From: Will Deacon <will.dea...@arm.com> This patch adds VDSO support for 64-bit applications. The VDSO code is currently used for sys_rt_sigreturn() and optimised gettimeofday() (using the user-accessible generic counter).
Signed-off-by: Will Deacon <will.dea...@arm.com> Signed-off-by: Catalin Marinas <catalin.mari...@arm.com> --- arch/arm64/include/asm/vdso.h | 41 +++++ arch/arm64/include/asm/vdso_datapage.h | 43 +++++ arch/arm64/kernel/vdso.c | 261 ++++++++++++++++++++++++++++ arch/arm64/kernel/vdso/.gitignore | 2 + arch/arm64/kernel/vdso/Makefile | 63 +++++++ arch/arm64/kernel/vdso/gen_vdso_offsets.sh | 15 ++ arch/arm64/kernel/vdso/gettimeofday.S | 242 ++++++++++++++++++++++++++ arch/arm64/kernel/vdso/note.S | 28 +++ arch/arm64/kernel/vdso/sigreturn.S | 37 ++++ arch/arm64/kernel/vdso/vdso.S | 33 ++++ arch/arm64/kernel/vdso/vdso.lds.S | 100 +++++++++++ 11 files changed, 865 insertions(+), 0 deletions(-) create mode 100644 arch/arm64/include/asm/vdso.h create mode 100644 arch/arm64/include/asm/vdso_datapage.h create mode 100644 arch/arm64/kernel/vdso.c create mode 100644 arch/arm64/kernel/vdso/.gitignore create mode 100644 arch/arm64/kernel/vdso/Makefile create mode 100755 arch/arm64/kernel/vdso/gen_vdso_offsets.sh create mode 100644 arch/arm64/kernel/vdso/gettimeofday.S create mode 100644 arch/arm64/kernel/vdso/note.S create mode 100644 arch/arm64/kernel/vdso/sigreturn.S create mode 100644 arch/arm64/kernel/vdso/vdso.S create mode 100644 arch/arm64/kernel/vdso/vdso.lds.S diff --git a/arch/arm64/include/asm/vdso.h b/arch/arm64/include/asm/vdso.h new file mode 100644 index 0000000..839ce00 --- /dev/null +++ b/arch/arm64/include/asm/vdso.h @@ -0,0 +1,41 @@ +/* + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef __ASM_VDSO_H +#define __ASM_VDSO_H + +#ifdef __KERNEL__ + +/* + * Default link address for the vDSO. + * Since we randomise the VDSO mapping, there's little point in trying + * to prelink this. + */ +#define VDSO_LBASE 0x0 + +#ifndef __ASSEMBLY__ + +#include <generated/vdso-offsets.h> + +#define VDSO_SYMBOL(base, name) \ +({ \ + (void *)(vdso_offset_##name - VDSO_LBASE + (unsigned long)(base)); \ +}) + +#endif /* !__ASSEMBLY__ */ + +#endif /* __KERNEL__ */ + +#endif /* __ASM_VDSO_H */ diff --git a/arch/arm64/include/asm/vdso_datapage.h b/arch/arm64/include/asm/vdso_datapage.h new file mode 100644 index 0000000..de66199 --- /dev/null +++ b/arch/arm64/include/asm/vdso_datapage.h @@ -0,0 +1,43 @@ +/* + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + */ +#ifndef __ASM_VDSO_DATAPAGE_H +#define __ASM_VDSO_DATAPAGE_H + +#ifdef __KERNEL__ + +#ifndef __ASSEMBLY__ + +struct vdso_data { + __u64 cs_cycle_last; /* Timebase at clocksource init */ + __u64 xtime_clock_sec; /* Kernel time */ + __u64 xtime_clock_nsec; + __u64 xtime_coarse_sec; /* Coarse time */ + __u64 xtime_coarse_nsec; + __u64 wtm_clock_sec; /* Wall to monotonic time */ + __u64 wtm_clock_nsec; + __u32 tb_seq_count; /* Timebase sequence counter */ + __u32 cs_mult; /* Clocksource multiplier */ + __u32 cs_shift; /* Clocksource shift */ + __u32 tz_minuteswest; /* Whacky timezone stuff */ + __u32 tz_dsttime; + __u32 use_syscall; +}; + +#endif /* !