Commit 66f4e88c authored by Dominik Brodowski's avatar Dominik Brodowski
Browse files

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: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
parent c7b95d51

arch/x86/include/asm/syscalls.h

+1 −0
Original line number Diff line number Diff line
@@ -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);

arch/x86/kernel/ioport.c

+6 −1
Original line number Diff line number Diff line
@@ -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

drivers/tty/vt/vt_ioctl.c

+3 −3
Original line number Diff line number Diff line
@@ -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

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