diff options
author | Alex Smith <alex.smith@imgtec.com> | 2015-10-21 08:54:38 (GMT) |
---|---|---|
committer | Ralf Baechle <ralf@linux-mips.org> | 2015-11-11 07:36:36 (GMT) |
commit | ebb5e78cc63417a35254a791de66e1cc84f963cc (patch) | |
tree | 49814946abe594cb8e7a11ce8d0a5fdaabb49d31 /arch/mips/include | |
parent | 22773aa9b95657f0adc2b5342428d9da7a6d5d02 (diff) | |
download | linux-ebb5e78cc63417a35254a791de66e1cc84f963cc.tar.xz |
MIPS: Initial implementation of a VDSO
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>
Diffstat (limited to 'arch/mips/include')
-rw-r--r-- | arch/mips/include/asm/abi.h | 5 | ||||
-rw-r--r-- | arch/mips/include/asm/elf.h | 7 | ||||
-rw-r--r-- | arch/mips/include/asm/processor.h | 8 | ||||
-rw-r--r-- | arch/mips/include/asm/vdso.h | 73 | ||||
-rw-r--r-- | arch/mips/include/uapi/asm/Kbuild | 2 | ||||
-rw-r--r-- | arch/mips/include/uapi/asm/auxvec.h | 17 |
6 files changed, 86 insertions, 26 deletions
diff --git a/arch/mips/include/asm/abi.h b/arch/mips/include/asm/abi.h index 37f8407..9407608 100644 --- a/arch/mips/include/asm/abi.h +++ b/arch/mips/include/asm/abi.h @@ -11,19 +11,20 @@ #include <asm/signal.h> #include <asm/siginfo.h> +#include <asm/vdso.h> struct mips_abi { int (* const setup_frame)(void *sig_return, struct ksignal *ksig, struct pt_regs *regs, sigset_t *set); - const unsigned long signal_return_offset; int (* const setup_rt_frame)(void *sig_return, struct ksignal *ksig, struct pt_regs *regs, sigset_t *set); - const unsigned long rt_signal_return_offset; const unsigned long restart; unsigned off_sc_fpregs; unsigned off_sc_fpc_csr; unsigned off_sc_used_math; + + struct mips_vdso_image *vdso; }; #endif /* _ASM_ABI_H */ diff --git a/arch/mips/include/asm/elf.h b/arch/mips/include/asm/elf.h index 53b2693..b01a6ff 100644 --- a/arch/mips/include/asm/elf.h +++ b/arch/mips/include/asm/elf.h @@ -8,6 +8,7 @@ #ifndef _ASM_ELF_H #define _ASM_ELF_H +#include <linux/auxvec.h> #include <linux/fs.h> #include <uapi/linux/elf.h> @@ -419,6 +420,12 @@ extern const char *__elf_platform; #define ELF_ET_DYN_BASE (TASK_SIZE / 3 * 2) #endif +#define ARCH_DLINFO \ +do { \ + NEW_AUX_ENT(AT_SYSINFO_EHDR, \ + (unsigned long)current->mm->context.vdso); \ +} while (0) + #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1 struct linux_binprm; extern int arch_setup_additional_pages(struct linux_binprm *bprm, diff --git a/arch/mips/include/asm/processor.h b/arch/mips/include/asm/processor.h index 59ee6dc..3f832c3 100644 --- a/arch/mips/include/asm/processor.h +++ b/arch/mips/include/asm/processor.h @@ -36,12 +36,6 @@ extern unsigned int vced_count, vcei_count; */ #define HAVE_ARCH_PICK_MMAP_LAYOUT 1 -/* - * A special page (the vdso) is mapped into all processes at the very - * top of the virtual memory space. - */ -#define SPECIAL_PAGES_SIZE PAGE_SIZE - #ifdef CONFIG_32BIT #ifdef CONFIG_KVM_GUEST /* User space process size is limited to 1GB in KVM Guest Mode */ @@ -80,7 +74,7 @@ extern unsigned int vced_count, vcei_count; #endif -#define STACK_TOP ((TASK_SIZE & PAGE_MASK) - SPECIAL_PAGES_SIZE) +#define STACK_TOP (TASK_SIZE & PAGE_MASK) /* * This decides where the kernel will search for a free chunk of vm diff --git a/arch/mips/include/asm/vdso.h b/arch/mips/include/asm/vdso.h index cca56aa..db2d45b 100644 --- a/arch/mips/include/asm/vdso.h +++ b/arch/mips/include/asm/vdso.h @@ -1,29 +1,70 @@ /* - * This file is subject to the terms and conditions of the GNU General Public - * License. See the file "COPYING" in the main directory of this archive - * for more details. + * Copyright (C) 2015 Imagination Technologies + * Author: Alex Smith <alex.smith@imgtec.com> * - * Copyright (C) 2009 Cavium Networks + * 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. */ #ifndef __ASM_VDSO_H #define __ASM_VDSO_H -#include <linux/types.h> +#include <linux/mm_types.h> +/** + * struct mips_vdso_image - Details of a VDSO image. + * @data: Pointer to VDSO image data (page-aligned). + * @size: Size of the VDSO image data (page-aligned). + * @off_sigreturn: Offset of the sigreturn() trampoline. + * @off_rt_sigreturn: Offset of the rt_sigreturn() trampoline. + * @mapping: Special mapping structure. + * + * This structure contains details of a VDSO image, including the image data + * and offsets of certain symbols required by the kernel. It is generated as + * part of the VDSO build process, aside from the mapping page array, which is + * populated at runtime. + */ +struct mips_vdso_image { + void *data; + unsigned long size; -#ifdef CONFIG_32BIT -struct mips_vdso { - u32 signal_trampoline[2]; - u32 rt_signal_trampoline[2]; + unsigned long off_sigreturn; + unsigned long off_rt_sigreturn; + + struct vm_special_mapping mapping; }; -#else /* !CONFIG_32BIT */ -struct mips_vdso { - u32 o32_signal_trampoline[2]; - u32 o32_rt_signal_trampoline[2]; - u32 rt_signal_trampoline[2]; - u32 n32_rt_signal_trampoline[2]; + +/* + * The following structures are auto-generated as part of the build for each + * ABI by genvdso, see arch/mips/vdso/Makefile. + */ + +extern struct mips_vdso_image vdso_image; + +#ifdef CONFIG_MIPS32_O32 +extern struct mips_vdso_image vdso_image_o32; +#endif + +#ifdef CONFIG_MIPS32_N32 +extern struct mips_vdso_image vdso_image_n32; +#endif + +/** + * union mips_vdso_data - Data provided by the kernel for the VDSO. + * + * This structure contains data needed by functions within the VDSO. It is + * populated by the kernel and mapped read-only into user memory. + * + * Note: Care should be taken when modifying as the layout must remain the same + * for both 64- and 32-bit (for 32-bit userland on 64-bit kernel). + */ +union mips_vdso_data { + struct { + }; + + u8 page[PAGE_SIZE]; }; -#endif /* CONFIG_32BIT */ #endif /* __ASM_VDSO_H */ diff --git a/arch/mips/include/uapi/asm/Kbuild b/arch/mips/include/uapi/asm/Kbuild index 96fe739..f2cf414 100644 --- a/arch/mips/include/uapi/asm/Kbuild +++ b/arch/mips/include/uapi/asm/Kbuild @@ -1,9 +1,9 @@ # UAPI Header export list include include/uapi/asm-generic/Kbuild.asm -generic-y += auxvec.h generic-y += ipcbuf.h +header-y += auxvec.h header-y += bitfield.h header-y += bitsperlong.h header-y += break.h diff --git a/arch/mips/include/uapi/asm/auxvec.h b/arch/mips/include/uapi/asm/auxvec.h new file mode 100644 index 0000000..c9c7195 --- /dev/null +++ b/arch/mips/include/uapi/asm/auxvec.h @@ -0,0 +1,17 @@ +/* + * 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. + */ + +#ifndef __ASM_AUXVEC_H +#define __ASM_AUXVEC_H + +/* Location of VDSO image. */ +#define AT_SYSINFO_EHDR 33 + +#endif /* __ASM_AUXVEC_H */ |