tty/vt: consolemap: introduce UNI_*() macros

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>
Link: https://lore.kernel.org/r/20220607104946.18710-10-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/vt/consolemap.c b/drivers/tty/vt/consolemap.c
index 016c1a0..e5fd225 100644 (file)
--- 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)
+#define UNI_GLYPH(uni)         ( (uni) & GENMASK( 5, 0))
+#define UNI(dir, row, glyph)   (((dir) << 11) | ((row) << 6) | (glyph))
+
 /**
  * struct uni_pagedict -- unicode directory
  *
@@ -265,7 +270,7 @@ static void set_inverse_trans_unicode(struct vc_data *conp,
                                glyph = p2[k];
                                if (glyph >= 0 && glyph < MAX_GLYPH
                                               && q[glyph] < 32)
-                                       q[glyph] = (i << 11) | (j << 6) | k;
+                                       q[glyph] = UNI(i, j, k);
                        }
                }
        }
@@ -497,7 +502,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
        int i, n;
        u16 **p1, *p2;
 
-       n = unicode >> 11;
+       n = UNI_DIR(unicode);
        p1 = p->uni_pgdir[n];
        if (!p1) {
                p1 = p->uni_pgdir[n] = kmalloc_array(UNI_DIR_ROWS,
@@ -508,7 +513,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
                        p1[i] = NULL;
        }
 
-       n = (unicode >> 6) & 0x1f;
+       n = UNI_ROW(unicode);
        p2 = p1[n];
        if (!p2) {
                p2 = p1[n] = kmalloc_array(UNI_ROW_GLYPHS, sizeof(u16), GFP_KERNEL);
@@ -518,7 +523,7 @@ con_insert_unipair(struct uni_pagedict *p, u_short unicode, u_short fontpos)
                memset(p2, 0xff, UNI_ROW_GLYPHS * sizeof(u16));
        }
 
-       p2[unicode & 0x3f] = fontpos;
+       p2[UNI_GLYPH(unicode)] = fontpos;
        
        p->sum += (fontpos << 20U) + unicode;
 
@@ -788,7 +793,7 @@ int con_get_unimap(struct vc_data *vc, ushort ct, ushort __user *uct, struct uni
                                                continue;
                                        if (ect < ct) {
                                                unilist[ect].unicode =
-                                                       (i<<11) | (j<<6) | k;
+                                                       UNI(i, j, k);
                                                unilist[ect].fontpos = *p2;
                                        }
                                        ect++;
@@ -857,9 +862,9 @@ conv_uni_to_pc(struct vc_data *conp, long ucs)
                return -3;
 
        p = *conp->vc_uni_pagedir_loc;
-       if ((p1 = p->uni_pgdir[ucs >> 11]) &&
-           (p2 = p1[(ucs >> 6) & 0x1f]) &&
-           (h = p2[ucs & 0x3f]) < MAX_GLYPH)
+       if ((p1 = p->uni_pgdir[UNI_DIR(ucs)]) &&
+           (p2 = p1[UNI_ROW(ucs)]) &&
+           (h = p2[UNI_GLYPH(ucs)]) < MAX_GLYPH)
                return h;
 
        return -4;              /* not found */