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/kernel | |
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/kernel')
-rw-r--r-- | arch/mips/kernel/signal.c | 12 | ||||
-rw-r--r-- | arch/mips/kernel/signal32.c | 7 | ||||
-rw-r--r-- | arch/mips/kernel/signal_n32.c | 5 | ||||
-rw-r--r-- | arch/mips/kernel/vdso.c | 160 |
4 files changed, 86 insertions, 98 deletions
diff --git a/arch/mips/kernel/signal.c b/arch/mips/kernel/signal.c index 2fec67b..bf792e2 100644 --- a/arch/mips/kernel/signal.c +++ b/arch/mips/kernel/signal.c @@ -36,7 +36,6 @@ #include <asm/ucontext.h> #include <asm/cpu-features.h> #include <asm/war.h> -#include <asm/vdso.h> #include <asm/dsp.h> #include <asm/inst.h> #include <asm/msa.h> @@ -752,16 +751,15 @@ static int setup_rt_frame(void *sig_return, struct ksignal *ksig, struct mips_abi mips_abi = { #ifdef CONFIG_TRAD_SIGNALS .setup_frame = setup_frame, - .signal_return_offset = offsetof(struct mips_vdso, signal_trampoline), #endif .setup_rt_frame = setup_rt_frame, - .rt_signal_return_offset = - offsetof(struct mips_vdso, rt_signal_trampoline), .restart = __NR_restart_syscall, .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs), .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr), .off_sc_used_math = offsetof(struct sigcontext, sc_used_math), + + .vdso = &vdso_image, }; static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) @@ -801,11 +799,11 @@ static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) } if (sig_uses_siginfo(&ksig->ka)) - ret = abi->setup_rt_frame(vdso + abi->rt_signal_return_offset, + ret = abi->setup_rt_frame(vdso + abi->vdso->off_rt_sigreturn, ksig, regs, oldset); else - ret = abi->setup_frame(vdso + abi->signal_return_offset, ksig, - regs, oldset); + ret = abi->setup_frame(vdso + abi->vdso->off_sigreturn, + ksig, regs, oldset); signal_setup_done(ret, ksig, 0); } diff --git a/arch/mips/kernel/signal32.c b/arch/mips/kernel/signal32.c index f7e89524..4909639 100644 --- a/arch/mips/kernel/signal32.c +++ b/arch/mips/kernel/signal32.c @@ -31,7 +31,6 @@ #include <asm/ucontext.h> #include <asm/fpu.h> #include <asm/war.h> -#include <asm/vdso.h> #include <asm/dsp.h> #include "signal-common.h" @@ -406,14 +405,12 @@ static int setup_rt_frame_32(void *sig_return, struct ksignal *ksig, */ struct mips_abi mips_abi_32 = { .setup_frame = setup_frame_32, - .signal_return_offset = - offsetof(struct mips_vdso, o32_signal_trampoline), .setup_rt_frame = setup_rt_frame_32, - .rt_signal_return_offset = - offsetof(struct mips_vdso, o32_rt_signal_trampoline), .restart = __NR_O32_restart_syscall, .off_sc_fpregs = offsetof(struct sigcontext32, sc_fpregs), .off_sc_fpc_csr = offsetof(struct sigcontext32, sc_fpc_csr), .off_sc_used_math = offsetof(struct sigcontext32, sc_used_math), + + .vdso = &vdso_image_o32, }; diff --git a/arch/mips/kernel/signal_n32.c b/arch/mips/kernel/signal_n32.c index 0d017fd..a7bc384 100644 --- a/arch/mips/kernel/signal_n32.c +++ b/arch/mips/kernel/signal_n32.c @@ -38,7 +38,6 @@ #include <asm/fpu.h> #include <asm/cpu-features.h> #include <asm/war.h> -#include <asm/vdso.h> #include "signal-common.h" @@ -151,11 +150,11 @@ static int setup_rt_frame_n32(void *sig_return, struct ksignal *ksig, struct mips_abi mips_abi_n32 = { .setup_rt_frame = setup_rt_frame_n32, - .rt_signal_return_offset = - offsetof(struct mips_vdso, n32_rt_signal_trampoline), .restart = __NR_N32_restart_syscall, .off_sc_fpregs = offsetof(struct sigcontext, sc_fpregs), .off_sc_fpc_csr = offsetof(struct sigcontext, sc_fpc_csr), .off_sc_used_math = offsetof(struct sigcontext, sc_used_math), + + .vdso = &vdso_image_n32, }; diff --git a/arch/mips/kernel/vdso.c b/arch/mips/kernel/vdso.c index ed2a278..56cc3c4 100644 --- a/arch/mips/kernel/vdso.c +++ b/arch/mips/kernel/vdso.c @@ -1,122 +1,116 @@ /* - * 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, 2010 Cavium Networks, Inc. + * 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 <linux/kernel.h> -#include <linux/err.h> -#include <linux/sched.h> -#include <linux/mm.h> -#include <linux/init.h> #include <linux/binfmts.h> #include <linux/elf.h> -#include <linux/vmalloc.h> -#include <linux/unistd.h> -#include <linux/random.h> +#include <linux/err.h> +#include <linux/init.