__ASSEMBLY__ */ + +#endif /* __KERNEL__ */ + +#endif /* __ASM_VDSO_DATAPAGE_H */ diff --git a/arch/arm64/kernel/vdso.c b/arch/arm64/kernel/vdso.c new file mode 100644 index 0000000..8d8a365 --- /dev/null +++ b/arch/arm64/kernel/vdso.c @@ -0,0 +1,261 @@ +/* + * VDSO implementation for AArch64 and vector page setup for AArch32. + * + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Author: Will Deacon <will.dea...@arm.com> + */ + +#include <linux/kernel.h> +#include <linux/clocksource.h> +#include <linux/elf.h> +#include <linux/err.h> +#include <linux/errno.h> +#include <linux/gfp.h> +#include <linux/mm.h> +#include <linux/sched.h> +#include <linux/signal.h> +#include <linux/slab.h> +#include <linux/vmalloc.h> + +#include <asm/cacheflush.h> +#include <asm/signal32.h> +#include <asm/vdso.h> +#include <asm/vdso_datapage.h> + +extern char vdso_start, vdso_end; +static unsigned long vdso_pages; +static struct page **vdso_pagelist; + +/* + * The vDSO data page. + */ +static union { + struct vdso_data data; + u8 page[PAGE_SIZE]; +} vdso_data_store __page_aligned_data; +struct vdso_data *vdso_data = &vdso_data_store.data; + +#ifdef CONFIG_AARCH32_EMULATION +/* + * Create and map the vectors page for AArch32 tasks. + */ +static struct page *vectors_page[1]; + +static int alloc_vectors_page(void) +{ + extern char __kuser_helper_start[], __kuser_helper_end[]; + int kuser_sz = __kuser_helper_end - __kuser_helper_start; + unsigned long vpage; + + vpage = get_zeroed_page(GFP_ATOMIC); + + if (!vpage) + return -ENOMEM; + + /* kuser helpers */ + memcpy((void *)vpage + 0x1000 - kuser_sz, __kuser_helper_start, + kuser_sz); + + /* sigreturn code */ + memcpy((void *)vpage + AARCH32_KERN_SIGRET_CODE_OFFSET, + aarch32_sigret_code, sizeof(aarch32_sigret_code)); + + flush_icache_range(vpage, vpage + PAGE_SIZE); + vectors_page[0] = virt_to_page(vpage); + + return 0; +} +arch_initcall(alloc_vectors_page); + +int aarch32_setup_vectors_page(struct linux_binprm *bprm, int uses_interp) +{ + struct mm_struct *mm = current->mm; + unsigned long addr = AARCH32_VECTORS_BASE; + int ret; + + down_write(&mm->mmap_sem); + current->mm->context.vdso = (void *)addr; + + /* Map vectors page at the high address. */ + ret = install_special_mapping(mm, addr, PAGE_SIZE, + VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC, + vectors_page); + + up_write(&mm->mmap_sem); + + return ret; +} +#endif /* CONFIG_AARCH32_EMULATION */ + +static int __init vdso_init(void) +{ + struct page *pg; + char *vbase; + int i, ret = 0; + + vdso_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT; + pr_info("vdso: %ld pages (%ld code, %ld data) at base %p\n", + vdso_pages + 1, vdso_pages, 1L, &vdso_start); + + /* Allocate the vDSO pagelist, plus a page for the data. */ + vdso_pagelist = kzalloc(sizeof(struct page *) * (vdso_pages + 1), + GFP_KERNEL); + if (vdso_pagelist == NULL) { + pr_err("Failed to allocate vDSO pagelist!