[PATCH v2 0/2] Fix the page table size of KASAN use.

[PATCH v2 0/2] Fix the page table size of KASAN use.

[Zong Li]

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. For example, if it only
allocates 200 pmd entries memory size for pmd page table, then the
original 201 entry will be used to other purpose, and cause the
unexpected fault when accessing the page table.

Zong Li (2):
  riscv: allocate a complete page size for each page table
  riscv: adjust the indent

 arch/riscv/mm/kasan_init.c | 52 ++++++++++++++++++++++----------------
 1 file changed, 30 insertions(+), 22 deletions(-)

-- 
2.25.0

[PATCH v2 1/2] riscv: allocate a complete page size for each page table

[Zong Li]

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

[PATCH v2 2/2] riscv: adjust the indent

[Zong Li]

Adjust the indent to match Linux coding style.

Changes in v2:
- Remove an unnecessary void* type casting. Suggested by Joe Perches.

Signed-off-by: Zong Li <zong.li@sifive.com>
---
 arch/riscv/mm/kasan_init.c | 25 ++++++++++++++-----------
 1 file changed, 14 insertions(+), 11 deletions(-)

diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index f8eaf7e73a23..abeb590e81f2 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -19,18 +19,20 @@ asmlinkage void __init kasan_early_init(void)
 	for (i = 0; i < PTRS_PER_PTE; ++i)
 		set_pte(kasan_early_shadow_pte + i,
 			mk_pte(virt_to_page(kasan_early_shadow_page),
-			PAGE_KERNEL));
+			       PAGE_KERNEL));
 
 	for (i = 0; i < PTRS_PER_PMD; ++i)
 		set_pmd(kasan_early_shadow_pmd + i,
-		 pfn_pmd(PFN_DOWN(__pa((uintptr_t)kasan_early_shadow_pte)),
-			__pgprot(_PAGE_TABLE)));
+			pfn_pmd(PFN_DOWN
+				(__pa((uintptr_t) kasan_early_shadow_pte)),
+				__pgprot(_PAGE_TABLE)));
 
 	for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
 	     i += PGDIR_SIZE, ++pgd)
 		set_pgd(pgd,
-		 pfn_pgd(PFN_DOWN(__pa(((uintptr_t)kasan_early_shadow_pmd))),
-			__pgprot(_PAGE_TABLE)));
+			pfn_pgd(PFN_DOWN
+				(__pa(((uintptr_t) kasan_early_shadow_pmd))),
+				__pgprot(_PAGE_TABLE)));
 
 	/* init for swapper_pg_dir */
 	pgd = pgd_offset_k(KASAN_SHADOW_START);
@@ -38,8 +40,9 @@ asmlinkage void __init kasan_early_init(void)
 	for (i = KASAN_SHADOW_START; i < KASAN_SHADOW_END;
 	     i += PGDIR_SIZE, ++pgd)
 		set_pgd(pgd,
-		 pfn_pgd(PFN_DOWN(__pa(((uintptr_t)kasan_early_shadow_pmd))),
-			__pgprot(_PAGE_TABLE)));
+			pfn_pgd(PFN_DOWN
+				(__pa(((uintptr_t) kasan_early_shadow_pmd))),
+				__pgprot(_PAGE_TABLE)));
 
 	flush_tlb_all();
 }
@@ -86,7 +89,7 @@ void __init kasan_init(void)
 	unsigned long i;
 
 	kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
-			(void *)kasan_mem_to_shadow((void *)VMALLOC_END));
+				    kasan_mem_to_shadow((void *)VMALLOC_END));
 
 	for_each_memblock(memory, reg) {
 		void *start = (void *)__va(reg->base);
@@ -95,14 +98,14 @@ void __init kasan_init(void)
 		if (start >= end)
 			break;
 
-		populate(kasan_mem_to_shadow(start),
-			 kasan_mem_to_shadow(end));
+		populate(kasan_mem_to_shadow(start), kasan_mem_to_shadow(end));
 	};
 
 	for (i = 0; i < PTRS_PER_PTE; i++)
 		set_pte(&kasan_early_shadow_pte[i],
 			mk_pte(virt_to_page(kasan_early_shadow_page),
-			__pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_ACCESSED)));
+			       __pgprot(_PAGE_PRESENT | _PAGE_READ |
+					_PAGE_ACCESSED)));
 
 	memset(kasan_early_shadow_page, 0, PAGE_SIZE);
 	init_task.kasan_depth = 0;
-- 
2.25.0