arch/ia64/ia32/ia32_support.c

   1 /*
   2  * IA32 helper functions
   3  *
   4  * Copyright (C) 1999 Arun Sharma <arun.sharma@intel.com>
   5  * Copyright (C) 2000 Asit K. Mallick <asit.k.mallick@intel.com>
   6  * Copyright (C) 2001-2002 Hewlett-Packard Co
   7  *      David Mosberger-Tang <davidm@hpl.hp.com>
   8  *
   9  * 06/16/00     A. Mallick      added csd/ssd/tssd for ia32 thread context
  10  * 02/19/01     D. Mosberger    dropped tssd; it's not needed
  11  * 09/14/01     D. Mosberger    fixed memory management for gdt/tss page
  12  * 09/29/01     D. Mosberger    added ia32_load_segment_descriptors()
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/init.h>
  17 #include <linux/mm.h>
  18 #include <linux/personality.h>
  19 #include <linux/sched.h>
  20
  21 #include <asm/intrinsics.h>
  22 #include <asm/page.h>
  23 #include <asm/pgtable.h>
  24 #include <asm/system.h>
  25 #include <asm/processor.h>
  26 #include <asm/uaccess.h>
  27
  28 #include "ia32priv.h"
  29
  30 extern void die_if_kernel (char *str, struct pt_regs *regs, long err);
  31
  32 struct exec_domain ia32_exec_domain;
  33 struct page *ia32_shared_page[NR_CPUS];
  34 unsigned long *ia32_boot_gdt;
  35 unsigned long *cpu_gdt_table[NR_CPUS];
  36 struct page *ia32_gate_page;
  37
  38 static unsigned long
  39 load_desc (u16 selector)
  40 {
  41         unsigned long *table, limit, index;
  42
  43         if (!selector)
  44                 return 0;
  45         if (selector & IA32_SEGSEL_TI) {
  46                 table = (unsigned long *) IA32_LDT_OFFSET;
  47                 limit = IA32_LDT_ENTRIES;
  48         } else {
  49                 table = cpu_gdt_table[smp_processor_id()];
  50                 limit = IA32_PAGE_SIZE / sizeof(ia32_boot_gdt[0]);
  51         }
  52         index = selector >> IA32_SEGSEL_INDEX_SHIFT;
  53         if (index >= limit)
  54                 return 0;
  55         return IA32_SEG_UNSCRAMBLE(table[index]);
  56 }
  57
  58 void
  59 ia32_load_segment_descriptors (struct task_struct *task)
  60 {
  61         struct pt_regs *regs = ia64_task_regs(task);
  62
  63         /* Setup the segment descriptors */
  64         regs->r24 = load_desc(regs->r16 >> 16);         /* ESD */
  65         regs->r27 = load_desc(regs->r16 >>  0);         /* DSD */
  66         regs->r28 = load_desc(regs->r16 >> 32);         /* FSD */
  67         regs->r29 = load_desc(regs->r16 >> 48);         /* GSD */
  68         regs->ar_csd = load_desc(regs->r17 >>  0);      /* CSD */
  69         regs->ar_ssd = load_desc(regs->r17 >> 16);      /* SSD */
  70 }
  71
  72 int
  73 ia32_clone_tls (struct task_struct *child, struct pt_regs *childregs)
  74 {
  75         struct desc_struct *desc;
  76         struct ia32_user_desc info;
  77         int idx;
  78
  79         if (copy_from_user(&info, (void __user *)(childregs->r14 & 0xffffffff), sizeof(info)))
  80                 return -EFAULT;
  81         if (LDT_empty(&info))
  82                 return -EINVAL;
  83
  84         idx = info.entry_number;
  85         if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
  86                 return -EINVAL;
  87
  88         desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
