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@xxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: Leonid Yegoshin <leonid.yegoshin@xxxxxxxxxx>
Cc: Manuel Lauss <manuel.lauss@xxxxxxxxx>
Cc: linux-mips@xxxxxxxxxxxxxx
---
arch/mips/mm/c-r4k.c | 11 +++++++++--
arch/mips/mm/init.c | 2 +-
2 files changed, 10 insertions(+), 3 deletions(-)
diff --git a/arch/mips/mm/c-r4k.c b/arch/mips/mm/c-r4k.c
index caac3d747a90..fc7289dfaf5a 100644
--- a/arch/mips/mm/c-r4k.c
+++ b/arch/mips/mm/c-r4k.c
@@ -492,7 +492,14 @@ static inline void local_r4k_flush_cache_range(void * args)
if (!(has_valid_asid(vma->vm_mm)))
return;
- r4k_blast_dcache();
+ /*
+ * If dcache can alias, we must blast it since mapping is changing.
+ * If executable, we must ensure any dirty lines are written back far
+ * enough to be visible to icache.
+ */
+ if (cpu_has_dc_aliases || (exec && !cpu_has_ic_fills_f_dc))
+ r4k_blast_dcache();
+ /* If executable, blast stale lines from icache */
if (exec)
r4k_blast_icache();
}
@@ -502,7 +509,7 @@ static void r4k_flush_cache_range(struct vm_area_struct *vma,
{
int exec = vma->vm_flags & VM_EXEC;
- if (cpu_has_dc_aliases || (exec && !cpu_has_ic_fills_f_dc))
+ if (cpu_has_dc_aliases || exec)
r4k_on_each_cpu(local_r4k_flush_cache_range, vma);
}
diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c
index 7e5fa0938c21..6c6a843b0d17 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));
}
--
2.4.10
