[v5,1/3] VT: Use macros to define ioctls

Commit Message

Alexey Gladkov April 17, 2024, 5:37 p.m. UTC

All other headers use _IOC() macros to describe ioctls for a long time
now. This header is stuck in the last century.

Simply use the _IO() macro. No other changes.

Signed-off-by: Alexey Gladkov <[e-mail]>
---
 include/uapi/linux/kd.h | 96 +++++++++++++++++++++--------------------
 1 file changed, 49 insertions(+), 47 deletions(-)

Comments

Greg KH April 18, 2024, 6:18 a.m. UTC | #1

On Wed, Apr 17, 2024 at 07:37:35PM +0200, Alexey Gladkov wrote:
> All other headers use _IOC() macros to describe ioctls for a long time
> now. This header is stuck in the last century.
> 
> Simply use the _IO() macro. No other changes.
> 
> Signed-off-by: Alexey Gladkov <[e-mail]>
> ---
>  include/uapi/linux/kd.h | 96 +++++++++++++++++++++--------------------
>  1 file changed, 49 insertions(+), 47 deletions(-)

This is a nice cleanup, thanks for doing it, I'll just take this one
change now if you don't object.

thanks,

greg k-h

Jiri Slaby May 29, 2024, 7:29 a.m. UTC | #2

On 18. 04. 24, 8:18, Greg Kroah-Hartman wrote:
> On Wed, Apr 17, 2024 at 07:37:35PM +0200, Alexey Gladkov wrote:
>> All other headers use _IOC() macros to describe ioctls for a long time
>> now. This header is stuck in the last century.
>>
>> Simply use the _IO() macro. No other changes.
>>
>> Signed-off-by: Alexey Gladkov <[e-mail]>
>> ---
>>   include/uapi/linux/kd.h | 96 +++++++++++++++++++++--------------------
>>   1 file changed, 49 insertions(+), 47 deletions(-)
> 
> This is a nice cleanup, thanks for doing it, I'll just take this one
> change now if you don't object.

Unfortunately, _IOC_NONE is 1 on some archs as noted by Arnd, and this 
commit changed the kd ioctl values in there which broke stuff as noted 
by Al.

We either:
* use _IOC(0, X, Y) in here, instead of _IO(X, Y), or
* define KDIOC(X) as _IOC(0, KD_IOCTL_BASE, X), or
* revert the commit which landed to -rc1 already.

thanks,

Arnd Bergmann May 29, 2024, 7:44 a.m. UTC | #3

On Wed, May 29, 2024, at 09:29, Jiri Slaby wrote:
> On 18. 04. 24, 8:18, Greg Kroah-Hartman wrote:
>> 
>> This is a nice cleanup, thanks for doing it, I'll just take this one
>> change now if you don't object.
>
> Unfortunately, _IOC_NONE is 1 on some archs as noted by Arnd, and this 
> commit changed the kd ioctl values in there which broke stuff as noted 
> by Al.
>
> We either:
> * use _IOC(0, X, Y) in here, instead of _IO(X, Y), or
> * define KDIOC(X) as _IOC(0, KD_IOCTL_BASE, X), or
> * revert the commit which landed to -rc1 already.

I would prefer a simple revert, as the other options may
end up more confusing. Another option might be a new
global macro, if we then go an convert all plain ioctl
command numbers to that.

      Arnd

Al Viro May 29, 2024, 8:44 a.m. UTC | #4

On Wed, May 29, 2024 at 09:29:23AM +0200, Jiri Slaby wrote:
> On 18. 04. 24, 8:18, Greg Kroah-Hartman wrote:
> > On Wed, Apr 17, 2024 at 07:37:35PM +0200, Alexey Gladkov wrote:
> > > All other headers use _IOC() macros to describe ioctls for a long time
> > > now. This header is stuck in the last century.
> > > 
> > > Simply use the _IO() macro. No other changes.
> > > 
> > > Signed-off-by: Alexey Gladkov <[e-mail]>
> > > ---
> > >   include/uapi/linux/kd.h | 96 +++++++++++++++++++++--------------------
> > >   1 file changed, 49 insertions(+), 47 deletions(-)
> > 
> > This is a nice cleanup, thanks for doing it, I'll just take this one
> > change now if you don't object.
> 
> Unfortunately, _IOC_NONE is 1 on some archs as noted by Arnd, and this
> commit changed the kd ioctl values in there which broke stuff as noted by
> Al.
> 
> We either:
> * use _IOC(0, X, Y) in here, instead of _IO(X, Y), or
> * define KDIOC(X) as _IOC(0, KD_IOCTL_BASE, X), or
> * revert the commit which landed to -rc1 already.

