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tile: implement gettimeofday() via vDSO

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This change creates the framework for vDSO calls, makes the existing
rt_sigreturn() mechanism use it, and adds a fast gettimeofday().
Now that we need to expose the vDSO address to userspace, we add
AT_SYSINFO_EHDR to the set of aux entries provided to userspace.
(You can disable any extra vDSO support by booting with vdso=0,
but the rt_sigreturn vDSO page will still be provided.)

Note that glibc has supported the tile vDSO since release 2.17.

Signed-off-by: Chris Metcalf <cmetcalf@tilera.com>
This commit is contained in:
Chris Metcalf 2013-08-07 15:33:32 -04:00
parent 0c1d1917c5
commit 4a556f4f56
22 changed files with 732 additions and 62 deletions
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3
arch/tile/Kconfig
View File

@ -64,6 +64,9 @@ config HUGETLB_SUPER_PAGES
depends on HUGETLB_PAGE && TILEGX
def_bool y
config GENERIC_TIME_VSYSCALL
def_bool y
# FIXME: tilegx can implement a more efficient rwsem.
config RWSEM_GENERIC_SPINLOCK
def_bool y

5
arch/tile/include/asm/elf.h
View File

@ -132,6 +132,11 @@ extern int dump_task_regs(struct task_struct *, elf_gregset_t *);
struct linux_binprm;
extern int arch_setup_additional_pages(struct linux_binprm *bprm,
int executable_stack);
#define ARCH_DLINFO \
do { \
NEW_AUX_ENT(AT_SYSINFO_EHDR, VDSO_BASE); \
} while (0)
#ifdef CONFIG_COMPAT
#define COMPAT_ELF_PLATFORM "tilegx-m32"

1
arch/tile/include/asm/mmu.h
View File

@ -22,6 +22,7 @@ struct mm_context {
* semaphore but atomically, but it is conservatively set.
*/
unsigned long priority_cached;
unsigned long vdso_base;
};
typedef struct mm_context mm_context_t;

8
arch/tile/include/asm/page.h
View File

@ -38,6 +38,12 @@
#define PAGE_MASK (~(PAGE_SIZE - 1))
#define HPAGE_MASK (~(HPAGE_SIZE - 1))
/*
* We do define AT_SYSINFO_EHDR to support vDSO,
* but don't use the gate mechanism.
*/
#define __HAVE_ARCH_GATE_AREA 1
/*
* If the Kconfig doesn't specify, set a maximum zone order that
* is enough so that we can create huge pages from small pages given
@ -246,7 +252,7 @@ static inline __attribute_const__ int get_order(unsigned long size)
#endif /* __tilegx__ */
#ifndef __ASSEMBLY__
#if !defined(__ASSEMBLY__) && !defined(VDSO_BUILD)
#ifdef CONFIG_HIGHMEM

6
arch/tile/include/asm/processor.h
View File

@ -180,10 +180,10 @@ struct thread_struct {
#define TASK_SIZE TASK_SIZE_MAX
#endif
/* We provide a minimal "vdso" a la x86; just the sigreturn code for now. */
#define VDSO_BASE (TASK_SIZE - PAGE_SIZE)
#define VDSO_BASE ((unsigned long)current->active_mm->context.vdso_base)
#define VDSO_SYM(x) (VDSO_BASE + (unsigned long)(x))
#define STACK_TOP VDSO_BASE
#define STACK_TOP TASK_SIZE
/* STACK_TOP_MAX is used temporarily in execve and should not check COMPAT. */
#define STACK_TOP_MAX TASK_SIZE_MAX

4
arch/tile/include/asm/sections.h
View File

@ -25,6 +25,10 @@ extern char _sinitdata[], _einitdata[];
/* Write-once data is writable only till the end of initialization. */
extern char __w1data_begin[], __w1data_end[];
extern char vdso_start[], vdso_end[];
#ifdef CONFIG_COMPAT
extern char vdso32_start[], vdso32_end[];
#endif
/* Not exactly sections, but PC comparison points in the code. */
extern char __rt_sigreturn[], __rt_sigreturn_end[];

