arch/x86/kernel/vsmp_64.c

   1 /*
   2  * vSMPowered(tm) systems specific initialization
   3  * Copyright (C) 2005 ScaleMP Inc.
   4  *
   5  * Use of this code is subject to the terms and conditions of the
   6  * GNU general public license version 2. See "COPYING" or
   7  * http://www.gnu.org/licenses/gpl.html
   8  *
   9  * Ravikiran Thirumalai <kiran@scalemp.com>,
  10  * Shai Fultheim <shai@scalemp.com>
  11  * Paravirt ops integration: Glauber de Oliveira Costa <gcosta@redhat.com>,
  12  *                           Ravikiran Thirumalai <kiran@scalemp.com>
  13  */
  14
  15 #include <linux/init.h>
  16 #include <linux/pci_ids.h>
  17 #include <linux/pci_regs.h>
  18 #include <linux/smp.h>
  19 #include <linux/irq.h>
  20
  21 #include <asm/apic.h>
  22 #include <asm/pci-direct.h>
  23 #include <asm/io.h>
  24 #include <asm/paravirt.h>
  25 #include <asm/setup.h>
  26
  27 #define TOPOLOGY_REGISTER_OFFSET 0x10
  28
  29 /* Flag below is initialized once during vSMP PCI initialization. */
  30 static int irq_routing_comply = 1;
  31
  32 #if defined CONFIG_PCI && defined CONFIG_PARAVIRT
  33 /*
  34  * Interrupt control on vSMPowered systems:
  35  * ~AC is a shadow of IF.  If IF is 'on' AC should be 'off'
  36  * and vice versa.
  37  */
  38
  39 asmlinkage __visible unsigned long vsmp_save_fl(void)
  40 {
  41         unsigned long flags = native_save_fl();
  42
  43         if (!(flags & X86_EFLAGS_IF) || (flags & X86_EFLAGS_AC))
  44                 flags &= ~X86_EFLAGS_IF;
  45         return flags;
  46 }
  47 PV_CALLEE_SAVE_REGS_THUNK(vsmp_save_fl);
  48
  49 __visible void vsmp_restore_fl(unsigned long flags)
  50 {
  51         if (flags & X86_EFLAGS_IF)
  52                 flags &= ~X86_EFLAGS_AC;
  53         else
  54                 flags |= X86_EFLAGS_AC;
  55         native_restore_fl(flags);
  56 }
  57 PV_CALLEE_SAVE_REGS_THUNK(vsmp_restore_fl);
  58
  59 asmlinkage __visible void vsmp_irq_disable(void)
  60 {
  61         unsigned long flags = native_save_fl();
  62
  63         native_restore_fl((flags & ~X86_EFLAGS_IF) | X86_EFLAGS_AC);
  64 }
  65 PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_disable);
  66
  67 asmlinkage __visible void vsmp_irq_enable(void)
  68 {
  69         unsigned long flags = native_save_fl();
  70
  71         native_restore_fl((flags | X86_EFLAGS_IF) & (~X86_EFLAGS_AC));
  72 }
  73 PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_enable);
  74
  75 static unsigned __init_or_module vsmp_patch(u8 type, u16 clobbers, void *ibuf,
  76                                   unsigned long addr, unsigned len)
  77 {
  78         switch (type) {
  79         case PARAVIRT_PATCH(pv_irq_ops.irq_enable):
  80         case PARAVIRT_PATCH(pv_irq_ops.irq_disable):
  81         case PARAVIRT_PATCH(pv_irq_ops.save_fl):
  82         case PARAVIRT_PATCH(pv_irq_ops.restore_fl):
  83                 return paravirt_patch_default(type, clobbers, ibuf, addr, len);
  84         default:
  85                 return native_patch(type, clobbers, ibuf, addr, len);
  86         }
  87
  88 }
  89
  90 static void __init set_vsmp_pv_ops(void)
  91 {
  92         void __iomem *address;
  93         unsigned int cap, ctl, cfg;
  94
  95         /* set vSMP magic bits to indicate vSMP capable kernel */
  96         cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
  97         address = early_ioremap(cfg, 8);
  98         cap = readl(address);
  99         ctl = readl(address + 4);
 100         printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
 101                cap, ctl);
 102
 103         /* If possible, let the vSMP foundation route the interrupt optimally */
 104 #ifdef CONFIG_SMP
 105         if (cap & ctl & BIT(8)) {
 106                 ctl &= ~BIT(8);
 107
 108                 /* Interrupt routing set to ignore */
 109                 irq_routing_comply = 0;
 110
 111 #ifdef CONFIG_PROC_FS
 112                 /* Don't let users change irq affinity via procfs */
 113                 no_irq_affinity = 1;
 114 #endif
