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, 530 insertions, 0 deletions

diff --git a/drivers/video/fbdev/chipsfb.c b/drivers/video/fbdev/chipsfb.c
new file mode 100644
index 000000000..946e30fcb
--- /dev/null
+++ b/drivers/video/fbdev/chipsfb.c
@@ -0,0 +1,530 @@
+/*
+ *  drivers/video/chipsfb.c -- frame buffer device for
+ *  Chips & Technologies 65550 chip.
+ *
+ *  Copyright (C) 1998-2002 Paul Mackerras
+ *
+ *  This file is derived from the Powermac "chips" driver:
+ *  Copyright (C) 1997 Fabio Riccardi.
+ *  And from the frame buffer device for Open Firmware-initialized devices:
+ *  Copyright (C) 1997 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.
+ */
+
+#include <linux/aperture.h>
+#include <linux/backlight.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/vmalloc.h>
+#include <linux/delay.h>
+#include <linux/interrupt.h>
+#include <linux/fb.h>
+#include <linux/pm.h>
+#include <linux/init.h>
+#include <linux/pci.h>
+#include <linux/console.h>
+
+#ifdef CONFIG_PMAC_BACKLIGHT
+#include <asm/backlight.h>
+#endif
+
+/*
+ * Since we access the display with inb/outb to fixed port numbers,
+ * we can only handle one 6555x chip.  -- paulus
+ */
+#define write_ind(num, val, ap, dp)	do { \
+	outb((num), (ap)); outb((val), (dp)); \
+} while (0)
+#define read_ind(num, var, ap, dp)	do { \
+	outb((num), (ap)); var = inb((dp)); \
+} while (0)
+
+/* extension registers */
+#define write_xr(num, val)	write_ind(num, val, 0x3d6, 0x3d7)
+#define read_xr(num, var)	read_ind(num, var, 0x3d6, 0x3d7)
+/* flat panel registers */
+#define write_fr(num, val)	write_ind(num, val, 0x3d0, 0x3d1)
+#define read_fr(num, var)	read_ind(num, var, 0x3d0, 0x3d1)
+/* CRTC registers */
+#define write_cr(num, val)	write_ind(num, val, 0x3d4, 0x3d5)
+#define read_cr(num, var)	read_ind(num, var, 0x3d4, 0x3d5)
+/* graphics registers */
+#define write_gr(num, val)	write_ind(num, val, 0x3ce, 0x3cf)
+#define read_gr(num, var)	read_ind(num, var, 0x3ce, 0x3cf)
+/* sequencer registers */
+#define write_sr(num, val)	write_ind(num, val, 0x3c4, 0x3c5)
+#define read_sr(num, var)	read_ind(num, var, 0x3c4, 0x3c5)
+/* attribute registers - slightly strange */
+#define write_ar(num, val)	do { \
+	inb(0x3da); write_ind(num, val, 0x3c0, 0x3c0); \
+} while (0)
+#define read_ar(num, var)	do { \
+	inb(0x3da); read_ind(num, var, 0x3c0, 0x3c1); \
+} while (0)
+
+/*
+ * Exported functions
+ */
+int chips_init(void);
+
+static int chipsfb_pci_init(struct pci_dev *dp, const struct pci_device_id *);
+static int chipsfb_check_var(struct fb_var_screeninfo *var,
+			     struct fb_info *info);
+static int chipsfb_set_par(struct fb_info *info);
+static int chipsfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
