From: "Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>
To: Jiri Slaby <jirislaby@kernel.org>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
linux-serial <linux-serial@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 10/36] tty/vt: consolemap: introduce UNI_*() macros
Date: Wed, 8 Jun 2022 11:02:33 +0300 (EEST) [thread overview]
Message-ID: <96808a-1c54-ed9b-ea35-565f49a6f360@linux.intel.com> (raw)
In-Reply-To: <e9fdf394-9dd2-b1d3-29c9-66eb3353c0ec@kernel.org>
[-- Attachment #1: Type: text/plain, Size: 3673 bytes --]
On Wed, 8 Jun 2022, Jiri Slaby wrote:
> On 08. 06. 22, 8:59, Jiri Slaby wrote:
> > On 07. 06. 22, 15:47, Ilpo Järvinen wrote:
> > > On Tue, 7 Jun 2022, Jiri Slaby wrote:
> > >
> > > > The code currently does shift, OR, and AND logic directly in the code.
> > > > It is not much obvious what happens there. Therefore define four macros
> > > > for that purpose and use them in the code. We use GENMASK() so that it
> > > > is clear which bits serve what purpose:
> > > > - UNI_GLYPH: bits 0.. 5
> > > > - UNI_ROW: bits 6..10
> > > > - UNI_DIR: bits 11..31
> > > >
> > > > Signed-off-by: Jiri Slaby <jslaby@suse.cz>
> > > > ---
> > > > drivers/tty/vt/consolemap.c | 21 +++++++++++++--------
> > > > 1 file changed, 13 insertions(+), 8 deletions(-)
> > > >
> > > > diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
> > > > index 016c1a0b4290..e5fd225e87bd 100644
> > > > --- a/drivers/tty/vt/consolemap.c
> > > > +++ b/drivers/tty/vt/consolemap.c
> > > > @@ -190,6 +190,11 @@ static int inv_translate[MAX_NR_CONSOLES];
> > > > #define UNI_DIR_ROWS 32U
> > > > #define UNI_ROW_GLYPHS 64U
> > > > +#define UNI_DIR(uni) ( (uni) >> 11)
> > > > +#define UNI_ROW(uni) (((uni) & GENMASK(10, 6)) >> 6)
> > >
> > > This is opencoding what FIELD_GET() does. Maybe just define these as
> > > masks and use FIELD_GET in the code below.
> >
> > Ah, great -- I was thinking there should be something for that purpose
> > already, but didn't find this. But let's define these UNI_* macros using
> > appropriate FIELD_GET(). (And not using FIELD_GET() in the code.)
> >
> > > > +#define UNI_GLYPH(uni) ( (uni) & GENMASK( 5, 0))
> > thanks,
>
> JFYI, I ended up with this diff to the original approach:
> --- a/drivers/tty/vt/consolemap.c
> +++ b/drivers/tty/vt/consolemap.c
> @@ -23,6 +23,8 @@
> * stack overflow.
> */
>
> +#include <linux/bitfield.h>
> +#include <linux/bits.h>
> #include <linux/module.h>
> #include <linux/kd.h>
> #include <linux/errno.h>
> @@ -190,10 +192,17 @@ static int inv_translate[MAX_NR_CONSOLES];
> #define UNI_DIR_ROWS 32U
> #define UNI_ROW_GLYPHS 64U
>
> -#define UNI_DIR(uni) ( (uni) >> 11)
> -#define UNI_ROW(uni) (((uni) & GENMASK(10, 6)) >> 6)
> -#define UNI_GLYPH(uni) ( (uni) & GENMASK( 5, 0))
> -#define UNI(dir, row, glyph) (((dir) << 11) | ((row) << 6) | (glyph))
> +#define UNI_DIR_BITS(max) GENMASK((max), 11)
> +#define UNI_ROW_BITS GENMASK(10, 6)
> +#define UNI_GLYPH_BITS GENMASK( 5, 0)
> +
> +#define UNI_DIR(uni) FIELD_GET(UNI_DIR_BITS(sizeof(uni) * 8 - 1), (uni))
That would be * BITS_PER_BYTE. But see below.
> +#define UNI_ROW(uni) FIELD_GET(UNI_ROW_BITS, (uni))
> +#define UNI_GLYPH(uni) FIELD_GET(UNI_GLYPH_BITS, (uni))
> +
> +#define UNI(dir, row, glyph) (FIELD_PREP(UNI_DIR_BITS(31), (dir)) | \
> + FIELD_PREP(UNI_ROW_BITS, (row)) | \
> + FIELD_PREP(UNI_GLYPH_BITS, (glyph)))
>
> /**
> * struct uni_pagedict -- unicode directory
>
> =======================================================
>
> More text, but easier to follow, I think. except the UNI_DIR_BITS() has to
> have a parameter, otherwise compilation raises a too-big value warning with
> use of UNI_DIR() in con_insert_unipair() where uni is only of ushort type.
It doesn't raise any warnings if I do:
#define UNI_DIR_BITS GENMASK(15, 11)
As UNI_DIRS is 32 it cannot ever be larger than that?
> Alternatively, we can cast uni to u32, but that produces worse assembly
> (extensions to u32 here and there).
