lkml.org 
[lkml]   [2018]   [Mar]   [29]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 099/109] x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm()
Date
Using this helper allows us to avoid the in-kernel calls to the
sys_ioperm() syscall. The ksys_ prefix denotes that this function is meant
as a drop-in replacement for the syscall. In particular, it uses the same
calling convention as sys_ioperm().

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Slaby <jslaby@suse.com>
Cc: x86@kernel.org
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
---
arch/x86/include/asm/syscalls.h | 1 +
arch/x86/kernel/ioport.c | 7 ++++++-
drivers/tty/vt/vt_ioctl.c | 6 +++---
3 files changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/syscalls.h b/arch/x86/include/asm/syscalls.h
index bad25bb80679..1c0bebbd039e 100644
--- a/arch/x86/include/asm/syscalls.h
+++ b/arch/x86/include/asm/syscalls.h
@@ -17,6 +17,7 @@

/* Common in X86_32 and X86_64 */
/* kernel/ioport.c */
+long ksys_ioperm(unsigned long from, unsigned long num, int turn_on);
asmlinkage long sys_ioperm(unsigned long, unsigned long, int);
asmlinkage long sys_iopl(unsigned int);

diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index 38deafebb21b..0fe1c8782208 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -23,7 +23,7 @@
/*
* this changes the io permissions bitmap in the current task.
*/
-SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
+long ksys_ioperm(unsigned long from, unsigned long num, int turn_on)
{
struct thread_struct *t = &current->thread;
struct tss_struct *tss;
@@ -96,6 +96,11 @@ SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
return 0;
}

+SYSCALL_DEFINE3(ioperm, unsigned long, from, unsigned long, num, int, turn_on)
+{
+ return ksys_ioperm(from, num, turn_on);
+}
+
/*
* sys_iopl has to be used when you want to access the IO ports
* beyond the 0x3ff range: to get the full 65536 ports bitmapped
diff --git a/drivers/tty/vt/vt_ioctl.c b/drivers/tty/vt/vt_ioctl.c
index d61be307256a..a78ad10a119b 100644
--- a/drivers/tty/vt/vt_ioctl.c
+++ b/drivers/tty/vt/vt_ioctl.c
@@ -57,7 +57,7 @@ extern struct tty_driver *console_driver;
*/

#ifdef CONFIG_X86
-#include <linux/syscalls.h>
+#include <asm/syscalls.h>
#endif

static void complete_change_console(struct vc_data *vc);
@@ -420,12 +420,12 @@ int vt_ioctl(struct tty_struct *tty,
ret = -EINVAL;
break;
}
- ret = sys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
+ ret = ksys_ioperm(arg, 1, (cmd == KDADDIO)) ? -ENXIO : 0;
break;

case KDENABIO:
case KDDISABIO:
- ret = sys_ioperm(GPFIRST, GPNUM,
+ ret = ksys_ioperm(GPFIRST, GPNUM,
(cmd == KDENABIO)) ? -ENXIO : 0;
break;
#endif
--
2.16.3
\
 
 \ /
  Last update: 2018-03-29 13:26    [W:0.357 / U:2.296 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site