diff options
| author | John David Anglin <dave.anglin@bell.net> | 2021-11-08 16:48:16 -0500 |
|---|---|---|
| committer | Helge Deller <deller@gmx.de> | 2021-11-13 22:10:56 +0100 |
| commit | 38860b2c8bb1b92f61396eb06a63adff916fc31d (patch) | |
| tree | 121428c7e59fe17646c82b4fcd3196cf83b9ed68 /arch/parisc/kernel/cache.c | |
| parent | f0d1cfac45abb1c47792cda19ed680c30cee22bb (diff) | |
parisc: Flush kernel data mapping in set_pte_at() when installing pte for user page
For years, there have been random segmentation faults in userspace on
SMP PA-RISC machines. It occurred to me that this might be a problem in
set_pte_at(). MIPS and some other architectures do cache flushes when
installing PTEs with the present bit set.
Here I have adapted the code in update_mmu_cache() to flush the kernel
mapping when the kernel flush is deferred, or when the kernel mapping
may alias with the user mapping. This simplifies calls to
update_mmu_cache().
I also changed the barrier in set_pte() from a compiler barrier to a
full memory barrier. I know this change is not sufficient to fix the
problem. It might not be needed.
I have had a few days of operation with 5.14.16 to 5.15.1 and haven't
seen any random segmentation faults on rp3440 or c8000 so far.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Cc: stable@kernel.org # 5.12+
Diffstat (limited to 'arch/parisc/kernel/cache.c')
| -rw-r--r-- | arch/parisc/kernel/cache.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/parisc/kernel/cache.c b/arch/parisc/kernel/cache.c index c61827e4928a..94150b91c96f 100644 --- a/arch/parisc/kernel/cache.c +++ b/arch/parisc/kernel/cache.c @@ -83,9 +83,9 @@ EXPORT_SYMBOL(flush_cache_all_local); #define pfn_va(pfn) __va(PFN_PHYS(pfn)) void -update_mmu_cache(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) +__update_cache(pte_t pte) { - unsigned long pfn = pte_pfn(*ptep); + unsigned long pfn = pte_pfn(pte); struct page *page; /* We don't have pte special. As a result, we can be called with |