diff options
Diffstat (limited to 'arch/arm64/kernel/vdso')
| -rw-r--r-- | arch/arm64/kernel/vdso/.gitignore | 2 | ||||
| -rw-r--r-- | arch/arm64/kernel/vdso/Makefile | 63 | ||||
| -rwxr-xr-x | arch/arm64/kernel/vdso/gen_vdso_offsets.sh | 15 | ||||
| -rw-r--r-- | arch/arm64/kernel/vdso/gettimeofday.S | 242 | ||||
| -rw-r--r-- | arch/arm64/kernel/vdso/note.S | 28 | ||||
| -rw-r--r-- | arch/arm64/kernel/vdso/sigreturn.S | 37 | ||||
| -rw-r--r-- | arch/arm64/kernel/vdso/vdso.S | 33 | ||||
| -rw-r--r-- | arch/arm64/kernel/vdso/vdso.lds.S | 100 |
8 files changed, 520 insertions, 0 deletions
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.deacon@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.deacon@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.deacon@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.deacon@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.deacon@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.deacon@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.deacon@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; |
