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
  27 #include "ia32priv.h"
  28
  29 extern void die_if_kernel (char *str, struct pt_regs *regs, long err);
  30
  31 struct exec_domain ia32_exec_domain;
  32 struct page *ia32_shared_page[(2*IA32_PAGE_SIZE + PAGE_SIZE - 1)/PAGE_SIZE];
  33 unsigned long *ia32_gdt;
  34
  35 static unsigned long
  36 load_desc (u16 selector)
  37 {
  38         unsigned long *table, limit, index;
  39
  40         if (!selector)
  41                 return 0;
  42         if (selector & IA32_SEGSEL_TI) {
  43                 table = (unsigned long *) IA32_LDT_OFFSET;
  44                 limit = IA32_LDT_ENTRIES;
  45         } else {
  46                 table = ia32_gdt;
  47                 limit = IA32_PAGE_SIZE / sizeof(ia32_gdt[0]);
  48         }
  49         index = selector >> IA32_SEGSEL_INDEX_SHIFT;
  50         if (index >= limit)
  51                 return 0;
  52         return IA32_SEG_UNSCRAMBLE(table[index]);
  53 }
  54
  55 void
  56 ia32_load_segment_descriptors (struct task_struct *task)
  57 {
  58         struct pt_regs *regs = ia64_task_regs(task);
  59
  60         /* Setup the segment descriptors */
  61         regs->r24 = load_desc(regs->r16 >> 16);         /* ESD */
  62         regs->r27 = load_desc(regs->r16 >>  0);         /* DSD */
  63         regs->r28 = load_desc(regs->r16 >> 32);         /* FSD */
  64         regs->r29 = load_desc(regs->r16 >> 48);         /* GSD */
  65         regs->ar_csd = load_desc(regs->r17 >>  0);      /* CSD */
  66         regs->ar_ssd = load_desc(regs->r17 >> 16);      /* SSD */
  67 }
  68
  69 void
  70 ia32_save_state (struct task_struct *t)
  71 {
  72         t->thread.eflag = ia64_getreg(_IA64_REG_AR_EFLAG);
  73         t->thread.fsr   = ia64_getreg(_IA64_REG_AR_FSR);
  74         t->thread.fcr   = ia64_getreg(_IA64_REG_AR_FCR);
  75         t->thread.fir   = ia64_getreg(_IA64_REG_AR_FIR);
  76         t->thread.fdr   = ia64_getreg(_IA64_REG_AR_FDR);
  77         ia64_set_kr(IA64_KR_IO_BASE, t->thread.old_iob);
  78         ia64_set_kr(IA64_KR_TSSD, t->thread.old_k1);
  79 }
  80
  81 void
  82 ia32_load_state (struct task_struct *t)
  83 {
  84         unsigned long eflag, fsr, fcr, fir, fdr, tssd;
  85         struct pt_regs *regs = ia64_task_regs(t);
  86         int nr = get_cpu();     /* LDT and TSS depend on CPU number: */
  87
  88         eflag = t->thread.eflag;
  89         fsr = t->thread.fsr;
  90         fcr = t->thread.fcr;
  91         fir = t->thread.fir;
  92         fdr = t->thread.fdr;
  93         tssd = load_desc(_TSS(nr));                                     /* TSSD */
  94
  95         ia64_setreg(_IA64_REG_AR_EFLAG, eflag);
  96         ia64_setreg(_IA64_REG_AR_FSR, fsr);
  97         ia64_setreg(_IA64_REG_AR_FCR, fcr);
  98         ia64_setreg(_IA64_REG_AR_FIR, fir);
  99         ia64_setreg(_IA64_REG_AR_FDR, fdr);
 100         current->thread.old_iob = ia64_get_kr(IA64_KR_IO_BASE);
 101         current->thread.old_k1 = ia64_get_kr(IA64_KR_TSSD);
 102         ia64_set_kr(IA64_KR_IO_BASE, IA32_IOBASE);
 103         ia64_set_kr(IA64_KR_TSSD, tssd);
 104
 105         regs->r17 = (_TSS(nr) << 48) | (_LDT(nr) << 32) | (__u32) regs->r17;
