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author | Cesar Eduardo Barros <cesarb@cesarb.net> | 2010-08-09 17:18:32 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2010-08-09 20:44:54 -0700 |
commit | 597781f3e51f48ef8e67be772196d9e9673752c4 (patch) | |
tree | 6e1974bc899889da40f2fde47b04a5ece0bd3399 /arch | |
parent | 3edd4fc9537d95e460d502987c63a90d6b9a7a82 (diff) | |
download | op-kernel-dev-597781f3e51f48ef8e67be772196d9e9673752c4.zip op-kernel-dev-597781f3e51f48ef8e67be772196d9e9673752c4.tar.gz |
kmap_atomic: make kunmap_atomic() harder to misuse
kunmap_atomic() is currently at level -4 on Rusty's "Hard To Misuse"
list[1] ("Follow common convention and you'll get it wrong"), except in
some architectures when CONFIG_DEBUG_HIGHMEM is set[2][3].
kunmap() takes a pointer to a struct page; kunmap_atomic(), however, takes
takes a pointer to within the page itself. This seems to once in a while
trip people up (the convention they are following is the one from
kunmap()).
Make it much harder to misuse, by moving it to level 9 on Rusty's list[4]
("The compiler/linker won't let you get it wrong"). This is done by
refusing to build if the type of its first argument is a pointer to a
struct page.
The real kunmap_atomic() is renamed to kunmap_atomic_notypecheck()
(which is what you would call in case for some strange reason calling it
with a pointer to a struct page is not incorrect in your code).
The previous version of this patch was compile tested on x86-64.
[1] http://ozlabs.org/~rusty/index.cgi/tech/2008-04-01.html
[2] In these cases, it is at level 5, "Do it right or it will always
break at runtime."
[3] At least mips and powerpc look very similar, and sparc also seems to
share a common ancestor with both; there seems to be quite some
degree of copy-and-paste coding here. The include/asm/highmem.h file
for these three archs mention x86 CPUs at its top.
[4] http://ozlabs.org/~rusty/index.cgi/tech/2008-03-30.html
[5] As an aside, could someone tell me why mn10300 uses unsigned long as
the first parameter of kunmap_atomic() instead of void *?
Signed-off-by: Cesar Eduardo Barros <cesarb@cesarb.net>
Cc: Russell King <linux@arm.linux.org.uk> (arch/arm)
Cc: Ralf Baechle <ralf@linux-mips.org> (arch/mips)
Cc: David Howells <dhowells@redhat.com> (arch/frv, arch/mn10300)
Cc: Koichi Yasutake <yasutake.koichi@jp.panasonic.com> (arch/mn10300)
Cc: Kyle McMartin <kyle@mcmartin.ca> (arch/parisc)
Cc: Helge Deller <deller@gmx.de> (arch/parisc)
Cc: "James E.J. Bottomley" <jejb@parisc-linux.org> (arch/parisc)
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> (arch/powerpc)
Cc: Paul Mackerras <paulus@samba.org> (arch/powerpc)
Cc: "David S. Miller" <davem@davemloft.net> (arch/sparc)
Cc: Thomas Gleixner <tglx@linutronix.de> (arch/x86)
Cc: Ingo Molnar <mingo@redhat.com> (arch/x86)
Cc: "H. Peter Anvin" <hpa@zytor.com> (arch/x86)
Cc: Arnd Bergmann <arnd@arndb.de> (include/asm-generic)
Cc: Rusty Russell <rusty@rustcorp.com.au> ("Hard To Misuse" list)
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch')
-rw-r--r-- | arch/arm/include/asm/highmem.h | 2 | ||||
-rw-r--r-- | arch/arm/mm/highmem.c | 4 | ||||
-rw-r--r-- | arch/frv/include/asm/highmem.h | 2 | ||||
-rw-r--r-- | arch/mips/include/asm/highmem.h | 4 | ||||
-rw-r--r-- | arch/mips/mm/highmem.c | 4 | ||||
-rw-r--r-- | arch/mn10300/include/asm/highmem.h | 2 | ||||
-rw-r--r-- | arch/parisc/include/asm/cacheflush.h | 2 | ||||
-rw-r--r-- | arch/powerpc/include/asm/highmem.h | 2 | ||||
-rw-r--r-- | arch/powerpc/mm/highmem.c | 4 | ||||
-rw-r--r-- | arch/sparc/include/asm/highmem.h | 2 | ||||
-rw-r--r-- | arch/sparc/mm/highmem.c | 4 | ||||
-rw-r--r-- | arch/x86/include/asm/highmem.h | 2 | ||||
-rw-r--r-- | arch/x86/mm/highmem_32.c | 4 |
13 files changed, 19 insertions, 19 deletions