49
arch/tile/include/asm/vdso.h Normal file
View File

@ -0,0 +1,49 @@
/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#ifndef __TILE_VDSO_H__
#define __TILE_VDSO_H__
#include <linux/types.h>
/*
* Note about the vdso_data structure:
*
* NEVER USE THEM IN USERSPACE CODE DIRECTLY. The layout of the
* structure is supposed to be known only to the function in the vdso
* itself and may change without notice.
*/
struct vdso_data {
__u64 tz_update_count; /* Timezone atomicity ctr */
__u64 tb_update_count; /* Timebase atomicity ctr */
__u64 xtime_tod_stamp; /* TOD clock for xtime */
__u64 xtime_clock_sec; /* Kernel time second */
__u64 xtime_clock_nsec; /* Kernel time nanosecond */
__u64 wtom_clock_sec; /* Wall to monotonic clock second */
__u64 wtom_clock_nsec; /* Wall to monotonic clock nanosecond */
__u32 mult; /* Cycle to nanosecond multiplier */
__u32 shift; /* Cycle to nanosecond divisor (power of two) */
__u32 tz_minuteswest; /* Minutes west of Greenwich */
__u32 tz_dsttime; /* Type of dst correction */
};
extern struct vdso_data *vdso_data;
/* __vdso_rt_sigreturn is defined with the addresses in the vdso page. */
extern void __vdso_rt_sigreturn(void);
extern int setup_vdso_pages(void);
#endif /* __TILE_VDSO_H__ */

3
arch/tile/include/uapi/asm/auxvec.h
View File

@ -15,6 +15,7 @@
#ifndef _ASM_TILE_AUXVEC_H
#define _ASM_TILE_AUXVEC_H
/* No extensions to auxvec */
/* The vDSO location. */
#define AT_SYSINFO_EHDR 33
#endif /* _ASM_TILE_AUXVEC_H */

4
arch/tile/kernel/Makefile
View File

@ -6,7 +6,7 @@ extra-y := vmlinux.lds head_$(BITS).o
obj-y := backtrace.o entry.o irq.o messaging.o \
pci-dma.o proc.o process.o ptrace.o reboot.o \
setup.o signal.o single_step.o stack.o sys.o \
sysfs.o time.o traps.o unaligned.o \
sysfs.o time.o traps.o unaligned.o vdso.o \
intvec_$(BITS).o regs_$(BITS).o tile-desc_$(BITS).o
obj-$(CONFIG_HARDWALL) += hardwall.o
@ -21,3 +21,5 @@ else
obj-$(CONFIG_PCI) += pci.o
endif
obj-$(CONFIG_TILE_USB) += usb.o
obj-y += vdso/

3
arch/tile/kernel/compat_signal.c
View File

@ -32,6 +32,7 @@
#include <asm/ucontext.h>
#include <asm/sigframe.h>
#include <asm/syscalls.h>
#include <asm/vdso.h>
#include <arch/interrupts.h>
struct compat_ucontext {
@ -227,7 +228,7 @@ int compat_setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
if (err)
goto give_sigsegv;
restorer = VDSO_BASE;
restorer = VDSO_SYM(&__vdso_rt_sigreturn);
if (ka->sa.sa_flags & SA_RESTORER)
restorer = ptr_to_compat_reg(ka->sa.sa_restorer);

16
arch/tile/kernel/entry.S
View File

@ -27,22 +27,6 @@ STD_ENTRY(current_text_addr)
{ move r0, lr; jrp lr }
STD_ENDPROC(current_text_addr)
/*
* We don't run this function directly, but instead copy it to a page
* we map into every user process. See vdso_setup().
*
* Note that libc has a copy of this function that it uses to compare
* against the PC when a stack backtrace ends, so if this code is
* changed, the libc implementation(s) should also be updated.
*/
.pushsection .data
ENTRY(__rt_sigreturn)
moveli TREG_SYSCALL_NR_NAME,__NR_rt_sigreturn
swint1
ENDPROC(__rt_sigreturn)
ENTRY(__rt_sigreturn_end)
.popsection
STD_ENTRY(dump_stack)
{ move r2, lr; lnk r1 }
{ move r4, r52; addli r1, r1, dump_stack - . }

3
arch/tile/kernel/signal.c
View File

@ -33,6 +33,7 @@
#include <asm/ucontext.h>
#include <asm/sigframe.h>
#include <asm/syscalls.h>
#include <asm/vdso.h>
#include <arch/interrupts.h>
#define DEBUG_SIG 0
@ -190,7 +191,7 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
if (err)
goto give_sigsegv;
restorer = VDSO_BASE;
restorer = VDSO_SYM(&__vdso_rt_sigreturn);
if (ka->sa.sa_flags & SA_RESTORER)
restorer = (unsigned long) ka->sa.sa_restorer;

