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 #if defined CONFIG_PCI && defined CONFIG_PARAVIRT
  30 /*
  31  * Interrupt control on vSMPowered systems:
  32  * ~AC is a shadow of IF.  If IF is 'on' AC should be 'off'
  33  * and vice versa.
  34  */
  35
  36 asmlinkage __visible unsigned long vsmp_save_fl(void)
  37 {
  38         unsigned long flags = native_save_fl();
  39
  40         if (!(flags & X86_EFLAGS_IF) || (flags & X86_EFLAGS_AC))
  41                 flags &= ~X86_EFLAGS_IF;
  42         return flags;
  43 }
  44 PV_CALLEE_SAVE_REGS_THUNK(vsmp_save_fl);
  45
  46 __visible void vsmp_restore_fl(unsigned long flags)
  47 {
  48         if (flags & X86_EFLAGS_IF)
  49                 flags &= ~X86_EFLAGS_AC;
  50         else
  51                 flags |= X86_EFLAGS_AC;
  52         native_restore_fl(flags);
  53 }
  54 PV_CALLEE_SAVE_REGS_THUNK(vsmp_restore_fl);
  55
  56 asmlinkage __visible void vsmp_irq_disable(void)
  57 {
  58         unsigned long flags = native_save_fl();
  59
  60         native_restore_fl((flags & ~X86_EFLAGS_IF) | X86_EFLAGS_AC);
  61 }
  62 PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_disable);
  63
  64 asmlinkage __visible void vsmp_irq_enable(void)
  65 {
  66         unsigned long flags = native_save_fl();
  67
  68         native_restore_fl((flags | X86_EFLAGS_IF) & (~X86_EFLAGS_AC));
  69 }
  70 PV_CALLEE_SAVE_REGS_THUNK(vsmp_irq_enable);
  71
  72 static unsigned __init vsmp_patch(u8 type, u16 clobbers, void *ibuf,
  73                                   unsigned long addr, unsigned len)
  74 {
  75         switch (type) {
  76         case PARAVIRT_PATCH(pv_irq_ops.irq_enable):
  77         case PARAVIRT_PATCH(pv_irq_ops.irq_disable):
  78         case PARAVIRT_PATCH(pv_irq_ops.save_fl):
  79         case PARAVIRT_PATCH(pv_irq_ops.restore_fl):
  80                 return paravirt_patch_default(type, clobbers, ibuf, addr, len);
  81         default:
  82                 return native_patch(type, clobbers, ibuf, addr, len);
  83         }
  84
  85 }
  86
  87 static void __init set_vsmp_pv_ops(void)
  88 {
  89         void __iomem *address;
  90         unsigned int cap, ctl, cfg;
  91
  92         /* set vSMP magic bits to indicate vSMP capable kernel */
  93         cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
  94         address = early_ioremap(cfg, 8);
  95         cap = readl(address);
  96         ctl = readl(address + 4);
  97         printk(KERN_INFO "vSMP CTL: capabilities:0x%08x  control:0x%08x\n",
  98                cap, ctl);
  99
 100         /* If possible, let the vSMP foundation route the interrupt optimally */
 101 #ifdef CONFIG_SMP
 102         if (cap & ctl & BIT(8)) {
 103                 ctl &= ~BIT(8);
 104
 105 #ifdef CONFIG_PROC_FS
 106                 /* Don't let users change irq affinity via procfs */
 107                 no_irq_affinity = 1;
 108 #endif
 109         }
 110 #endif
 111
 112         if (cap & ctl & (1 << 4)) {
 113                 /* Setup irq ops and turn on vSMP  IRQ fastpath handling */
 114                 pv_irq_ops.irq_disable = PV_CALLEE_SAVE(vsmp_irq_disable);
 115                 pv_irq_ops.irq_enable  = PV_CALLEE_SAVE(vsmp_irq_enable);
 116                 pv_irq_ops.save_fl  = PV_CALLEE_SAVE(vsmp_save_fl);
 117                 pv_irq_ops.restore_fl  = PV_CALLEE_SAVE(vsmp_restore_fl);
 118                 pv_init_ops.patch = vsmp_patch;
 119                 ctl &= ~(1 << 4);
 120         }
 121         writel(ctl, address + 4);
 122         ctl = readl(address + 4);
 123         pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
 124
 125         early_iounmap(address, 8);
 126 }
 127 #else
 128 static void __init set_vsmp_pv_ops(void)
 129 {
 130 }
 131 #endif
 132
 133 #ifdef CONFIG_PCI
 134 static int is_vsmp = -1;
 135
 136 static void __init detect_vsmp_box(void)
 137 {
 138         is_vsmp = 0;
 139
 140         if (!early_pci_allowed())
 141                 return;
 142
 143         /* Check if we are running on a ScaleMP vSMPowered box */
 144         if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
 145              (PCI_VENDOR_ID_SCALEMP | (PCI_DEVICE_ID_SCALEMP_VSMP_CTL << 16)))
 146                 is_vsmp = 1;
 147 }
 148
 149 static int is_vsmp_box(void)
 150 {
 151         if (is_vsmp != -1)
 152                 return is_vsmp;
 153         else {
 154                 WARN_ON_ONCE(1);
 155                 return 0;
 156         }
 157 }
 158
 159 #else
 160 static void __init detect_vsmp_box(void)
 161 {
 162 }
 163 static int is_vsmp_box(void)
 164 {
 165         return 0;
 166 }
 167 #endif
 168
 169 static void __init vsmp_cap_cpus(void)
 170 {
 171 #if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP)
 172         void __iomem *address;
 173         unsigned int cfg, topology, node_shift, maxcpus;
 174
 175         /*
 176          * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
 177          * ones present in the first board, unless explicitly overridden by
 178          * setup_max_cpus
 179          */
 180         if (setup_max_cpus != NR_CPUS)
 181                 return;
 182
 183         /* Read the vSMP Foundation topology register */
 184         cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
 185         address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
 186         if (WARN_ON(!address))
 187                 return;
 188
 189         topology = readl(address);
 190         node_shift = (topology >> 16) & 0x7;
 191         if (!node_shift)
 192                 /* The value 0 should be decoded as 8 */
 193                 node_shift = 8;
 194         maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
 195
 196         pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
 197                 maxcpus);
 198         setup_max_cpus = maxcpus;
 199         early_iounmap(address, 4);
 200 #endif
 201 }
 202
 203 static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
 204 {
 205         return hard_smp_processor_id() >> index_msb;
 206 }
 207
 208 static void vsmp_apic_post_init(void)
 209 {
 210         /* need to update phys_pkg_id */
 211         apic->phys_pkg_id = apicid_phys_pkg_id;
 212 }
 213
 214 void __init vsmp_init(void)
 215 {
 216         detect_vsmp_box();
 217         if (!is_vsmp_box())
 218                 return;
 219
 220         x86_platform.apic_post_init = vsmp_apic_post_init;
 221
 222         vsmp_cap_cpus();
 223
 224         set_vsmp_pv_ops();
 225         return;
 226 }