mirror of
https://github.com/AuxXxilium/linux_dsm_epyc7002.git
synced 2024-12-28 11:18:45 +07:00
ebb5e78cc6
Add an initial implementation of a proper (i.e. an ELF shared library)
VDSO. With this commit it does not export any symbols, it only replaces
the current signal return trampoline page. A later commit will add user
implementations of gettimeofday()/clock_gettime().
To support both new toolchains and old ones which don't generate ABI
flags section, we define its content manually and then use a tool
(genvdso) to patch up the section to have the correct name and type.
genvdso also extracts symbol offsets ({,rt_}sigreturn) needed by the
kernel, and generates a C file containing a "struct mips_vdso_image"
containing both the VDSO data and these offsets. This C file is
compiled into the kernel.
On 64-bit kernels we require a different VDSO for each supported ABI,
so we may build up to 3 different VDSOs. The VDSO to use is selected by
the mips_abi structure.
A kernel/user shared data page is created and mapped below the VDSO
image. This is currently empty, but will be used by the user time
function implementations which are added later.
[markos.chandras@imgtec.com:
- Add more comments
- Move abi detection in genvdso.h since it's the get_symbol function
that needs it.
- Add an R6 specific way to calculate the base address of VDSO in order
to avoid the branch instruction which affects performance.
- Do not patch .gnu.attributes since it's not needed for dynamic linking.
- Simplify Makefile a little bit.
- checkpatch fixes
- Restrict VDSO support for binutils < 2.25 for pre-R6
- Include atomic64.h for O32 variant on MIPS64]
Signed-off-by: Alex Smith <alex.smith@imgtec.com>
Signed-off-by: Markos Chandras <markos.chandras@imgtec.com>
Cc: Matthew Fortune <matthew.fortune@imgtec.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/11337/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
69 lines
1.8 KiB
ArmAsm
69 lines
1.8 KiB
ArmAsm
/*
|
|
* Copyright (C) 2015 Imagination Technologies
|
|
* Author: Alex Smith <alex.smith@imgtec.com>
|
|
*
|
|
* This program is free software; you can redistribute it and/or modify it
|
|
* under the terms of the GNU General Public License as published by the
|
|
* Free Software Foundation; either version 2 of the License, or (at your
|
|
* option) any later version.
|
|
*/
|
|
|
|
#include "vdso.h"
|
|
|
|
#include <linux/elfnote.h>
|
|
#include <linux/version.h>
|
|
|
|
ELFNOTE_START(Linux, 0, "a")
|
|
.long LINUX_VERSION_CODE
|
|
ELFNOTE_END
|
|
|
|
/*
|
|
* The .MIPS.abiflags section must be defined with the FP ABI flags set
|
|
* to 'any' to be able to link with both old and new libraries.
|
|
* Newer toolchains are capable of automatically generating this, but we want
|
|
* to work with older toolchains as well. Therefore, we define the contents of
|
|
* this section here (under different names), and then genvdso will patch
|
|
* it to have the correct name and type.
|
|
*
|
|
* We base the .MIPS.abiflags section on preprocessor definitions rather than
|
|
* CONFIG_* because we need to match the particular ABI we are building the
|
|
* VDSO for.
|
|
*
|
|
* See https://dmz-portal.mips.com/wiki/MIPS_O32_ABI_-_FR0_and_FR1_Interlinking
|
|
* for the .MIPS.abiflags section description.
|
|
*/
|
|
|
|
.section .mips_abiflags, "a"
|
|
.align 3
|
|
__mips_abiflags:
|
|
.hword 0 /* version */
|
|
.byte __mips /* isa_level */
|
|
|
|
/* isa_rev */
|
|
#ifdef __mips_isa_rev
|
|
.byte __mips_isa_rev
|
|
#else
|
|
.byte 0
|
|
#endif
|
|
|
|
/* gpr_size */
|
|
#ifdef __mips64
|
|
.byte 2 /* AFL_REG_64 */
|
|
#else
|
|
.byte 1 /* AFL_REG_32 */
|
|
#endif
|
|
|
|
/* cpr1_size */
|
|
#if (defined(__mips_isa_rev) && __mips_isa_rev >= 6) || defined(__mips64)
|
|
.byte 2 /* AFL_REG_64 */
|
|
#else
|
|
.byte 1 /* AFL_REG_32 */
|
|
#endif
|
|
|
|
.byte 0 /* cpr2_size (AFL_REG_NONE) */
|
|
.byte 0 /* fp_abi (Val_GNU_MIPS_ABI_FP_ANY) */
|
|
.word 0 /* isa_ext */
|
|
.word 0 /* ases */
|
|
.word 0 /* flags1 */
|
|
.word 0 /* flags2 */
|