 106         regs->r30 = load_desc(_LDT(nr));                                /* LDTD */
 107         put_cpu();
 108 }
 109
 110 /*
 111  * Setup IA32 GDT and TSS
 112  */
 113 void
 114 ia32_gdt_init (void)
 115 {
 116         unsigned long *tss;
 117         unsigned long ldt_size;
 118         int nr;
 119
 120         ia32_shared_page[0] = alloc_page(GFP_KERNEL);
 121         ia32_gdt = page_address(ia32_shared_page[0]);
 122         tss = ia32_gdt + IA32_PAGE_SIZE/sizeof(ia32_gdt[0]);
 123
 124         if (IA32_PAGE_SIZE == PAGE_SIZE) {
 125                 ia32_shared_page[1] = alloc_page(GFP_KERNEL);
 126                 tss = page_address(ia32_shared_page[1]);
 127         }
 128
 129         /* CS descriptor in IA-32 (scrambled) format */
 130         ia32_gdt[__USER_CS >> 3] = IA32_SEG_DESCRIPTOR(0, (IA32_PAGE_OFFSET-1) >> IA32_PAGE_SHIFT,
 131                                                        0xb, 1, 3, 1, 1, 1, 1);
 132
 133         /* DS descriptor in IA-32 (scrambled) format */
 134         ia32_gdt[__USER_DS >> 3] = IA32_SEG_DESCRIPTOR(0, (IA32_PAGE_OFFSET-1) >> IA32_PAGE_SHIFT,
 135                                                        0x3, 1, 3, 1, 1, 1, 1);
 136
 137         /* We never change the TSS and LDT descriptors, so we can share them across all CPUs.  */
 138         ldt_size = PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
 139         for (nr = 0; nr < NR_CPUS; ++nr) {
 140                 ia32_gdt[_TSS(nr) >> IA32_SEGSEL_INDEX_SHIFT]
 141                         = IA32_SEG_DESCRIPTOR(IA32_TSS_OFFSET, 235,
 142                                               0xb, 0, 3, 1, 1, 1, 0);
 143                 ia32_gdt[_LDT(nr) >> IA32_SEGSEL_INDEX_SHIFT]
 144                         = IA32_SEG_DESCRIPTOR(IA32_LDT_OFFSET, ldt_size - 1,
 145                                               0x2, 0, 3, 1, 1, 1, 0);
 146         }
 147 }
 148
 149 /*
 150  * Handle bad IA32 interrupt via syscall
 151  */
 152 void
 153 ia32_bad_interrupt (unsigned long int_num, struct pt_regs *regs)
 154 {
 155         siginfo_t siginfo;
 156
 157         die_if_kernel("Bad IA-32 interrupt", regs, int_num);
 158
 159         siginfo.si_signo = SIGTRAP;
 160         siginfo.si_errno = int_num;     /* XXX is it OK to abuse si_errno like this? */
 161         siginfo.si_flags = 0;
 162         siginfo.si_isr = 0;
 163         siginfo.si_addr = 0;
 164         siginfo.si_imm = 0;
 165         siginfo.si_code = TRAP_BRKPT;
 166         force_sig_info(SIGTRAP, &siginfo, current);
 167 }
 168
 169 void
 170 ia32_cpu_init (void)
 171 {
 172         /* initialize global ia32 state - CR0 and CR4 */
 173         ia64_setreg(_IA64_REG_AR_CFLAG, (((ulong) IA32_CR4 << 32) | IA32_CR0));
 174 }
 175
 176 static int __init
 177 ia32_init (void)
 178 {
 179         ia32_exec_domain.name = "Linux/x86";
 180         ia32_exec_domain.handler = NULL;
 181         ia32_exec_domain.pers_low = PER_LINUX32;
 182         ia32_exec_domain.pers_high = PER_LINUX32;
 183         ia32_exec_domain.signal_map = default_exec_domain.signal_map;
 184         ia32_exec_domain.signal_invmap = default_exec_domain.signal_invmap;
 185         register_exec_domain(&ia32_exec_domain);
 186         return 0;
 187 }
 188
 189 __initcall(ia32_init);