+			     u_int transp, struct fb_info *info);
+static int chipsfb_blank(int blank, struct fb_info *info);
+
+static const struct fb_ops chipsfb_ops = {
+	.owner		= THIS_MODULE,
+	FB_DEFAULT_IOMEM_OPS,
+	.fb_check_var	= chipsfb_check_var,
+	.fb_set_par	= chipsfb_set_par,
+	.fb_setcolreg	= chipsfb_setcolreg,
+	.fb_blank	= chipsfb_blank,
+};
+
+static int chipsfb_check_var(struct fb_var_screeninfo *var,
+			     struct fb_info *info)
+{
+	if (var->xres > 800 || var->yres > 600
+	    || var->xres_virtual > 800 || var->yres_virtual > 600
+	    || (var->bits_per_pixel != 8 && var->bits_per_pixel != 16)
+	    || var->nonstd
+	    || (var->vmode & FB_VMODE_MASK) != FB_VMODE_NONINTERLACED)
+		return -EINVAL;
+
+	var->xres = var->xres_virtual = 800;
+	var->yres = var->yres_virtual = 600;
+
+	return 0;
+}
+
+static int chipsfb_set_par(struct fb_info *info)
+{
+	if (info->var.bits_per_pixel == 16) {
+		write_cr(0x13, 200);		// Set line length (doublewords)
+		write_xr(0x81, 0x14);		// 15 bit (555) color mode
+		write_xr(0x82, 0x00);		// Disable palettes
+		write_xr(0x20, 0x10);		// 16 bit blitter mode
+
+		info->fix.line_length = 800*2;
+		info->fix.visual = FB_VISUAL_TRUECOLOR;
+
+		info->var.red.offset = 10;
+		info->var.green.offset = 5;
+		info->var.blue.offset = 0;
+		info->var.red.length = info->var.green.length =
+			info->var.blue.length = 5;
+
+	} else {
+		/* p->var.bits_per_pixel == 8 */
+		write_cr(0x13, 100);		// Set line length (doublewords)
+		write_xr(0x81, 0x12);		// 8 bit color mode
+		write_xr(0x82, 0x08);		// Graphics gamma enable
+		write_xr(0x20, 0x00);		// 8 bit blitter mode
+
+		info->fix.line_length = 800;
+		info->fix.visual = FB_VISUAL_PSEUDOCOLOR;
+
+ 		info->var.red.offset = info->var.green.offset =
+			info->var.blue.offset = 0;
+		info->var.red.length = info->var.green.length =
+			info->var.blue.length = 8;
+
+	}
+	return 0;
+}
+
+static int chipsfb_blank(int blank, struct fb_info *info)
+{
+	return 1;	/* get fb_blank to set the colormap to all black */
+}
+
+static int chipsfb_setcolreg(u_int regno, u_int red, u_int green, u_int blue,
+			     u_int transp, struct fb_info *info)
+{
+	if (regno > 255)
+		return 1;
+	red >>= 8;
+	green >>= 8;
+	blue >>= 8;
+	outb(regno, 0x3c8);
+	udelay(1);
+	outb(red, 0x3c9);
+	outb(green, 0x3c9);
+	outb(blue, 0x3c9);
+
+	return 0;
+}
+
+struct chips_init_reg {
+	unsigned char addr;
+	unsigned char data;
+};
+
+static struct chips_init_reg chips_init_sr[] = {
+	{ 0x00, 0x03 },
+	{ 0x01, 0x01 },
+	{ 0x02, 0x0f },
+	{ 0x04, 0x0e }
+};
+
+static struct chips_init_reg chips_init_gr[] = {
+	{ 0x05, 0x00 },
+	{ 0x06, 0x0d },
+	{ 0x08, 0xff }
+};
+
+static struct chips_init_reg chips_init_ar[] = {