5
arch/tile/kernel/stack.c
View File

@ -29,6 +29,7 @@
#include <asm/switch_to.h>
#include <asm/sigframe.h>
#include <asm/stack.h>
#include <asm/vdso.h>
#include <arch/abi.h>
#include <arch/interrupts.h>
@ -119,7 +120,7 @@ static struct pt_regs *valid_fault_handler(struct KBacktraceIterator* kbt)
/* Is the pc pointing to a sigreturn trampoline? */
static int is_sigreturn(unsigned long pc)
{
return (pc == VDSO_BASE);
return current->mm && (pc == VDSO_SYM(&__vdso_rt_sigreturn));
}
/* Return a pt_regs pointer for a valid signal handler frame */
@ -128,7 +129,7 @@ static struct pt_regs *valid_sigframe(struct KBacktraceIterator* kbt,
{
BacktraceIterator *b = &kbt->it;
if (b->pc == VDSO_BASE && b->sp < PAGE_OFFSET &&
if (is_sigreturn(b->pc) && b->sp < PAGE_OFFSET &&
b->sp % sizeof(long) == 0) {
int retval;
pagefault_disable();

37
arch/tile/kernel/time.c
View File

@ -23,8 +23,10 @@
#include <linux/smp.h>
#include <linux/delay.h>
#include <linux/module.h>
#include <linux/timekeeper_internal.h>
#include <asm/irq_regs.h>
#include <asm/traps.h>
#include <asm/vdso.h>
#include <hv/hypervisor.h>
#include <arch/interrupts.h>
#include <arch/spr_def.h>
@ -110,7 +112,6 @@ void __init time_init(void)
setup_tile_timer();
}
/*
* Define the tile timer clock event device. The timer is driven by
* the TILE_TIMER_CONTROL register, which consists of a 31-bit down
@ -237,3 +238,37 @@ cycles_t ns2cycles(unsigned long nsecs)
struct clock_event_device *dev = &__raw_get_cpu_var(tile_timer);
return ((u64)nsecs * dev->mult) >> dev->shift;
}
void update_vsyscall_tz(void)
{
/* Userspace gettimeofday will spin while this value is odd. */
++vdso_data->tz_update_count;
smp_wmb();
vdso_data->tz_minuteswest = sys_tz.tz_minuteswest;
vdso_data->tz_dsttime = sys_tz.tz_dsttime;
smp_wmb();
++vdso_data->tz_update_count;
}
void update_vsyscall(struct timekeeper *tk)
{
struct timespec wall_time = tk_xtime(tk);
struct timespec *wtm = &tk->wall_to_monotonic;
struct clocksource *clock = tk->clock;
if (clock != &cycle_counter_cs)
return;
/* Userspace gettimeofday will spin while this value is odd. */
++vdso_data->tb_update_count;
smp_wmb();
vdso_data->xtime_tod_stamp = clock->cycle_last;
vdso_data->xtime_clock_sec = wall_time.tv_sec;
vdso_data->xtime_clock_nsec = wall_time.tv_nsec;
vdso_data->wtom_clock_sec = wtm->tv_sec;
vdso_data->wtom_clock_nsec = wtm->tv_nsec;
vdso_data->mult = clock->mult;
vdso_data->shift = clock->shift;
smp_wmb();
++vdso_data->tb_update_count;
}

