sched_ext: Maintain an online cid mask in the scheduler arenagrafted

Schedulers on the default cid mapping treat [0, nr_online_cids) as the
online set and restart on hotplug. Schedulers that install their own mapping
with scx_bpf_cid_override() have no way to learn which cids are online: the
count no longer identifies members and the CPU-form cpumask is unusable from
cid programs. This is an obvious hole in the cid API.

Add scx_bpf_online_cmask(), a kernel-maintained cmask in the scheduler's
arena, allocated alongside the per-CPU scratch masks and populated after the
cid mapping is finalized and before ops.init(), for child schedulers too.
The pointer stays valid through ops.exit() with no reference to take. It is
the arena offset as a void pointer, the same form struct_ops arena arguments
arrive in. The verifier types the void return as a scalar for the program's
arena cast.

The mask follows the SCX hotplug notifications: seeded from cpu_active_mask
and updated before ops.cid_online/offline() runs, so it lags cpu_online_mask
only inside a hotplug transition. Updates walk the scheduler list under the
lock that also serializes unlinking. Reads are live, not atomic snapshots.
Root initialization excludes hotplug.

v2: Reworded the getter kerneldoc (Andrea Righi).

Signed-off-by: Tejun Heo <tj@kernel.org>
Reviewed-by: Andrea Righi <arighi@nvidia.com>