+	{ 0x10, 0x01 },
+	{ 0x12, 0x0f },
+	{ 0x13, 0x00 }
+};
+
+static struct chips_init_reg chips_init_cr[] = {
+	{ 0x00, 0x7f },
+	{ 0x01, 0x63 },
+	{ 0x02, 0x63 },
+	{ 0x03, 0x83 },
+	{ 0x04, 0x66 },
+	{ 0x05, 0x10 },
+	{ 0x06, 0x72 },
+	{ 0x07, 0x3e },
+	{ 0x08, 0x00 },
+	{ 0x09, 0x40 },
+	{ 0x0c, 0x00 },
+	{ 0x0d, 0x00 },
+	{ 0x10, 0x59 },
+	{ 0x11, 0x0d },
+	{ 0x12, 0x57 },
+	{ 0x13, 0x64 },
+	{ 0x14, 0x00 },
+	{ 0x15, 0x57 },
+	{ 0x16, 0x73 },
+	{ 0x17, 0xe3 },
+	{ 0x18, 0xff },
+	{ 0x30, 0x02 },
+	{ 0x31, 0x02 },
+	{ 0x32, 0x02 },
+	{ 0x33, 0x02 },
+	{ 0x40, 0x00 },
+	{ 0x41, 0x00 },
+	{ 0x40, 0x80 }
+};
+
+static struct chips_init_reg chips_init_fr[] = {
+	{ 0x01, 0x02 },
+	{ 0x03, 0x08 },
+	{ 0x04, 0x81 },
+	{ 0x05, 0x21 },
+	{ 0x08, 0x0c },
+	{ 0x0a, 0x74 },
+	{ 0x0b, 0x11 },
+	{ 0x10, 0x0c },
+	{ 0x11, 0xe0 },
+	/* { 0x12, 0x40 }, -- 3400 needs 40, 2400 needs 48, no way to tell */
+	{ 0x20, 0x63 },
+	{ 0x21, 0x68 },
+	{ 0x22, 0x19 },
+	{ 0x23, 0x7f },
+	{ 0x24, 0x68 },
+	{ 0x26, 0x00 },
+	{ 0x27, 0x0f },
+	{ 0x30, 0x57 },
+	{ 0x31, 0x58 },
+	{ 0x32, 0x0d },
+	{ 0x33, 0x72 },
+	{ 0x34, 0x02 },
+	{ 0x35, 0x22 },
+	{ 0x36, 0x02 },
+	{ 0x37, 0x00 }
+};
+
+static struct chips_init_reg chips_init_xr[] = {
+	{ 0xce, 0x00 },		/* set default memory clock */
+	{ 0xcc, 0x43 },		/* memory clock ratio */
+	{ 0xcd, 0x18 },
+	{ 0xce, 0xa1 },
+	{ 0xc8, 0x84 },
+	{ 0xc9, 0x0a },
+	{ 0xca, 0x00 },
+	{ 0xcb, 0x20 },
+	{ 0xcf, 0x06 },
+	{ 0xd0, 0x0e },
+	{ 0x09, 0x01 },
+	{ 0x0a, 0x02 },
+	{ 0x0b, 0x01 },
+	{ 0x20, 0x00 },
+	{ 0x40, 0x03 },
+	{ 0x41, 0x01 },
+	{ 0x42, 0x00 },
+	{ 0x80, 0x82 },
+	{ 0x81, 0x12 },
+	{ 0x82, 0x08 },
+	{ 0xa0, 0x00 },
+	{ 0xa8, 0x00 }
+};
+
+static void chips_hw_init(void)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(chips_init_xr); ++i)
+		write_xr(chips_init_xr[i].addr, chips_init_xr[i].data);
+	outb(0x29, 0x3c2); /* set misc output reg */
+	for (i = 0; i < ARRAY_SIZE(chips_init_sr); ++i)
+		write_sr(chips_init_sr[i].addr, chips_init_sr[i].data);
+	for (i = 0; i < ARRAY_SIZE(chips_init_gr); ++i)
+		write_gr(chips_init_gr[i].addr, chips_init_gr[i].data);
+	for (i = 0; i < ARRAY_SIZE(chips_init_ar); ++i)
+		write_ar(chips_init_ar[i].addr, chips_init_ar[i].data);
+	for (i = 0; i < ARRAY_SIZE(chips_init_cr); ++i)
+		write_cr(chips_init_cr[i].addr, chips_init_cr[i].data);
+	for (i = 0; i < ARRAY_SIZE(chips_init_fr); ++i)
+		write_fr(chips_init_fr[i].addr, chips_init_fr[i].data);
+}
+
+static const struct fb_fix_screeninfo chipsfb_fix = {
+	.id =		"C&T 65550",
+	.type =		FB_TYPE_PACKED_PIXELS,
+	.visual =	FB_VISUAL_PSEUDOCOLOR,
+	.accel =	FB_ACCEL_NONE,
+	.line_length =	800,
+
+// FIXME: Assumes 1MB frame buffer, but 65550 supports 1MB or 2MB.
