Commit c4e259c8 authored by Will Deacon's avatar Will Deacon Committed by Russell King
Browse files

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



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: default avatarWill Deacon <will.deacon@arm.com>
Signed-off-by: default avatarRussell King <rmk+kernel@arm.linux.org.uk>
parent 8925ec4c

arch/arm/mm/flush.c

+20 −3
Original line number Diff line number Diff line
@@ -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_icache_alias(pfn,vaddr,len)	do { } while (0)

#endif



static void flush_ptrace_access_other(void *args)
@@ -117,9 +131,12 @@ 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;

		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,

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