From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: From: Amit Daniel Kachhap Subject: [RFC PATCH 10/14] riscv/crash_dump: Use the new interface copy_oldmem_page_buf Date: Fri, 3 Dec 2021 16:12:27 +0530 Message-Id: <20211203104231.17597-11-amit.kachhap@arm.com> In-Reply-To: <20211203104231.17597-1-amit.kachhap@arm.com> References: <20211203104231.17597-1-amit.kachhap@arm.com> List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "kexec" Errors-To: kexec-bounces+dwmw2=infradead.org@lists.infradead.org To: linux-kernel@vger.kernel.org Cc: Christoph Hellwig , Vincenzo Frascino , Kevin Brodsky , linux-fsdevel , kexec , Amit Daniel Kachhap , Paul Walmsley , Palmer Dabbelt , Albert Ou , linux-riscv The current interface copy_oldmem_page() passes user pointer without __user annotation and hence does unnecessary user/kernel pointer conversions during its implementation. Use the interface copy_oldmem_page_buf() to avoid this issue. Cc: Paul Walmsley Cc: Palmer Dabbelt Cc: Albert Ou Cc: linux-riscv Signed-off-by: Amit Daniel Kachhap --- arch/riscv/kernel/crash_dump.c | 25 +++++++++++++------------ 1 file changed, 13 insertions(+), 12 deletions(-) diff --git a/arch/riscv/kernel/crash_dump.c b/arch/riscv/kernel/crash_dump.c index 86cc0ada5752..3a8fadcd1278 100644 --- a/arch/riscv/kernel/crash_dump.c +++ b/arch/riscv/kernel/crash_dump.c @@ -9,20 +9,21 @@ #include /** - * copy_oldmem_page() - copy one page from old kernel memory + * copy_oldmem_page_buf() - copy one page from old kernel memory * @pfn: page frame number to be copied - * @buf: buffer where the copied page is placed + * @ubuf: user buffer where the copied page is placed; use copy_to_user() if + * this pointer is not NULL + * @kbuf: kernel buffer where the copied page is placed; use memcpy() if this + * pointer is not NULL * @csize: number of bytes to copy * @offset: offset in bytes into the page - * @userbuf: if set, @buf is in a user address space * - * This function copies one page from old kernel memory into buffer pointed by - * @buf. If @buf is in userspace, set @userbuf to %1. Returns number of bytes - * copied or negative error in case of failure. + * This function copies one page from old kernel memory into the buffer pointed + * by either @ubuf or @kbuf. Returns number of bytes copied or negative error in + * case of failure. */ -ssize_t copy_oldmem_page(unsigned long pfn, char *buf, - size_t csize, unsigned long offset, - int userbuf) +ssize_t copy_oldmem_page_buf(unsigned long pfn, char __user *ubuf, char *kbuf, + size_t csize, unsigned long offset) { void *vaddr; @@ -33,13 +34,13 @@ ssize_t copy_oldmem_page(unsigned long pfn, char *buf, if (!vaddr) return -ENOMEM; - if (userbuf) { - if (copy_to_user((char __user *)buf, vaddr + offset, csize)) { + if (ubuf) { + if (copy_to_user(ubuf, vaddr + offset, csize)) { memunmap(vaddr); return -EFAULT; } } else - memcpy(buf, vaddr + offset, csize); + memcpy(kbuf, vaddr + offset, csize); memunmap(vaddr); return csize; -- 2.17.1 _______________________________________________ kexec mailing list kexec@lists.infradead.org http://lists.infradead.org/mailman/listinfo/kexec