\n"); + return -ENOMEM; + } + + /* Grab the vDSO code pages. */ + for (i = 0; i < vdso_pages; i++) { + pg = virt_to_page(&vdso_start + i*PAGE_SIZE); + ClearPageReserved(pg); + get_page(pg); + vdso_pagelist[i] = pg; + } + + /* Sanity check the shared object header. */ + vbase = vmap(vdso_pagelist, 1, 0, PAGE_KERNEL); + if (vbase == NULL) { + pr_err("Failed to map vDSO pagelist!\n"); + return -ENOMEM; + } else if (memcmp(vbase, "\177ELF", 4)) { + pr_err("vDSO is not a valid ELF object!\n"); + ret = -EINVAL; + goto unmap; + } + + /* Grab the vDSO data page. */ + pg = virt_to_page(vdso_data); + get_page(pg); + vdso_pagelist[i] = pg; + +unmap: + vunmap(vbase); + return ret; +} +arch_initcall(vdso_init); + +int arch_setup_additional_pages(struct linux_binprm *bprm, + int uses_interp) +{ + struct mm_struct *mm = current->mm; + unsigned long vdso_base, vdso_mapping_len; + int ret; + + /* Be sure to map the data page */ + vdso_mapping_len = (vdso_pages + 1) << PAGE_SHIFT; + + down_write(&mm->mmap_sem); + vdso_base = get_unmapped_area(NULL, 0, vdso_mapping_len, 0, 0); + if (IS_ERR_VALUE(vdso_base)) { + ret = vdso_base; + goto up_fail; + } + mm->context.vdso = (void *)vdso_base; + + ret = install_special_mapping(mm, vdso_base, vdso_mapping_len, + VM_READ|VM_EXEC| + VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC, + vdso_pagelist); + if (ret) { + mm->context.vdso = NULL; + goto up_fail; + } + +up_fail: + up_write(&mm->mmap_sem); + + return ret; +} + +const char *arch_vma_name(struct vm_area_struct *vma) +{ + /* + * We can re-use the vdso pointer in mm_context_t for identifying + * the vectors page for compat applications. The vDSO will always + * sit above TASK_UNMAPPED_BASE and so we don't need to worry about + * it conflicting with the vectors base. + */ + if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso) { +#ifdef CONFIG_AARCH32_EMULATION + if (vma->vm_start == AARCH32_VECTORS_BASE) + return "[vectors]"; +#endif + return "[vdso]"; + } + + return NULL; +} + +/* + * We define AT_SYSINFO_EHDR, so we need these function stubs to keep + * Linux happy. + */ +int in_gate_area_no_mm(unsigned long addr) +{ + return 0; +} + +int in_gate_area(struct mm_struct *mm, unsigned long addr) +{ + return 0; +} + +struct vm_area_struct *get_gate_vma(struct mm_struct *mm) +{ + return NULL; +} + +/* + * Update the vDSO data page to keep in sync with kernel timekeeping. + */ +void update_vsyscall(struct timespec *ts, struct timespec *wtm, + struct clocksource *clock, u32 mult) +{ + struct timespec xtime_coarse; + u32 use_syscall = strcmp(clock->name, "arch_sys_counter"); + + ++vdso_data->tb_seq_count; + smp_wmb(); + + xtime_coarse = __current_kernel_time(); + vdso_data->use_syscall = use_syscall; + vdso_data->xtime_coarse_sec = xtime_coarse.tv_sec; + vdso_data->xtime_coarse_nsec = xtime_coarse.tv_nsec; + + if (!use_syscall) { + vdso_data->cs_cycle_last = clock->cycle_last; + vdso_data->xtime_clock_sec = ts->tv_sec; + vdso_data->xtime_clock_nsec = ts->tv_nsec; + vdso_data->cs_mult = mult; + vdso_data->cs_shift = clock->shift; + vdso_data->wtm_clock_sec = wtm->tv_sec; + vdso_data->wtm_clock_nsec = wtm->tv_nsec; + } + + smp_wmb(); + ++vdso_data->tb_seq_count; +} + +void update_vsyscall_tz(void) +{ + ++vdso_data->tb_seq_count; + smp_wmb(); + vdso_data->tz_minuteswest = sys_tz.tz_minuteswest; + vdso_data->tz_dsttime = sys_tz.tz_dsttime; + smp_wmb(); + ++vdso_data->tb_seq_count; +} diff --git a/arch/arm64/kernel/vdso/.gitignore b/arch/arm64/kernel/vdso/.gitignore new file mode 100644 index 0000000..b8cc94e --- /dev/null +++ b/arch/arm64/kernel/vdso/.gitignore @@ -0,0 +1,2 @@ +vdso.lds +vdso-offsets.h diff --git a/arch/arm64/kernel/vdso/Makefile b/arch/arm64/kernel/vdso/Makefile new file mode 100644 index 0000000..d8064af --- /dev/null +++ b/arch/arm64/kernel/vdso/Makefile @@ -0,0 +1,63 @@ +# +# Building a vDSO image for AArch64. +# +# Author: Will Deacon <will.dea...@arm.com> +# Heavily based on the vDSO Makefiles for other archs. +# + +obj-vdso := gettimeofday.o note.o sigreturn.o + +# Build rules +targets := $(obj-vdso) vdso.so vdso.so.dbg +obj-vdso := $(addprefix $(obj)/, $(obj-vdso)) + +ccflags-y := -shared -fno-common -fno-builtin +ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 \ + $(call cc-ldoption, -Wl$(comma)--hash-style=sysv) + +obj-y += vdso.o +extra-y += vdso.lds vdso-offsets.h +CPPFLAGS_vdso.lds += -P -C -U$(ARCH) + +# Force dependency (incbin is bad) +$(obj)/vdso.o : $(obj)/vdso.so + +# Link rule for the .so file, .lds has to be first +$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso) + $(call if_changed,vdsold) + +# Strip rule for the .so file +$(obj)/%.so: OBJCOPYFLAGS := -S +$(obj)/%.so: $(obj)/%.so.dbg FORCE + $(call if_changed,objcopy) + +# Generate VDSO offsets using helper script +gen-vdsosym := $(srctree)/$(src)/gen_vdso_offsets.sh +quiet_cmd_vdsosym = VDSOSYM $@ +define cmd_vdsosym + $(NM) $< | $(gen-vdsosym) | LC_ALL=C sort > $@ && \ + cp $@ include/generated/ +endef + +$(obj)/vdso-offsets.h: $(obj)/vdso.so.dbg FORCE + $(call if_changed,vdsosym) + +# Assembly rules for the .S files +$(obj-vdso): %.o: %.S + $(call if_changed_dep,vdsoas) + +# Actual build commands +quiet_cmd_vdsold = VDSOL $@ + cmd_vdsold = $(CC) $(c_flags) -Wl,-T $^ -o $@ +quiet_cmd_vdsoas = VDSOA $@ + cmd_vdsoas = $(CC) $(a_flags) -c -o $@ $< + +# Install commands for the unstripped file +quiet_cmd_vdso_install = INSTALL $@ + cmd_vdso_install = cp $(obj)/$@.dbg $(MODLIB)/vdso/$@ + +vdso.so: $(obj)/vdso.so.dbg + @mkdir -p $(MODLIB)/vdso + $(call cmd,vdso_install) + +vdso_install: vdso.so diff --git a/arch/arm64/kernel/vdso/gen_vdso_offsets.sh b/arch/arm64/kernel/vdso/gen_vdso_offsets.sh new file mode 100755 index 0000000..01924ff --- /dev/null +++ b/arch/arm64/kernel/vdso/gen_vdso_offsets.sh @@ -0,0 +1,15 @@ +#!/bin/sh + +# +# Match symbols in the DSO that look like VDSO_*; produce a header file +# of constant offsets into the shared object. +# +# Doing this inside the Makefile will break the $(filter-out) function, +# causing Kbuild to rebuild the vdso-offsets header file every time. +# +# Author: Will Deacon <will.dea...