839052d27e
The patch aims to fix a performance issue for the syscall personality(PER_LINUX32). On IA-64 box, the syscall personality (PER_LINUX32) has poor performance because it failed to find the Linux/x86 execution domain. Then it tried to load the kernel module however it failed always and it used the default execution domain PER_LINUX instead. Requesting kernel modules is very expensive. It caused the performance issue. (see the function lookup_exec_domain in kernel/exec_domain.c). To resolve the issue, execution domain Linux/x86 is always registered in initialization time for IA-64 architecture. Signed-off-by: Xiaolan Huang <xiaolan.huang@intel.com> Signed-off-by: Tony Luck <tony.luck@intel.com>
253 lines
6.4 KiB
C
253 lines
6.4 KiB
C
/*
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* IA32 helper functions
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*
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* Copyright (C) 1999 Arun Sharma <arun.sharma@intel.com>
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* Copyright (C) 2000 Asit K. Mallick <asit.k.mallick@intel.com>
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* Copyright (C) 2001-2002 Hewlett-Packard Co
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* David Mosberger-Tang <davidm@hpl.hp.com>
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*
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* 06/16/00 A. Mallick added csd/ssd/tssd for ia32 thread context
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* 02/19/01 D. Mosberger dropped tssd; it's not needed
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* 09/14/01 D. Mosberger fixed memory management for gdt/tss page
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* 09/29/01 D. Mosberger added ia32_load_segment_descriptors()
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/mm.h>
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#include <linux/sched.h>
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#include <asm/intrinsics.h>
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#include <asm/page.h>
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#include <asm/pgtable.h>
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#include <asm/system.h>
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#include <asm/processor.h>
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#include <asm/uaccess.h>
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#include "ia32priv.h"
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extern int die_if_kernel (char *str, struct pt_regs *regs, long err);
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struct page *ia32_shared_page[NR_CPUS];
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unsigned long *ia32_boot_gdt;
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unsigned long *cpu_gdt_table[NR_CPUS];
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struct page *ia32_gate_page;
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static unsigned long
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load_desc (u16 selector)
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{
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unsigned long *table, limit, index;
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if (!selector)
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return 0;
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if (selector & IA32_SEGSEL_TI) {
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table = (unsigned long *) IA32_LDT_OFFSET;
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limit = IA32_LDT_ENTRIES;
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} else {
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table = cpu_gdt_table[smp_processor_id()];
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limit = IA32_PAGE_SIZE / sizeof(ia32_boot_gdt[0]);
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}
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index = selector >> IA32_SEGSEL_INDEX_SHIFT;
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if (index >= limit)
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return 0;
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return IA32_SEG_UNSCRAMBLE(table[index]);
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}
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void
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ia32_load_segment_descriptors (struct task_struct *task)
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{
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struct pt_regs *regs = task_pt_regs(task);
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/* Setup the segment descriptors */
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regs->r24 = load_desc(regs->r16 >> 16); /* ESD */
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regs->r27 = load_desc(regs->r16 >> 0); /* DSD */
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regs->r28 = load_desc(regs->r16 >> 32); /* FSD */
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regs->r29 = load_desc(regs->r16 >> 48); /* GSD */
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regs->ar_csd = load_desc(regs->r17 >> 0); /* CSD */
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regs->ar_ssd = load_desc(regs->r17 >> 16); /* SSD */
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}
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int
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ia32_clone_tls (struct task_struct *child, struct pt_regs *childregs)
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{
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struct desc_struct *desc;
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struct ia32_user_desc info;
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int idx;
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if (copy_from_user(&info, (void __user *)(childregs->r14 & 0xffffffff), sizeof(info)))
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return -EFAULT;
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if (LDT_empty(&info))
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return -EINVAL;
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idx = info.entry_number;
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if (idx < GDT_ENTRY_TLS_MIN || idx > GDT_ENTRY_TLS_MAX)
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return -EINVAL;
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desc = child->thread.tls_array + idx - GDT_ENTRY_TLS_MIN;
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desc->a = LDT_entry_a(&info);
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desc->b = LDT_entry_b(&info);
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/* XXX: can this be done in a cleaner way ? */
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load_TLS(&child->thread, smp_processor_id());
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ia32_load_segment_descriptors(child);
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load_TLS(¤t->thread, smp_processor_id());
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return 0;
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}
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void
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ia32_save_state (struct task_struct *t)
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{
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t->thread.eflag = ia64_getreg(_IA64_REG_AR_EFLAG);
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t->thread.fsr = ia64_getreg(_IA64_REG_AR_FSR);
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t->thread.fcr = ia64_getreg(_IA64_REG_AR_FCR);
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t->thread.fir = ia64_getreg(_IA64_REG_AR_FIR);
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t->thread.fdr = ia64_getreg(_IA64_REG_AR_FDR);
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ia64_set_kr(IA64_KR_IO_BASE, t->thread.old_iob);
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ia64_set_kr(IA64_KR_TSSD, t->thread.old_k1);
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}
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void
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ia32_load_state (struct task_struct *t)
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{
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unsigned long eflag, fsr, fcr, fir, fdr, tssd;
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struct pt_regs *regs = task_pt_regs(t);
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eflag = t->thread.eflag;
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fsr = t->thread.fsr;
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fcr = t->thread.fcr;
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fir = t->thread.fir;
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fdr = t->thread.fdr;
