diff options
| author | Venki Pallipadi <venkatesh.pallipadi@intel.com> | 2008-04-26 11:32:12 -0700 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-04-26 21:28:29 +0200 |
| commit | 0124cecfc85a6664b1ad5f1d28cf0ab8df66fc42 (patch) | |
| tree | dfbbb8cf4a294ed52dc9a224ccb57ea601d25532 | |
| parent | 4a27214d7be31e122db4102166f49ec15958e8e9 (diff) | |
x86, PAT: disable /dev/mem mmap RAM with PAT
disable /dev/mem mmap of RAM with PAT. It makes things safer and
eliminates aliasing. A future improvement would be to avoid the
range_is_allowed duplication.
Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/mm/pat.c | 31 |
1 files changed, 31 insertions, 0 deletions
diff --git a/arch/x86/mm/pat.c b/arch/x86/mm/pat.c index 9851265e4d6..e7ca7fc48d1 100644 --- a/arch/x86/mm/pat.c +++ b/arch/x86/mm/pat.c @@ -16,6 +16,7 @@ #include <asm/msr.h> #include <asm/tlbflush.h> #include <asm/processor.h> +#include <asm/page.h> #include <asm/pgtable.h> #include <asm/pat.h> #include <asm/e820.h> @@ -477,6 +478,33 @@ pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, return vma_prot; } +#ifdef CONFIG_NONPROMISC_DEVMEM +/* This check is done in drivers/char/mem.c in case of NONPROMISC_DEVMEM*/ +static inline int range_is_allowed(unsigned long pfn, unsigned long size) +{ + return 1; +} +#else +static inline int range_is_allowed(unsigned long pfn, unsigned long size) +{ + u64 from = ((u64)pfn) << PAGE_SHIFT; + u64 to = from + size; + u64 cursor = from; + + while (cursor < to) { + if (!devmem_is_allowed(pfn)) { + printk(KERN_INFO + "Program %s tried to access /dev/mem between %Lx->%Lx.\n", + current->comm, from, to); + return 0; + } + cursor += PAGE_SIZE; + pfn++; + } + return 1; +} +#endif /* CONFIG_NONPROMISC_DEVMEM */ + int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, unsigned long size, pgprot_t *vma_prot) { @@ -485,6 +513,9 @@ int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, unsigned long ret_flags; int retval; + if (!range_is_allowed(pfn, size)) + return 0; + if (file->f_flags & O_SYNC) { flags = _PAGE_CACHE_UC; } |