linux-kernel - [PATCH 5.7 104/120] riscv: kasan: use local_tlb_flush_all() to avoid uninitialized __sbi

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Date:   Mon,  3 Aug 2020 14:19:22 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Vincent Chen <vincent.chen@...ive.com>,
        Palmer Dabbelt <palmerdabbelt@...gle.com>,
        Sasha Levin <sashal@...nel.org>
Subject: [PATCH 5.7 104/120] riscv: kasan: use local_tlb_flush_all() to avoid uninitialized __sbi_rfence

From: Vincent Chen <vincent.chen@...ive.com>

[ Upstream commit 4cb699d0447be8e0906539f93cbe41e19598ee5a ]

It fails to boot the v5.8-rc4 kernel with CONFIG_KASAN because kasan_init
and kasan_early_init use uninitialized __sbi_rfence as executing the
tlb_flush_all(). Actually, at this moment, only the CPU which is
responsible for the system initialization enables the MMU. Other CPUs are
parking at the .Lsecondary_start. Hence the tlb_flush_all() is able to be
replaced by local_tlb_flush_all() to avoid using uninitialized
__sbi_rfence.

Signed-off-by: Vincent Chen <vincent.chen@...ive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@...gle.com>
Signed-off-by: Sasha Levin <sashal@...nel.org>
---
 arch/riscv/mm/kasan_init.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index ec0ca90dd9000..7a580c8ad6034 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -44,7 +44,7 @@ asmlinkage void __init kasan_early_init(void)
 				(__pa(((uintptr_t) kasan_early_shadow_pmd))),
 				__pgprot(_PAGE_TABLE)));
 
-	flush_tlb_all();
+	local_flush_tlb_all();
 }
 
 static void __init populate(void *start, void *end)
@@ -79,7 +79,7 @@ static void __init populate(void *start, void *end)
 			pfn_pgd(PFN_DOWN(__pa(&pmd[offset])),
 				__pgprot(_PAGE_TABLE)));
 
-	flush_tlb_all();
+	local_flush_tlb_all();
 	memset(start, 0, end - start);
 }
 
-- 
2.25.1