+// * "3500" PowerBook G3 (the original PB G3) has 2MB.
+// * 2400 has 1MB composed of 2 Mitsubishi M5M4V4265CTP DRAM chips.
+//   Motherboard actually supports 2MB -- there are two blank locations
+//   for a second pair of DRAMs.  (Thanks, Apple!)
+// * 3400 has 1MB (I think).  Don't know if it's expandable.
+// -- Tim Seufert
+	.smem_len =	0x100000,	/* 1MB */
+};
+
+static const struct fb_var_screeninfo chipsfb_var = {
+	.xres = 800,
+	.yres = 600,
+	.xres_virtual = 800,
+	.yres_virtual = 600,
+	.bits_per_pixel = 8,
+	.red = { .length = 8 },
+	.green = { .length = 8 },
+	.blue = { .length = 8 },
+	.height = -1,
+	.width = -1,
+	.vmode = FB_VMODE_NONINTERLACED,
+	.pixclock = 10000,
+	.left_margin = 16,
+	.right_margin = 16,
+	.upper_margin = 16,
+	.lower_margin = 16,
+	.hsync_len = 8,
+	.vsync_len = 8,
+};
+
+static void init_chips(struct fb_info *p, unsigned long addr)
+{
+	fb_memset_io(p->screen_base, 0, 0x100000);
+
+	p->fix = chipsfb_fix;
+	p->fix.smem_start = addr;
+
+	p->var = chipsfb_var;
+
+	p->fbops = &chipsfb_ops;
+
+	fb_alloc_cmap(&p->cmap, 256, 0);
+
+	chips_hw_init();
+}
+
+static int chipsfb_pci_init(struct pci_dev *dp, const struct pci_device_id *ent)
+{
+	struct fb_info *p;
+	unsigned long addr;
+	unsigned short cmd;
+	int rc;
+
+	rc = aperture_remove_conflicting_pci_devices(dp, "chipsfb");
+	if (rc)
+		return rc;
+
+	rc = pci_enable_device(dp);
+	if (rc < 0) {
+		dev_err(&dp->dev, "Cannot enable PCI device\n");
+		goto err_out;
+	}
+
+	if ((dp->resource[0].flags & IORESOURCE_MEM) == 0) {
+		rc = -ENODEV;
+		goto err_disable;
+	}
+	addr = pci_resource_start(dp, 0);
+	if (addr == 0) {
+		rc = -ENODEV;
+		goto err_disable;
+	}
+
+	p = framebuffer_alloc(0, &dp->dev);
+	if (p == NULL) {
+		rc = -ENOMEM;
+		goto err_disable;
+	}
+
+	if (pci_request_region(dp, 0, "chipsfb") != 0) {
+		dev_err(&dp->dev, "Cannot request framebuffer\n");
+		rc = -EBUSY;
+		goto err_release_fb;
+	}
+
+#ifdef __BIG_ENDIAN
+	addr += 0x800000;	// Use big-endian aperture
+#endif
+
+	/* we should use pci_enable_device here, but,
+	   the device doesn't declare its I/O ports in its BARs
+	   so pci_enable_device won't turn on I/O responses */
+	pci_read_config_word(dp, PCI_COMMAND, &cmd);
+	cmd |= 3;	/* enable memory and IO space */
+	pci_write_config_word(dp, PCI_COMMAND, cmd);
+
+#ifdef CONFIG_PMAC_BACKLIGHT
+	/* turn on the backlight */
+	mutex_lock(&pmac_backlight_mutex);
+	if (pmac_backlight) {
+		pmac_backlight->props.power = BACKLIGHT_POWER_ON;
+		backlight_update_status(pmac_backlight);
+	}
+	mutex_unlock(&pmac_backlight_mutex);
+#endif /* CONFIG_PMAC_BACKLIGHT */
