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/sched.h>
  19
  20 #include <asm/intrinsics.h>
  21 #include <asm/page.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/system.h>
  24 #include <asm/processor.h>
  25 #include <asm/uaccess.h>
  26
  27 #include "ia32priv.h"
  28
  29 extern int die_if_kernel (char *str, struct pt_regs *regs, long err);
  30
  31 struct page *ia32_shared_page[NR_CPUS];
  32 unsigned long *ia32_boot_gdt;
  33 unsigned long *cpu_gdt_table[NR_CPUS];
  34 struct page *ia32_gate_page;
  35
  36 static unsigned long
  37 load_desc (u16 selector)
  38 {
  39         unsigned long *table, limit, index;
  40
  41         if (!selector)
  42                 return 0;
  43         if (selector & IA32_SEGSEL_TI) {
  44                 table = (unsigned long *) IA32_LDT_OFFSET;
  45                 limit = IA32_LDT_ENTRIES;
  46         } else {
  47                 table = cpu_gdt_table[smp_processor_id()];
  48                 limit = IA32_PAGE_SIZE / sizeof(ia32_boot_gdt[0]);
  49         }
  50         index = selector >> IA32_SEGSEL_INDEX_SHIFT;
  51         if (index >= limit)
  52                 return 0;
  53         return IA32_SEG_UNSCRAMBLE(table[index]);
  54 }
  55
  56 void
  57 ia32_load_segment_descriptors (struct task_struct *task)
  58 {
  59         struct pt_regs *regs = task_pt_regs(task);
  60
  61         /* Setup the segment descriptors */
  62         regs->r24 = load_desc(regs->r16 >> 16);         /* ESD */
  63         regs->r27 = load_desc(regs->r16 >>  0);         /* DSD */
  64         regs->r28 = load_desc(regs->r16 >> 32);         /* FSD */
  65         regs->r29 = load_desc(regs->r16 >> 48);         /* GSD */
  66         regs->ar_csd = load_desc(regs->r17 >>  0);      /* CSD */
  67         regs->ar_ssd = load_desc(regs->r17 >> 16);      /* SSD */
  68 }
  69
  70 int
  71 ia32_clone_tls (struct task_struct *child, struct pt_regs *childregs)
  72 {
  73         struct desc_struct *desc;
  74         struct ia32_user_desc info;
  75         int idx;
  76
  77         if (copy_from_user(&info, (void __user *)(childregs->r14 & 0xffffffff), sizeof(info)))
  78                 return -EFAULT;
  79         if (LDT_empty(&info))
  80                 return -EINVAL;
  81
  82         idx = info.entry_number;
  83         if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
  84                 return -EINVAL;
  85
  86         desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
  87         desc->a = LDT_entry_a(&info);
  88         desc->b = LDT_entry_b(&info);
  89
  90         /* XXX: can this be done in a cleaner way ? */
  91         load_TLS(&child->thread, smp_processor_id());
  92         ia32_load_segment_descriptors(child);
  93         load_TLS(&current->thread, smp_processor_id());
  94
  95         return 0;
  96 }
  97
  98 void
  99 ia32_save_state (struct task_struct *t)
 100 {
 101         t->thread.eflag = ia64_getreg(_IA64_REG_AR_EFLAG);
 102         t->thread.fsr   = ia64_getreg(_IA64_REG_AR_FSR);
 103         t->thread.fcr   = ia64_getreg(_IA64_REG_AR_FCR);
 104         t->thread.fir   = ia64_getreg(_IA64_REG_AR_FIR);
 105         t->thread.fdr   = ia64_getreg(_IA64_REG_AR_FDR);
 106         ia64_set_kr(IA64_KR_IO_BASE, t->thread.old_iob);
 107         ia64_set_kr(IA64_KR_TSSD, t->thread.old_k1);
 108 }
 109
 110 void
 111 ia32_load_state (struct task_struct *t)
 112 {
 113         unsigned long eflag, fsr, fcr, fir, fdr, tssd;
 114         struct pt_regs *regs = task_pt_regs(t);
 115
 116         eflag = t->thread.eflag;
 117         fsr = t->thread.fsr;
 118         fcr = t->thread.fcr;
 119         fir = t->thread.fir;
 120         fdr = t->thread.fdr;
 121         tssd = load_desc(_TSS);                                 /* TSSD */
 122
 123         ia64_setreg(_IA64_REG_AR_EFLAG, eflag);
 124         ia64_setreg(_IA64_REG_AR_FSR, fsr);
 125         ia64_setreg(_IA64_REG_AR_FCR, fcr);
 126         ia64_setreg(_IA64_REG_AR_FIR, fir);
 127         ia64_setreg(_IA64_REG_AR_FDR, fdr);
 128         current->thread.old_iob = ia64_get_kr(IA64_KR_IO_BASE);
 129         current->thread.old_k1 = ia64_get_kr(IA64_KR_TSSD);
 130         ia64_set_kr(IA64_KR_IO_BASE, IA32_IOBASE);