1 files changed, 368 insertions, 0 deletions

diff --git a/drivers/video/fbdev/platinumfb.h b/drivers/video/fbdev/platinumfb.h
new file mode 100644
index 000000000..f6bd77caf
--- /dev/null
+++ b/drivers/video/fbdev/platinumfb.h
@@ -0,0 +1,368 @@
+/*
+ * linux/drivers/video/platinumfb-hw.c -- Frame buffer device for the
+ * Platinum on-board video in PowerMac 7200s (and some clones based
+ * on the same motherboard.)
+ *
+ *  Created 09 Feb 1998 by Jon Howell <jonh@cs.dartmouth.edu>
+ *
+ * Copyright (C) 1998 Jon Howell
+ *
+ *  based on drivers/macintosh/platinum.c: Console support
+ * 	for PowerMac "platinum" display adaptor.
+ *  Copyright (C) 1996 Paul Mackerras and Mark Abene.
+ *
+ *  based on skeletonfb.c:
+ *  Created 28 Dec 1997 by Geert Uytterhoeven
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file COPYING in the main directory of this archive
+ * for more details.
+ */
+
+/*
+ * Structure of the registers for the DACula colormap device.
+ */
+struct cmap_regs {
+	unsigned char addr;
+	char pad1[15];
+	unsigned char d1;
+	char pad2[15];
+	unsigned char d2;
+	char pad3[15];
+	unsigned char lut;
+	char pad4[15];
+};
+
+/*
+ * Structure of the registers for the "platinum" display adaptor".
+ */
+struct preg {			/* padded register */
+	unsigned r;			/* notice this is 32 bits. */
+	char pad[12];
+};
+
+struct platinum_regs {
+	struct preg reg[128];
+};
+
+/*
+ * Register initialization tables for the platinum display.
+ *
+ * It seems that there are two different types of platinum display
+ * out there.  Older ones use the values in clocksel[1], for which
+ * the formula for the clock frequency seems to be
+ *	F = 14.3MHz * c0 / (c1 & 0x1f) / (1 << (c1 >> 5))
+ * Newer ones use the values in clocksel[0], for which the formula
+ * seems to be
+ *	F = 15MHz * c0 / ((c1 & 0x1f) + 2) / (1 << (c1 >> 5))
+ */
+struct platinum_regvals {
+	int	fb_offset;
+	int	pitch[3];
+	unsigned regs[26];
+	unsigned char offset[3];
+	unsigned char mode[3];
+	unsigned char dacula_ctrl[3];
+	unsigned char clock_params[2][2];
+};
+
+#define DIV2	0x20
+#define DIV4	0x40
+#define DIV8	0x60
+#define DIV16	0x80
+
+/* 1280x1024, 75Hz (20) */
+static struct platinum_regvals platinum_reg_init_20 = {
+	0x5c00,
+	{ 1312, 2592, 2592 },
+	{ 0xffc, 4, 0, 0, 0, 0, 0x428, 0,
+	  0, 0xb3, 0xd3, 0x12, 0x1a5, 0x23, 0x28, 0x2d,
+	  0x5e, 0x19e, 0x1a4, 0x854, 0x852, 4, 9, 0x50,
+	  0x850, 0x851 }, { 0x58, 0x5d, 0x5d },
+	{ 0, 0xff, 0xff }, { 0x51, 0x55, 0x55 },
+	{{ 45, 3 }, { 66, 7 }}
+};
+
+/* 1280x960, 75Hz (19) */
+static struct platinum_regvals platinum_reg_init_19 = {
+	0x5c00,
+	{ 1312, 2592, 2592 },
+	{ 0xffc, 4, 0, 0, 0, 0, 0x428, 0,
+	  0, 0xb2, 0xd2, 0x12, 0x1a3, 0x23, 0x28, 0x2d,
+	  0x5c, 0x19c, 0x1a2, 0x7d0, 0x7ce, 4, 9, 0x4c,
+	  0x7cc, 0x7cd }, { 0x56, 0x5b, 0x5b },
+	{ 0, 0xff, 0xff }, { 0x51, 0x55, 0x55 },
+	{{ 42, 3 }, { 44, 5 }}
+};
+
+/* 1152x870, 75Hz (18) */
+static struct platinum_regvals platinum_reg_init_18 = {
+	0x11b0,
+	{ 1184, 2336, 4640 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x38f, 0,
+	  0, 0x294, 0x16c, 0x20, 0x2d7, 0x3f, 0x49, 0x53,
+	  0x82, 0x2c2, 0x2d6, 0x726, 0x724, 4, 9, 0x52,
+	  0x71e, 0x722 }, { 0x74, 0x7c, 0x81 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 26, 0 + DIV2 }, { 42, 6 }}
+};
+
+/* 1024x768, 75Hz (17) */
+static struct platinum_regvals platinum_reg_init_17 = {
+	0x10b0,
+	{ 1056, 2080, 4128 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x254, 0x14b, 0x18, 0x295, 0x2f, 0x32, 0x3b,
+	  0x80, 0x280, 0x296, 0x648, 0x646, 4, 9, 0x40,
+	  0x640, 0x644 }, { 0x72, 0x7a, 0x7f },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 54, 3 + DIV2 }, { 67, 12 }}
+};
+
+/* 1024x768, 75Hz (16) */
+static struct platinum_regvals platinum_reg_init_16 = {