212
arch/tile/kernel/vdso.c Normal file
View File

@ -0,0 +1,212 @@
/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/binfmts.h>
#include <linux/compat.h>
#include <linux/elf.h>
#include <linux/mm.h>
#include <linux/pagemap.h>
#include <asm/vdso.h>
#include <asm/mman.h>
#include <asm/sections.h>
#include <arch/sim.h>
/* The alignment of the vDSO. */
#define VDSO_ALIGNMENT PAGE_SIZE
static unsigned int vdso_pages;
static struct page **vdso_pagelist;
#ifdef CONFIG_COMPAT
static unsigned int vdso32_pages;
static struct page **vdso32_pagelist;
#endif
static int vdso_ready;
/*
* 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;
static unsigned int __read_mostly vdso_enabled = 1;
static struct page **vdso_setup(void *vdso_kbase, unsigned int pages)
{
int i;
struct page **pagelist;
pagelist = kzalloc(sizeof(struct page *) * (pages + 1), GFP_KERNEL);
BUG_ON(pagelist == NULL);
for (i = 0; i < pages - 1; i++) {
struct page *pg = virt_to_page(vdso_kbase + i*PAGE_SIZE);
ClearPageReserved(pg);
pagelist[i] = pg;
}
pagelist[pages - 1] = virt_to_page(vdso_data);
pagelist[pages] = NULL;
return pagelist;
}
static int __init vdso_init(void)
{
int data_pages = sizeof(vdso_data_store) >> PAGE_SHIFT;
/*
* We can disable vDSO support generally, but we need to retain
* one page to support the two-bundle (16-byte) rt_sigreturn path.
*/
if (!vdso_enabled) {
size_t offset = (unsigned long)&__vdso_rt_sigreturn;
static struct page *sigret_page;
sigret_page = alloc_page(GFP_KERNEL | __GFP_ZERO);
BUG_ON(sigret_page == NULL);
vdso_pagelist = &sigret_page;
vdso_pages = 1;
BUG_ON(offset >= PAGE_SIZE);
memcpy(page_address(sigret_page) + offset,
vdso_start + offset, 16);
#ifdef CONFIG_COMPAT
vdso32_pages = vdso_pages;
vdso32_pagelist = vdso_pagelist;
#endif
vdso_ready = 1;
return 0;
}
vdso_pages = (vdso_end - vdso_start) >> PAGE_SHIFT;
vdso_pages += data_pages;
vdso_pagelist = vdso_setup(vdso_start, vdso_pages);
#ifdef CONFIG_COMPAT
vdso32_pages = (vdso32_end - vdso32_start) >> PAGE_SHIFT;
vdso32_pages += data_pages;
vdso32_pagelist = vdso_setup(vdso32_start, vdso32_pages);
#endif
smp_wmb();
vdso_ready = 1;
return 0;
}
arch_initcall(vdso_init);
const char *arch_vma_name(struct vm_area_struct *vma)
{
if (vma->vm_mm && vma->vm_start == VDSO_BASE)
return "[vdso]";
#ifndef __tilegx__
if (vma->vm_start == MEM_USER_INTRPT)
return "[intrpt]";
#endif
return NULL;
}
struct vm_area_struct *get_gate_vma(struct mm_struct *mm)
{
return NULL;
}
int in_gate_area(struct mm_struct *mm, unsigned long address)
{
return 0;
}
int in_gate_area_no_mm(unsigned long address)
{
return 0;
}
int setup_vdso_pages(void)
{
struct page **pagelist;
unsigned long pages;
struct mm_struct *mm = current->mm;
unsigned long vdso_base = 0;
int retval = 0;
if (!vdso_ready)
return 0;
mm->context.vdso_base = 0;
pagelist = vdso_pagelist;
pages = vdso_pages;
#ifdef CONFIG_COMPAT
if (is_compat_task()) {
pagelist = vdso32_pagelist;
pages = vdso32_pages;
}
#endif
/*
* vDSO has a problem and was disabled, just don't "enable" it for the
* process.
*/
if (pages == 0)
return 0;
vdso_base = get_unmapped_area(NULL, vdso_base,
(pages << PAGE_SHIFT) +
((VDSO_ALIGNMENT - 1) & PAGE_MASK),
0, 0);
if (IS_ERR_VALUE(vdso_base)) {
retval = vdso_base;
return retval;
}
/* Add required alignment. */
vdso_base = ALIGN(vdso_base, VDSO_ALIGNMENT);
/*
* Put vDSO base into mm struct. We need to do this before calling
* install_special_mapping or the perf counter mmap tracking code
* will fail to recognise it as a vDSO (since arch_vma_name fails).
*/
mm->context.vdso_base = vdso_base;
/*
* our vma flags don't have VM_WRITE so by default, the process isn't
* allowed to write those pages.
* gdb can break that with ptrace interface, and thus trigger COW on
* those pages but it's then your responsibility to never do that on
* the "data" page of the vDSO or you'll stop getting kernel updates
* and your nice userland gettimeofday will be totally dead.
* It's fine to use that for setting breakpoints in the vDSO code
* pages though
*/
retval = install_special_mapping(mm, vdso_base,
pages << PAGE_SHIFT,
VM_READ|VM_EXEC |
VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
pagelist);
if (retval)
mm->context.vdso_base = 0;
return retval;
}
static __init int vdso_func(char *s)
{
return kstrtouint(s, 0, &vdso_enabled);
}
__setup("vdso=", vdso_func);

