Merge branches 'misc', 'vdso' and 'fixes' into for-next

Conflicts:
	arch/arm/mm/proc-macros.S

arch/arm/Makefile

@@ -263,6 +263,7 @@ core-$(CONFIG_FPE_FASTFPE)	+= $(FASTFPE_OBJ)
 core-$(CONFIG_VFP)		+= arch/arm/vfp/
 core-$(CONFIG_XEN)		+= arch/arm/xen/
 core-$(CONFIG_KVM_ARM_HOST) 	+= arch/arm/kvm/
+core-$(CONFIG_VDSO)		+= arch/arm/vdso/
 
 # If we have a machine-specific directory, then include it in the build.
 core-y				+= arch/arm/kernel/ arch/arm/mm/ arch/arm/common/
@@ -320,6 +321,12 @@ dtbs: prepare scripts
 dtbs_install:
 	$(Q)$(MAKE) $(dtbinst)=$(boot)/dts
 
+PHONY += vdso_install
+vdso_install:
+ifeq ($(CONFIG_VDSO),y)
+	$(Q)$(MAKE) $(build)=arch/arm/vdso $@
+endif
+
 # We use MRPROPER_FILES and CLEAN_FILES now
 archclean:
 	$(Q)$(MAKE) $(clean)=$(boot)
@@ -344,4 +351,5 @@ define archhelp
   echo  '                  Install using (your) ~/bin/$(INSTALLKERNEL) or'
   echo  '                  (distribution) /sbin/$(INSTALLKERNEL) or'
   echo  '                  install to $$(INSTALL_PATH) and run lilo'
+  echo  '  vdso_install  - Install unstripped vdso.so to $$(INSTALL_MOD_PATH)/vdso'
 endef

arch/arm/include/asm/Kbuild

@@ -1,6 +1,5 @@
 
 
-generic-y += auxvec.h
 generic-y += bitsperlong.h
 generic-y += cputime.h
 generic-y += current.h

arch/arm/include/asm/auxvec.h

@@ -0,0 +1 @@
+#include <uapi/asm/auxvec.h>

arch/arm/include/asm/elf.h

@@ -1,7 +1,9 @@
 #ifndef __ASMARM_ELF_H
 #define __ASMARM_ELF_H
 
+#include <asm/auxvec.h>
 #include <asm/hwcap.h>
+#include <asm/vdso_datapage.h>
 
 /*
  * ELF register definitions..
@@ -115,7 +117,7 @@ int dump_task_regs(struct task_struct *t, elf_gregset_t *elfregs);
    the loader.  We need to make sure that it is out of the way of the program
    that it will "exec", and that there is sufficient room for the brk.  */
 
-#define ELF_ET_DYN_BASE	(2 * TASK_SIZE / 3)
+#define ELF_ET_DYN_BASE	(TASK_SIZE / 3 * 2)
 
 /* When the program starts, a1 contains a pointer to a function to be 
    registered with atexit, as per the SVR4 ABI.  A value of 0 means we 
@@ -130,6 +132,13 @@ extern unsigned long arch_randomize_brk(struct mm_struct *mm);
 #define arch_randomize_brk arch_randomize_brk
 
 #ifdef CONFIG_MMU
+#ifdef CONFIG_VDSO
+#define ARCH_DLINFO						\
+do {								\
+	NEW_AUX_ENT(AT_SYSINFO_EHDR,				\
+		    (elf_addr_t)current->mm->context.vdso);	\
+} while (0)
+#endif
 #define ARCH_HAS_SETUP_ADDITIONAL_PAGES 1
 struct linux_binprm;
 int arch_setup_additional_pages(struct linux_binprm *, int);

arch/arm/include/asm/mmu.h

@@ -11,6 +11,9 @@ typedef struct {
 #endif
 	unsigned int	vmalloc_seq;
 	unsigned long	sigpage;
+#ifdef CONFIG_VDSO
+	unsigned long	vdso;
+#endif
 } mm_context_t;
 
 #ifdef CONFIG_CPU_HAS_ASID

arch/arm/include/asm/vdso.h

@@ -0,0 +1,32 @@
+#ifndef __ASM_VDSO_H
+#define __ASM_VDSO_H
+
+#ifdef __KERNEL__
+
+#ifndef __ASSEMBLY__
+
+struct mm_struct;
+
+#ifdef CONFIG_VDSO
+
+void arm_install_vdso(struct mm_struct *mm, unsigned long addr);
+
+extern char vdso_start, vdso_end;
+
+extern unsigned int vdso_total_pages;
+
+#else /* CONFIG_VDSO */
+
+static inline void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
+{
+}
+
+#define vdso_total_pages 0
+
+#endif /* CONFIG_VDSO */
+
+#endif /* __ASSEMBLY__ */
+
+#endif /* __KERNEL__ */
+
+#endif /* __ASM_VDSO_H */

arch/arm/include/asm/vdso_datapage.h

@@ -0,0 +1,60 @@
+/*
+ * Adapted from arm64 version.
+ *
+ * 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__
+
+#include <asm/page.h>
+
+/* Try to be cache-friendly on systems that don't implement the
+ * generic timer: fit the unconditionally updated fields in the first
+ * 32 bytes.
+ */
+struct vdso_data {
+	u32 seq_count;		/* sequence count - odd during updates */
+	u16 tk_is_cntvct;	/* fall back to syscall if false */
+	u16 cs_shift;		/* clocksource shift */
+	u32 xtime_coarse_sec;	/* coarse time */
+	u32 xtime_coarse_nsec;
+
+	u32 wtm_clock_sec;	/* wall to monotonic offset */
+	u32 wtm_clock_nsec;
+	u32 xtime_clock_sec;	/* CLOCK_REALTIME - seconds */
+	u32 cs_mult;		/* clocksource multiplier */
+
+	u64 cs_cycle_last;	/* last cycle value */
+	u64 cs_mask;		/* clocksource mask */
+
+	u64 xtime_clock_snsec;	/* CLOCK_REALTIME sub-ns base */
+	u32 tz_minuteswest;	/* timezone info for gettimeofday(2) */
+	u32 tz_dsttime;
+};
+
+union vdso_data_store {
+	struct vdso_data data;
+	u8 page[PAGE_SIZE];
+};
+
+#endif /* !__ASSEMBLY__ */
+
+#endif /* __KERNEL__ */
+
+#endif /* __ASM_VDSO_DATAPAGE_H */

arch/arm/include/uapi/asm/Kbuild

@@ -1,6 +1,7 @@
 # UAPI Header export list
 include include/uapi/asm-generic/Kbuild.asm
 
