1
linux/arch/parisc/include/asm/cacheflush.h
Cesar Eduardo Barros 597781f3e5 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>
2010-08-09 20:44:54 -07:00

148 lines
4.4 KiB
C

#ifndef _PARISC_CACHEFLUSH_H
#define _PARISC_CACHEFLUSH_H
#include <linux/mm.h>
#include <linux/uaccess.h>
/* The usual comment is "Caches aren't brain-dead on the <architecture>".
* Unfortunately, that doesn't apply to PA-RISC. */
/* Internal implementation */
void flush_data_cache_local(void *); /* flushes local data-cache only */
void flush_instruction_cache_local(void *); /* flushes local code-cache only */
#ifdef CONFIG_SMP
void flush_data_cache(void); /* flushes data-cache only (all processors) */
void flush_instruction_cache(void); /* flushes i-cache only (all processors) */
#else
#define flush_data_cache() flush_data_cache_local(NULL)
#define flush_instruction_cache() flush_instruction_cache_local(NULL)
#endif
#define flush_cache_dup_mm(mm) flush_cache_mm(mm)
void flush_user_icache_range_asm(unsigned long, unsigned long);
void flush_kernel_icache_range_asm(unsigned long, unsigned long);
void flush_user_dcache_range_asm(unsigned long, unsigned long);
void flush_kernel_dcache_range_asm(unsigned long, unsigned long);
void flush_kernel_dcache_page_asm(void *);
void flush_kernel_icache_page(void *);
void flush_user_dcache_page(unsigned long);
void flush_user_icache_page(unsigned long);
void flush_user_dcache_range(unsigned long, unsigned long);
void flush_user_icache_range(unsigned long, unsigned long);
/* Cache flush operations */
void flush_cache_all_local(void);
void flush_cache_all(void);
void flush_cache_mm(struct mm_struct *mm);
#define flush_kernel_dcache_range(start,size) \
flush_kernel_dcache_range_asm((start), (start)+(size));
/* vmap range flushes and invalidates. Architecturally, we don't need
* the invalidate, because the CPU should refuse to speculate once an
* area has been flushed, so invalidate is left empty */
static inline void flush_kernel_vmap_range(void *vaddr, int size)
{
unsigned long start = (unsigned long)vaddr;
flush_kernel_dcache_range_asm(start, start + size);
}
static inline void invalidate_kernel_vmap_range(void *vaddr, int size)
{
}
#define flush_cache_vmap(start, end) flush_cache_all()
#define flush_cache_vunmap(start, end) flush_cache_all()
#define ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE 1
extern void flush_dcache_page(struct page *page);
#define flush_dcache_mmap_lock(mapping) \
spin_lock_irq(&(mapping)->tree_lock)
#define flush_dcache_mmap_unlock(mapping) \
spin_unlock_irq(&(mapping)->tree_lock)
#define flush_icache_page(vma,page) do { \
flush_kernel_dcache_page(page); \
flush_kernel_icache_page(page_address(page)); \
} while (0)
#define flush_icache_range(s,e) do { \
flush_kernel_dcache_range_asm(s,e); \
flush_kernel_icache_range_asm(s,e); \
} while (0)
#define copy_to_user_page(vma, page, vaddr, dst, src, len) \
do { \
flush_cache_page(vma, vaddr, page_to_pfn(page)); \
memcpy(dst, src, len); \
flush_kernel_dcache_range_asm((unsigned long)dst, (unsigned long)dst + len); \
} while (0)
#define copy_from_user_page(vma, page, vaddr, dst, src, len) \
do { \
flush_cache_page(vma, vaddr, page_to_pfn(page)); \
memcpy(dst, src, len); \
} while (0)
void flush_cache_page(struct vm_area_struct *vma, unsigned long vmaddr, unsigned long pfn);
void flush_cache_range(struct vm_area_struct *vma,
unsigned long start, unsigned long end);
#define ARCH_HAS_FLUSH_ANON_PAGE
static inline void
flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned long vmaddr)
{
if (PageAnon(page))
flush_user_dcache_page(vmaddr);
}
#define ARCH_HAS_FLUSH_KERNEL_DCACHE_PAGE
void flush_kernel_dcache_page_addr(void *addr);
static inline void flush_kernel_dcache_page(struct page *page)
{
flush_kernel_dcache_page_addr(page_address(page));
}
#ifdef CONFIG_DEBUG_RODATA
void mark_rodata_ro(void);
#endif
#ifdef CONFIG_PA8X00
/* Only pa8800, pa8900 needs this */
#include <asm/kmap_types.h>
#define ARCH_HAS_KMAP
void kunmap_parisc(void *addr);
static inline void *kmap(struct page *page)
{
might_sleep();
return page_address(page);
}
#define kunmap(page) kunmap_parisc(page_address(page))
static inline void *kmap_atomic(struct page *page, enum km_type idx)
{
pagefault_disable();
return page_address(page);
}
static inline void kunmap_atomic_notypecheck(void *addr, enum km_type idx)
{
kunmap_parisc(addr);
pagefault_enable();
}
#define kmap_atomic_prot(page, idx, prot) kmap_atomic(page, idx)
#define kmap_atomic_pfn(pfn, idx) kmap_atomic(pfn_to_page(pfn), (idx))
#define kmap_atomic_to_page(ptr) virt_to_page(ptr)
#endif
#endif /* _PARISC_CACHEFLUSH_H */