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author | Alexandre Ghiti <alexghiti@rivosinc.com> | 2023-08-09 18:46:33 +0200 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-08-30 16:11:06 +0200 |
commit | 07fad410aa6e90131cd1ba8d12bd1f9488f85af5 (patch) | |
tree | fecc8bdb7982eb723d033f2d4a74300bf1e6721d /mm | |
parent | a8a60bc8027e099b8dd9e13b49b393db2d940004 (diff) | |
download | linux-07fad410aa6e90131cd1ba8d12bd1f9488f85af5.tar.gz |
mm: add a call to flush_cache_vmap() in vmap_pfn()
commit a50420c79731fc5cf27ad43719c1091e842a2606 upstream. flush_cache_vmap() must be called after new vmalloc mappings are installed in the page table in order to allow architectures to make sure the new mapping is visible. It could lead to a panic since on some architectures (like powerpc), the page table walker could see the wrong pte value and trigger a spurious page fault that can not be resolved (see commit f1cb8f9beba8 ("powerpc/64s/radix: avoid ptesync after set_pte and ptep_set_access_flags")). But actually the patch is aiming at riscv: the riscv specification allows the caching of invalid entries in the TLB, and since we recently removed the vmalloc page fault handling, we now need to emit a tlb shootdown whenever a new vmalloc mapping is emitted (https://lore.kernel.org/linux-riscv/20230725132246.817726-1-alexghiti@rivosinc.com/). That's a temporary solution, there are ways to avoid that :) Link: https://lkml.kernel.org/r/20230809164633.1556126-1-alexghiti@rivosinc.com Fixes: 3e9a9e256b1e ("mm: add a vmap_pfn function") Reported-by: Dylan Jhong <dylan@andestech.com> Closes: https://lore.kernel.org/linux-riscv/ZMytNY2J8iyjbPPy@atctrx.andestech.com/ Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Palmer Dabbelt <palmer@rivosinc.com> Acked-by: Palmer Dabbelt <palmer@rivosinc.com> Reviewed-by: Dylan Jhong <dylan@andestech.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/vmalloc.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d5dc361dc104..80bd104a4d42 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2909,6 +2909,10 @@ void *vmap_pfn(unsigned long *pfns, unsigned int count, pgprot_t prot) free_vm_area(area); return NULL; } + + flush_cache_vmap((unsigned long)area->addr, + (unsigned long)area->addr + count * PAGE_SIZE); + return area->addr; } EXPORT_SYMBOL_GPL(vmap_pfn); |