+header-y += auxvec.h
 header-y += byteorder.h
 header-y += fcntl.h
 header-y += hwcap.h

arch/arm/include/uapi/asm/auxvec.h

@@ -0,0 +1,7 @@
+#ifndef __ASM_AUXVEC_H
+#define __ASM_AUXVEC_H
+
+/* VDSO location */
+#define AT_SYSINFO_EHDR	33
+
+#endif

arch/arm/kernel/Makefile

@@ -75,6 +75,7 @@ obj-$(CONFIG_HW_PERF_EVENTS)	+= perf_event.o perf_event_cpu.o
 CFLAGS_pj4-cp0.o		:= -marm
 AFLAGS_iwmmxt.o			:= -Wa,-mcpu=iwmmxt
 obj-$(CONFIG_ARM_CPU_TOPOLOGY)  += topology.o
+obj-$(CONFIG_VDSO)		+= vdso.o
 
 ifneq ($(CONFIG_ARCH_EBSA110),y)
   obj-y		+= io.o

arch/arm/kernel/asm-offsets.c

@@ -25,6 +25,7 @@
 #include <asm/memory.h>
 #include <asm/procinfo.h>
 #include <asm/suspend.h>
+#include <asm/vdso_datapage.h>
 #include <asm/hardware/cache-l2x0.h>
 #include <linux/kbuild.h>
 
@@ -209,6 +210,10 @@ int main(void)
   DEFINE(KVM_VGIC_VCTRL,	offsetof(struct kvm, arch.vgic.vctrl_base));
 #endif
   DEFINE(KVM_VTTBR,		offsetof(struct kvm, arch.vttbr));
+#endif
+  BLANK();
+#ifdef CONFIG_VDSO
+  DEFINE(VDSO_DATA_SIZE,	sizeof(union vdso_data_store));
 #endif
   return 0; 
 }

arch/arm/kernel/process.c

@@ -334,7 +334,7 @@ const char *arch_vma_name(struct vm_area_struct *vma)
 }
 
 /* If possible, provide a placement hint at a random offset from the
- * stack for the signal page.
+ * stack for the sigpage and vdso pages.
  */
 static unsigned long sigpage_addr(const struct mm_struct *mm,
 				  unsigned int npages)
@@ -378,6 +378,7 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 {
 	struct mm_struct *mm = current->mm;
 	struct vm_area_struct *vma;
+	unsigned long npages;
 	unsigned long addr;
 	unsigned long hint;
 	int ret = 0;
@@ -387,9 +388,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 	if (!signal_page)
 		return -ENOMEM;
 
+	npages = 1; /* for sigpage */
+	npages += vdso_total_pages;
+
 	down_write(&mm->mmap_sem);
-	hint = sigpage_addr(mm, 1);
-	addr = get_unmapped_area(NULL, hint, PAGE_SIZE, 0, 0);
+	hint = sigpage_addr(mm, npages);
+	addr = get_unmapped_area(NULL, hint, npages << PAGE_SHIFT, 0, 0);
 	if (IS_ERR_VALUE(addr)) {
 		ret = addr;
 		goto up_fail;
@@ -406,6 +410,12 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
 
 	mm->context.sigpage = addr;
 
+	/* Unlike the sigpage, failure to install the vdso is unlikely
+	 * to be fatal to the process, so no error check needed
+	 * here.
+	 */
+	arm_install_vdso(mm, addr + PAGE_SIZE);
+
  up_fail:
 	up_write(&mm->mmap_sem);
 	return ret;

arch/arm/kernel/setup.c

@@ -246,12 +246,9 @@ static int __get_cpu_architecture(void)
 		if (cpu_arch)
 			cpu_arch += CPU_ARCH_ARMv3;
 	} else if ((read_cpuid_id() & 0x000f0000) == 0x000f0000) {
-		unsigned int mmfr0;
-
 		/* Revised CPUID format. Read the Memory Model Feature
 		 * Register 0 and check for VMSAv7 or PMSAv7 */
-		asm("mrc	p15, 0, %0, c0, c1, 4"
-		    : "=r" (mmfr0));
+		unsigned int mmfr0 = read_cpuid_ext(CPUID_EXT_MMFR0);
 		if ((mmfr0 & 0x0000000f) >= 0x00000003 ||
 		    (mmfr0 & 0x000000f0) >= 0x00000030)
 			cpu_arch = CPU_ARCH_ARMv7;