Revert, IMO.  If nothing else, _IO... macros are there to
	* document the copyin/copyout direction
	* make sure that argument size mismatches between the kernel
and userland get caught

Turning 16bit hex constants into that won't serve any purpose other
than preventing such patches in the future; adding a comment would
deal with that just fine.

BTW, the original odd choice for _IOC_NONE appears to have been motivated
by avoiding conflicts with legacy ioctl numbers: in CSRG repo there's
this:
commit 02cbc6a653b48bb4ec6052cbe6b3979530011c46
Author: Sam Leffler <[e-mail]>
Date:   Mon Aug 2 02:22:17 1982 -0800

    new ioctl's

...

+/*
+ * Ioctl's have the command encoded in the lower word,
+ * and the size of any in or out parameters in the upper
+ * word.  The high 2 bits of the upper word are used
+ * to encode the in/out status of the parameter; for now
+ * we restrict parameters to at most 128 bytes.
+ */
+#define        IOCPARM_MASK    0x7f            /* parameters must be < 128 bytes */
+#define        IOC_VOID        0x20000000      /* no parameters */
+#define        IOC_OUT         0x40000000      /* copy out parameters */
+#define        IOC_IN          0x80000000      /* copy in parameters */
+#define        IOC_INOUT       (IOC_IN|IOC_OUT)
+/* the 0x20000000 is so we can distinguish new ioctl's from old */
+#define        _IO(x,y)        (IOC_VOID|('x'<<8)|y)
+#define        _IOR(x,y,t)     (IOC_OUT|((sizeof(t)&IOCPARM_MASK)<<16)|('x'<<8)|y)
+#define        _IOW(x,y,t)     (IOC_IN|((sizeof(t)&IOCPARM_MASK)<<16)|('x'<<8)|y)
+/* this should be _IORW, but stdio got there first */
+#define        _IOWR(x,y,t)    (IOC_INOUT|((sizeof(t)&IOCPARM_MASK)<<16)|('x'<<8)|y)

FWIW, the upper limit on parameter size went up from 128 bytes to 8Kb in

commit 856ed9ecd2795280feed42baf3889ac7c7f9a26d
Author: Mike Karels <[e-mail]>
Date:   Thu Feb 19 22:16:28 1987 -0800

    larger ioctl's (for disklabels)

Wonder what got us (in sparc port?) to lift it from 8Kb to 16Kb...
In our historical tree that has happened in
commit 1c29224f169362b671a4bef4cd864464ef810d42
Author: Pete Zaitcev <[e-mail]>
Date:   Sun Mar 2 08:45:12 2003 -0800

    [SPARC32/64]: Expand ioctl size field in backwards-compatible way.

No explanations there...

Patch

diff --git a/include/uapi/linux/kd.h b/include/uapi/linux/kd.h
index 6b384065c013..8ddb2219a84b 100644
--- a/include/uapi/linux/kd.h
+++ b/include/uapi/linux/kd.h
@@ -5,60 +5,61 @@ 
 #include <linux/compiler.h>
 
 /* 0x4B is 'K', to avoid collision with termios and vt */
+#define KD_IOCTL_BASE	'K'
 
-#define GIO_FONT	0x4B60	/* gets font in expanded form */
-#define PIO_FONT	0x4B61	/* use font in expanded form */
+#define GIO_FONT	_IO(KD_IOCTL_BASE, 0x60)	/* gets font in expanded form */
+#define PIO_FONT	_IO(KD_IOCTL_BASE, 0x61)	/* use font in expanded form */
 