@arm.com +# + +LC_ALL=C +sed -n -e 's/^00*/0/' -e \ +'s/^\([0-9a-fA-F]*\) . VDSO_\([a-zA-Z0-9_]*\)$/\#define vdso_offset_\2\t0x\1/p' diff --git a/arch/arm64/kernel/vdso/gettimeofday.S b/arch/arm64/kernel/vdso/gettimeofday.S new file mode 100644 index 0000000..dcb8c20 --- /dev/null +++ b/arch/arm64/kernel/vdso/gettimeofday.S @@ -0,0 +1,242 @@ +/* + * Userspace implementations of gettimeofday() and friends. + * + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Author: Will Deacon <will.dea...@arm.com> + */ + +#include <linux/linkage.h> +#include <asm/asm-offsets.h> +#include <asm/unistd.h> + +#define NSEC_PER_SEC_LO16 0xca00 +#define NSEC_PER_SEC_HI16 0x3b9a + +vdso_data .req x6 +use_syscall .req w7 +seqcnt .req w8 + + .macro seqcnt_acquire +9999: ldr seqcnt, [vdso_data, #VDSO_TB_SEQ_COUNT] + tbnz seqcnt, #0, 9999b + dmb ishld + ldr use_syscall, [vdso_data, #VDSO_USE_SYSCALL] + .endm + + .macro seqcnt_read, cnt + dmb ishld + ldr \cnt, [vdso_data, #VDSO_TB_SEQ_COUNT] + .endm + + .macro seqcnt_check, cnt, fail + cmp \cnt, seqcnt + b.ne \fail + .endm + + .text + +/* int __kernel_gettimeofday(struct timeval *tv, struct timezone *tz); */ +ENTRY(__kernel_gettimeofday) + .cfi_startproc + mov x2, x30 + .cfi_register x30, x2 + + /* Acquire the sequence counter and get the timespec. */ + adr vdso_data, _vdso_data +1: seqcnt_acquire + cbnz use_syscall, 4f + + /* If tv is NULL, skip to the timezone code. */ + cbz x0, 2f + bl __do_get_tspec + seqcnt_check w13, 1b + + /* Convert ns to us. */ + mov x11, #1000 + udiv x10, x10, x11 + stp x9, x10, [x0, #TVAL_TV_SEC] +2: + /* If tz is NULL, return 0. */ + cbz x1, 3f + ldp w4, w5, [vdso_data, #VDSO_TZ_MINWEST] + seqcnt_read w13 + seqcnt_check w13, 1b + stp w4, w5, [x1, #TZ_MINWEST] +3: + mov x0, xzr + ret x2 +4: + /* Syscall fallback. */ + mov x8, #__NR_gettimeofday + svc #0 + ret x2 + .cfi_endproc +ENDPROC(__kernel_gettimeofday) + +/* int __kernel_clock_gettime(clockid_t clock_id, struct timespec *tp); */ +ENTRY(__kernel_clock_gettime) + .cfi_startproc + cmp w0, #CLOCK_REALTIME + ccmp w0, #CLOCK_MONOTONIC, #0x4, ne + b.ne 2f + + mov x2, x30 + .cfi_register x30, x2 + + /* Get kernel timespec. */ + adr vdso_data, _vdso_data +1: seqcnt_acquire + cbnz use_syscall, 7f + + bl __do_get_tspec + seqcnt_check w13, 1b + + cmp w0, #CLOCK_MONOTONIC + b.ne 6f + + /* Get wtm timespec. */ + ldp x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC] + + /* Check the sequence counter. */ + seqcnt_read w13 + seqcnt_check w13, 1b + b 4f +2: + cmp w0, #CLOCK_REALTIME_COARSE + ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne + b.ne 8f + + /* Get coarse timespec. */ + adr vdso_data, _vdso_data +3: seqcnt_acquire + ldp x9, x10, [vdso_data, #VDSO_XTIME_CRS_SEC] + + cmp w0, #CLOCK_MONOTONIC_COARSE + b.ne 6f + + /* Get wtm timespec. */ + ldp x14, x15, [vdso_data, #VDSO_WTM_CLK_SEC] + + /* Check the sequence counter. */ + seqcnt_read w13 + seqcnt_check w13, 3b +4: + /* Add on wtm timespec. */ + add x9, x9, x14 + add x10, x10, x15 + + /* Normalise the new timespec. */ + mov x14, #NSEC_PER_SEC_LO16 + movk x14, #NSEC_PER_SEC_HI16, lsl #16 + cmp x10, x14 + b.lt 5f + sub x10, x10, x14 + add x9, x9, #1 +5: + cmp x10, #0 + b.ge 6f + add x10, x10, x14 + sub x9, x9, #1 + +6: /* Store to the user timespec. */ + stp x9, x10, [x1, #TSPEC_TV_SEC] + mov x0, xzr + ret x2 +7: + mov x30, x2 +8: /* Syscall fallback. */ + mov x8, #__NR_clock_gettime + svc #0 + ret + .cfi_endproc +ENDPROC(__kernel_clock_gettime) + +/* int __kernel_clock_getres(clockid_t clock_id, struct timespec *res); */ +ENTRY(__kernel_clock_getres) + .cfi_startproc + cbz w1, 3f + + cmp w0, #CLOCK_REALTIME + ccmp w0, #CLOCK_MONOTONIC, #0x4, ne + b.ne 1f + + ldr x2, 5f + b 2f +1: + cmp w0, #CLOCK_REALTIME_COARSE + ccmp w0, #CLOCK_MONOTONIC_COARSE, #0x4, ne + b.ne 4f + ldr x2, 6f +2: + stp xzr, x2, [x1] + +3: /* res == NULL. */ + mov w0, wzr + ret + +4: /* Syscall fallback. */ + mov x8, #__NR_clock_getres + svc #0 + ret +5: + .quad CLOCK_REALTIME_RES +6: + .quad CLOCK_COARSE_RES + .cfi_endproc +ENDPROC(__kernel_clock_getres) + +/* + * Read the current time from the architected counter. + * Expects vdso_data to be initialised. + * Clobbers the temporary registers (x9 - x15). + * Returns: + * - (x9, x10) = (ts->tv_sec, ts->tv_nsec) + * - (x11, x12) = (xtime->tv_sec, xtime->tv_nsec) + * - w13 = vDSO sequence counter + */ +ENTRY(__do_get_tspec) + .cfi_startproc + + /* Read from the vDSO data page. */ + ldr x10, [vdso_data, #VDSO_CS_CYCLE_LAST] + ldp x11, x12, [vdso_data, #VDSO_XTIME_CLK_SEC] + ldp w14, w15, [vdso_data, #VDSO_CS_MULT] + seqcnt_read w13 + + /* Read the physical counter. */ + isb + mrs x9, cntpct_el0 + + /* Calculate cycle delta and convert to ns. */ + sub x10, x9, x10 + /* We can only guarantee 56 bits of precision. */ + movn x9, #0xff0, lsl #48 + and x10, x9, x10 + mul x10, x10, x14 + lsr x10, x10, x15 + + /* Use the kernel time to calculate the new timespec. */ + add x10, x12, x10 + mov x14, #NSEC_PER_SEC_LO16 + movk x14, #NSEC_PER_SEC_HI16, lsl #16 + udiv x15, x10, x14 + add x9, x15, x11 + mul x14, x14, x15 + sub x10, x10, x14 + + ret + .cfi_endproc +ENDPROC(__do_get_tspec) diff --git a/arch/arm64/kernel/vdso/note.S b/arch/arm64/kernel/vdso/note.S new file mode 100644 index 0000000..b82c85e --- /dev/null +++ b/arch/arm64/kernel/vdso/note.S @@ -0,0 +1,28 @@ +/* + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Author: Will Deacon <will.dea...@arm.com> + * + * This supplies .note.* sections to go into the PT_NOTE inside the vDSO text. + * Here we can supply some information useful to userland. + */ + +#include <linux/uts.h> +#include <linux/version.h> +#include <linux/elfnote.h> + +ELFNOTE_START(Linux, 0, "a") + .long LINUX_VERSION_CODE +ELFNOTE_END diff --git a/arch/arm64/kernel/vdso/sigreturn.S b/arch/arm64/kernel/vdso/sigreturn.S new file mode 100644 index 0000000..20d98ef --- /dev/null +++ b/arch/arm64/kernel/vdso/sigreturn.S @@ -0,0 +1,37 @@ +/* + * Sigreturn trampoline for returning from a signal when the SA_RESTORER + * flag is not set. + * + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Author: Will Deacon <will.dea...