4a556f4f56
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>
88 lines
2.1 KiB
ArmAsm
88 lines
2.1 KiB
ArmAsm
/*
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* Copyright 2012 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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#define VDSO_VERSION_STRING LINUX_2.6
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OUTPUT_ARCH(tile)
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/* The ELF entry point can be used to set the AT_SYSINFO value. */
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ENTRY(__vdso_rt_sigreturn);
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SECTIONS
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{
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. = SIZEOF_HEADERS;
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.hash : { *(.hash) } :text
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.gnu.hash : { *(.gnu.hash) }
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.dynsym : { *(.dynsym) }
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.dynstr : { *(.dynstr) }
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.gnu.version : { *(.gnu.version) }
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.gnu.version_d : { *(.gnu.version_d) }
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.gnu.version_r : { *(.gnu.version_r) }
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.note : { *(.note.*) } :text :note
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.dynamic : { *(.dynamic) } :text :dynamic
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.eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
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.eh_frame : { KEEP (*(.eh_frame)) } :text
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.rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
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/*
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* This linker script is used both with -r and with -shared.
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* For the layouts to match, we need to skip more than enough
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* space for the dynamic symbol table et al. If this amount
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* is insufficient, ld -shared will barf. Just increase it here.
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*/
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. = 0x1000;
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.text : { *(.text .text.*) } :text
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.data : {
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*(.got.plt) *(.got)
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*(.data .data.* .gnu.linkonce.d.*)
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*(.dynbss)
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*(.bss .bss.* .gnu.linkonce.b.*)
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}
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}
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/*
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* We must supply the ELF program headers explicitly to get just one
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* PT_LOAD segment, and set the flags explicitly to make segments read-only.
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*/
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PHDRS
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{
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text PT_LOAD FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */
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dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
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note PT_NOTE FLAGS(4); /* PF_R */
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eh_frame_hdr PT_GNU_EH_FRAME;
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}
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/*
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* This controls what userland symbols we export from the vDSO.
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*/
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VERSION
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{
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VDSO_VERSION_STRING {
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global:
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__vdso_rt_sigreturn;
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__vdso_gettimeofday;
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gettimeofday;
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local:*;
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};
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}
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