From: Liu Shixin <liushixin2@huawei.com>
To: Paul Walmsley <paul.walmsley@sifive.com>,
Palmer Dabbelt <palmer@dabbelt.com>,
Albert Ou <aou@eecs.berkeley.edu>,
Alexander Potapenko <glider@google.com>,
Marco Elver <elver@google.com>,
Dmitry Vyukov <dvyukov@google.com>
Cc: <linux-riscv@lists.infradead.org>, <linux-kernel@vger.kernel.org>,
<kasan-dev@googlegroups.com>
Subject: Re: [PATCH -next] riscv: Enable KFENCE for riscv64
Date: Wed, 9 Jun 2021 14:17:55 +0800 [thread overview]
Message-ID: <0a3ee489-47db-47f5-6192-794457fc74f8@huawei.com> (raw)
In-Reply-To: <20210529080340.2987212-1-liushixin2@huawei.com>
Hi, everybody,
I perfected the patch based on the previous advice. How about this version?
Thanks,
On 2021/5/29 16:03, Liu Shixin wrote:
> Add architecture specific implementation details for KFENCE and enable
> KFENCE for the riscv64 architecture. In particular, this implements the
> required interface in <asm/kfence.h>.
>
> KFENCE requires that attributes for pages from its memory pool can
> individually be set. Therefore, force the kfence pool to be mapped at
> page granularity.
>
> Testing this patch using the testcases in kfence_test.c and all passed.
>
> Signed-off-by: Liu Shixin <liushixin2@huawei.com>
> ---
> 1. Add helper function split_pmd_page() which is used to split a pmd to ptes.
> 2. Add the judgment on the result of pte_alloc_one_kernel().
>
> arch/riscv/Kconfig | 1 +
> arch/riscv/include/asm/kfence.h | 63 +++++++++++++++++++++++++++++++++
> arch/riscv/mm/fault.c | 11 +++++-
> 3 files changed, 74 insertions(+), 1 deletion(-)
> create mode 100644 arch/riscv/include/asm/kfence.h
>
> diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig
> index 4982130064ef..2f4903a7730f 100644
> --- a/arch/riscv/Kconfig
> +++ b/arch/riscv/Kconfig
> @@ -65,6 +65,7 @@ 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);
> }
>
_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv
next prev parent reply other threads:[~2021-06-09 6:18 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-29 8:03 [PATCH -next] riscv: Enable KFENCE for riscv64 Liu Shixin
2021-06-09 6:17 ` Liu Shixin [this message]
2021-06-11 1:33 ` Kefeng Wang
2021-06-11 11:37 ` Alexander Potapenko
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=0a3ee489-47db-47f5-6192-794457fc74f8@huawei.com \
--to=liushixin2@huawei.com \
--cc=aou@eecs.berkeley.edu \
--cc=dvyukov@google.com \
--cc=elver@google.com \
--cc=glider@google.com \
--cc=kasan-dev@googlegroups.com \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-riscv@lists.infradead.org \
--cc=palmer@dabbelt.com \
--cc=paul.walmsley@sifive.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).