From: Arnd Bergmann <arnd@arndb.de>
To: Guoyun Sun <sunguoyun@loongson.cn>
Cc: Ralf Baechle <ralf@linux-mips.org>,
Paul Burton <paulburton@kernel.org>,
James Hogan <jhogan@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Christian Brauner <christian.brauner@ubuntu.com>,
Heiko Carstens <heiko.carstens@de.ibm.com>,
David Howells <dhowells@redhat.com>,
Geert Uytterhoeven <geert@linux-m68k.org>,
Catalin Marinas <catalin.marinas@arm.com>,
"open list:BROADCOM NVRAM DRIVER" <linux-mips@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Tiezhu Yang <yangtiezhu@loongson.cn>,
Xuefeng Li <lixuefeng@loongson.cn>
Subject: Re: [PATCH V2] MIPS: Add get_thread_area syscall
Date: Fri, 13 Dec 2019 10:12:29 +0100 [thread overview]
Message-ID: <CAK8P3a1nLz2FDxw28DBXVma9E2saWpGtt+y6tYm4jros6TUF6w@mail.gmail.com> (raw)
In-Reply-To: <1576225834-16389-1-git-send-email-sunguoyun@loongson.cn>
On Fri, Dec 13, 2019 at 9:30 AM Guoyun Sun <sunguoyun@loongson.cn> wrote:
Thanks for fixing the numbers. On second look, I saw another problem:
> diff --git a/arch/mips/kernel/syscall.c b/arch/mips/kernel/syscall.c
> index c333e57..20bf4c5 100644
> --- a/arch/mips/kernel/syscall.c
> +++ b/arch/mips/kernel/syscall.c
> @@ -94,6 +94,16 @@ SYSCALL_DEFINE1(set_thread_area, unsigned long, addr)
> return 0;
> }
>
> +SYSCALL_DEFINE1(get_thread_area, unsigned long __user *, u_info)
> +{
> + struct thread_info *ti = task_thread_info(current);
> +
> + if (copy_to_user(u_info, &(ti->tp_value), sizeof(ti->tp_value)))
> + return -EFAULT;
> +
> + return 0;
> +}
> +
This won't work for compat mode, when tp_value is a different size
in kernel and user space. You could either add a COMPAT_SYSCALL_DEFINE1()
variant, or handle it like
if (in_compat_syscall())
return put_user(ti->tp_value, (__u32 *)u_info);
return put_user(ti->tp_value, u_info);
Arnd
prev parent reply other threads:[~2019-12-13 9:12 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-12-13 8:30 [PATCH V2] MIPS: Add get_thread_area syscall Guoyun Sun
2019-12-13 9:12 ` Arnd Bergmann [this message]
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