MIPS: c-r4k: Sync icache when it fills from dcache

It is still necessary to handle icache coherency in flush_cache_range()
and copy_to_user_page() when the icache fills from the dcache, even
though the dcache does not need to be written back. However when this
handling was added in commit 2eaa7ec286db ("[MIPS] Handle I-cache
coherency in flush_cache_range()"), it did not do any icache flushing
when it fills from dcache.

Therefore fix r4k_flush_cache_range() to run
local_r4k_flush_cache_range() without taking into account whether icache
fills from dcache, so that the icache coherency gets handled. Checks are
also added in local_r4k_flush_cache_range() so that the dcache blast
doesn't take place when icache fills from dcache.

A test to mmap a page PROT_READ|PROT_WRITE, modify code in it, and
mprotect it to VM_READ|VM_EXEC (similar to case described in above
commit) can hit this case quite easily to verify the fix.

A similar check was added in commit f8829caee311 ("[MIPS] Fix aliasing
bug in copy_to_user_page / copy_from_user_page"), so also fix
copy_to_user_page() similarly, to call flush_cache_page() without taking
into account whether icache fills from dcache, since flush_cache_page()
already takes that into account to avoid performing a dcache flush.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Leonid Yegoshin <leonid.yegoshin@imgtec.com>
Cc: Manuel Lauss <manuel.lauss@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12179/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 7e5fa09..6c6a843 100644
--- a/arch/mips/mm/init.c
+++ b/arch/mips/mm/init.c
@@ -196,7 +196,7 @@ void copy_to_user_page(struct vm_area_struct *vma,
 		if (cpu_has_dc_aliases)
 			SetPageDcacheDirty(page);
 	}
-	if ((vma->vm_flags & VM_EXEC) && !cpu_has_ic_fills_f_dc)
+	if (vma->vm_flags & VM_EXEC)
 		flush_cache_page(vma, vaddr, page_to_pfn(page));
 }