ops 



We define a check function in order to avoid trouble with the include
files.  Then the higher level __this_cpu macros are modified to invoke
the preemption check.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: default avatarChristoph Lameter <cl@linux.com>
Acked-by: default avatarIngo Molnar <mingo@kernel.org>
Cc: Tejun Heo <tj@kernel.org>
Tested-by: default avatarGrygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 293b6a4c

include/linux/percpu.h

+29 −10
Original line number Diff line number Diff line
@@ -173,6 +173,12 @@ extern phys_addr_t per_cpu_ptr_to_phys(void *addr); 


extern void __bad_size_call_parameter(void);



#ifdef CONFIG_DEBUG_PREEMPT

extern void __this_cpu_preempt_check(const char *op);

#else

static inline void __this_cpu_preempt_check(const char *op) { }

#endif



#define __pcpu_size_call_return(stem, variable)				\

({	typeof(variable) pscr_ret__;					\

	__verify_pcpu_ptr(&(variable));					\
@@ -725,18 +731,24 @@ do { \ 


/*

 * Generic percpu operations for context that are safe from preemption/interrupts.

 * Checks will be added here soon.

 */

#ifndef __this_cpu_read

# define __this_cpu_read(pcp)	__pcpu_size_call_return(raw_cpu_read_, (pcp))

# define __this_cpu_read(pcp) \

	(__this_cpu_preempt_check("read"),__pcpu_size_call_return(raw_cpu_read_, (pcp)))

#endif



#ifndef __this_cpu_write

# define __this_cpu_write(pcp, val)	__pcpu_size_call(raw_cpu_write_, (pcp), (val))

# define __this_cpu_write(pcp, val)					\

do { __this_cpu_preempt_check("write");					\

     __pcpu_size_call(raw_cpu_write_, (pcp), (val));			\

} while (0)

#endif



#ifndef __this_cpu_add

# define __this_cpu_add(pcp, val)	__pcpu_size_call(raw_cpu_add_, (pcp), (val))

# define __this_cpu_add(pcp, val)					 \

do { __this_cpu_preempt_check("add");					\

	__pcpu_size_call(raw_cpu_add_, (pcp), (val));			\

} while (0)

#endif



#ifndef __this_cpu_sub
@@ -752,16 +764,23 @@ do { \ 
#endif



#ifndef __this_cpu_and

# define __this_cpu_and(pcp, val)	__pcpu_size_call(raw_cpu_and_, (pcp), (val))

# define __this_cpu_and(pcp, val)					\

do { __this_cpu_preempt_check("and");					\

	__pcpu_size_call(raw_cpu_and_, (pcp), (val));			\

} while (0)



#endif



#ifndef __this_cpu_or

# define __this_cpu_or(pcp, val)	__pcpu_size_call(raw_cpu_or_, (pcp), (val))

# define __this_cpu_or(pcp, val)					\

do { __this_cpu_preempt_check("or");					\

	__pcpu_size_call(raw_cpu_or_, (pcp), (val));			\

} while (0)

#endif



#ifndef __this_cpu_add_return

# define __this_cpu_add_return(pcp, val)	\

	__pcpu_size_call_return2(raw_cpu_add_return_, pcp, val)

	(__this_cpu_preempt_check("add_return"),__pcpu_size_call_return2(raw_cpu_add_return_, pcp, val))

#endif



#define __this_cpu_sub_return(pcp, val)	__this_cpu_add_return(pcp, -(typeof(pcp))(val))
@@ -770,17 +789,17 @@ do { \ 


#ifndef __this_cpu_xchg

# define __this_cpu_xchg(pcp, nval)	\

	__pcpu_size_call_return2(raw_cpu_xchg_, (pcp), nval)

	(__this_cpu_preempt_check("xchg"),__pcpu_size_call_return2(raw_cpu_xchg_, (pcp), nval))

#endif



#ifndef __this_cpu_cmpxchg

# define __this_cpu_cmpxchg(pcp, oval, nval)	\

	__pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval)

	(__this_cpu_preempt_check("cmpxchg"),__pcpu_size_call_return2(raw_cpu_cmpxchg_, pcp, oval, nval))

#endif



#ifndef __this_cpu_cmpxchg_double

# define __this_cpu_cmpxchg_double(pcp1, pcp2, oval1, oval2, nval1, nval2)	\

	__pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2))

	(__this_cpu_preempt_check("cmpxchg_double"),__pcpu_double_call_return_bool(raw_cpu_cmpxchg_double_, (pcp1), (pcp2), (oval1), (oval2), (nval1), (nval2)))

#endif



#endif /* __LINUX_PERCPU_H */

lib/smp_processor_id.c

+14 −4
Original line number Diff line number Diff line
@@ -7,7 +7,8 @@ 
#include <linux/kallsyms.h>

#include <linux/sched.h>



notrace unsigned int debug_smp_processor_id(void)

notrace static unsigned int check_preemption_disabled(const char *what1,

							const char *what2)

{

	int this_cpu = raw_smp_processor_id();
@@ -38,9 +39,9 @@ notrace unsigned int debug_smp_processor_id(void) 
	if (!printk_ratelimit())

		goto out_enable;



	printk(KERN_ERR "BUG: using smp_processor_id() in preemptible [%08x] "

			"code: %s/%d\n",

			preempt_count() - 1, current->comm, current->pid);

	printk(KERN_ERR "BUG: using %s%s() in preemptible [%08x] code: %s/%d\n",

		what1, what2, preempt_count() - 1, current->comm, current->pid);



	print_symbol("caller is %s\n", (long)__builtin_return_address(0));

	dump_stack();
@@ -50,5 +51,14 @@ notrace unsigned int debug_smp_processor_id(void) 
	return this_cpu;

}



notrace unsigned int debug_smp_processor_id(void)

{

	return check_preemption_disabled("smp_processor_id", "");

}

EXPORT_SYMBOL(debug_smp_processor_id);



notrace void __this_cpu_preempt_check(const char *op)

{

	check_preemption_disabled("__this_cpu_", op);

}

EXPORT_SYMBOL(__this_cpu_preempt_check);