+	0x10b0,
+	{ 1056, 2080, 4128 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x250, 0x147, 0x17, 0x28f, 0x2f, 0x35, 0x47,
+	  0x82, 0x282, 0x28e, 0x640, 0x63e, 4, 9, 0x3c,
+	  0x63c, 0x63d }, { 0x74, 0x7c, 0x81 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 20, 0 + DIV2 }, { 11, 2 }}
+};
+
+/* 1024x768, 70Hz (15) */
+static struct platinum_regvals platinum_reg_init_15 = {
+	0x10b0,
+	{ 1056, 2080, 4128 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x254, 0x14b, 0x22, 0x297, 0x43, 0x49, 0x5b,
+	  0x86, 0x286, 0x296, 0x64c, 0x64a, 0xa, 0xf, 0x44,
+	  0x644, 0x646 }, { 0x78, 0x80, 0x85 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 19, 0 + DIV2 }, { 110, 21 }}
+};
+
+/* 1024x768, 60Hz (14) */
+static struct platinum_regvals platinum_reg_init_14 = {
+	0x10b0,
+	{ 1056, 2080, 4128 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x25a, 0x14f, 0x22, 0x29f, 0x43, 0x49, 0x5b,
+	  0x8e, 0x28e, 0x29e, 0x64c, 0x64a, 0xa, 0xf, 0x44,
+	  0x644, 0x646 }, { 0x80, 0x88, 0x8d },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 71, 6 + DIV2 }, { 118, 13 + DIV2 }}
+};
+
+/* 832x624, 75Hz (13) */
+static struct platinum_regvals platinum_reg_init_13 = {
+	0x70,
+	{ 864, 1680, 3344 },	/* MacOS does 1680 instead of 1696 to fit 16bpp in 1MB,
+				 * and we use 3344 instead of 3360 to fit in 2Mb
+				 */
+	{ 0xff0, 4, 0, 0, 0, 0, 0x299, 0,
+	  0, 0x21e, 0x120, 0x10, 0x23f, 0x1f, 0x25, 0x37,
+	  0x8a, 0x22a, 0x23e, 0x536, 0x534, 4, 9, 0x52,
+	  0x532, 0x533 }, { 0x7c, 0x84, 0x89 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 30, 0 + DIV4 }, { 56, 7 + DIV2 }}
+};
+
+/* 800x600, 75Hz (12) */
+static struct platinum_regvals platinum_reg_init_12 = {
+	0x1010,
+	{ 832, 1632, 3232 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x1ce, 0x108, 0x14, 0x20f, 0x27, 0x30, 0x39,
+	  0x72, 0x202, 0x20e, 0x4e2, 0x4e0, 4, 9, 0x2e,
+	  0x4de, 0x4df }, { 0x64, 0x6c, 0x71 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 122, 7 + DIV4 }, { 62, 9 + DIV2 }}
+};
+
+/* 800x600, 72Hz (11) */
+static struct platinum_regvals platinum_reg_init_11 = {
+	0x1010,
+	{ 832, 1632, 3232 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x1ca, 0x104, 0x1e, 0x207, 0x3b, 0x44, 0x4d,
+	  0x56, 0x1e6, 0x206, 0x534, 0x532, 0xa, 0xe, 0x38,
+	  0x4e8, 0x4ec }, { 0x48, 0x50, 0x55 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 26, 0 + DIV4 }, { 42, 6 + DIV2 }}
+};
+
+/* 800x600, 60Hz (10) */
+static struct platinum_regvals platinum_reg_init_10 = {
+	0x1010,
+	{ 832, 1632, 3232 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x1ce, 0x108, 0x20, 0x20f, 0x3f, 0x45, 0x5d,
+	  0x66, 0x1f6, 0x20e, 0x4e8, 0x4e6, 6, 0xa, 0x34,
+	  0x4e4, 0x4e5 }, { 0x58, 0x60, 0x65 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 54, 3 + DIV4 }, { 95, 1 + DIV8 }}
+};
+
+/* 800x600, 56Hz (9) --unsupported? copy of mode 10 for now... */
+static struct platinum_regvals platinum_reg_init_9 = {
+	0x1010,
+	{ 832, 1632, 3232 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x1ce, 0x108, 0x20, 0x20f, 0x3f, 0x45, 0x5d,
+	  0x66, 0x1f6, 0x20e, 0x4e8, 0x4e6, 6, 0xa, 0x34,
+	  0x4e4, 0x4e5 }, { 0x58, 0x60, 0x65 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 54, 3 + DIV4 }, { 88, 1 + DIV8 }}
+};
+
+/* 768x576, 50Hz Interlaced-PAL (8) */
+static struct platinum_regvals platinum_reg_init_8 = {
+	0x1010,
+	{ 800, 1568, 3104 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0xc8, 0xec, 0x11, 0x1d7, 0x22, 0x25, 0x36,
+	  0x47, 0x1c7, 0x1d6, 0x271, 0x270, 4, 9, 0x27,
+	  0x267, 0x26b }, { 0x39, 0x41, 0x46 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 31, 0 + DIV16 }, { 74, 9 + DIV8 }}
+};
+
+/* 640x870, 75Hz Portrait (7) */
+static struct platinum_regvals platinum_reg_init_7 = {
+	0xb10,
