Unverified Commit 7ab72c59 authored Sep 15, 2022 by Andrew Bresticker Committed by Palmer Dabbelt Sep 22, 2022

riscv: Make VM_WRITE imply VM_READ



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: 2139619b ("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>

parent 568035b0

arch/riscv/mm/fault.c

+2 −1

Original line number	Diff line number	Diff line
		@@ -184,7 +184,8 @@ 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;