arch/arm/kernel/vdso.c

@@ -0,0 +1,337 @@
+/*
+ * Adapted from arm64 version.
+ *
+ * Copyright (C) 2012 ARM Limited
+ * Copyright (C) 2015 Mentor Graphics Corporation.
+ *
+ * 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/>.
+ */
+
+#include <linux/elf.h>
+#include <linux/err.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/of.h>
+#include <linux/printk.h>
+#include <linux/slab.h>
+#include <linux/timekeeper_internal.h>
+#include <linux/vmalloc.h>
+#include <asm/arch_timer.h>
+#include <asm/barrier.h>
+#include <asm/cacheflush.h>
+#include <asm/page.h>
+#include <asm/vdso.h>
+#include <asm/vdso_datapage.h>
+#include <clocksource/arm_arch_timer.h>
+
+#define MAX_SYMNAME	64
+
+static struct page **vdso_text_pagelist;
+
+/* Total number of pages needed for the data and text portions of the VDSO. */
+unsigned int vdso_total_pages __read_mostly;
+
+/*
+ * The VDSO data page.
+ */
+static union vdso_data_store vdso_data_store __page_aligned_data;
+static struct vdso_data *vdso_data = &vdso_data_store.data;
+
+static struct page *vdso_data_page;
+static struct vm_special_mapping vdso_data_mapping = {
+	.name = "[vvar]",
+	.pages = &vdso_data_page,
+};
+
+static struct vm_special_mapping vdso_text_mapping = {
+	.name = "[vdso]",
+};
+
+struct elfinfo {
+	Elf32_Ehdr	*hdr;		/* ptr to ELF */
+	Elf32_Sym	*dynsym;	/* ptr to .dynsym section */
+	unsigned long	dynsymsize;	/* size of .dynsym section */
+	char		*dynstr;	/* ptr to .dynstr section */
+};
+
+/* Cached result of boot-time check for whether the arch timer exists,
+ * and if so, whether the virtual counter is useable.
+ */
+static bool cntvct_ok __read_mostly;
+
+static bool __init cntvct_functional(void)
+{
+	struct device_node *np;
+	bool ret = false;
+
+	if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
+		goto out;
+
+	/* The arm_arch_timer core should export
+	 * arch_timer_use_virtual or similar so we don't have to do
+	 * this.
+	 */
+	np = of_find_compatible_node(NULL, NULL, "arm,armv7-timer");
+	if (!np)
+		goto out_put;
+
+	if (of_property_read_bool(np, "arm,cpu-registers-not-fw-configured"))
+		goto out_put;
+
+	ret = true;
+
+out_put:
+	of_node_put(np);
+out:
+	return ret;
+}
+
+static void * __init find_section(Elf32_Ehdr *ehdr, const char *name,
+				  unsigned long *size)
+{
+	Elf32_Shdr *sechdrs;
+	unsigned int i;
+	char *secnames;
+
+	/* Grab section headers and strings so we can tell who is who */
+	sechdrs = (void *)ehdr + ehdr->e_shoff;
+	secnames = (void *)ehdr + sechdrs[ehdr->e_shstrndx].sh_offset;
+
+	/* Find the section they want */
+	for (i = 1; i < ehdr->e_shnum; i++) {
+		if (strcmp(secnames + sechdrs[i].sh_name, name) == 0) {
+			if (size)
+				*size = sechdrs[i].sh_size;
+			return (void *)ehdr + sechdrs[i].sh_offset;
+		}
+	}
+
+	if (size)
+		*size = 0;
+	return NULL;
+}
+
+static Elf32_Sym * __init find_symbol(struct elfinfo *lib, const char *symname)
+{
+	unsigned int i;
+
+	for (i = 0; i < (lib->dynsymsize / sizeof(Elf32_Sym)); i++) {
+		char name[MAX_SYMNAME], *c;
+
+		if (lib->dynsym[i].st_name == 0)
+			continue;
+		strlcpy(name, lib->dynstr + lib->dynsym[i].st_name,
+			MAX_SYMNAME);
+		c = strchr(name, '@');
+		if (c)
+			*c = 0;
+		if (strcmp(symname, name) == 0)
+			return &lib->dynsym[i];
+	}
+	return NULL;
+}
+
+static void __init vdso_nullpatch_one(struct elfinfo *lib, const char *symname)
+{
+	Elf32_Sym *sym;
+
+	sym = find_symbol(lib, symname);
+	if (!sym)
+		return;
+
+	sym->st_name = 0;
+}
+
+static void __init patch_vdso(void *ehdr)
+{
+	struct elfinfo einfo;
+
+	einfo = (struct elfinfo) {
+		.hdr = ehdr,
+	};
+
+	einfo.dynsym = find_section(einfo.hdr, ".dynsym", &einfo.dynsymsize);
+	einfo.dynstr = find_section(einfo.hdr, ".dynstr", NULL);
+
+	/* If the virtual counter is absent or non-functional we don't
+	 * want programs to incur the slight additional overhead of
+	 * dispatching through the VDSO only to fall back to syscalls.
+	 */
+	if (!cntvct_ok) {
+		vdso_nullpatch_one(&einfo, "__vdso_gettimeofday");
+		vdso_nullpatch_one(&einfo, "__vdso_clock_gettime");
+	}
+}
+
+static int __init vdso_init(void)
+{
+	unsigned int text_pages;
+	int i;
+
+	if (memcmp(&vdso_start, "\177ELF", 4)) {
+		pr_err("VDSO is not a valid ELF object!\n");
+		return -ENOEXEC;
+	}
+
+	text_pages = (&vdso_end - &vdso_start) >> PAGE_SHIFT;
+	pr_debug("vdso: %i text pages at base %p\n", text_pages, &vdso_start);
+
+	/* Allocate the VDSO text pagelist */
+	vdso_text_pagelist = kcalloc(text_pages, sizeof(struct page *),
+				     GFP_KERNEL);
+	if (vdso_text_pagelist == NULL)
+		return -ENOMEM;
+
+	/* Grab the VDSO data page. */
+	vdso_data_page = virt_to_page(vdso_data);
+
+	/* Grab the VDSO text pages. */
+	for (i = 0; i < text_pages; i++) {
+		struct page *page;
+
+		page = virt_to_page(&vdso_start + i * PAGE_SIZE);
+		vdso_text_pagelist[i] = page;
+	}
+
+	vdso_text_mapping.pages = vdso_text_pagelist;
+
+	vdso_total_pages = 1; /* for the data/vvar page */
+	vdso_total_pages += text_pages;
+
+	cntvct_ok = cntvct_functional();
+
+	patch_vdso(&vdso_start);
+
+	return 0;
+}
+arch_initcall(vdso_init);
+
+static int install_vvar(struct mm_struct *mm, unsigned long addr)
+{
+	struct vm_area_struct *vma;
+
+	vma = _install_special_mapping(mm, addr, PAGE_SIZE,
+				       VM_READ | VM_MAYREAD,
+				       &vdso_data_mapping);
+
+	return IS_ERR(vma) ? PTR_ERR(vma) : 0;
+}
+
+/* assumes mmap_sem is write-locked */
+void arm_install_vdso(struct mm_struct *mm, unsigned long addr)
+{
+	struct vm_area_struct *vma;
+	unsigned long len;
+
+	mm->context.vdso = 0;
+
+	if (vdso_text_pagelist == NULL)
+		return;
+
+	if (install_vvar(mm, addr))
+		return;
+
+	/* Account for vvar page. */
+	addr += PAGE_SIZE;
+	len = (vdso_total_pages - 1) << PAGE_SHIFT;
+
+	vma = _install_special_mapping(mm, addr, len,
+		VM_READ | VM_EXEC | VM_MAYREAD | VM_MAYWRITE | VM_MAYEXEC,
+		&vdso_text_mapping);
+
+	if (!IS_ERR(vma))
+		mm->context.vdso = addr;
+}
+
+static void vdso_write_begin(struct vdso_data *vdata)
+{
+	++vdso_data->seq_count;
+	smp_wmb(); /* Pairs with smp_rmb in vdso_read_retry */
+}
+
+static void vdso_write_end(struct vdso_data *vdata)
+{
+	smp_wmb(); /* Pairs with smp_rmb in vdso_read_begin */
+	++vdso_data->seq_count;
+}
+
+static bool tk_is_cntvct(const struct timekeeper *tk)
+{
+	if (!IS_ENABLED(CONFIG_ARM_ARCH_TIMER))
+		return false;
+
+	if (strcmp(tk->tkr.clock->name, "arch_sys_counter") != 0)
+		return false;
+
+	return true;
+}
+
+/**
+ * update_vsyscall - update the vdso data page
+ *
+ * Increment the sequence counter, making it odd, indicating to
+ * userspace that an update is in progress.  Update the fields used
+ * for coarse clocks and, if the architected system timer is in use,
+ * the fields used for high precision clocks.  Increment the sequence
+ * counter again, making it even, indicating to userspace that the
+ * update is finished.
+ *
+ * Userspace is expected to sample seq_count before reading any other
+ * fields from the data page.  If seq_count is odd, userspace is
+ * expected to wait until it becomes even.  After copying data from
+ * the page, userspace must sample seq_count again; if it has changed
+ * from its previous value, userspace must retry the whole sequence.
+ *
+ * Calls to update_vsyscall are serialized by the timekeeping core.
+ */
+void update_vsyscall(struct timekeeper *tk)
+{
+	struct timespec xtime_coarse;
+	struct timespec64 *wtm = &tk->wall_to_monotonic;
+
+	if (!cntvct_ok) {
+		/* The entry points have been zeroed, so there is no
+		 * point in updating the data page.
+		 */
+		return;
+	}
+
+	vdso_write_begin(vdso_data);
+
+	xtime_coarse = __current_kernel_time();
+	vdso_data->tk_is_cntvct			= tk_is_cntvct(tk);
+	vdso_data->xtime_coarse_sec		= xtime_coarse.tv_sec;
+	vdso_data->xtime_coarse_nsec		= xtime_coarse.tv_nsec;
+	vdso_data->wtm_clock_sec		= wtm->tv_sec;
+	vdso_data->wtm_clock_nsec		= wtm->tv_nsec;
+
+	if (vdso_data->tk_is_cntvct) {
+		vdso_data->cs_cycle_last	= tk->tkr.cycle_last;
+		vdso_data->xtime_clock_sec	= tk->xtime_sec;
+		vdso_data->xtime_clock_snsec	= tk->tkr.xtime_nsec;
+		vdso_data->cs_mult		= tk->tkr.mult;
+		vdso_data->cs_shift		= tk->tkr.shift;
+		vdso_data->cs_mask		= tk->tkr.mask;
+	}
+
+	vdso_write_end(vdso_data);
+
+	flush_dcache_page(virt_to_page(vdso_data));
+}
+
+void update_vsyscall_tz(void)
+{
+	vdso_data->tz_minuteswest	= sys_tz.tz_minuteswest;
+	vdso_data->tz_dsttime		= sys_tz.tz_dsttime;
+	flush_dcache_page(virt_to_page(vdso_data));
+}

