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ARM: 6386/1: flush_ptrace_access: invalidate correct I-cache alias

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copy_to_user_page can be used by access_process_vm to write to an
executable page of a process using a mapping acquired by kmap.
For systems with I-cache aliasing, flushing the I-cache using the
Kernel mapping may leave stale data in the I-cache if the user
mapping is of a different colour.

This patch introduces a flush_icache_alias function to flush.c,
which calls flush_icache_range with a mapping of the specified
colour. flush_ptrace_access is then modified to call this new
function instead of coherent_kern_range in the case of an aliasing
I-cache and a non-aliasing D-cache.

Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This commit is contained in:
Will Deacon 2010-09-13 16:19:41 +01:00 committed by Russell King
parent 8925ec4c53
commit c4e259c859
1 changed files with 20 additions and 3 deletions
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23
arch/arm/mm/flush.c
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@ -40,6 +40,18 @@ static void flush_pfn_alias(unsigned long pfn, unsigned long vaddr)
: "cc");
}
static void flush_icache_alias(unsigned long pfn, unsigned long vaddr, unsigned long len)
{
unsigned long colour = CACHE_COLOUR(vaddr);
unsigned long offset = vaddr & (PAGE_SIZE - 1);
unsigned long to;
set_pte_ext(TOP_PTE(ALIAS_FLUSH_START) + colour, pfn_pte(pfn, PAGE_KERNEL), 0);
to = ALIAS_FLUSH_START + (colour << PAGE_SHIFT) + offset;
flush_tlb_kernel_page(to);
flush_icache_range(to, to + len);
}
void flush_cache_mm(struct mm_struct *mm)
{
if (cache_is_vivt()) {
@ -90,8 +102,10 @@ void flush_cache_page(struct vm_area_struct *vma, unsigned long user_addr, unsig
if (vma->vm_flags & VM_EXEC && icache_is_vivt_asid_tagged())
__flush_icache_all();
}
#else
#define flush_pfn_alias(pfn,vaddr) do { } while (0)
#define flush_pfn_alias(pfn,vaddr) do { } while (0)
#define flush_icache_alias(pfn,vaddr,len) do { } while (0)
#endif
static void flush_ptrace_access_other(void *args)
@ -117,10 +131,13 @@ void flush_ptrace_access(struct vm_area_struct *vma, struct page *page,
return;
}
/* VIPT non-aliasing cache */
/* VIPT non-aliasing D-cache */
if (vma->vm_flags & VM_EXEC) {
unsigned long addr = (unsigned long)kaddr;
__cpuc_coherent_kern_range(addr, addr + len);
if (icache_is_vipt_aliasing())
flush_icache_alias(page_to_pfn(page), uaddr, len);
else
__cpuc_coherent_kern_range(addr, addr + len);
if (cache_ops_need_broadcast())
smp_call_function(flush_ptrace_access_other,
NULL, 1);