--
i.
next prev parent reply other threads:[~2022-06-08 8:43 UTC|newest]
Thread overview: 74+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-06-07 10:49 [PATCH 01/36] tty/vt: consolemap: use ARRAY_SIZE() Jiri Slaby
2022-06-07 10:49 ` [PATCH 02/36] tty/vt: consolemap: rename and document struct uni_pagedir Jiri Slaby
2022-06-07 12:36 ` Ilpo Järvinen
2022-06-08 5:42 ` Jiri Slaby
2022-06-07 10:49 ` [PATCH 03/36] tty/vt: consolemap: define UNI_* macros for constants Jiri Slaby
2022-06-07 13:21 ` Ilpo Järvinen
2022-06-08 6:55 ` Jiri Slaby
2022-06-08 9:54 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 04/36] tty/vt: consolemap: decrypt inverse_translate() Jiri Slaby
2022-06-07 12:54 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 05/36] tty/vt: consolemap: remove extern from function decls Jiri Slaby
2022-06-07 13:33 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 06/36] tty/vt: consolemap: convert macros to static inlines Jiri Slaby
2022-06-07 13:31 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 07/36] tty/vt: consolemap: make parameters of inverse_translate() saner Jiri Slaby
2022-06-07 13:32 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 08/36] tty/vt: consolemap: one line = one statement Jiri Slaby
2022-06-07 13:35 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 09/36] tty/vt: consolemap: use | for binary addition Jiri Slaby
2022-06-07 13:36 ` Ilpo Järvinen
2022-06-07 13:40 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 10/36] tty/vt: consolemap: introduce UNI_*() macros Jiri Slaby
2022-06-07 13:47 ` Ilpo Järvinen
2022-06-08 6:59 ` Jiri Slaby
2022-06-08 7:30 ` Jiri Slaby
2022-06-08 8:02 ` Ilpo Järvinen [this message]
2022-06-08 8:18 ` Jiri Slaby
2022-06-07 10:49 ` [PATCH 11/36] tty/vt: consolemap: zero uni_pgdir using kcalloc() Jiri Slaby
2022-06-07 13:51 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 12/36] tty/vt: consolemap: use sizeof(*pointer) instead of sizeof(type) Jiri Slaby
2022-06-07 14:00 ` Ilpo Järvinen
2022-06-07 18:13 ` Jiri Slaby
2022-06-08 7:23 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 13/36] tty/vt: consolemap: make con_set_unimap() more readable Jiri Slaby
2022-06-07 14:06 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 14/36] tty/vt: consolemap: make con_get_unimap() " Jiri Slaby
2022-06-07 14:11 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 15/36] tty/vt: consolemap: make p1 increment less confusing in con_get_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 16/36] tty/vt: consolemap: check put_user() " Jiri Slaby
2022-06-07 14:19 ` Ilpo Järvinen
2022-06-08 7:40 ` Jiri Slaby
2022-06-08 8:13 ` Ilpo Järvinen
2022-06-08 10:38 ` Andy Shevchenko
2022-06-08 10:43 ` Greg Kroah-Hartman
2022-06-08 8:02 ` David Laight
2022-06-08 8:11 ` Jiri Slaby
2022-06-08 8:13 ` Jiri Slaby
2022-06-09 8:51 ` Jiri Slaby
2022-06-07 10:49 ` [PATCH 17/36] tty/vt: consolemap: introduce enum translation_map and use it Jiri Slaby
2022-06-07 10:49 ` [PATCH 18/36] tty/vt: consolemap: remove glyph < 0 check from set_inverse_trans_unicode() Jiri Slaby
2022-06-07 10:49 ` [PATCH 19/36] tty/vt: consolemap: extract dict unsharing to con_unshare_unimap() Jiri Slaby
2022-06-07 14:30 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 20/36] tty/vt: consolemap: saner variable names in set_inverse_trans_unicode() Jiri Slaby
2022-06-07 14:34 ` Ilpo Järvinen
2022-06-07 10:49 ` [PATCH 21/36] tty/vt: consolemap: saner variable names in conv_uni_to_pc() Jiri Slaby
2022-06-07 10:49 ` [PATCH 22/36] tty/vt: consolemap: saner variable names in con_insert_unipair() Jiri Slaby
2022-06-07 10:49 ` [PATCH 23/36] tty/vt: consolemap: saner variable names in con_unify_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 24/36] tty/vt: consolemap: saner variable names in con_do_clear_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 25/36] tty/vt: consolemap: saner variable names in con_unshare_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 26/36] tty/vt: consolemap: saner variable names in con_release_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 27/36] tty/vt: consolemap: saner variable names in con_copy_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 28/36] tty/vt: consolemap: saner variable names in con_get_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 29/36] tty/vt: consolemap: saner variable names in con_set_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 30/36] tty/vt: consolemap: saner variable names in con_set_default_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 31/36] tty/vt: consolemap: make conv_uni_to_pc() more readable Jiri Slaby
2022-06-07 10:49 ` [PATCH 32/36] tty/vt: consolemap: remove superfluous whitespace Jiri Slaby
2022-06-07 10:49 ` [PATCH 33/36] tty/vt: consolemap: change refcount only if needed in con_do_clear_unimap() Jiri Slaby
2022-06-07 15:31 ` Ilpo Järvinen
2022-06-08 7:44 ` Jiri Slaby
2022-06-07 10:49 ` [PATCH 34/36] tty/vt: consolemap: extract con_allocate_new() from con_do_clear_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 35/36] tty/vt: consolemap: use con_allocate_new() in con_unshare_unimap() Jiri Slaby
2022-06-07 10:49 ` [PATCH 36/36] tty/vt: consolemap: walk the buffer only once in con_set_trans_old() Jiri Slaby
2022-06-07 16:25 ` Ilpo Järvinen
2022-06-07 12:36 ` [PATCH 01/36] tty/vt: consolemap: use ARRAY_SIZE() Ilpo Järvinen
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