Commit e9ed22e6 authored by John David Anglin's avatar John David Anglin Committed by Helge Deller

parisc: Fix flush_anon_page on PA8800/PA8900

Anonymous pages are allocated with the shared mappings colouring,
SHM_COLOUR. Since the alias boundary on machines with PA8800 and
PA8900 processors is unknown, flush_user_cache_page() might not
flush all mappings of a shared anonymous page. Flushing the whole
data cache flushes all mappings.

This won't fix all coherency issues with shared mappings but it
seems to work well in practice.  I haven't seen any random memory
faults in almost a month on a rp3440 running as a debian buildd
machine.

There is a small preformance hit.
Signed-off-by: default avatarJohn David Anglin <dave.anglin@bell.net>
Signed-off-by: default avatarHelge Deller <deller@gmx.de>
Cc: stable@vger.kernel.org   # v5.18+
parent d16c5c7c
...@@ -722,7 +722,10 @@ void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned lon ...@@ -722,7 +722,10 @@ void flush_anon_page(struct vm_area_struct *vma, struct page *page, unsigned lon
return; return;
if (parisc_requires_coherency()) { if (parisc_requires_coherency()) {
flush_user_cache_page(vma, vmaddr); if (vma->vm_flags & VM_SHARED)
flush_data_cache();
else
flush_user_cache_page(vma, vmaddr);
return; return;
} }
......
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