arch/arm/mach-vexpress/Kconfig

@@ -42,6 +42,7 @@ if ARCH_VEXPRESS
 config ARCH_VEXPRESS_CORTEX_A5_A9_ERRATA
 	bool "Enable A5 and A9 only errata work-arounds"
 	default y
+	select ARM_ERRATA_643719 if SMP
 	select ARM_ERRATA_720789
 	select PL310_ERRATA_753970 if CACHE_L2X0
 	help

arch/arm/mm/Kconfig

@@ -738,7 +738,7 @@ config CPU_ICACHE_DISABLE
 
 config CPU_DCACHE_DISABLE
 	bool "Disable D-Cache (C-bit)"
-	depends on CPU_CP15
+	depends on CPU_CP15 && !SMP
 	help
 	  Say Y here to disable the processor data cache. Unless
 	  you have a reason not to or are unsure, say N.
@@ -825,6 +825,20 @@ config KUSER_HELPERS
 	  Say N here only if you are absolutely certain that you do not
 	  need these helpers; otherwise, the safe option is to say Y.
 
+config VDSO
+	bool "Enable VDSO for acceleration of some system calls"
+	depends on AEABI && MMU
+	default y if ARM_ARCH_TIMER
+	select GENERIC_TIME_VSYSCALL
+	help
+	  Place in the process address space an ELF shared object
+	  providing fast implementations of gettimeofday and
+	  clock_gettime.  Systems that implement the ARM architected
+	  timer will receive maximum benefit.
+
+	  You must have glibc 2.22 or later for programs to seamlessly
+	  take advantage of this.
+
 config DMA_CACHE_RWFO
 	bool "Enable read/write for ownership DMA cache maintenance"
 	depends on CPU_V6K && SMP

arch/arm/mm/cache-l2x0.c

@@ -1131,23 +1131,22 @@ static void __init l2c310_of_parse(const struct device_node *np,
 	}
 
 	ret = l2x0_cache_size_of_parse(np, aux_val, aux_mask, &assoc, SZ_512K);
-	if (ret)
-		return;
-
-	switch (assoc) {
-	case 16:
-		*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		*aux_val |= L310_AUX_CTRL_ASSOCIATIVITY_16;
-		*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		break;
-	case 8:
-		*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
-		break;
-	default:
-		pr_err("L2C-310 OF cache associativity %d invalid, only 8 or 16 permitted\n",
-		       assoc);
-		break;
+	if (!ret) {
+		switch (assoc) {
+		case 16:
+			*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			*aux_val |= L310_AUX_CTRL_ASSOCIATIVITY_16;
+			*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			break;
+		case 8:
+			*aux_val &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			*aux_mask &= ~L2X0_AUX_CTRL_ASSOC_MASK;
+			break;
+		default:
+			pr_err("L2C-310 OF cache associativity %d invalid, only 8 or 16 permitted\n",
+			       assoc);
+			break;
+		}
 	}
 
 	prefetch = l2x0_saved_regs.prefetch_ctrl;

arch/arm/mm/dma-mapping.c

@@ -171,7 +171,7 @@ static int __dma_supported(struct device *dev, u64 mask, bool warn)
 	 */
 	if (sizeof(mask) != sizeof(dma_addr_t) &&
 	    mask > (dma_addr_t)~0 &&
-	    dma_to_pfn(dev, ~0) < max_pfn) {
+	    dma_to_pfn(dev, ~0) < max_pfn - 1) {
 		if (warn) {
 			dev_warn(dev, "Coherent DMA mask %#llx is larger than dma_addr_t allows\n",
 				 mask);
@@ -1150,13 +1150,28 @@ static struct page **__iommu_alloc_buffer(struct device *dev, size_t size,
 	gfp |= __GFP_NOWARN | __GFP_HIGHMEM;
 
 	while (count) {
-		int j, order = __fls(count);
+		int j, order;
+
+		for (order = __fls(count); order > 0; --order) {
+			/*
+			 * We do not want OOM killer to be invoked as long
+			 * as we can fall back to single pages, so we force
+			 * __GFP_NORETRY for orders higher than zero.
+			 */
+			pages[i] = alloc_pages(gfp | __GFP_NORETRY, order);
+			if (pages[i])
+				break;
+		}
 
-		pages[i] = alloc_pages(gfp, order);
-		while (!pages[i] && order)
-			pages[i] = alloc_pages(gfp, --order);
-		if (!pages[i])
-			goto error;
+		if (!pages[i]) {
+			/*
+			 * Fall back to single page allocation.
+			 * Might invoke OOM killer as last resort.
+			 */
+			pages[i] = alloc_pages(gfp, 0);
+			if (!pages[i])
+				goto error;
+		}
 
 		if (order) {
 			split_page(pages[i], order);

arch/arm/mm/fault.c

@@ -552,6 +552,7 @@ do_DataAbort(unsigned long addr, unsigned int fsr, struct pt_regs *regs)
 
 	pr_alert("Unhandled fault: %s (0x%03x) at 0x%08lx\n",
 		inf->name, fsr, addr);
+	show_pte(current->mm, addr);
 
 	info.si_signo = inf->sig;
 	info.si_errno = 0;

arch/arm/mm/pageattr.c

@@ -49,7 +49,10 @@ static int change_memory_common(unsigned long addr, int numpages,
 		WARN_ON_ONCE(1);
 	}
 
