![Chris Metcalf](/assets/img/avatar_default.png)
This change creates the framework for vDSO calls, makes the existing rt_sigreturn() mechanism use it, and adds a fast gettimeofday(). Now that we need to expose the vDSO address to userspace, we add AT_SYSINFO_EHDR to the set of aux entries provided to userspace. (You can disable any extra vDSO support by booting with vdso=0, but the rt_sigreturn vDSO page will still be provided.) Note that glibc has supported the tile vDSO since release 2.17. Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
155 lines
3.7 KiB
C
155 lines
3.7 KiB
C
/*
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* Copyright 2010 Tilera Corporation. All Rights Reserved.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation, version 2.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE, GOOD TITLE or
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* NON INFRINGEMENT. See the GNU General Public License for
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* more details.
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*/
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#include <linux/mm.h>
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#include <linux/pagemap.h>
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#include <linux/binfmts.h>
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#include <linux/compat.h>
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#include <linux/mman.h>
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#include <linux/elf.h>
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#include <asm/pgtable.h>
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#include <asm/pgalloc.h>
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#include <asm/sections.h>
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#include <asm/vdso.h>
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#include <arch/sim.h>
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/* Notify a running simulator, if any, that an exec just occurred. */
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static void sim_notify_exec(const char *binary_name)
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{
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unsigned char c;
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do {
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c = *binary_name++;
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__insn_mtspr(SPR_SIM_CONTROL,
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(SIM_CONTROL_OS_EXEC
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| (c << _SIM_CONTROL_OPERATOR_BITS)));
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} while (c);
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}
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static int notify_exec(struct mm_struct *mm)
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{
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char *buf, *path;
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struct vm_area_struct *vma;
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if (!sim_is_simulator())
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return 1;
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if (mm->exe_file == NULL)
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return 0;
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for (vma = current->mm->mmap; ; vma = vma->vm_next) {
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if (vma == NULL)
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return 0;
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if (vma->vm_file == mm->exe_file)
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break;
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}
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buf = (char *) __get_free_page(GFP_KERNEL);
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if (buf == NULL)
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return 0;
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path = d_path(&mm->exe_file->f_path, buf, PAGE_SIZE);
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if (IS_ERR(path)) {
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free_page((unsigned long)buf);
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return 0;
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}
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/*
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* Notify simulator of an ET_DYN object so we know the load address.
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* The somewhat cryptic overuse of SIM_CONTROL_DLOPEN allows us
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* to be backward-compatible with older simulator releases.
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*/
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if (vma->vm_start == (ELF_ET_DYN_BASE & PAGE_MASK)) {
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char buf[64];
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int i;
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snprintf(buf, sizeof(buf), "0x%lx:@", vma->vm_start);
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for (i = 0; ; ++i) {
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char c = buf[i];
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__insn_mtspr(SPR_SIM_CONTROL,
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(SIM_CONTROL_DLOPEN
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| (c << _SIM_CONTROL_OPERATOR_BITS)));
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if (c == '\0')
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break;
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}
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}
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sim_notify_exec(path);
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free_page((unsigned long)buf);
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return 1;
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}
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/* Notify a running simulator, if any, that we loaded an interpreter. */
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static void sim_notify_interp(unsigned long load_addr)
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{
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size_t i;
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for (i = 0; i < sizeof(load_addr); i++) {
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unsigned char c = load_addr >> (i * 8);
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__insn_mtspr(SPR_SIM_CONTROL,
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(SIM_CONTROL_OS_INTERP
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| (c << _SIM_CONTROL_OPERATOR_BITS)));
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}
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}
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int arch_setup_additional_pages(struct linux_binprm *bprm,
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int executable_stack)
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{
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struct mm_struct *mm = current->mm;
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int retval = 0;
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down_write(&mm->mmap_sem);
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/*
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* Notify the simulator that an exec just occurred.
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* If we can't find the filename of the mapping, just use
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* whatever was passed as the linux_binprm filename.
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*/
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if (!notify_exec(mm))
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sim_notify_exec(bprm->filename);
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retval = setup_vdso_pages();
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#ifndef __tilegx__
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/*
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* Set up a user-interrupt mapping here; the user can't
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* create one themselves since it is above TASK_SIZE.
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* We make it unwritable by default, so the model for adding
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* interrupt vectors always involves an mprotect.
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*/
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if (!retval) {
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unsigned long addr = MEM_USER_INTRPT;
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addr = mmap_region(NULL, addr, INTRPT_SIZE,
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VM_READ|VM_EXEC|
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VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, 0);
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if (addr > (unsigned long) -PAGE_SIZE)
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retval = (int) addr;
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}
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#endif
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up_write(&mm->mmap_sem);
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return retval;
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}
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void elf_plat_init(struct pt_regs *regs, unsigned long load_addr)
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{
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/* Zero all registers. */
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memset(regs, 0, sizeof(*regs));
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/* Report the interpreter's load address. */
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sim_notify_interp(load_addr);
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}
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