-#define GIO_FONTX	0x4B6B	/* get font using struct consolefontdesc */
-#define PIO_FONTX	0x4B6C	/* set font using struct consolefontdesc */
+#define GIO_FONTX	_IO(KD_IOCTL_BASE, 0x6B)	/* get font using struct consolefontdesc */
+#define PIO_FONTX	_IO(KD_IOCTL_BASE, 0x6C)	/* set font using struct consolefontdesc */
 struct consolefontdesc {
 	unsigned short charcount;	/* characters in font (256 or 512) */
 	unsigned short charheight;	/* scan lines per character (1-32) */
 	char __user *chardata;		/* font data in expanded form */
 };
 
-#define PIO_FONTRESET   0x4B6D	/* reset to default font */
+#define PIO_FONTRESET	_IO(KD_IOCTL_BASE, 0x6D)	/* reset to default font */
 
-#define GIO_CMAP	0x4B70	/* gets colour palette on VGA+ */
-#define PIO_CMAP	0x4B71	/* sets colour palette on VGA+ */
+#define GIO_CMAP	_IO(KD_IOCTL_BASE, 0x70)	/* gets colour palette on VGA+ */
+#define PIO_CMAP	_IO(KD_IOCTL_BASE, 0x71)	/* sets colour palette on VGA+ */
 
-#define KIOCSOUND	0x4B2F	/* start sound generation (0 for off) */
-#define KDMKTONE	0x4B30	/* generate tone */
+#define KIOCSOUND	_IO(KD_IOCTL_BASE, 0x2F)	/* start sound generation (0 for off) */
+#define KDMKTONE	_IO(KD_IOCTL_BASE, 0x30)	/* generate tone */
 
-#define KDGETLED	0x4B31	/* return current led state */
-#define KDSETLED	0x4B32	/* set led state [lights, not flags] */
+#define KDGETLED	_IO(KD_IOCTL_BASE, 0x31)	/* return current led state */
+#define KDSETLED	_IO(KD_IOCTL_BASE, 0x32)	/* set led state [lights, not flags] */
 #define 	LED_SCR		0x01	/* scroll lock led */
 #define 	LED_NUM		0x02	/* num lock led */
 #define 	LED_CAP		0x04	/* caps lock led */
 
-#define KDGKBTYPE	0x4B33	/* get keyboard type */
+#define KDGKBTYPE	_IO(KD_IOCTL_BASE, 0x33)	/* get keyboard type */
 #define 	KB_84		0x01
 #define 	KB_101		0x02 	/* this is what we always answer */
 #define 	KB_OTHER	0x03
 
-#define KDADDIO		0x4B34	/* add i/o port as valid */
-#define KDDELIO		0x4B35	/* del i/o port as valid */
-#define KDENABIO	0x4B36	/* enable i/o to video board */
-#define KDDISABIO	0x4B37	/* disable i/o to video board */
+#define KDADDIO		_IO(KD_IOCTL_BASE, 0x34)	/* add i/o port as valid */
+#define KDDELIO		_IO(KD_IOCTL_BASE, 0x35)	/* del i/o port as valid */
+#define KDENABIO	_IO(KD_IOCTL_BASE, 0x36)	/* enable i/o to video board */
+#define KDDISABIO	_IO(KD_IOCTL_BASE, 0x37)	/* disable i/o to video board */
 
-#define KDSETMODE	0x4B3A	/* set text/graphics mode */
+#define KDSETMODE	_IO(KD_IOCTL_BASE, 0x3A)	/* set text/graphics mode */
 #define		KD_TEXT		0x00
 #define		KD_GRAPHICS	0x01
 #define		KD_TEXT0	0x02	/* obsolete */
 #define		KD_TEXT1	0x03	/* obsolete */
-#define KDGETMODE	0x4B3B	/* get current mode */
+#define KDGETMODE	_IO(KD_IOCTL_BASE, 0x3B)	/* get current mode */
 
