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x86/ioport: add ksys_ioperm() helper; remove in-kernel calls to sys_ioperm() 

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>
This commit is contained in:
Dominik Brodowski 2018-03-11 11:34:38 +01:00
parent c7b95d5156
commit 66f4e88cc6
3 changed files with 10 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
arch/x86/include/asm/syscalls.h
View File

@ -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);

7
arch/x86/kernel/ioport.c
View File

@ -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

6
drivers/tty/vt/vt_ioctl.c
View File

@ -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