118
arch/tile/kernel/vdso/Makefile Normal file
View File

@ -0,0 +1,118 @@
# Symbols present in the vdso
vdso-syms = rt_sigreturn gettimeofday
# Files to link into the vdso
obj-vdso = $(patsubst %, v%.o, $(vdso-syms))
# Build rules
targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.lds
obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
# vdso32 is only for tilegx -m32 compat task.
VDSO32-$(CONFIG_COMPAT) := y
obj-y += vdso.o
obj-$(VDSO32-y) += vdso32.o
extra-y += vdso.lds
CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
# vDSO code runs in userspace and -pg doesn't help with profiling anyway.
CFLAGS_REMOVE_vdso.o = -pg
CFLAGS_REMOVE_vdso32.o = -pg
CFLAGS_REMOVE_vrt_sigreturn.o = -pg
CFLAGS_REMOVE_vrt_sigreturn32.o = -pg
CFLAGS_REMOVE_vgettimeofday.o = -pg
CFLAGS_REMOVE_vgettimeofday32.o = -pg
ifdef CONFIG_FEEDBACK_COLLECT
# vDSO code runs in userspace, not collecting feedback data.
CFLAGS_REMOVE_vdso.o = -ffeedback-generate
CFLAGS_REMOVE_vdso32.o = -ffeedback-generate
CFLAGS_REMOVE_vrt_sigreturn.o = -ffeedback-generate
CFLAGS_REMOVE_vrt_sigreturn32.o = -ffeedback-generate
CFLAGS_REMOVE_vgettimeofday.o = -ffeedback-generate
CFLAGS_REMOVE_vgettimeofday32.o = -ffeedback-generate
endif
# Disable gcov profiling for VDSO code
GCOV_PROFILE := n
# Force dependency
$(obj)/vdso.o: $(obj)/vdso.so
# link rule for the .so file, .lds has to be first
SYSCFLAGS_vdso.so.dbg = $(c_flags)
$(obj)/vdso.so.dbg: $(src)/vdso.lds $(obj-vdso)
$(call if_changed,vdsold)
# We also create a special relocatable object that should mirror the symbol
# table and layout of the linked DSO. With ld -R we can then refer to
# these symbols in the kernel code rather than hand-coded addresses.
extra-y += vdso-syms.o
$(obj)/built-in.o: $(obj)/vdso-syms.o
$(obj)/built-in.o: ld_flags += -R $(obj)/vdso-syms.o
SYSCFLAGS_vdso.so.dbg = -shared -s -Wl,-soname=linux-vdso.so.1 \
$(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
SYSCFLAGS_vdso_syms.o = -r
$(obj)/vdso-syms.o: $(src)/vdso.lds $(obj)/vrt_sigreturn.o FORCE
$(call if_changed,vdsold)
# strip rule for the .so file
$(obj)/%.so: OBJCOPYFLAGS := -S
$(obj)/%.so: $(obj)/%.so.dbg FORCE
$(call if_changed,objcopy)
# actual build commands
# The DSO images are built using a special linker script
# Add -lgcc so tilepro gets static muldi3 and lshrdi3 definitions.
# Make sure only to export the intended __vdso_xxx symbol offsets.
quiet_cmd_vdsold = VDSOLD $@
cmd_vdsold = $(CC) $(KCFLAGS) -nostdlib $(SYSCFLAGS_$(@F)) \
-Wl,-T,$(filter-out FORCE,$^) -o $@.tmp -lgcc && \
$(CROSS_COMPILE)objcopy \
$(patsubst %, -G __vdso_%, $(vdso-syms)) $@.tmp $@
# 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)
vdso32.so: $(obj)/vdso32.so.dbg
$(call cmd,vdso_install)
vdso_install: vdso.so
vdso32_install: vdso32.so
KBUILD_AFLAGS_32 := $(filter-out -m64,$(KBUILD_AFLAGS))
KBUILD_AFLAGS_32 += -m32 -s
KBUILD_CFLAGS_32 := $(filter-out -m64,$(KBUILD_CFLAGS))
KBUILD_CFLAGS_32 += -m32 -fPIC -shared
obj-vdso32 = $(patsubst %, v%32.o, $(vdso-syms))
obj-vdso32 := $(addprefix $(obj)/, $(obj-vdso32))
targets += $(obj-vdso32) vdso32.so vdso32.so.dbg
$(obj-vdso32:%=%): KBUILD_AFLAGS = $(KBUILD_AFLAGS_32)
$(obj-vdso32:%=%): KBUILD_CFLAGS = $(KBUILD_CFLAGS_32)
$(obj)/vgettimeofday32.o: $(obj)/vgettimeofday.c
$(call if_changed,cc_o_c)
$(obj)/vrt_sigreturn32.o: $(obj)/vrt_sigreturn.S
$(call if_changed,as_o_S)
# Force dependency
$(obj)/vdso32.o: $(obj)/vdso32.so
SYSCFLAGS_vdso32.so.dbg = -m32 -shared -s -Wl,-soname=linux-vdso32.so.1 \
$(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
$(obj)/vdso32.so.dbg: $(src)/vdso.lds $(obj-vdso32)
$(call if_changed,vdsold)