-#define KDMAPDISP	0x4B3C	/* map display into address space */
-#define KDUNMAPDISP	0x4B3D	/* unmap display from address space */
+#define KDMAPDISP	_IO(KD_IOCTL_BASE, 0x3C)	/* map display into address space */
+#define KDUNMAPDISP	_IO(KD_IOCTL_BASE, 0x3D)	/* unmap display from address space */
 
 typedef char scrnmap_t;
 #define		E_TABSZ		256
-#define GIO_SCRNMAP	0x4B40	/* get screen mapping from kernel */
-#define PIO_SCRNMAP	0x4B41	/* put screen mapping table in kernel */
-#define GIO_UNISCRNMAP  0x4B69	/* get full Unicode screen mapping */
-#define PIO_UNISCRNMAP  0x4B6A  /* set full Unicode screen mapping */
+#define GIO_SCRNMAP	_IO(KD_IOCTL_BASE, 0x40)	/* get screen mapping from kernel */
+#define PIO_SCRNMAP	_IO(KD_IOCTL_BASE, 0x41)	/* put screen mapping table in kernel */
+#define GIO_UNISCRNMAP	_IO(KD_IOCTL_BASE, 0x69)	/* get full Unicode screen mapping */
+#define PIO_UNISCRNMAP	_IO(KD_IOCTL_BASE, 0x6A)	/* set full Unicode screen mapping */
 
-#define GIO_UNIMAP	0x4B66	/* get unicode-to-font mapping from kernel */
+#define GIO_UNIMAP	_IO(KD_IOCTL_BASE, 0x66)	/* get unicode-to-font mapping from kernel */
 struct unipair {
 	unsigned short unicode;
 	unsigned short fontpos;
@@ -67,8 +68,8 @@  struct unimapdesc {
 	unsigned short entry_ct;
 	struct unipair __user *entries;
 };
-#define PIO_UNIMAP	0x4B67	/* put unicode-to-font mapping in kernel */
-#define PIO_UNIMAPCLR	0x4B68	/* clear table, possibly advise hash algorithm */
+#define PIO_UNIMAP	_IO(KD_IOCTL_BASE, 0x67)	/* put unicode-to-font mapping in kernel */
+#define PIO_UNIMAPCLR	_IO(KD_IOCTL_BASE, 0x68)	/* clear table, possibly advise hash algorithm */
 struct unimapinit {
 	unsigned short advised_hashsize;  /* 0 if no opinion */
 	unsigned short advised_hashstep;  /* 0 if no opinion */
@@ -83,19 +84,19 @@  struct unimapinit {
 #define		K_MEDIUMRAW	0x02
 #define		K_UNICODE	0x03
 #define		K_OFF		0x04
-#define KDGKBMODE	0x4B44	/* gets current keyboard mode */
-#define KDSKBMODE	0x4B45	/* sets current keyboard mode */
+#define KDGKBMODE	_IO(KD_IOCTL_BASE, 0x44)	/* gets current keyboard mode */
+#define KDSKBMODE	_IO(KD_IOCTL_BASE, 0x45)	/* sets current keyboard mode */
 
 #define		K_METABIT	0x03
 #define		K_ESCPREFIX	0x04
-#define KDGKBMETA	0x4B62	/* gets meta key handling mode */
-#define KDSKBMETA	0x4B63	/* sets meta key handling mode */
+#define KDGKBMETA	_IO(KD_IOCTL_BASE, 0x62)	/* gets meta key handling mode */
+#define KDSKBMETA	_IO(KD_IOCTL_BASE, 0x63)	/* sets meta key handling mode */
 
 #define		K_SCROLLLOCK	0x01
 #define		K_NUMLOCK	0x02
 #define		K_CAPSLOCK	0x04
-#define	KDGKBLED	0x4B64	/* get led flags (not lights) */
-#define	KDSKBLED	0x4B65	/* set led flags (not lights) */
+#define	KDGKBLED	_IO(KD_IOCTL_BASE, 0x64)	/* get led flags (not lights) */
+#define	KDSKBLED	_IO(KD_IOCTL_BASE, 0x65)	/* set led flags (not lights) */
 
 struct kbentry {
 	unsigned char kb_table;
@@ -107,15 +108,15 @@  struct kbentry {
 #define		K_ALTTAB	0x02
 #define		K_ALTSHIFTTAB	0x03
 
