From e178d670f251b6947d6be99c0014e9a57ad4f0e0 Mon Sep 17 00:00:00 2001
From: Nylon Chen <nylon7@andestech.com>
Date: Sat, 16 Jan 2021 13:58:35 +0800
Subject: [PATCH] riscv/kasan: add KASAN_VMALLOC support
It references to x86/s390 architecture.
So, it doesn't map the early shadow page to cover VMALLOC space.
Prepopulate top level page table for the range that would otherwise be
empty.
lower levels are filled dynamically upon memory allocation while
booting.
Signed-off-by: Nylon Chen <nylon7@andestech.com>
Signed-off-by: Nick Hu <nickhu@andestech.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
---
arch/riscv/Kconfig | 1 +
arch/riscv/mm/kasan_init.c | 57 +++++++++++++++++++++++++++++++++++++-
2 files changed, 57 insertions(+), 1 deletion(-)
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
index 8eadd1cbd524e..3832a537c5d64 100644
--- a/arch/riscv/Kconfig
+++ b/arch/riscv/Kconfig
@@ -57,6 +57,7 @@ config RISCV
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_KASAN if MMU && 64BIT
+ select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT
select HAVE_ARCH_KGDB
select HAVE_ARCH_KGDB_QXFER_PKT
select HAVE_ARCH_MMAP_RND_BITS if MMU
diff --git a/arch/riscv/mm/kasan_init.c b/arch/riscv/mm/kasan_init.c
index 12ddd1f6bf70c..4b9149f963d36 100644
--- a/arch/riscv/mm/kasan_init.c
+++ b/arch/riscv/mm/kasan_init.c
@@ -9,6 +9,19 @@
#include <linux/pgtable.h>
#include <asm/tlbflush.h>
#include <asm/fixmap.h>
+#include <asm/pgalloc.h>
+
+static __init void *early_alloc(size_t size, int node)
+{
+ void *ptr = memblock_alloc_try_nid(size, size,
+ __pa(MAX_DMA_ADDRESS), MEMBLOCK_ALLOC_ACCESSIBLE, node);
+
+ if (!ptr)
+ panic("%pS: Failed to allocate %zu bytes align=%zx nid=%d from=%llx\n",
+ __func__, size, size, node, (u64)__pa(MAX_DMA_ADDRESS));
+
+ return ptr;
+}
extern pgd_t early_pg_dir[PTRS_PER_PGD];
asmlinkage void __init kasan_early_init(void)
@@ -83,6 +96,40 @@ static void __init populate(void *start, void *end)
memset(start, 0, end - start);
}
+void __init kasan_shallow_populate(void *start, void *end)
+{
+ unsigned long vaddr = (unsigned long)start & PAGE_MASK;
+ unsigned long vend = PAGE_ALIGN((unsigned long)end);
+ unsigned long pfn;
+ int index;
+ void *p;
+ pud_t *pud_dir, *pud_k;
+ pgd_t *pgd_dir, *pgd_k;
+ p4d_t *p4d_dir, *p4d_k;
+
+ while (vaddr < vend) {
+ index = pgd_index(vaddr);
+ pfn = csr_read(CSR_SATP) & SATP_PPN;
+ pgd_dir = (pgd_t *)pfn_to_virt(pfn) + index;
+ pgd_k = init_mm.pgd + index;
+ pgd_dir = pgd_offset_k(vaddr);
+ set_pgd(pgd_dir, *pgd_k);
+
+ p4d_dir = p4d_offset(pgd_dir, vaddr);
+ p4d_k = p4d_offset(pgd_k, vaddr);
+
+ vaddr = (vaddr + PUD_SIZE) & PUD_MASK;
+ pud_dir = pud_offset(p4d_dir, vaddr);
+ pud_k = pud_offset(p4d_k, vaddr);
+
+ if (pud_present(*pud_dir)) {
+ p = early_alloc(PAGE_SIZE, NUMA_NO_NODE);
+ pud_populate(&init_mm, pud_dir, p);
+ }
+ vaddr += PAGE_SIZE;
+ }
+}
+
void __init kasan_init(void)
{
phys_addr_t _start, _end;
@@ -90,7 +137,15 @@ void __init kasan_init(void)
kasan_populate_early_shadow((void *)KASAN_SHADOW_START,
(void *)kasan_mem_to_shadow((void *)
- VMALLOC_END));
+ VMEMMAP_END));
+ if (IS_ENABLED(CONFIG_KASAN_VMALLOC))
+ kasan_shallow_populate(
+ (void *)kasan_mem_to_shadow((void *)VMALLOC_START),
+ (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
+ else
+ kasan_populate_early_shadow(
+ (void *)kasan_mem_to_shadow((void *)VMALLOC_START),
+ (void *)kasan_mem_to_shadow((void *)VMALLOC_END));
for_each_mem_range(i, &_start, &_end) {
void *start = (void *)_start;
--
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