diff --git a/arch/arm/include/asm/highmem.h b/arch/arm/include/asm/highmem.h index feb988a..5aff581 100644 --- a/arch/arm/include/asm/highmem.h +++ b/arch/arm/include/asm/highmem.h @@ -36,7 +36,7 @@ extern void kunmap_high_l1_vipt(struct page *page, pte_t saved_pte); extern void *kmap(struct page *page); extern void kunmap(struct page *page); extern void *kmap_atomic(struct page *page, enum km_type type); -extern void kunmap_atomic(void *kvaddr, enum km_type type); +extern void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type); extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type); extern struct page *kmap_atomic_to_page(const void *ptr); #endif diff --git a/arch/arm/mm/highmem.c b/arch/arm/mm/highmem.c index 6ab2440..1fbdb55 100644 --- a/arch/arm/mm/highmem.c +++ b/arch/arm/mm/highmem.c @@ -82,7 +82,7 @@ void *kmap_atomic(struct page *page, enum km_type type) } EXPORT_SYMBOL(kmap_atomic); -void kunmap_atomic(void *kvaddr, enum km_type type) +void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type) { unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; unsigned int idx = type + KM_TYPE_NR * smp_processor_id(); @@ -103,7 +103,7 @@ void kunmap_atomic(void *kvaddr, enum km_type type) } pagefault_enable(); } -EXPORT_SYMBOL(kunmap_atomic); +EXPORT_SYMBOL(kunmap_atomic_notypecheck); void *kmap_atomic_pfn(unsigned long pfn, enum km_type type) { diff --git a/arch/frv/include/asm/highmem.h b/arch/frv/include/asm/highmem.h index 68e4677..cb4c317 100644 --- a/arch/frv/include/asm/highmem.h +++ b/arch/frv/include/asm/highmem.h @@ -152,7 +152,7 @@ do { \ asm volatile("tlbpr %0,gr0,#4,#1" : : "r"(vaddr) : "memory"); \ } while(0) -static inline void kunmap_atomic(void *kvaddr, enum km_type type) +static inline void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type) { switch (type) { case 0: __kunmap_atomic_primary(0, 2); break; diff --git a/arch/mips/include/asm/highmem.h b/arch/mips/include/asm/highmem.h index 25adfb0..75753ca 100644 --- a/arch/mips/include/asm/highmem.h +++ b/arch/mips/include/asm/highmem.h @@ -48,14 +48,14 @@ extern void kunmap_high(struct page *page); extern void *__kmap(struct page *page); extern void __kunmap(struct page *page); extern void *__kmap_atomic(struct page *page, enum km_type type); -extern void __kunmap_atomic(void *kvaddr, enum km_type type); +extern void __kunmap_atomic_notypecheck(void *kvaddr, enum km_type type); extern void *kmap_atomic_pfn(unsigned long pfn, enum km_type type); extern struct page *__kmap_atomic_to_page(void *ptr); #define kmap __kmap #define kunmap __kunmap #define kmap_atomic __kmap_atomic -#define kunmap_atomic __kunmap_atomic +#define kunmap_atomic_notypecheck __kunmap_atomic_notypecheck #define kmap_atomic_to_page __kmap_atomic_to_page #define flush_cache_kmaps() flush_cache_all() diff --git a/arch/mips/mm/highmem.c b/arch/mips/mm/highmem.c index 127d732..6a2b1bf 100644 --- a/arch/mips/mm/highmem.c +++ b/arch/mips/mm/highmem.c @@ -64,7 +64,7 @@ void *__kmap_atomic(struct page *page, enum km_type type) } EXPORT_SYMBOL(__kmap_atomic); -void __kunmap_atomic(void *kvaddr, enum km_type type) +void __kunmap_atomic_notypecheck(void *kvaddr, enum km_type type) { #ifdef CONFIG_DEBUG_HIGHMEM unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; @@ -87,7 +87,7 @@ void __kunmap_atomic(void *kvaddr, enum km_type type) pagefault_enable(); } -EXPORT_SYMBOL(__kunmap_atomic); +EXPORT_SYMBOL(__kunmap_atomic_notypecheck); /* * This is the same as kmap_atomic() but can map memory that doesn't diff --git a/arch/mn10300/include/asm/highmem.h b/arch/mn10300/include/asm/highmem.h index 90f2abb..b0b187a 100644 --- a/arch/mn10300/include/asm/highmem.h +++ b/arch/mn10300/include/asm/highmem.h @@ -91,7 +91,7 @@ static inline unsigned long kmap_atomic(struct page *page, enum km_type type) return vaddr; } -static inline void kunmap_atomic(unsigned long vaddr, enum km_type type) +static inline void kunmap_atomic_notypecheck(unsigned long vaddr, enum km_type type) { #if HIGHMEM_DEBUG enum fixed_addresses idx = type + KM_TYPE_NR * smp_processor_id(); diff --git a/arch/parisc/include/asm/cacheflush.h b/arch/parisc/include/asm/cacheflush.h index 4556d82..dba11ae 100644 --- a/arch/parisc/include/asm/cacheflush.h +++ b/arch/parisc/include/asm/cacheflush.h @@ -132,7 +132,7 @@ static inline void *kmap_atomic(struct page *page, enum km_type idx) return page_address(page); } -static inline void kunmap_atomic(void *addr, enum km_type idx) +static inline void kunmap_atomic_notypecheck(void *addr, enum km_type idx) { kunmap_parisc(addr); pagefault_enable(); diff --git a/arch/powerpc/include/asm/highmem.h b/arch/powerpc/include/asm/highmem.h index a74c4ee..d10d64a 100644 --- a/arch/powerpc/include/asm/highmem.h +++ b/arch/powerpc/include/asm/highmem.h @@ -62,7 +62,7 @@ extern void *kmap_high(struct page *page); extern void kunmap_high(struct page *page); extern void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot); -extern void kunmap_atomic(void *kvaddr, enum km_type type); +extern void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type); static inline void *kmap(struct page *page) { diff --git a/arch/powerpc/mm/highmem.c b/arch/powerpc/mm/highmem.c index c2186c7..857d417 100644 --- a/arch/powerpc/mm/highmem.c +++ b/arch/powerpc/mm/highmem.c @@ -52,7 +52,7 @@ void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot) } EXPORT_SYMBOL(kmap_atomic_prot); -void kunmap_atomic(void *kvaddr, enum km_type type) +void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type) { #ifdef CONFIG_DEBUG_HIGHMEM unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; @@ -74,4 +74,4 @@ void kunmap_atomic(void *kvaddr, enum km_type type) #endif pagefault_enable(); } -EXPORT_SYMBOL(kunmap_atomic); +EXPORT_SYMBOL(kunmap_atomic_notypecheck); diff --git a/arch/sparc/include/asm/highmem.h b/arch/sparc/include/asm/highmem.h index 3de42e7..ec23b0a 100644 --- a/arch/sparc/include/asm/highmem.h +++ b/arch/sparc/include/asm/highmem.h @@ -71,7 +71,7 @@ static inline void kunmap(struct page *page) } extern void *kmap_atomic(struct page *page, enum km_type type); -extern void kunmap_atomic(void *kvaddr, enum km_type type); +extern void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type); extern struct page *kmap_atomic_to_page(void *vaddr); #define flush_cache_kmaps() flush_cache_all() diff --git a/arch/sparc/mm/highmem.c b/arch/sparc/mm/highmem.c index 7916feb..e139e9c 100644 --- a/arch/sparc/mm/highmem.c +++ b/arch/sparc/mm/highmem.c @@ -65,7 +65,7 @@ void *kmap_atomic(struct page *page, enum km_type type) } EXPORT_SYMBOL(kmap_atomic); -void kunmap_atomic(void *kvaddr, enum km_type type) +void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type) { #ifdef CONFIG_DEBUG_HIGHMEM unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; @@ -100,7 +100,7 @@ void kunmap_atomic(void *kvaddr, enum km_type type) pagefault_enable(); } -EXPORT_SYMBOL(kunmap_atomic); +EXPORT_SYMBOL(kunmap_atomic_notypecheck); /* We may be fed a pagetable here by ptep_to_xxx and others. */ struct page *kmap_atomic_to_page(void *ptr) diff --git a/arch/x86/include/asm/highmem.h b/arch/x86/include/asm/highmem.h index a726650..8caac76 100644 --- a/arch/x86/include/asm/highmem.h +++ b/arch/x86/include/asm/highmem.h @@ -61,7 +61,7 @@ void *kmap(struct page *page); void kunmap(struct page *page); void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot); void *kmap_atomic(struct page *page, enum km_type type); -void kunmap_atomic(void *kvaddr, enum km_type type); +void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type); void *kmap_atomic_pfn(unsigned long pfn, enum km_type type); void *kmap_atomic_prot_pfn(unsigned long pfn, enum km_type type, pgprot_t prot); struct page *kmap_atomic_to_page(void *ptr); diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c index 63a6ba6..5e8fa12 100644 --- a/arch/x86/mm/highmem_32.c +++ b/arch/x86/mm/highmem_32.c @@ -53,7 +53,7 @@ void *kmap_atomic(struct page *page, enum km_type type) return kmap_atomic_prot(page, type, kmap_prot); } -void kunmap_atomic(void *kvaddr, enum km_type type) +void kunmap_atomic_notypecheck(void *kvaddr, enum km_type type) { unsigned long vaddr = (unsigned long) kvaddr & PAGE_MASK; enum fixed_addresses idx = type + KM_TYPE_NR*smp_processor_id(); @@ -102,7 +102,7 @@ struct page *kmap_atomic_to_page(void *ptr) EXPORT_SYMBOL(kmap); EXPORT_SYMBOL(kunmap); EXPORT_SYMBOL(kmap_atomic); -EXPORT_SYMBOL(kunmap_atomic); +EXPORT_SYMBOL(kunmap_atomic_notypecheck); EXPORT_SYMBOL(kmap_atomic_prot); EXPORT_SYMBOL(kmap_atomic_to_page); |