  89         desc->a = LDT_entry_a(&info);
  90         desc->b = LDT_entry_b(&info);
  91
  92         /* XXX: can this be done in a cleaner way ? */
  93         load_TLS(&child->thread, smp_processor_id());
  94         ia32_load_segment_descriptors(child);
  95         load_TLS(&current->thread, smp_processor_id());
  96
  97         return 0;
  98 }
  99
 100 void
 101 ia32_save_state (struct task_struct *t)
 102 {
 103         t->thread.eflag = ia64_getreg(_IA64_REG_AR_EFLAG);
 104         t->thread.fsr   = ia64_getreg(_IA64_REG_AR_FSR);
 105         t->thread.fcr   = ia64_getreg(_IA64_REG_AR_FCR);
 106         t->thread.fir   = ia64_getreg(_IA64_REG_AR_FIR);
 107         t->thread.fdr   = ia64_getreg(_IA64_REG_AR_FDR);
 108         ia64_set_kr(IA64_KR_IO_BASE, t->thread.old_iob);
 109         ia64_set_kr(IA64_KR_TSSD, t->thread.old_k1);
 110 }
 111
 112 void
 113 ia32_load_state (struct task_struct *t)
 114 {
 115         unsigned long eflag, fsr, fcr, fir, fdr, tssd;
 116         struct pt_regs *regs = ia64_task_regs(t);
 117
 118         eflag = t->thread.eflag;
 119         fsr = t->thread.fsr;
 120         fcr = t->thread.fcr;
 121         fir = t->thread.fir;
 122         fdr = t->thread.fdr;
 123         tssd = load_desc(_TSS);                                 /* TSSD */
 124
 125         ia64_setreg(_IA64_REG_AR_EFLAG, eflag);
 126         ia64_setreg(_IA64_REG_AR_FSR, fsr);
 127         ia64_setreg(_IA64_REG_AR_FCR, fcr);
 128         ia64_setreg(_IA64_REG_AR_FIR, fir);
 129         ia64_setreg(_IA64_REG_AR_FDR, fdr);
 130         current->thread.old_iob = ia64_get_kr(IA64_KR_IO_BASE);
 131         current->thread.old_k1 = ia64_get_kr(IA64_KR_TSSD);
 132         ia64_set_kr(IA64_KR_IO_BASE, IA32_IOBASE);
 133         ia64_set_kr(IA64_KR_TSSD, tssd);
 134
 135         regs->r17 = (_TSS << 48) | (_LDT << 32) | (__u32) regs->r17;
 136         regs->r30 = load_desc(_LDT);                            /* LDTD */
 137         load_TLS(&t->thread, smp_processor_id());
 138 }
 139
 140 /*
 141  * Setup IA32 GDT and TSS
 142  */
 143 void
 144 ia32_gdt_init (void)
 145 {
 146         int cpu = smp_processor_id();
 147
 148         ia32_shared_page[cpu] = alloc_page(GFP_KERNEL);
 149         if (!ia32_shared_page[cpu])
 150                 panic("failed to allocate ia32_shared_page[%d]\n", cpu);
 151
 152         cpu_gdt_table[cpu] = page_address(ia32_shared_page[cpu]);
 153
 154         /* Copy from the boot cpu's GDT */
 155         memcpy(cpu_gdt_table[cpu], ia32_boot_gdt, PAGE_SIZE);
 156 }
 157
 158
 159 /*
 160  * Setup IA32 GDT and TSS
 161  */
 162 static void
 163 ia32_boot_gdt_init (void)
 164 {
 165         unsigned long ldt_size;
 166
 167         ia32_shared_page[0] = alloc_page(GFP_KERNEL);
 168         if (!ia32_shared_page[0])
 169                 panic("failed to allocate ia32_shared_page[0]\n");
 170
 171         ia32_boot_gdt = page_address(ia32_shared_page[0]);
 172         cpu_gdt_table[0] = ia32_boot_gdt;
 173
 174         /* CS descriptor in IA-32 (scrambled) format */
 175         ia32_boot_gdt[__USER_CS >> 3]
 176                 = IA32_SEG_DESCRIPTOR(0, (IA32_GATE_END-1) >> IA32_PAGE_SHIFT,
 177                                       0xb, 1, 3, 1, 1, 1, 1);
