Commit 632bbfee authored by Jan Blunck's avatar Jan Blunck Committed by Linus Torvalds
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[PATCH] trigger a syntax error if percpu macros are incorrectly used 



get_cpu_var()/per_cpu()/__get_cpu_var() arguments must be simple
identifiers.  Otherwise the arch dependent implementations might break.

This patch enforces the correct usage of the macros by producing a syntax
error if the variable is not a simple identifier.

Signed-off-by: default avatarJan Blunck <jblunck@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 0a2966b4

include/asm-generic/percpu.h

+3 −1
Original line number Diff line number Diff line
@@ -14,7 +14,9 @@ extern unsigned long __per_cpu_offset[NR_CPUS]; 
    __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name



/* var is in discarded region: offset to particular copy we want */

#define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]))

#define per_cpu(var, cpu) (*({				\

	extern int simple_indentifier_##var(void);	\

	RELOC_HIDE(&per_cpu__##var, __per_cpu_offset[cpu]); }))

#define __get_cpu_var(var) per_cpu(var, smp_processor_id())

#define __raw_get_cpu_var(var) per_cpu(var, raw_smp_processor_id())

include/asm-s390/percpu.h

+11 −9
Original line number Diff line number Diff line
@@ -15,16 +15,18 @@ 
 */

#if defined(__s390x__) && defined(MODULE)



#define __reloc_hide(var,offset) \

  (*({ unsigned long *__ptr; \

#define __reloc_hide(var,offset) (*({			\

	extern int simple_indentifier_##var(void);	\

	unsigned long *__ptr;				\

	asm ( "larl %0,per_cpu__"#var"@GOTENT"		\

	    : "=a" (__ptr) : "X" (per_cpu__##var) );	\

	(typeof(&per_cpu__##var))((*__ptr) + (offset));	}))



#else



#define __reloc_hide(var, offset) \

  (*({ unsigned long __ptr; \

#define __reloc_hide(var, offset) (*({				\

	extern int simple_indentifier_##var(void);		\

	unsigned long __ptr;					\

	asm ( "" : "=a" (__ptr) : "0" (&per_cpu__##var) );	\

	(typeof(&per_cpu__##var)) (__ptr + (offset)); }))

include/asm-x86_64/percpu.h

+9 −3
Original line number Diff line number Diff line
@@ -21,9 +21,15 @@ 
    __attribute__((__section__(".data.percpu"))) __typeof__(type) per_cpu__##name



/* var is in discarded region: offset to particular copy we want */

#define per_cpu(var, cpu) (*RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)))

#define __get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))

#define __raw_get_cpu_var(var) (*RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()))

#define per_cpu(var, cpu) (*({				\

	extern int simple_indentifier_##var(void);	\

	RELOC_HIDE(&per_cpu__##var, __per_cpu_offset(cpu)); }))

#define __get_cpu_var(var) (*({				\

	extern int simple_indentifier_##var(void);	\

	RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()); }))

#define __raw_get_cpu_var(var) (*({			\

	extern int simple_indentifier_##var(void);	\

	RELOC_HIDE(&per_cpu__##var, __my_cpu_offset()); }))



/* A macro to avoid #include hell... */

#define percpu_modcopy(pcpudst, src, size)			\

include/linux/percpu.h

+8 −2
Original line number Diff line number Diff line
@@ -11,8 +11,14 @@ 
#define PERCPU_ENOUGH_ROOM 32768

#endif



/* Must be an lvalue. */

#define get_cpu_var(var) (*({ preempt_disable(); &__get_cpu_var(var); }))

/*

 * 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) (*({				\

	extern int simple_indentifier_##var(void);	\

	preempt_disable();				\

	&__get_cpu_var(var); }))

#define put_cpu_var(var) preempt_enable()



#ifdef CONFIG_SMP

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