 131         ia64_set_kr(IA64_KR_TSSD, tssd);
 132
 133         regs->r17 = (_TSS << 48) | (_LDT << 32) | (__u32) regs->r17;
 134         regs->r30 = load_desc(_LDT);                            /* LDTD */
 135         load_TLS(&t->thread, smp_processor_id());
 136 }
 137
 138 /*
 139  * Setup IA32 GDT and TSS
 140  */
 141 void
 142 ia32_gdt_init (void)
 143 {
 144         int cpu = smp_processor_id();
 145
 146         ia32_shared_page[cpu] = alloc_page(GFP_KERNEL);
 147         if (!ia32_shared_page[cpu])
 148                 panic("failed to allocate ia32_shared_page[%d]\n", cpu);
 149
 150         cpu_gdt_table[cpu] = page_address(ia32_shared_page[cpu]);
 151
 152         /* Copy from the boot cpu's GDT */
 153         memcpy(cpu_gdt_table[cpu], ia32_boot_gdt, PAGE_SIZE);
 154 }
 155
 156
 157 /*
 158  * Setup IA32 GDT and TSS
 159  */
 160 static void
 161 ia32_boot_gdt_init (void)
 162 {
 163         unsigned long ldt_size;
 164
 165         ia32_shared_page[0] = alloc_page(GFP_KERNEL);
 166         if (!ia32_shared_page[0])
 167                 panic("failed to allocate ia32_shared_page[0]\n");
 168
 169         ia32_boot_gdt = page_address(ia32_shared_page[0]);
 170         cpu_gdt_table[0] = ia32_boot_gdt;
 171
 172         /* CS descriptor in IA-32 (scrambled) format */
 173         ia32_boot_gdt[__USER_CS >> 3]
 174                 = IA32_SEG_DESCRIPTOR(0, (IA32_GATE_END-1) >> IA32_PAGE_SHIFT,
 175                                       0xb, 1, 3, 1, 1, 1, 1);
 176
 177         /* DS descriptor in IA-32 (scrambled) format */
 178         ia32_boot_gdt[__USER_DS >> 3]
 179                 = IA32_SEG_DESCRIPTOR(0, (IA32_GATE_END-1) >> IA32_PAGE_SHIFT,
 180                                       0x3, 1, 3, 1, 1, 1, 1);
 181
 182         ldt_size = PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
 183         ia32_boot_gdt[TSS_ENTRY] = IA32_SEG_DESCRIPTOR(IA32_TSS_OFFSET, 235,
 184                                                        0xb, 0, 3, 1, 1, 1, 0);
 185         ia32_boot_gdt[LDT_ENTRY] = IA32_SEG_DESCRIPTOR(IA32_LDT_OFFSET, ldt_size - 1,
 186                                                        0x2, 0, 3, 1, 1, 1, 0);
 187 }
 188
 189 static void
 190 ia32_gate_page_init(void)
 191 {
 192         unsigned long *sr;
 193
 194         ia32_gate_page = alloc_page(GFP_KERNEL);
 195         sr = page_address(ia32_gate_page);
 196         /* This is popl %eax ; movl $,%eax ; int $0x80 */
 197         *sr++ = 0xb858 | (__IA32_NR_sigreturn << 16) | (0x80cdUL << 48);
 198
 199         /* This is movl $,%eax ; int $0x80 */
 200         *sr = 0xb8 | (__IA32_NR_rt_sigreturn << 8) | (0x80cdUL << 40);
 201 }
 202
 203 void
 204 ia32_mem_init(void)
 205 {
 206         ia32_boot_gdt_init();
 207         ia32_gate_page_init();
 208 }
 209
 210 /*
 211  * Handle bad IA32 interrupt via syscall
 212  */
 213 void
 214 ia32_bad_interrupt (unsigned long int_num, struct pt_regs *regs)
 215 {
 216         siginfo_t siginfo;
 217
 218         if (die_if_kernel("Bad IA-32 interrupt", regs, int_num))
 219                 return;
 220
 221         siginfo.si_signo = SIGTRAP;
 222         siginfo.si_errno = int_num;     /* XXX is it OK to abuse si_errno like this? */
 223         siginfo.si_flags = 0;
 224         siginfo.si_isr = 0;
 225         siginfo.si_addr = NULL;
 226         siginfo.si_imm = 0;
 227         siginfo.si_code = TRAP_BRKPT;
 228         force_sig_info(SIGTRAP, &siginfo, current);
 229 }
 230
 231 void
 232 ia32_cpu_init (void)
 233 {
 234         /* initialize global ia32 state - CR0 and CR4 */
 235         ia64_setreg(_IA64_REG_AR_CFLAG, (((ulong) IA32_CR4 << 32) | IA32_CR0));
 236 }
 237
 238 static int __init
 239 ia32_init (void)
 240 {
 241 #if PAGE_SHIFT > IA32_PAGE_SHIFT
 242         {
 243                 extern struct kmem_cache *ia64_partial_page_cachep;
 244
 245                 ia64_partial_page_cachep = kmem_cache_create("ia64_partial_page_cache",
 246                                         sizeof(struct ia64_partial_page),
 247                                         0, SLAB_PANIC, NULL);
 248         }
 249 #endif
 250         return 0;
 251 }
 252
 253 __initcall(ia32_init);