+
+#ifdef CONFIG_PPC
+	p->screen_base = ioremap_wc(addr, 0x200000);
+#else
+	p->screen_base = ioremap(addr, 0x200000);
+#endif
+	if (p->screen_base == NULL) {
+		dev_err(&dp->dev, "Cannot map framebuffer\n");
+		rc = -ENOMEM;
+		goto err_release_pci;
+	}
+
+	pci_set_drvdata(dp, p);
+
+	init_chips(p, addr);
+
+	rc = register_framebuffer(p);
+	if (rc < 0) {
+		dev_err(&dp->dev,"C&T 65550 framebuffer failed to register\n");
+		goto err_unmap;
+	}
+
+	dev_info(&dp->dev,"fb%d: Chips 65550 frame buffer"
+		 " (%dK RAM detected)\n",
+		 p->node, p->fix.smem_len / 1024);
+
+	return 0;
+
+ err_unmap:
+	iounmap(p->screen_base);
+ err_release_pci:
+	pci_release_region(dp, 0);
+ err_release_fb:
+	framebuffer_release(p);
+ err_disable:
+	pci_disable_device(dp);
+ err_out:
+	return rc;
+}
+
+static void chipsfb_remove(struct pci_dev *dp)
+{
+	struct fb_info *p = pci_get_drvdata(dp);
+
+	if (p->screen_base == NULL)
+		return;
+	unregister_framebuffer(p);
+	iounmap(p->screen_base);
+	p->screen_base = NULL;
+	pci_release_region(dp, 0);
+}
+
+#ifdef CONFIG_PM
+static int chipsfb_pci_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+        struct fb_info *p = pci_get_drvdata(pdev);
+
+	if (state.event == pdev->dev.power.power_state.event)
+		return 0;
+	if (!(state.event & PM_EVENT_SLEEP))
+		goto done;
+
+	console_lock();
+	chipsfb_blank(1, p);
+	fb_set_suspend(p, 1);
+	console_unlock();
+ done:
+	pdev->dev.power.power_state = state;
+	return 0;
+}
+
+static int chipsfb_pci_resume(struct pci_dev *pdev)
+{
+        struct fb_info *p = pci_get_drvdata(pdev);
+
+	console_lock();
+	fb_set_suspend(p, 0);
+	chipsfb_blank(0, p);
+	console_unlock();
+
+	pdev->dev.power.power_state = PMSG_ON;
+	return 0;
+}
+#endif /* CONFIG_PM */
+
+
+static struct pci_device_id chipsfb_pci_tbl[] = {
+	{ PCI_VENDOR_ID_CT, PCI_DEVICE_ID_CT_65550, PCI_ANY_ID, PCI_ANY_ID },
+	{ 0 }
+};
+
+MODULE_DEVICE_TABLE(pci, chipsfb_pci_tbl);
+
+static struct pci_driver chipsfb_driver = {
+	.name =		"chipsfb",
+	.id_table =	chipsfb_pci_tbl,
+	.probe =	chipsfb_pci_init,
+	.remove =	chipsfb_remove,
+#ifdef CONFIG_PM
+	.suspend =	chipsfb_pci_suspend,
+	.resume =	chipsfb_pci_resume,
+#endif
+};
+
+int __init chips_init(void)
+{
+	if (fb_modesetting_disabled("chipsfb"))
+		return -ENODEV;
+
+	if (fb_get_options("chipsfb", NULL))
+		return -ENODEV;
+
+	return pci_register_driver(&chipsfb_driver);
+}
+
+module_init(chips_init);
+
+static void __exit chipsfb_exit(void)
+{
+	pci_unregister_driver(&chipsfb_driver);
+}
+
+MODULE_DESCRIPTION("Chips & Technologies 65550 frame buffer driver");
+MODULE_LICENSE("GPL");