-	if (!is_module_address(start) || !is_module_address(end - 1))
+	if (start < MODULES_VADDR || start >= MODULES_END)
+		return -EINVAL;
+
+	if (end < MODULES_VADDR || start >= MODULES_END)
 		return -EINVAL;
 
 	data.set_mask = set_mask;

arch/arm/mm/proc-arm940.S

@@ -297,26 +297,16 @@ __arm940_setup:
 	mcr	p15, 0, r0, c6,	c0, 1
 
 	ldr	r0, =(CONFIG_DRAM_BASE & 0xFFFFF000) @ base[31:12] of RAM
-	ldr	r1, =(CONFIG_DRAM_SIZE >> 12)	@ size of RAM (must be >= 4KB)
-	mov	r2, #10				@ 11 is the minimum (4KB)
-1:	add	r2, r2, #1			@ area size *= 2
-	mov	r1, r1, lsr #1
-	bne	1b				@ count not zero r-shift
-	orr	r0, r0, r2, lsl #1		@ the area register value
-	orr	r0, r0, #1			@ set enable bit
-	mcr	p15, 0, r0, c6,	c1, 0		@ set area 1, RAM
-	mcr	p15, 0, r0, c6,	c1, 1
+	ldr	r7, =CONFIG_DRAM_SIZE >> 12	@ size of RAM (must be >= 4KB)
+	pr_val	r3, r0, r7, #1
+	mcr	p15, 0, r3, c6,	c1, 0		@ set area 1, RAM
+	mcr	p15, 0, r3, c6,	c1, 1
 
 	ldr	r0, =(CONFIG_FLASH_MEM_BASE & 0xFFFFF000) @ base[31:12] of FLASH
-	ldr	r1, =(CONFIG_FLASH_SIZE >> 12)	@ size of FLASH (must be >= 4KB)
-	mov	r2, #10				@ 11 is the minimum (4KB)
-1:	add	r2, r2, #1			@ area size *= 2
-	mov	r1, r1, lsr #1
-	bne	1b				@ count not zero r-shift
-	orr	r0, r0, r2, lsl #1		@ the area register value
-	orr	r0, r0, #1			@ set enable bit
-	mcr	p15, 0, r0, c6,	c2, 0		@ set area 2, ROM/FLASH
-	mcr	p15, 0, r0, c6,	c2, 1
+	ldr	r7, =CONFIG_FLASH_SIZE		@ size of FLASH (must be >= 4KB)
+	pr_val	r3, r0, r6, #1
+	mcr	p15, 0, r3, c6,	c2, 0		@ set area 2, ROM/FLASH
+	mcr	p15, 0, r3, c6,	c2, 1
 
 	mov	r0, #0x06
 	mcr	p15, 0, r0, c2, c0, 0		@ Region 1&2 cacheable

arch/arm/mm/proc-arm946.S

@@ -343,24 +343,14 @@ __arm946_setup:
 	mcr	p15, 0, r0, c6,	c0, 0		@ set region 0, default
 
 	ldr	r0, =(CONFIG_DRAM_BASE & 0xFFFFF000) @ base[31:12] of RAM
-	ldr	r1, =(CONFIG_DRAM_SIZE >> 12)	@ size of RAM (must be >= 4KB)
-	mov	r2, #10				@ 11 is the minimum (4KB)
-1:	add	r2, r2, #1			@ area size *= 2
-	mov	r1, r1, lsr #1
-	bne	1b				@ count not zero r-shift
-	orr	r0, r0, r2, lsl #1		@ the region register value
-	orr	r0, r0, #1			@ set enable bit
-	mcr	p15, 0, r0, c6,	c1, 0		@ set region 1, RAM
+	ldr	r7, =CONFIG_DRAM_SIZE		@ size of RAM (must be >= 4KB)
+	pr_val	r3, r0, r7, #1
+	mcr	p15, 0, r3, c6, c1, 0
 
 	ldr	r0, =(CONFIG_FLASH_MEM_BASE & 0xFFFFF000) @ base[31:12] of FLASH
-	ldr	r1, =(CONFIG_FLASH_SIZE >> 12)	@ size of FLASH (must be >= 4KB)
-	mov	r2, #10				@ 11 is the minimum (4KB)
-1:	add	r2, r2, #1			@ area size *= 2
-	mov	r1, r1, lsr #1
-	bne	1b				@ count not zero r-shift
-	orr	r0, r0, r2, lsl #1		@ the region register value
-	orr	r0, r0, #1			@ set enable bit
-	mcr	p15, 0, r0, c6,	c2, 0		@ set region 2, ROM/FLASH
+	ldr	r7, =CONFIG_FLASH_SIZE		@ size of FLASH (must be >= 4KB)
+	pr_val	r3, r0, r7, #1
+	mcr	p15, 0, r3, c6, c2, 0
 
 	mov	r0, #0x06
 	mcr	p15, 0, r0, c2, c0, 0		@ region 1,2 d-cacheable

arch/arm/mm/proc-macros.S

@@ -335,3 +335,27 @@ ENTRY(\name\()_tlb_fns)
 .macro	initfn, func, base
 	.long	\func - \base
 .endm
+
+	/*
+	 * Macro to calculate the log2 size for the protection region
+	 * registers. This calculates rd = log2(size) - 1.  tmp must
+	 * not be the same register as rd.
+	 */
+.macro	pr_sz, rd, size, tmp
+	mov	\tmp, \size, lsr #12
+	mov	\rd, #11
+1:	movs	\tmp, \tmp, lsr #1
+	addne	\rd, \rd, #1
+	bne	1b
+.endm
+
+	/*
+	 * Macro to generate a protection region register value
+	 * given a pre-masked address, size, and enable bit.
+	 * Corrupts size.
+	 */
+.macro	pr_val, dest, addr, size, enable
+	pr_sz	\dest, \size, \size		@ calculate log2(size) - 1
+	orr	\dest, \addr, \dest, lsl #1	@ mask in the region size
+	orr	\dest, \dest, \enable
+.endm

