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vsmp_64.c
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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 <[email protected]>,
10  * Shai Fultheim <[email protected]>
11  * Paravirt ops integration: Glauber de Oliveira Costa <[email protected]>,
12  * Ravikiran Thirumalai <[email protected]>
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 static 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 static 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 static 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 static 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_or_module vsmp_patch(u8 type, u16 clobbers, void *ibuf,
73  unsigned long addr, unsigned len)
74 {
75  switch (type) {
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 #ifdef CONFIG_PROC_FS
105  /* Don't let users change irq affinity via procfs */
106  no_irq_affinity = 1;
107 #endif
108  }
109 #endif
110 
111  if (cap & ctl & (1 << 4)) {
112  /* Setup irq ops and turn on vSMP IRQ fastpath handling */
113  pv_irq_ops.irq_disable = PV_CALLEE_SAVE(vsmp_irq_disable);
114  pv_irq_ops.irq_enable = PV_CALLEE_SAVE(vsmp_irq_enable);
115  pv_irq_ops.save_fl = PV_CALLEE_SAVE(vsmp_save_fl);
116  pv_irq_ops.restore_fl = PV_CALLEE_SAVE(vsmp_restore_fl);
117  pv_init_ops.patch = vsmp_patch;
118  ctl &= ~(1 << 4);
119  }
120  writel(ctl, address + 4);
121  ctl = readl(address + 4);
122  pr_info("vSMP CTL: control set to:0x%08x\n", ctl);
123 
124  early_iounmap(address, 8);
125 }
126 #else
127 static void __init set_vsmp_pv_ops(void)
128 {
129 }
130 #endif
131 
132 #ifdef CONFIG_PCI
133 static int is_vsmp = -1;
134 
135 static void __init detect_vsmp_box(void)
136 {
137  is_vsmp = 0;
138 
139  if (!early_pci_allowed())
140  return;
141 
142  /* Check if we are running on a ScaleMP vSMPowered box */
143  if (read_pci_config(0, 0x1f, 0, PCI_VENDOR_ID) ==
145  is_vsmp = 1;
146 }
147 
148 int is_vsmp_box(void)
149 {
150  if (is_vsmp != -1)
151  return is_vsmp;
152  else {
153  WARN_ON_ONCE(1);
154  return 0;
155  }
156 }
157 
158 #else
159 static void __init detect_vsmp_box(void)
160 {
161 }
162 int is_vsmp_box(void)
163 {
164  return 0;
165 }
166 #endif
167 
168 static void __init vsmp_cap_cpus(void)
169 {
170 #if !defined(CONFIG_X86_VSMP) && defined(CONFIG_SMP)
171  void __iomem *address;
172  unsigned int cfg, topology, node_shift, maxcpus;
173 
174  /*
175  * CONFIG_X86_VSMP is not configured, so limit the number CPUs to the
176  * ones present in the first board, unless explicitly overridden by
177  * setup_max_cpus
178  */
179  if (setup_max_cpus != NR_CPUS)
180  return;
181 
182  /* Read the vSMP Foundation topology register */
183  cfg = read_pci_config(0, 0x1f, 0, PCI_BASE_ADDRESS_0);
184  address = early_ioremap(cfg + TOPOLOGY_REGISTER_OFFSET, 4);
185  if (WARN_ON(!address))
186  return;
187 
188  topology = readl(address);
189  node_shift = (topology >> 16) & 0x7;
190  if (!node_shift)
191  /* The value 0 should be decoded as 8 */
192  node_shift = 8;
193  maxcpus = (topology & ((1 << node_shift) - 1)) + 1;
194 
195  pr_info("vSMP CTL: Capping CPUs to %d (CONFIG_X86_VSMP is unset)\n",
196  maxcpus);
197  setup_max_cpus = maxcpus;
198  early_iounmap(address, 4);
199 #endif
200 }
201 
202 static int apicid_phys_pkg_id(int initial_apic_id, int index_msb)
203 {
204  return hard_smp_processor_id() >> index_msb;
205 }
206 
207 /*
208  * In vSMP, all cpus should be capable of handling interrupts, regardless of
209  * the APIC used.
210  */
211 static void fill_vector_allocation_domain(int cpu, struct cpumask *retmask,
212  const struct cpumask *mask)
213 {
214  cpumask_setall(retmask);
215 }
216 
217 static void vsmp_apic_post_init(void)
218 {
219  /* need to update phys_pkg_id */
220  apic->phys_pkg_id = apicid_phys_pkg_id;
221  apic->vector_allocation_domain = fill_vector_allocation_domain;
222 }
223 
224 void __init vsmp_init(void)
225 {
226  detect_vsmp_box();
227  if (!is_vsmp_box())
228  return;
229 
230  x86_platform.apic_post_init = vsmp_apic_post_init;
231 
232  vsmp_cap_cpus();
233 
234  set_vsmp_pv_ops();
235  return;
236 }