linux-kernel - [PATCH 1/3] RISC-V: Fix .init section permission update

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Message-Id: <20210129190038.1001626-1-atish.patra@wdc.com>
Date:   Fri, 29 Jan 2021 11:00:36 -0800
From:   Atish Patra <atish.patra@....com>
To:     linux-kernel@...r.kernel.org
Cc:     Atish Patra <atish.patra@....com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Albert Ou <aou@...s.berkeley.edu>,
        Anup Patel <anup.patel@....com>,
        Ard Biesheuvel <ardb@...nel.org>,
        "Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
        linux-riscv@...ts.infradead.org,
        Nick Desaulniers <ndesaulniers@...ogle.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Paul Walmsley <paul.walmsley@...ive.com>,
        Sebastien Van Cauwenberghe <svancau@...il.com>,
        Zong Li <zong.li@...ive.com>
Subject: [PATCH 1/3] RISC-V: Fix .init section permission update

.init section permission should only updated to non-execute if
STRICT_KERNEL_RWX is enabled. Otherwise, this will lead to a kernel hang.

Fixes: 19a00869028f ("RISC-V: Protect all kernel sections including init early")

Suggested-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Reported-by: Geert Uytterhoeven <geert@...ux-m68k.org>
Signed-off-by: Atish Patra <atish.patra@....com>
---
 arch/riscv/kernel/setup.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index 3fa3f26dde85..c7c0655dd45b 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c
@@ -293,6 +293,8 @@ void free_initmem(void)
 	unsigned long init_begin = (unsigned long)__init_begin;
 	unsigned long init_end = (unsigned long)__init_end;
 
-	set_memory_rw_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
+	if (IS_ENABLED(CONFIG_STRICT_KERNEL_RWX))
+		set_memory_rw_nx(init_begin, (init_end - init_begin) >> PAGE_SHIFT);
+
 	free_initmem_default(POISON_FREE_INITMEM);
 }
-- 
2.25.1