arch/arm/vdso/.gitignore

@@ -0,0 +1 @@
+vdso.lds

arch/arm/vdso/Makefile

@@ -0,0 +1,74 @@
+hostprogs-y := vdsomunge
+
+obj-vdso := vgettimeofday.o datapage.o
+
+# Build rules
+targets := $(obj-vdso) vdso.so vdso.so.dbg vdso.so.raw vdso.lds
+obj-vdso := $(addprefix $(obj)/, $(obj-vdso))
+
+ccflags-y := -shared -fPIC -fno-common -fno-builtin -fno-stack-protector
+ccflags-y += -nostdlib -Wl,-soname=linux-vdso.so.1 -DDISABLE_BRANCH_PROFILING
+ccflags-y += -Wl,--no-undefined $(call cc-ldoption, -Wl$(comma)--hash-style=sysv)
+
+obj-y += vdso.o
+extra-y += vdso.lds
+CPPFLAGS_vdso.lds += -P -C -U$(ARCH)
+
+CFLAGS_REMOVE_vdso.o = -pg
+
+# Force -O2 to avoid libgcc dependencies
+CFLAGS_REMOVE_vgettimeofday.o = -pg -Os
+CFLAGS_vgettimeofday.o = -O2
+
+# Disable gcov profiling for VDSO code
+GCOV_PROFILE := n
+
+# Force dependency
+$(obj)/vdso.o : $(obj)/vdso.so
+
+# Link rule for the .so file
+$(obj)/vdso.so.raw: $(src)/vdso.lds $(obj-vdso) FORCE
+	$(call if_changed,vdsold)
+
+$(obj)/vdso.so.dbg: $(obj)/vdso.so.raw $(obj)/vdsomunge FORCE
+	$(call if_changed,vdsomunge)
+
+# Strip rule for the .so file
+$(obj)/%.so: OBJCOPYFLAGS := -S
+$(obj)/%.so: $(obj)/%.so.dbg FORCE
+	$(call if_changed,objcopy)
+
+# Actual build commands
+quiet_cmd_vdsold = VDSO    $@
+      cmd_vdsold = $(CC) $(c_flags) -Wl,-T $(filter %.lds,$^) $(filter %.o,$^) \
+                   $(call cc-ldoption, -Wl$(comma)--build-id) \
+                   -Wl,-Bsymbolic -Wl,-z,max-page-size=4096 \
+                   -Wl,-z,common-page-size=4096 -o $@
+
+quiet_cmd_vdsomunge = MUNGE   $@
+      cmd_vdsomunge = $(objtree)/$(obj)/vdsomunge $< $@
+
+#
+# Install the unstripped copy of vdso.so.dbg.  If our toolchain
+# supports build-id, install .build-id links as well.
+#
+# Cribbed from arch/x86/vdso/Makefile.
+#
+quiet_cmd_vdso_install = INSTALL $<
+define cmd_vdso_install
+	cp $< "$(MODLIB)/vdso/vdso.so"; \
+	if readelf -n $< | grep -q 'Build ID'; then \
+	  buildid=`readelf -n $< |grep 'Build ID' |sed -e 's/^.*Build ID: \(.*\)$$/\1/'`; \
+	  first=`echo $$buildid | cut -b-2`; \
+	  last=`echo $$buildid | cut -b3-`; \
+	  mkdir -p "$(MODLIB)/vdso/.build-id/$$first"; \
+	  ln -sf "../../vdso.so" "$(MODLIB)/vdso/.build-id/$$first/$$last.debug"; \
+	fi
+endef
+
+$(MODLIB)/vdso: FORCE
+	@mkdir -p $(MODLIB)/vdso
+
+PHONY += vdso_install
+vdso_install: $(obj)/vdso.so.dbg $(MODLIB)/vdso FORCE
+	$(call cmd,vdso_install)

arch/arm/vdso/datapage.S

@@ -0,0 +1,15 @@
+#include <linux/linkage.h>
+#include <asm/asm-offsets.h>
+
+	.align 2
+.L_vdso_data_ptr:
+	.long	_start - . - VDSO_DATA_SIZE
+
+ENTRY(__get_datapage)
+	.fnstart
+	adr	r0, .L_vdso_data_ptr
+	ldr	r1, [r0]
+	add	r0, r0, r1
+	bx	lr
+	.fnend
+ENDPROC(__get_datapage)

arch/arm/vdso/vdso.S

@@ -0,0 +1,35 @@
+/*
+ * Adapted from arm64 version.
+ *
+ * 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/arm/vdso/vdso.so"
+	.balign PAGE_SIZE
+vdso_end:
+
+	.previous

arch/arm/vdso/vdso.lds.S

@@ -0,0 +1,87 @@
+/*
+ * Adapted from arm64 version.
+ *
+ * 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("elf32-littlearm", "elf32-bigarm", "elf32-littlearm")
+OUTPUT_ARCH(arm)
+
+SECTIONS
+{
+	PROVIDE(_start = .);
+
+	. = 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
+
+
+	.eh_frame_hdr	: { *(.eh_frame_hdr) }		:text	:eh_frame_hdr
+	.eh_frame	: { KEEP (*(.eh_frame)) }	:text
+
+	.dynamic	: { *(.dynamic) }		:text	:dynamic
+
+	.rodata		: { *(.rodata*) }		:text
+
+	.text		: { *(.text*) }			:text	=0xe7f001f2
+
+	.got		: { *(.got) }
+	.rel.plt	: { *(.rel.plt) }
+
+	/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;
+}
+
+VERSION
+{
+	LINUX_2.6 {
+	global:
+		__vdso_clock_gettime;
+		__vdso_gettimeofday;
+	local: *;
+	};
+}

