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| author | John David Anglin <[email protected]> | 2021-11-08 21:48:16 +0000 |
|---|---|---|
| committer | Helge Deller <[email protected]> | 2021-11-13 21:10:56 +0000 |
| commit | 38860b2c8bb1b92f61396eb06a63adff916fc31d (patch) | |
| tree | 121428c7e59fe17646c82b4fcd3196cf83b9ed68 /drivers/fpga/xilinx-pr-decoupler.c | |
| parent | parisc: Fix implicit declaration of function '__kernel_text_address' (diff) | |
| download | kernel-38860b2c8bb1b92f61396eb06a63adff916fc31d.tar.gz kernel-38860b2c8bb1b92f61396eb06a63adff916fc31d.zip | |
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 <[email protected]>
Signed-off-by: Helge Deller <[email protected]>
Cc: [email protected] # 5.12+
Diffstat (limited to 'drivers/fpga/xilinx-pr-decoupler.c')
0 files changed, 0 insertions, 0 deletions