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tssd = load_desc(_TSS); /* TSSD */
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ia64_setreg(_IA64_REG_AR_EFLAG, eflag);
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ia64_setreg(_IA64_REG_AR_FSR, fsr);
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ia64_setreg(_IA64_REG_AR_FCR, fcr);
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ia64_setreg(_IA64_REG_AR_FIR, fir);
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ia64_setreg(_IA64_REG_AR_FDR, fdr);
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current->thread.old_iob = ia64_get_kr(IA64_KR_IO_BASE);
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current->thread.old_k1 = ia64_get_kr(IA64_KR_TSSD);
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ia64_set_kr(IA64_KR_IO_BASE, IA32_IOBASE);
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ia64_set_kr(IA64_KR_TSSD, tssd);
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regs->r17 = (_TSS << 48) | (_LDT << 32) | (__u32) regs->r17;
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regs->r30 = load_desc(_LDT); /* LDTD */
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load_TLS(&t->thread, smp_processor_id());
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}
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/*
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* Setup IA32 GDT and TSS
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*/
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void
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ia32_gdt_init (void)
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{
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int cpu = smp_processor_id();
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ia32_shared_page[cpu] = alloc_page(GFP_KERNEL);
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if (!ia32_shared_page[cpu])
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panic("failed to allocate ia32_shared_page[%d]\n", cpu);
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cpu_gdt_table[cpu] = page_address(ia32_shared_page[cpu]);
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/* Copy from the boot cpu's GDT */
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memcpy(cpu_gdt_table[cpu], ia32_boot_gdt, PAGE_SIZE);
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}
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/*
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* Setup IA32 GDT and TSS
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*/
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static void
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ia32_boot_gdt_init (void)
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{
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unsigned long ldt_size;
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ia32_shared_page[0] = alloc_page(GFP_KERNEL);
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if (!ia32_shared_page[0])
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panic("failed to allocate ia32_shared_page[0]\n");
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ia32_boot_gdt = page_address(ia32_shared_page[0]);
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cpu_gdt_table[0] = ia32_boot_gdt;
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/* CS descriptor in IA-32 (scrambled) format */
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ia32_boot_gdt[__USER_CS >> 3]
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= IA32_SEG_DESCRIPTOR(0, (IA32_GATE_END-1) >> IA32_PAGE_SHIFT,
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0xb, 1, 3, 1, 1, 1, 1);
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/* DS descriptor in IA-32 (scrambled) format */
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ia32_boot_gdt[__USER_DS >> 3]
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= IA32_SEG_DESCRIPTOR(0, (IA32_GATE_END-1) >> IA32_PAGE_SHIFT,
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0x3, 1, 3, 1, 1, 1, 1);
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ldt_size = PAGE_ALIGN(IA32_LDT_ENTRIES*IA32_LDT_ENTRY_SIZE);
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ia32_boot_gdt[TSS_ENTRY] = IA32_SEG_DESCRIPTOR(IA32_TSS_OFFSET, 235,
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0xb, 0, 3, 1, 1, 1, 0);
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ia32_boot_gdt[LDT_ENTRY] = IA32_SEG_DESCRIPTOR(IA32_LDT_OFFSET, ldt_size - 1,
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0x2, 0, 3, 1, 1, 1, 0);
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}
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static void
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ia32_gate_page_init(void)
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{
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unsigned long *sr;
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ia32_gate_page = alloc_page(GFP_KERNEL);
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sr = page_address(ia32_gate_page);
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/* This is popl %eax ; movl $,%eax ; int $0x80 */
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*sr++ = 0xb858 | (__IA32_NR_sigreturn << 16) | (0x80cdUL << 48);
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/* This is movl $,%eax ; int $0x80 */
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*sr = 0xb8 | (__IA32_NR_rt_sigreturn << 8) | (0x80cdUL << 40);
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}
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void
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ia32_mem_init(void)
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{
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ia32_boot_gdt_init();
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ia32_gate_page_init();
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}
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/*
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* Handle bad IA32 interrupt via syscall
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*/
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void
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ia32_bad_interrupt (unsigned long int_num, struct pt_regs *regs)
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{
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siginfo_t siginfo;
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if (die_if_kernel("Bad IA-32 interrupt", regs, int_num))
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return;
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siginfo.si_signo = SIGTRAP;
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siginfo.si_errno = int_num; /* XXX is it OK to abuse si_errno like this? */
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siginfo.si_flags = 0;
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siginfo.si_isr = 0;
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siginfo.si_addr = NULL;
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siginfo.si_imm = 0;
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siginfo.si_code = TRAP_BRKPT;
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force_sig_info(SIGTRAP, &siginfo, current);
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}
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void
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ia32_cpu_init (void)
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{
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/* initialize global ia32 state - CR0 and CR4 */
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ia64_setreg(_IA64_REG_AR_CFLAG, (((ulong) IA32_CR4 << 32) | IA32_CR0));
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}
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static int __init
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ia32_init (void)
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{
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#if PAGE_SHIFT > IA32_PAGE_SHIFT
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{
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extern struct kmem_cache *ia64_partial_page_cachep;
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ia64_partial_page_cachep = kmem_cache_create("ia64_partial_page_cache",
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sizeof(struct ia64_partial_page),
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0, SLAB_PANIC, NULL);
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}
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#endif
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return 0;
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}
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__initcall(ia32_init);
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