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    Subject[PATCH 5.17 097/298] riscv: read-only pages should not be writable
    Date
    From: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>

    [ Upstream commit 630f972d76d6460235e84e1aa034ee06f9c8c3a9 ]

    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>
    Link: https://lore.kernel.org/r/20220528014132.91052-1-heinrich.schuchardt@canonical.com
    Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    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) {
    --
    2.35.1


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