arch/arm/vdso/vdsomunge.c

@@ -0,0 +1,201 @@
+/*
+ * Copyright 2015 Mentor Graphics Corporation.
+ *
+ * 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 of the
+ * License.
+ *
+ * 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/>.
+ *
+ *
+ * vdsomunge - Host program which produces a shared object
+ * architecturally specified to be usable by both soft- and hard-float
+ * programs.
+ *
+ * The Procedure Call Standard for the ARM Architecture (ARM IHI
+ * 0042E) says:
+ *
+ *	6.4.1 VFP and Base Standard Compatibility
+ *
+ *	Code compiled for the VFP calling standard is compatible with
+ *	the base standard (and vice-versa) if no floating-point or
+ *	containerized vector arguments or results are used.
+ *
+ * And ELF for the ARM Architecture (ARM IHI 0044E) (Table 4-2) says:
+ *
+ *	If both EF_ARM_ABI_FLOAT_XXXX bits are clear, conformance to the
+ *	base procedure-call standard is implied.
+ *
+ * The VDSO is built with -msoft-float, as with the rest of the ARM
+ * kernel, and uses no floating point arguments or results.  The build
+ * process will produce a shared object that may or may not have the
+ * EF_ARM_ABI_FLOAT_SOFT flag set (it seems to depend on the binutils
+ * version; binutils starting with 2.24 appears to set it).  The
+ * EF_ARM_ABI_FLOAT_HARD flag should definitely not be set, and this
+ * program will error out if it is.
+ *
+ * If the soft-float flag is set, this program clears it.  That's all
+ * it does.
+ */
+
+#define _GNU_SOURCE
+
+#include <byteswap.h>
+#include <elf.h>
+#include <errno.h>
+#include <error.h>
+#include <fcntl.h>
+#include <stdbool.h>
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <sys/mman.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <unistd.h>
+
+#if __BYTE_ORDER__ == __ORDER_LITTLE_ENDIAN__
+#define HOST_ORDER ELFDATA2LSB
+#elif __BYTE_ORDER__ == __ORDER_BIG_ENDIAN__
+#define HOST_ORDER ELFDATA2MSB
+#endif
+
+/* Some of the ELF constants we'd like to use were added to <elf.h>
+ * relatively recently.
+ */
+#ifndef EF_ARM_EABI_VER5
+#define EF_ARM_EABI_VER5 0x05000000
+#endif
+
+#ifndef EF_ARM_ABI_FLOAT_SOFT
+#define EF_ARM_ABI_FLOAT_SOFT 0x200
+#endif
+
+#ifndef EF_ARM_ABI_FLOAT_HARD
+#define EF_ARM_ABI_FLOAT_HARD 0x400
+#endif
+
+static const char *outfile;
+
+static void cleanup(void)
+{
+	if (error_message_count > 0 && outfile != NULL)
+		unlink(outfile);
+}
+
+static Elf32_Word read_elf_word(Elf32_Word word, bool swap)
+{
+	return swap ? bswap_32(word) : word;
+}
+
+static Elf32_Half read_elf_half(Elf32_Half half, bool swap)
+{
+	return swap ? bswap_16(half) : half;
+}
+
+static void write_elf_word(Elf32_Word val, Elf32_Word *dst, bool swap)
+{
+	*dst = swap ? bswap_32(val) : val;
+}
+
+int main(int argc, char **argv)
+{
+	const Elf32_Ehdr *inhdr;
+	bool clear_soft_float;
+	const char *infile;
+	Elf32_Word e_flags;
+	const void *inbuf;
+	struct stat stat;
+	void *outbuf;
+	bool swap;
+	int outfd;
+	int infd;
+
+	atexit(cleanup);
+
+	if (argc != 3)
+		error(EXIT_FAILURE, 0, "Usage: %s [infile] [outfile]", argv[0]);
+
+	infile = argv[1];
+	outfile = argv[2];
+
+	infd = open(infile, O_RDONLY);
+	if (infd < 0)
+		error(EXIT_FAILURE, errno, "Cannot open %s", infile);
+
+	if (fstat(infd, &stat) != 0)
+		error(EXIT_FAILURE, errno, "Failed stat for %s", infile);
+
+	inbuf = mmap(NULL, stat.st_size, PROT_READ, MAP_PRIVATE, infd, 0);
+	if (inbuf == MAP_FAILED)
+		error(EXIT_FAILURE, errno, "Failed to map %s", infile);
+
+	close(infd);
+
+	inhdr = inbuf;
+
+	if (memcmp(&inhdr->e_ident, ELFMAG, SELFMAG) != 0)
+		error(EXIT_FAILURE, 0, "Not an ELF file");
+
+	if (inhdr->e_ident[EI_CLASS] != ELFCLASS32)
+		error(EXIT_FAILURE, 0, "Unsupported ELF class");
+
+	swap = inhdr->e_ident[EI_DATA] != HOST_ORDER;
+
+	if (read_elf_half(inhdr->e_type, swap) != ET_DYN)
+		error(EXIT_FAILURE, 0, "Not a shared object");
+
+	if (read_elf_half(inhdr->e_machine, swap) != EM_ARM) {
+		error(EXIT_FAILURE, 0, "Unsupported architecture %#x",
+		      inhdr->e_machine);
+	}
+
+	e_flags = read_elf_word(inhdr->e_flags, swap);
+
+	if (EF_ARM_EABI_VERSION(e_flags) != EF_ARM_EABI_VER5) {
+		error(EXIT_FAILURE, 0, "Unsupported EABI version %#x",
+		      EF_ARM_EABI_VERSION(e_flags));
+	}
+
+	if (e_flags & EF_ARM_ABI_FLOAT_HARD)
+		error(EXIT_FAILURE, 0,
+		      "Unexpected hard-float flag set in e_flags");
+
+	clear_soft_float = !!(e_flags & EF_ARM_ABI_FLOAT_SOFT);
+
+	outfd = open(outfile, O_RDWR | O_CREAT | O_TRUNC, S_IRUSR | S_IWUSR);
+	if (outfd < 0)
+		error(EXIT_FAILURE, errno, "Cannot open %s", outfile);
+
+	if (ftruncate(outfd, stat.st_size) != 0)
+		error(EXIT_FAILURE, errno, "Cannot truncate %s", outfile);
+
+	outbuf = mmap(NULL, stat.st_size, PROT_READ | PROT_WRITE, MAP_SHARED,
+		      outfd, 0);
+	if (outbuf == MAP_FAILED)
+		error(EXIT_FAILURE, errno, "Failed to map %s", outfile);
+
+	close(outfd);
+
+	memcpy(outbuf, inbuf, stat.st_size);
+
+	if (clear_soft_float) {
+		Elf32_Ehdr *outhdr;
+
+		outhdr = outbuf;
+		e_flags &= ~EF_ARM_ABI_FLOAT_SOFT;
+		write_elf_word(e_flags, &outhdr->e_flags, swap);
+	}
+
+	if (msync(outbuf, stat.st_size, MS_SYNC) != 0)
+		error(EXIT_FAILURE, errno, "Failed to sync %s", outfile);
+
+	return EXIT_SUCCESS;
+}

