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riscv: Make VM_WRITE imply VM_READ

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commit 7ab72c597356be1e7f0f3d856e54ce78527f43c8 upstream.

RISC-V does not presently have write-only mappings as that PTE bit pattern
is considered reserved in the privileged spec, so allow handling of read
faults in VMAs that have VM_WRITE without VM_READ in order to be consistent
with other architectures that have similar limitations.

Fixes: 2139619bcad7 ("riscv: mmap with PROT_WRITE but no PROT_READ is invalid")
Reviewed-by: Atish Patra <atishp@rivosinc.com>
Signed-off-by: Andrew Bresticker <abrestic@rivosinc.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20220915193702.2201018-2-abrestic@rivosinc.com/
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Andrew Bresticker 2022-09-15 15:37:01 -04:00 committed by Greg Kroah-Hartman
parent d8c6f9b2e1
commit d15dca1d46
1 changed files with 2 additions and 1 deletions
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3
arch/riscv/mm/fault.c
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@ -167,7 +167,8 @@ static inline bool access_error(unsigned long cause, struct vm_area_struct *vma)
}
break;
case EXC_LOAD_PAGE_FAULT:
if (!(vma->vm_flags & VM_READ)) {
/* Write implies read */
if (!(vma->vm_flags & (VM_READ | VM_WRITE))) {
return true;
}
break;