The patch below does not apply to the 5.4-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
Possible dependencies:
7ab72c597356 ("riscv: Make VM_WRITE imply VM_READ")
afb8c6fee8ce ("riscv/mm/fault: Move access error check to function")
6747430197ed ("riscv/mm/fault: Move FAULT_FLAG_WRITE handling in do_page_fault()")
ac416a724f11 ("riscv/mm/fault: Move vmalloc fault handling to vmalloc_fault()")
a51271d99cdd ("riscv/mm/fault: Move bad area handling to bad_area()")
cac4d1dc85be ("riscv/mm/fault: Move no context handling to no_context()")
d8ed45c5dcd4 ("mmap locking API: use coccinelle to convert mmap_sem rwsem call sites")
7ae77150d94d ("Merge tag 'powerpc-5.8-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux")
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
>From 7ab72c597356be1e7f0f3d856e54ce78527f43c8 Mon Sep 17 00:00:00 2001
From: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
Date: Thu, 15 Sep 2022 15:37:01 -0400
Subject: [PATCH] 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: 2139619bcad7 ("riscv: mmap with PROT_WRITE but no PROT_READ is invalid")
Reviewed-by: Atish Patra <atishp@xxxxxxxxxxxx>
Signed-off-by: Andrew Bresticker <abrestic@xxxxxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/20220915193702.2201018-2-abrestic@xxxxxxxxxxxx/
Signed-off-by: Palmer Dabbelt <palmer@xxxxxxxxxxxx>
diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c
index f2fbd1400b7c..d86f7cebd4a7 100644
--- a/arch/riscv/mm/fault.c
+++ b/arch/riscv/mm/fault.c
@@ -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;