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/slab.h> +#include <asm/abi.h> #include <asm/vdso.h> -#include <asm/uasm.h> -#include <asm/processor.h> + +/* Kernel-provided data used by the VDSO. */ +static union mips_vdso_data vdso_data __page_aligned_data; /* - * Including <asm/unistd.h> would give use the 64-bit syscall numbers ... + * Mapping for the VDSO data pages. The real pages are mapped manually, as + * what we map and where within the area they are mapped is determined at + * runtime. */ -#define __NR_O32_sigreturn 4119 -#define __NR_O32_rt_sigreturn 4193 -#define __NR_N32_rt_sigreturn 6211 +static struct page *no_pages[] = { NULL }; +static struct vm_special_mapping vdso_vvar_mapping = { + .name = "[vvar]", + .pages = no_pages, +}; -static struct page *vdso_page; - -static void __init install_trampoline(u32 *tramp, unsigned int sigreturn) +static void __init init_vdso_image(struct mips_vdso_image *image) { - uasm_i_addiu(&tramp, 2, 0, sigreturn); /* li v0, sigreturn */ - uasm_i_syscall(&tramp, 0); + unsigned long num_pages, i; + + BUG_ON(!PAGE_ALIGNED(image->data)); + BUG_ON(!PAGE_ALIGNED(image->size)); + + num_pages = image->size / PAGE_SIZE; + + for (i = 0; i < num_pages; i++) { + image->mapping.pages[i] = + virt_to_page(image->data + (i * PAGE_SIZE)); + } } static int __init init_vdso(void) { - struct mips_vdso *vdso; - - vdso_page = alloc_page(GFP_KERNEL); - if (!vdso_page) - panic("Cannot allocate vdso"); - - vdso = vmap(&vdso_page, 1, 0, PAGE_KERNEL); - if (!vdso) - panic("Cannot map vdso"); - clear_page(vdso); - - install_trampoline(vdso->rt_signal_trampoline, __NR_rt_sigreturn); -#ifdef CONFIG_32BIT - install_trampoline(vdso->signal_trampoline, __NR_sigreturn); -#else - install_trampoline(vdso->n32_rt_signal_trampoline, - __NR_N32_rt_sigreturn); - install_trampoline(vdso->o32_signal_trampoline, __NR_O32_sigreturn); - install_trampoline(vdso->o32_rt_signal_trampoline, - __NR_O32_rt_sigreturn); + init_vdso_image(&vdso_image); + +#ifdef CONFIG_MIPS32_O32 + init_vdso_image(&vdso_image_o32); #endif - vunmap(vdso); +#ifdef CONFIG_MIPS32_N32 + init_vdso_image(&vdso_image_n32); +#endif return 0; } subsys_initcall(init_vdso); -static unsigned long vdso_addr(unsigned long start) -{ - unsigned long offset = 0UL; - - if (current->flags & PF_RANDOMIZE) { - offset = get_random_int(); - offset <<= PAGE_SHIFT; - if (TASK_IS_32BIT_ADDR) - offset &= 0xfffffful; - else - offset &= 0xffffffful; - } - - return STACK_TOP + offset; -} - int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp) { - int ret; - unsigned long addr; + struct mips_vdso_image *image = current->thread.abi->vdso; struct mm_struct *mm = current->mm; + unsigned long base, vdso_addr; + struct vm_area_struct *vma; + int ret; down_write(&mm->mmap_sem); - addr = vdso_addr(mm->start_stack); - - addr = get_unmapped_area(NULL, addr, PAGE_SIZE, 0, 0); - if (IS_ERR_VALUE(addr)) { - ret = addr; - goto up_fail; + base = get_unmapped_area(NULL, 0, PAGE_SIZE + image->size, 0, 0); + if (IS_ERR_VALUE(base)) { + ret = base; + goto out; } - ret = install_special_mapping(mm, addr, PAGE_SIZE, - VM_READ|VM_EXEC| - VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, - &vdso_page); + vdso_addr = base + PAGE_SIZE; + + vma = _install_special_mapping(mm, base, PAGE_SIZE, + VM_READ | VM_MAYREAD, + &vdso_vvar_mapping); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + goto out; + } + /* Map data page. */ + ret = remap_pfn_range(vma, base, + virt_to_phys(&vdso_data) >> PAGE_SHIFT, + PAGE_SIZE, PAGE_READONLY); if (ret) - goto up_fail; + goto out; + + /* Map VDSO image. */ + vma = _install_special_mapping(mm, vdso_addr, image->size, + VM_READ | VM_EXEC | + VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC, + &image->mapping); + if (IS_ERR(vma)) { + ret = PTR_ERR(vma); + goto out; + } - mm->context.vdso = (void *)addr; + mm->context.vdso = (void *)vdso_addr; + ret = 0; -up_fail: +out: up_write(&mm->mmap_sem); return ret; } - -const char *arch_vma_name(struct vm_area_struct *vma) -{ - if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) - return "[vdso]"; - return NULL; -} |