Re: [PATCH] riscv: read-only pages should not be writable

On 5/28/22 11:13, Ard Biesheuvel wrote:

On Sat, 28 May 2022 at 03:41, Heinrich Schuchardt heinrich.schuchardt@canonical.com wrote:

...

If EFI pages are marked as read-only, we should remove the _PAGE_WRITE flag.

The current code overwrites an unused value.

Fixes: b91540d52a08b ("RISC-V: Add EFI runtime services") Signed-off-by: Heinrich Schuchardt heinrich.schuchardt@canonical.com

---

arch/riscv/kernel/efi.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/efi.c b/arch/riscv/kernel/efi.c index 024159298231..1aa540350abd 100644 --- a/arch/riscv/kernel/efi.c +++ b/arch/riscv/kernel/efi.c @@ -65,7 +65,7 @@ static int __init set_permissions(pte_t *ptep, unsigned long addr, void *data)

     if (md->attribute & EFI_MEMORY_RO) {
             val = pte_val(pte) & ~_PAGE_WRITE;

•           val = pte_val(pte) | _PAGE_READ;
  

•           val |= _PAGE_READ;
             pte = __pte(val);
     }
     if (md->attribute & EFI_MEMORY_XP) {
  

-- 2.36.1

Thanks Heinrich

Queued in efi/urgent.

I guess this should also be down-ported to 5.15 and 5.10.

Best regards

Heinrich