 115         }
 116 #endif
 117
 118         if (cap & ctl & (1 << 4)) {
 119                 /* Setup irq ops and turn on vSMP  IRQ fastpath handling */
 120                 pv_irq_ops.irq_disable = PV_CALLEE_SAVE(vsmp_irq_disable);
 121                 pv_irq_ops.irq_enable  = PV_CALLEE_SAVE(vsmp_irq_enable);
 122                 pv_irq_ops.save_fl  = PV_CALLEE_SAVE(vsmp_save_fl);
 123                 pv_irq_ops.restore_fl  = PV_CALLEE_SAVE(vsmp_restore_fl);
 124                 pv_init_ops.patch = vsmp_patch;
 125                 ctl &= ~(1 << 4);
 126         }
 127         writel(ctl, address + 4);
 128         ctl = readl(address + 4);
 129         pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
 130
 131         early_iounmap(address, 8);
 132 }
 133 #else
 134 static void __init set_vsmp_pv_ops(void)
 135 {
 136 }
 137 #endif
 138
 139 #ifdef CONFIG_PCI
 140 static int is_vsmp = -1;
 141
 142 static void __init detect_vsmp_box(void)
 143 {
 144         is_vsmp = 0;
 145
 146         if (!early_pci_allowed())
 147                 return;
 148
 149         /* Check if we are running on a ScaleMP vSMPowered box */
 150         if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
 151              (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
 152                 is_vsmp = 1;
 153 }
 154
 155 static int is_vsmp_box(void)
 156 {
 157         if (is_vsmp != -1)
 158                 return is_vsmp;
 159         else {
 160                 WARN_ON_ONCE(1);
 161                 return 0;
 162         }
 163 }
 164
 165 #else
 166 static void __init detect_vsmp_box(void)
 167 {
 168 }
 169 static int is_vsmp_box(void)
 170 {
 171         return 0;
 172 }
 173 #endif
 174
 175 static void __init vsmp_cap_cpus(void)
 176 {
 177 #if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP)
 178         void __iomem *address;
 179         unsigned int cfg, topology, node_shift, maxcpus;
 180
 181         /*
 182          * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
 183          * ones present in the first board, unless explicitly overridden by
 184          * setup_max_cpus
 185          */
 186         if (setup_max_cpus != NR_CPUS)
 187                 return;
 188
 189         /* Read the vSMP Foundation topology register */
 190         cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
 191         address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
 192         if (WARN_ON(!address))
 193                 return;
 194
 195         topology = readl(address);
 196         node_shift = (topology >> 16) & 0x7;
 197         if (!node_shift)
 198                 /* The value 0 should be decoded as 8 */
 199                 node_shift = 8;
 200         maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
 201
 202         pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
 203                 maxcpus);
 204         setup_max_cpus = maxcpus;
 205         early_iounmap(address, 4);
 206 #endif
 207 }
 208
 209 static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
 210 {
 211         return hard_smp_processor_id() >> index_msb;
 212 }
 213
 214 /*
 215  * In vSMP, all cpus should be capable of handling interrupts, regardless of
 216  * the APIC used.
 217  */
 218 static void fill_vector_allocation_domain(int cpu, struct cpumask *retmask,
 219                                           const struct cpumask *mask)
 220 {
 221         cpumask_setall(retmask);
 222 }
 223
 224 static void vsmp_apic_post_init(void)
 225 {
 226         /* need to update phys_pkg_id */
 227         apic->phys_pkg_id = apicid_phys_pkg_id;
 228
 229         if (!irq_routing_comply)
 230                 apic->vector_allocation_domain = fill_vector_allocation_domain;
 231 }
 232
 233 void __init vsmp_init(void)
 234 {
 235         detect_vsmp_box();
 236         if (!is_vsmp_box())
 237                 return;
 238
 239         x86_platform.apic_post_init = vsmp_apic_post_init;
 240
 241         vsmp_cap_cpus();
 242
 243         set_vsmp_pv_ops();
 244         return;
 245 }