Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
From:   Zong Li <zong.li@sifive.com>
To:     paul.walmsley@sifive.com, palmer@dabbelt.com,
        aou@eecs.berkeley.edu, linux-riscv@lists.infradead.org,
        linux-kernel@vger.kernel.org
Cc:     Zong Li <zong.li@sifive.com>
Subject: [PATCH 1/2] riscv: allocate a complete page size for each page table
Date:   Fri,  7 Feb 2020 17:52:44 +0800
Message-Id: <20200207095245.21955-2-zong.li@sifive.com>
In-Reply-To: <20200207095245.21955-1-zong.li@sifive.com>
References: <20200207095245.21955-1-zong.li@sifive.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

Each page table should be created by allocating a complete page size
for it. Otherwise, the content of the page table would be corrupted
somewhere through memory allocation which allocates the memory at the
middle of the page table for other use.

Signed-off-by: Zong Li <zong.li@sifive.com>
---
 arch/riscv/mm/kasan_init.c | 27 ++++++++++++++++-----------
 1 file changed, 16 insertions(+), 11 deletions(-)

diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index f0cc86040587..f8eaf7e73a23 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -46,29 +46,34 @@ asmlinkage void __init kasan_early_init(void)
 
 static void __init populate(void *start, void *end)
 {
-	unsigned long i;
+	unsigned long i, offset;
 	unsigned long vaddr = (unsigned long)start & PAGE_MASK;
 	unsigned long vend = PAGE_ALIGN((unsigned long)end);
 	unsigned long n_pages = (vend - vaddr) / PAGE_SIZE;
+	unsigned long n_ptes =
+	    ((n_pages + PTRS_PER_PTE) & -PTRS_PER_PTE) / PTRS_PER_PTE;
 	unsigned long n_pmds =
-		(n_pages % PTRS_PER_PTE) ? n_pages / PTRS_PER_PTE + 1 :
-						n_pages / PTRS_PER_PTE;
+	    ((n_ptes + PTRS_PER_PMD) & -PTRS_PER_PMD) / PTRS_PER_PMD;
+
+	pte_t *pte =
+	    memblock_alloc(n_ptes * PTRS_PER_PTE * sizeof(pte_t), PAGE_SIZE);
+	pmd_t *pmd =
+	    memblock_alloc(n_pmds * PTRS_PER_PMD * sizeof(pmd_t), PAGE_SIZE);
 	pgd_t *pgd = pgd_offset_k(vaddr);
-	pmd_t *pmd = memblock_alloc(n_pmds * sizeof(pmd_t), PAGE_SIZE);
-	pte_t *pte = memblock_alloc(n_pages * sizeof(pte_t), PAGE_SIZE);
 
 	for (i = 0; i < n_pages; i++) {
 		phys_addr_t phys = memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
-
-		set_pte(pte + i, pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
+		set_pte(&pte[i], pfn_pte(PHYS_PFN(phys), PAGE_KERNEL));
 	}
 
-	for (i = 0; i < n_pmds; ++pgd, i += PTRS_PER_PMD)
-		set_pgd(pgd, pfn_pgd(PFN_DOWN(__pa(((uintptr_t)(pmd + i)))),
+	for (i = 0, offset = 0; i < n_ptes; i++, offset += PTRS_PER_PTE)
+		set_pmd(&pmd[i],
+			pfn_pmd(PFN_DOWN(__pa(&pte[offset])),
 				__pgprot(_PAGE_TABLE)));
 
-	for (i = 0; i < n_pages; ++pmd, i += PTRS_PER_PTE)
-		set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa((uintptr_t)(pte + i))),
+	for (i = 0, offset = 0; i < n_pmds; i++, offset += PTRS_PER_PMD)
+		set_pgd(&pgd[i],
+			pfn_pgd(PFN_DOWN(__pa(&pmd[offset])),
 				__pgprot(_PAGE_TABLE)));
 
 	flush_tlb_all();
-- 
2.25.0