linux-kernel - [PATCH -fixes v3 6/6] riscv: Fix kasan pud population

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Message-Id: <20220225123953.3251327-7-alexandre.ghiti@canonical.com>
Date:   Fri, 25 Feb 2022 13:39:53 +0100
From:   Alexandre Ghiti <alexandre.ghiti@...onical.com>
To:     Paul Walmsley <paul.walmsley@...ive.com>,
        Palmer Dabbelt <palmer@...belt.com>,
        Albert Ou <aou@...s.berkeley.edu>,
        Andrey Ryabinin <ryabinin.a.a@...il.com>,
        Alexander Potapenko <glider@...gle.com>,
        Andrey Konovalov <andreyknvl@...il.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Alexandre Ghiti <alexandre.ghiti@...onical.com>,
        Aleksandr Nogikh <nogikh@...gle.com>,
        Nick Hu <nickhu@...estech.com>,
        linux-riscv@...ts.infradead.org, linux-kernel@...r.kernel.org,
        kasan-dev@...glegroups.com
Subject: [PATCH -fixes v3 6/6] riscv: Fix kasan pud population

In sv48, the kasan inner regions are not aligned on PGDIR_SIZE and then
when we populate the kasan linear mapping region, we clear the kasan
vmalloc region which is in the same PGD.

Fix this by copying the content of the kasan early pud after allocating a
new PGD for the first time.

Fixes: e8a62cc26ddf ("riscv: Implement sv48 support")
Signed-off-by: Alexandre Ghiti <alexandre.ghiti@...onical.com>
---
 arch/riscv/mm/kasan_init.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index 85e849318389..cd1a145257b7 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -113,8 +113,11 @@ static void __init kasan_populate_pud(pgd_t *pgd,
 		base_pud = pt_ops.get_pud_virt(pfn_to_phys(_pgd_pfn(*pgd)));
 	} else {
 		base_pud = (pud_t *)pgd_page_vaddr(*pgd);
-		if (base_pud == lm_alias(kasan_early_shadow_pud))
+		if (base_pud == lm_alias(kasan_early_shadow_pud)) {
 			base_pud = memblock_alloc(PTRS_PER_PUD * sizeof(pud_t), PAGE_SIZE);
+			memcpy(base_pud, (void *)kasan_early_shadow_pud,
+			       sizeof(pud_t) * PTRS_PER_PUD);
+		}
 	}
 
 	pudp = base_pud + pud_index(vaddr);
-- 
2.32.0