diff options
| -rw-r--r-- | arch/riscv/Kconfig | 1 | ||||
| -rw-r--r-- | arch/riscv/include/asm/kfence.h | 63 | ||||
| -rw-r--r-- | arch/riscv/mm/fault.c | 11 |
3 files changed, 74 insertions, 1 deletions
diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index a71b1d2cab3d..9ff363306237 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -64,6 +64,7 @@ config RISCV select HAVE_ARCH_JUMP_LABEL_RELATIVE select HAVE_ARCH_KASAN if MMU && 64BIT select HAVE_ARCH_KASAN_VMALLOC if MMU && 64BIT + select HAVE_ARCH_KFENCE 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/include/asm/kfence.h b/arch/riscv/include/asm/kfence.h new file mode 100644 index 000000000000..d887a54042aa --- /dev/null +++ b/arch/riscv/include/asm/kfence.h @@ -0,0 +1,63 @@ +/* SPDX-License-Identifier: GPL-2.0 */ + +#ifndef _ASM_RISCV_KFENCE_H +#define _ASM_RISCV_KFENCE_H + +#include <linux/kfence.h> +#include <linux/pfn.h> +#include <asm-generic/pgalloc.h> +#include <asm/pgtable.h> + +static inline int split_pmd_page(unsigned long addr) +{ + int i; + unsigned long pfn = PFN_DOWN(__pa((addr & PMD_MASK))); + pmd_t *pmd = pmd_off_k(addr); + pte_t *pte = pte_alloc_one_kernel(&init_mm); + + if (!pte) + return -ENOMEM; + + for (i = 0; i < PTRS_PER_PTE; i++) + set_pte(pte + i, pfn_pte(pfn + i, PAGE_KERNEL)); + set_pmd(pmd, pfn_pmd(PFN_DOWN(__pa(pte)), PAGE_TABLE)); + + flush_tlb_kernel_range(addr, addr + PMD_SIZE); + return 0; +} + +static inline bool arch_kfence_init_pool(void) +{ + int ret; + unsigned long addr; + pmd_t *pmd; + + for (addr = (unsigned long)__kfence_pool; is_kfence_address((void *)addr); + addr += PAGE_SIZE) { + pmd = pmd_off_k(addr); + + if (pmd_leaf(*pmd)) { + ret = split_pmd_page(addr); + if (ret) + return false; + } + } + + return true; +} + +static inline bool kfence_protect_page(unsigned long addr, bool protect) +{ + pte_t *pte = virt_to_kpte(addr); + + if (protect) + set_pte(pte, __pte(pte_val(*pte) & ~_PAGE_PRESENT)); + else + set_pte(pte, __pte(pte_val(*pte) | _PAGE_PRESENT)); + + flush_tlb_kernel_range(addr, addr + PAGE_SIZE); + + return true; +} + +#endif /* _ASM_RISCV_KFENCE_H */ diff --git a/arch/riscv/mm/fault.c b/arch/riscv/mm/fault.c index 096463cc6fff..aa08dd2f8fae 100644 --- a/arch/riscv/mm/fault.c +++ b/arch/riscv/mm/fault.c @@ -14,6 +14,7 @@ #include <linux/signal.h> #include <linux/uaccess.h> #include <linux/kprobes.h> +#include <linux/kfence.h> #include <asm/ptrace.h> #include <asm/tlbflush.h> @@ -45,7 +46,15 @@ static inline void no_context(struct pt_regs *regs, unsigned long addr) * Oops. The kernel tried to access some bad page. We'll have to * terminate things with extreme prejudice. */ - msg = (addr < PAGE_SIZE) ? "NULL pointer dereference" : "paging request"; + if (addr < PAGE_SIZE) + msg = "NULL pointer dereference"; + else { + if (kfence_handle_page_fault(addr, regs->cause == EXC_STORE_PAGE_FAULT, regs)) + return; + + msg = "paging request"; + } + die_kernel_fault(msg, addr, regs); } |