@arm.com> + */ + +#include <linux/linkage.h> +#include <asm/unistd.h> + + .text + + nop +ENTRY(__kernel_rt_sigreturn) + .cfi_startproc + .cfi_signal_frame + .cfi_def_cfa x29, 0 + .cfi_offset x29, 0 * 8 + .cfi_offset x30, 1 * 8 + mov x8, #__NR_rt_sigreturn + svc #0 + .cfi_endproc +ENDPROC(__kernel_rt_sigreturn) diff --git a/arch/arm64/kernel/vdso/vdso.S b/arch/arm64/kernel/vdso/vdso.S new file mode 100644 index 0000000..60c1db5 --- /dev/null +++ b/arch/arm64/kernel/vdso/vdso.S @@ -0,0 +1,33 @@ +/* + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Author: Will Deacon <will.dea...@arm.com> + */ + +#include <linux/init.h> +#include <linux/linkage.h> +#include <linux/const.h> +#include <asm/page.h> + + __PAGE_ALIGNED_DATA + + .globl vdso_start, vdso_end + .balign PAGE_SIZE +vdso_start: + .incbin "arch/arm64/kernel/vdso/vdso.so" + .balign PAGE_SIZE +vdso_end: + + .previous diff --git a/arch/arm64/kernel/vdso/vdso.lds.S b/arch/arm64/kernel/vdso/vdso.lds.S new file mode 100644 index 0000000..8154b8d --- /dev/null +++ b/arch/arm64/kernel/vdso/vdso.lds.S @@ -0,0 +1,100 @@ +/* + * GNU linker script for the VDSO library. +* + * Copyright (C) 2012 ARM Limited + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <http://www.gnu.org/licenses/>. + * + * Author: Will Deacon <will.dea...@arm.com> + * Heavily based on the vDSO linker scripts for other archs. + */ + +#include <linux/const.h> +#include <asm/page.h> +#include <asm/vdso.h> + +OUTPUT_FORMAT("elf64-littleaarch64", "elf64-bigaarch64", "elf64-littleaarch64") +OUTPUT_ARCH(aarch64) + +SECTIONS +{ + . = VDSO_LBASE + SIZEOF_HEADERS; + + .hash : { *(.hash) } :text + .gnu.hash : { *(.gnu.hash) } + .dynsym : { *(.dynsym) } + .dynstr : { *(.dynstr) } + .gnu.version : { *(.gnu.version) } + .gnu.version_d : { *(.gnu.version_d) } + .gnu.version_r : { *(.gnu.version_r) } + + .note : { *(.note.*) } :text :note + + . = ALIGN(16); + + .text : { *(.text*) } :text =0xd503201f + PROVIDE (__etext = .); + PROVIDE (_etext = .); + PROVIDE (etext = .); + + .eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr + .eh_frame : { KEEP (*(.eh_frame)) } :text + + .dynamic : { *(.dynamic) } :text :dynamic + + .rodata : { *(.rodata*) } :text + + _end = .; + PROVIDE(end = .); + + . = ALIGN(PAGE_SIZE); + PROVIDE(_vdso_data = .); + + /DISCARD/ : { + *(.note.GNU-stack) + *(.data .data.* .gnu.linkonce.d.* .sdata*) + *(.bss .sbss .dynbss .dynsbss) + } +} + +/* + * We must supply the ELF program headers explicitly to get just one + * PT_LOAD segment, and set the flags explicitly to make segments read-only. + */ +PHDRS +{ + text PT_LOAD FLAGS(5) FILEHDR PHDRS; /* PF_R|PF_X */ + dynamic PT_DYNAMIC FLAGS(4); /* PF_R */ + note PT_NOTE FLAGS(4); /* PF_R */ + eh_frame_hdr PT_GNU_EH_FRAME; +} + +/* + * This controls what symbols we export from the DSO. + */ +VERSION +{ + LINUX_2.6.39 { + global: + __kernel_rt_sigreturn; + __kernel_gettimeofday; + __kernel_clock_gettime; + __kernel_clock_getres; + local: *; + }; +} + +/* + * Make the sigreturn code visible to the kernel. + */ +VDSO_sigtramp = __kernel_rt_sigreturn; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