+	{ 672, 1312, 2592 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x176, 0xd0, 0x14, 0x19f, 0x27, 0x2d, 0x3f,
+	  0x4a, 0x18a, 0x19e, 0x72c, 0x72a, 4, 9, 0x58,
+	  0x724, 0x72a }, { 0x3c, 0x44, 0x49 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 30, 0 + DIV4 }, { 56, 7 + DIV2 }}
+};
+
+/* 640x480, 67Hz (6) */
+static struct platinum_regvals platinum_reg_init_6 = {
+	0x1010,
+	{ 672, 1312, 2592 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x209, 0,
+	  0, 0x18e, 0xd8, 0x10, 0x1af, 0x1f, 0x25, 0x37,
+	  0x4a, 0x18a, 0x1ae, 0x41a, 0x418, 4, 9, 0x52,
+	  0x412, 0x416 }, { 0x3c, 0x44, 0x49 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 99, 4 + DIV8 }, { 42, 5 + DIV4 }}
+};
+
+/* 640x480, 60Hz (5) */
+static struct platinum_regvals platinum_reg_init_5 = {
+	0x1010,
+	{ 672, 1312, 2592 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x15e, 0xc8, 0x18, 0x18f, 0x2f, 0x35, 0x3e,
+	  0x42, 0x182, 0x18e, 0x41a, 0x418, 2, 7, 0x44,
+	  0x404, 0x408 }, { 0x34, 0x3c, 0x41 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 26, 0 + DIV8 }, { 14, 2 + DIV4 }}
+};
+
+/* 640x480, 60Hz Interlaced-NTSC (4) */
+static struct platinum_regvals platinum_reg_init_4 = {
+	0x1010,
+	{ 672, 1312, 2592 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0xa5, 0xc3, 0xe, 0x185, 0x1c, 0x1f, 0x30,
+	  0x37, 0x177, 0x184, 0x20d, 0x20c, 5, 0xb, 0x23,
+	  0x203, 0x206 }, { 0x29, 0x31, 0x36 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 94, 5 + DIV16 }, { 48, 7 + DIV8 }}
+};
+
+/* 640x480, 50Hz Interlaced-PAL (3) */
+static struct platinum_regvals platinum_reg_init_3 = {
+	0x1010,
+	{ 672, 1312, 2592 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0xc8, 0xec, 0x11, 0x1d7, 0x22, 0x25, 0x36,
+	  0x67, 0x1a7, 0x1d6, 0x271, 0x270, 4, 9, 0x57,
+	  0x237, 0x26b }, { 0x59, 0x61, 0x66 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 31, 0 + DIV16 }, { 74, 9 + DIV8 }}
+};
+
+/* 512x384, 60Hz (2) */
+static struct platinum_regvals platinum_reg_init_2 = {
+	0x1010,
+	{ 544, 1056, 2080 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0x25c, 0x140, 0x10, 0x27f, 0x1f, 0x2b, 0x4f,
+	  0x68, 0x268, 0x27e, 0x32e, 0x32c, 4, 9, 0x2a,
+	  0x32a, 0x32b }, { 0x5a, 0x62, 0x67 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 33, 2 + DIV8 }, { 79, 9 + DIV8 }}
+};
+
+/* 512x384, 60Hz Interlaced-NTSC (1) */
+static struct platinum_regvals platinum_reg_init_1 = {
+	0x1010,
+	{ 544, 1056, 2080 },
+	{ 0xff0, 4, 0, 0, 0, 0, 0x320, 0,
+	  0, 0xa5, 0xc3, 0xe, 0x185, 0x1c, 0x1f, 0x30,
+	  0x57, 0x157, 0x184, 0x20d, 0x20c, 5, 0xb, 0x53,
+	  0x1d3, 0x206 }, { 0x49, 0x51, 0x56 },
+	{ 2, 0, 0xff }, { 0x11, 0x15, 0x19 },
+	{{ 94, 5 + DIV16 }, { 48, 7 + DIV8 }}
+};
+
+static struct platinum_regvals *platinum_reg_init[VMODE_MAX] = {
+	&platinum_reg_init_1,
+	&platinum_reg_init_2,
+	&platinum_reg_init_3,
+	&platinum_reg_init_4,
+	&platinum_reg_init_5,
+	&platinum_reg_init_6,
+	&platinum_reg_init_7,
+	&platinum_reg_init_8,
+	&platinum_reg_init_9,
+	&platinum_reg_init_10,
+	&platinum_reg_init_11,
+	&platinum_reg_init_12,
+	&platinum_reg_init_13,
+	&platinum_reg_init_14,
+	&platinum_reg_init_15,
+	&platinum_reg_init_16,
+	&platinum_reg_init_17,
+	&platinum_reg_init_18,
+	&platinum_reg_init_19,
+	&platinum_reg_init_20
+};
+
+struct vmode_attr {
+	int hres;
+	int vres;
+	int vfreq;
+	int interlaced;
+};
+
+struct vmode_attr vmode_attrs[VMODE_MAX] = {
+	{512, 384, 60, 1},
+	{512, 384, 60},
+	{640, 480, 50, 1},
+	{640, 480, 60, 1},
+	{640, 480, 60},
+	{640, 480, 67},
+	{640, 870, 75},
+	{768, 576, 50, 1},
+	{800, 600, 56},
+	{800, 600, 60},
+	{800, 600, 72},
+	{800, 600, 75},
+	{832, 624, 75},
+	{1024, 768, 60},
+	{1024, 768, 72},
+	{1024, 768, 75},
+	{1024, 768, 75},
+	{1152, 870, 75},
+	{1280, 960, 75},
+	{1280, 1024, 75}
+};
+