-#define KDGKBENT	0x4B46	/* gets one entry in translation table */
-#define KDSKBENT	0x4B47	/* sets one entry in translation table */
+#define KDGKBENT	_IO(KD_IOCTL_BASE, 0x46)	/* gets one entry in translation table */
+#define KDSKBENT	_IO(KD_IOCTL_BASE, 0x47)	/* sets one entry in translation table */
 
 struct kbsentry {
 	unsigned char kb_func;
 	unsigned char kb_string[512];
 };
-#define KDGKBSENT	0x4B48	/* gets one function key string entry */
-#define KDSKBSENT	0x4B49	/* sets one function key string entry */
+#define KDGKBSENT	_IO(KD_IOCTL_BASE, 0x48)	/* gets one function key string entry */
+#define KDSKBSENT	_IO(KD_IOCTL_BASE, 0x49)	/* sets one function key string entry */
 
 struct kbdiacr {
         unsigned char diacr, base, result;
@@ -124,8 +125,8 @@  struct kbdiacrs {
         unsigned int kb_cnt;    /* number of entries in following array */
 	struct kbdiacr kbdiacr[256];    /* MAX_DIACR from keyboard.h */
 };
-#define KDGKBDIACR      0x4B4A  /* read kernel accent table */
-#define KDSKBDIACR      0x4B4B  /* write kernel accent table */
+#define KDGKBDIACR	_IO(KD_IOCTL_BASE, 0x4A)  /* read kernel accent table */
+#define KDSKBDIACR	_IO(KD_IOCTL_BASE, 0x4B)  /* write kernel accent table */
 
 struct kbdiacruc {
 	unsigned int diacr, base, result;
@@ -134,16 +135,16 @@  struct kbdiacrsuc {
         unsigned int kb_cnt;    /* number of entries in following array */
 	struct kbdiacruc kbdiacruc[256];    /* MAX_DIACR from keyboard.h */
 };
-#define KDGKBDIACRUC    0x4BFA  /* read kernel accent table - UCS */
-#define KDSKBDIACRUC    0x4BFB  /* write kernel accent table - UCS */
+#define KDGKBDIACRUC	_IO(KD_IOCTL_BASE, 0xFA)  /* read kernel accent table - UCS */
+#define KDSKBDIACRUC	_IO(KD_IOCTL_BASE, 0xFB)  /* write kernel accent table - UCS */
 
 struct kbkeycode {
 	unsigned int scancode, keycode;
 };
-#define KDGETKEYCODE	0x4B4C	/* read kernel keycode table entry */
-#define KDSETKEYCODE	0x4B4D	/* write kernel keycode table entry */
+#define KDGETKEYCODE	_IO(KD_IOCTL_BASE, 0x4C)	/* read kernel keycode table entry */
+#define KDSETKEYCODE	_IO(KD_IOCTL_BASE, 0x4D)	/* write kernel keycode table entry */
 
-#define KDSIGACCEPT	0x4B4E	/* accept kbd generated signals */
+#define KDSIGACCEPT	_IO(KD_IOCTL_BASE, 0x4E)	/* accept kbd generated signals */
 
 struct kbd_repeat {
 	int delay;	/* in msec; <= 0: don't change */
@@ -151,10 +152,11 @@  struct kbd_repeat {
 			/* earlier this field was misnamed "rate" */
 };
 
-#define KDKBDREP        0x4B52  /* set keyboard delay/repeat rate;
-				 * actually used values are returned */
+#define KDKBDREP	_IO(KD_IOCTL_BASE, 0x52)	/* set keyboard delay/repeat rate;
+							 * actually used values are returned
+							 */
 
-#define KDFONTOP	0x4B72	/* font operations */
+#define KDFONTOP	_IO(KD_IOCTL_BASE, 0x72)	/* font operations */
 
 struct console_font_op {
 	unsigned int op;	/* operation code KD_FONT_OP_* */