28
arch/tile/kernel/vdso/vdso.S Normal file
View File

@ -0,0 +1,28 @@
/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/page.h>
__PAGE_ALIGNED_DATA
.global vdso_start, vdso_end
.align PAGE_SIZE
vdso_start:
.incbin "arch/tile/kernel/vdso/vdso.so"
.align PAGE_SIZE
vdso_end:
.previous

87
arch/tile/kernel/vdso/vdso.lds.S Normal file
View File

@ -0,0 +1,87 @@
/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#define VDSO_VERSION_STRING LINUX_2.6
OUTPUT_ARCH(tile)
/* The ELF entry point can be used to set the AT_SYSINFO value. */
ENTRY(__vdso_rt_sigreturn);
SECTIONS
{
. = 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
.dynamic : { *(.dynamic) } :text :dynamic
.eh_frame_hdr : { *(.eh_frame_hdr) } :text :eh_frame_hdr
.eh_frame : { KEEP (*(.eh_frame)) } :text
.rodata : { *(.rodata .rodata.* .gnu.linkonce.r.*) }
/*
* This linker script is used both with -r and with -shared.
* For the layouts to match, we need to skip more than enough
* space for the dynamic symbol table et al. If this amount
* is insufficient, ld -shared will barf. Just increase it here.
*/
. = 0x1000;
.text : { *(.text .text.*) } :text
.data : {
*(.got.plt) *(.got)
*(.data .data.* .gnu.linkonce.d.*)
*(.dynbss)
*(.bss .bss.* .gnu.linkonce.b.*)
}
}
/*
* 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 userland symbols we export from the vDSO.
*/
VERSION
{
VDSO_VERSION_STRING {
global:
__vdso_rt_sigreturn;
__vdso_gettimeofday;
gettimeofday;
local:*;
};
}

28
arch/tile/kernel/vdso/vdso32.S Normal file
View File

@ -0,0 +1,28 @@
/*
* Copyright 2013 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/init.h>
#include <linux/linkage.h>
#include <asm/page.h>
__PAGE_ALIGNED_DATA
.global vdso32_start, vdso32_end
.align PAGE_SIZE
vdso32_start:
.incbin "arch/tile/kernel/vdso/vdso32.so"
.align PAGE_SIZE
vdso32_end:
.previous