 178
 179         /* DS descriptor in IA-32 (scrambled) format */
 180         ia32_boot_gdt[__USER_DS >> 3]
 181                 = IA32_SEG_DESCRIPTOR(0, (IA32_GATE_END-1) >> IA32_PAGE_SHIFT,
 182                                       0x3, 1, 3, 1, 1, 1, 1);
 183
 184         ldt_size = PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
 185         ia32_boot_gdt[TSS_ENTRY] = IA32_SEG_DESCRIPTOR(IA32_TSS_OFFSET, 235,
 186                                                        0xb, 0, 3, 1, 1, 1, 0);
 187         ia32_boot_gdt[LDT_ENTRY] = IA32_SEG_DESCRIPTOR(IA32_LDT_OFFSET, ldt_size - 1,
 188                                                        0x2, 0, 3, 1, 1, 1, 0);
 189 }
 190
 191 static void
 192 ia32_gate_page_init(void)
 193 {
 194         unsigned long *sr;
 195
 196         ia32_gate_page = alloc_page(GFP_KERNEL);
 197         sr = page_address(ia32_gate_page);
 198         /* This is popl %eax ; movl $,%eax ; int $0x80 */
 199         *sr++ = 0xb858 | (__IA32_NR_sigreturn << 16) | (0x80cdUL << 48);
 200
 201         /* This is movl $,%eax ; int $0x80 */
 202         *sr = 0xb8 | (__IA32_NR_rt_sigreturn << 8) | (0x80cdUL << 40);
 203 }
 204
 205 void
 206 ia32_mem_init(void)
 207 {
 208         ia32_boot_gdt_init();
 209         ia32_gate_page_init();
 210 }
 211
 212 /*
 213  * Handle bad IA32 interrupt via syscall
 214  */
 215 void
 216 ia32_bad_interrupt (unsigned long int_num, struct pt_regs *regs)
 217 {
 218         siginfo_t siginfo;
 219
 220         die_if_kernel("Bad IA-32 interrupt", regs, int_num);
 221
 222         siginfo.si_signo = SIGTRAP;
 223         siginfo.si_errno = int_num;     /* XXX is it OK to abuse si_errno like this? */
 224         siginfo.si_flags = 0;
 225         siginfo.si_isr = 0;
 226         siginfo.si_addr = NULL;
 227         siginfo.si_imm = 0;
 228         siginfo.si_code = TRAP_BRKPT;
 229         force_sig_info(SIGTRAP, &siginfo, current);
 230 }
 231
 232 void
 233 ia32_cpu_init (void)
 234 {
 235         /* initialize global ia32 state - CR0 and CR4 */
 236         ia64_setreg(_IA64_REG_AR_CFLAG, (((ulong) IA32_CR4 << 32) | IA32_CR0));
 237 }
 238
 239 static int __init
 240 ia32_init (void)
 241 {
 242         ia32_exec_domain.name = "Linux/x86";
 243         ia32_exec_domain.handler = NULL;
 244         ia32_exec_domain.pers_low = PER_LINUX32;
 245         ia32_exec_domain.pers_high = PER_LINUX32;
 246         ia32_exec_domain.signal_map = default_exec_domain.signal_map;
 247         ia32_exec_domain.signal_invmap = default_exec_domain.signal_invmap;
 248         register_exec_domain(&ia32_exec_domain);
 249
 250 #if PAGE_SHIFT > IA32_PAGE_SHIFT
 251         {
 252                 extern kmem_cache_t *partial_page_cachep;
 253
 254                 partial_page_cachep = kmem_cache_create("partial_page_cache",
 255                                                         sizeof(struct partial_page), 0, 0,
 256                                                         NULL, NULL);
 257                 if (!partial_page_cachep)
 258                         panic("Cannot create partial page SLAB cache");
 259         }
 260 #endif
 261         return 0;
 262 }
 263
 264 __initcall(ia32_init);