From: Heinrich Schuchardt <heinrich.schuchardt@canonical.com>
Date: Sat, 28 May 2022 01:41:32 +0000 (+0200)
Subject: riscv: read-only pages should not be writable
X-Git-Tag: v5.15.73~3156
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6005d36fbc82611a7a632265f75557d3063b8d4c;p=platform%2Fkernel%2Flinux-rpi.git

riscv: read-only pages should not be writable

[ 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>
---

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) {