arch/arm/vdso/vgettimeofday.c

@@ -0,0 +1,282 @@
+/*
+ * Copyright 2015 Mentor Graphics Corporation.
+ *
+ * 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 of the
+ * License.
+ *
+ * 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/>.
+ */
+
+#include <linux/compiler.h>
+#include <linux/hrtimer.h>
+#include <linux/time.h>
+#include <asm/arch_timer.h>
+#include <asm/barrier.h>
+#include <asm/bug.h>
+#include <asm/page.h>
+#include <asm/unistd.h>
+#include <asm/vdso_datapage.h>
+
+#ifndef CONFIG_AEABI
+#error This code depends on AEABI system call conventions
+#endif
+
+extern struct vdso_data *__get_datapage(void);
+
+static notrace u32 __vdso_read_begin(const struct vdso_data *vdata)
+{
+	u32 seq;
+repeat:
+	seq = ACCESS_ONCE(vdata->seq_count);
+	if (seq & 1) {
+		cpu_relax();
+		goto repeat;
+	}
+	return seq;
+}
+
+static notrace u32 vdso_read_begin(const struct vdso_data *vdata)
+{
+	u32 seq;
+
+	seq = __vdso_read_begin(vdata);
+
+	smp_rmb(); /* Pairs with smp_wmb in vdso_write_end */
+	return seq;
+}
+
+static notrace int vdso_read_retry(const struct vdso_data *vdata, u32 start)
+{
+	smp_rmb(); /* Pairs with smp_wmb in vdso_write_begin */
+	return vdata->seq_count != start;
+}
+
+static notrace long clock_gettime_fallback(clockid_t _clkid,
+					   struct timespec *_ts)
+{
+	register struct timespec *ts asm("r1") = _ts;
+	register clockid_t clkid asm("r0") = _clkid;
+	register long ret asm ("r0");
+	register long nr asm("r7") = __NR_clock_gettime;
+
+	asm volatile(
+	"	swi #0\n"
+	: "=r" (ret)
+	: "r" (clkid), "r" (ts), "r" (nr)
+	: "memory");
+
+	return ret;
+}
+
+static notrace int do_realtime_coarse(struct timespec *ts,
+				      struct vdso_data *vdata)
+{
+	u32 seq;
+
+	do {
+		seq = vdso_read_begin(vdata);
+
+		ts->tv_sec = vdata->xtime_coarse_sec;
+		ts->tv_nsec = vdata->xtime_coarse_nsec;
+
+	} while (vdso_read_retry(vdata, seq));
+
+	return 0;
+}
+
+static notrace int do_monotonic_coarse(struct timespec *ts,
+				       struct vdso_data *vdata)
+{
+	struct timespec tomono;
+	u32 seq;
+
+	do {
+		seq = vdso_read_begin(vdata);
+
+		ts->tv_sec = vdata->xtime_coarse_sec;
+		ts->tv_nsec = vdata->xtime_coarse_nsec;
+
+		tomono.tv_sec = vdata->wtm_clock_sec;
+		tomono.tv_nsec = vdata->wtm_clock_nsec;
+
+	} while (vdso_read_retry(vdata, seq));
+
+	ts->tv_sec += tomono.tv_sec;
+	timespec_add_ns(ts, tomono.tv_nsec);
+
+	return 0;
+}
+
+#ifdef CONFIG_ARM_ARCH_TIMER
+
+static notrace u64 get_ns(struct vdso_data *vdata)
+{
+	u64 cycle_delta;
+	u64 cycle_now;
+	u64 nsec;
+
+	cycle_now = arch_counter_get_cntvct();
+
+	cycle_delta = (cycle_now - vdata->cs_cycle_last) & vdata->cs_mask;
+
+	nsec = (cycle_delta * vdata->cs_mult) + vdata->xtime_clock_snsec;
+	nsec >>= vdata->cs_shift;
+
+	return nsec;
+}
+
+static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata)
+{
+	u64 nsecs;
+	u32 seq;
+
+	do {
+		seq = vdso_read_begin(vdata);
+
+		if (!vdata->tk_is_cntvct)
+			return -1;
+
+		ts->tv_sec = vdata->xtime_clock_sec;
+		nsecs = get_ns(vdata);
+
+	} while (vdso_read_retry(vdata, seq));
+
+	ts->tv_nsec = 0;
+	timespec_add_ns(ts, nsecs);
+
+	return 0;
+}
+
+static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata)
+{
+	struct timespec tomono;
+	u64 nsecs;
+	u32 seq;
+
+	do {
+		seq = vdso_read_begin(vdata);
+
+		if (!vdata->tk_is_cntvct)
+			return -1;
+
+		ts->tv_sec = vdata->xtime_clock_sec;
+		nsecs = get_ns(vdata);
+
+		tomono.tv_sec = vdata->wtm_clock_sec;
+		tomono.tv_nsec = vdata->wtm_clock_nsec;
+
+	} while (vdso_read_retry(vdata, seq));
+
+	ts->tv_sec += tomono.tv_sec;
+	ts->tv_nsec = 0;
+	timespec_add_ns(ts, nsecs + tomono.tv_nsec);
+
+	return 0;
+}
+
+#else /* CONFIG_ARM_ARCH_TIMER */
+
+static notrace int do_realtime(struct timespec *ts, struct vdso_data *vdata)
+{
+	return -1;
+}
+
+static notrace int do_monotonic(struct timespec *ts, struct vdso_data *vdata)
+{
+	return -1;
+}
+
+#endif /* CONFIG_ARM_ARCH_TIMER */
+
+notrace int __vdso_clock_gettime(clockid_t clkid, struct timespec *ts)
+{
+	struct vdso_data *vdata;
+	int ret = -1;
+
+	vdata = __get_datapage();
+
+	switch (clkid) {
+	case CLOCK_REALTIME_COARSE:
+		ret = do_realtime_coarse(ts, vdata);
+		break;
+	case CLOCK_MONOTONIC_COARSE:
+		ret = do_monotonic_coarse(ts, vdata);
+		break;
+	case CLOCK_REALTIME:
+		ret = do_realtime(ts, vdata);
+		break;
+	case CLOCK_MONOTONIC:
+		ret = do_monotonic(ts, vdata);
+		break;
+	default:
+		break;
+	}
+
+	if (ret)
+		ret = clock_gettime_fallback(clkid, ts);
+
+	return ret;
+}
+
+static notrace long gettimeofday_fallback(struct timeval *_tv,
+					  struct timezone *_tz)
+{
+	register struct timezone *tz asm("r1") = _tz;
+	register struct timeval *tv asm("r0") = _tv;
+	register long ret asm ("r0");
+	register long nr asm("r7") = __NR_gettimeofday;
+
+	asm volatile(
+	"	swi #0\n"
+	: "=r" (ret)
+	: "r" (tv), "r" (tz), "r" (nr)
+	: "memory");
+
+	return ret;
+}
+
+notrace int __vdso_gettimeofday(struct timeval *tv, struct timezone *tz)
+{
+	struct timespec ts;
+	struct vdso_data *vdata;
+	int ret;
+
+	vdata = __get_datapage();
+
+	ret = do_realtime(&ts, vdata);
+	if (ret)
+		return gettimeofday_fallback(tv, tz);
+
+	if (tv) {
+		tv->tv_sec = ts.tv_sec;
+		tv->tv_usec = ts.tv_nsec / 1000;
+	}
+	if (tz) {
+		tz->tz_minuteswest = vdata->tz_minuteswest;
+		tz->tz_dsttime = vdata->tz_dsttime;
+	}
+
+	return ret;
+}
+
+/* Avoid unresolved references emitted by GCC */
+
+void __aeabi_unwind_cpp_pr0(void)
+{
+}
+
+void __aeabi_unwind_cpp_pr1(void)
+{
+}
+
+void __aeabi_unwind_cpp_pr2(void)
+{
+}