107
arch/tile/kernel/vdso/vgettimeofday.c Normal file
View File

@ -0,0 +1,107 @@
/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#define VDSO_BUILD /* avoid some shift warnings for -m32 in <asm/page.h> */
#include <linux/time.h>
#include <asm/timex.h>
#include <asm/vdso.h>
#if CHIP_HAS_SPLIT_CYCLE()
static inline cycles_t get_cycles_inline(void)
{
unsigned int high = __insn_mfspr(SPR_CYCLE_HIGH);
unsigned int low = __insn_mfspr(SPR_CYCLE_LOW);
unsigned int high2 = __insn_mfspr(SPR_CYCLE_HIGH);
while (unlikely(high != high2)) {
low = __insn_mfspr(SPR_CYCLE_LOW);
high = high2;
high2 = __insn_mfspr(SPR_CYCLE_HIGH);
}
return (((cycles_t)high) << 32) | low;
}
#define get_cycles get_cycles_inline
#endif
/*
* Find out the vDSO data page address in the process address space.
*/
inline unsigned long get_datapage(void)
{
unsigned long ret;
/* vdso data page located in the 2nd vDSO page. */
asm volatile ("lnk %0" : "=r"(ret));
ret &= ~(PAGE_SIZE - 1);
ret += PAGE_SIZE;
return ret;
}
int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
{
cycles_t cycles;
unsigned long count, sec, ns;
volatile struct vdso_data *vdso_data;
vdso_data = (struct vdso_data *)get_datapage();
/* The use of the timezone is obsolete, normally tz is NULL. */
if (unlikely(tz != NULL)) {
while (1) {
/* Spin until the update finish. */
count = vdso_data->tz_update_count;
if (count & 1)
continue;
tz->tz_minuteswest = vdso_data->tz_minuteswest;
tz->tz_dsttime = vdso_data->tz_dsttime;
/* Check whether updated, read again if so. */
if (count == vdso_data->tz_update_count)
break;
}
}
if (unlikely(tv == NULL))
return 0;
while (1) {
/* Spin until the update finish. */
count = vdso_data->tb_update_count;
if (count & 1)
continue;
cycles = (get_cycles() - vdso_data->xtime_tod_stamp);
ns = (cycles * vdso_data->mult) >> vdso_data->shift;
sec = vdso_data->xtime_clock_sec;
ns += vdso_data->xtime_clock_nsec;
if (ns >= NSEC_PER_SEC) {
ns -= NSEC_PER_SEC;
sec += 1;
}
/* Check whether updated, read again if so. */
if (count == vdso_data->tb_update_count)
break;
}
tv->tv_sec = sec;
tv->tv_usec = ns / 1000;
return 0;
}
int gettimeofday(struct timeval *tv, struct timezone *tz)
__attribute__((weak, alias("__vdso_gettimeofday")));

30
arch/tile/kernel/vdso/vrt_sigreturn.S Normal file
View File

@ -0,0 +1,30 @@
/*
* Copyright 2012 Tilera Corporation. All Rights Reserved.
*
* 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, version 2.
*
* 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, GOOD TITLE or
* NON INFRINGEMENT. See the GNU General Public License for
* more details.
*/
#include <linux/linkage.h>
#include <arch/abi.h>
#include <asm/unistd.h>
/*
* Note that libc has a copy of this function that it uses to compare
* against the PC when a stack backtrace ends, so if this code is
* changed, the libc implementation(s) should also be updated.
*/
ENTRY(__vdso_rt_sigreturn)
moveli TREG_SYSCALL_NR_NAME, __NR_rt_sigreturn
swint1
/* We don't use ENDPROC to avoid tagging this symbol as FUNC,
* which confuses the perf tool.
*/
END(__vdso_rt_sigreturn)

37
arch/tile/mm/elf.c
View File

@ -21,6 +21,7 @@
#include <asm/pgtable.h>
#include <asm/pgalloc.h>
#include <asm/sections.h>
#include <asm/vdso.h>
#include <arch/sim.h>
/* Notify a running simulator, if any, that an exec just occurred. */
@ -102,37 +103,10 @@ static void sim_notify_interp(unsigned long load_addr)
}
/* Kernel address of page used to map read-only kernel data into userspace. */
static void *vdso_page;
/* One-entry array used for install_special_mapping. */
static struct page *vdso_pages[1];
static int __init vdso_setup(void)
{
vdso_page = (void *)get_zeroed_page(GFP_ATOMIC);
memcpy(vdso_page, __rt_sigreturn, __rt_sigreturn_end - __rt_sigreturn);
vdso_pages[0] = virt_to_page(vdso_page);
return 0;
}
device_initcall(vdso_setup);
const char *arch_vma_name(struct vm_area_struct *vma)
{
if (vma->vm_private_data == vdso_pages)
return "[vdso]";
#ifndef __tilegx__
if (vma->vm_start == MEM_USER_INTRPT)
return "[intrpt]";
#endif
return NULL;
}
int arch_setup_additional_pages(struct linux_binprm *bprm,
int executable_stack)
{
struct mm_struct *mm = current->mm;
unsigned long vdso_base;
int retval = 0;
down_write(&mm->mmap_sem);
@ -145,14 +119,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm,
if (!notify_exec(mm))
sim_notify_exec(bprm->filename);
/*
* MAYWRITE to allow gdb to COW and set breakpoints
*/
vdso_base = VDSO_BASE;
retval = install_special_mapping(mm, vdso_base, PAGE_SIZE,
VM_READ|VM_EXEC|
VM_MAYREAD|VM_MAYWRITE|VM_MAYEXEC,
vdso_pages);
retval = setup_vdso_pages();
#ifndef __tilegx__
/*