ARM: 8329/1: miscellaneous vdso infrastructure, preparation

Define the layout of the data structure shared between kernel and
userspace.

Track the vdso address in the mm_context; needed for communicating
AT_SYSINFO_EHDR to the ELF loader.

Add declarations for arm_install_vdso; implementation is in a
following patch.

Define AT_SYSINFO_EHDR, and, if CONFIG_VDSO=y, report the vdso shared
object address via the ELF auxiliary vector.

Note - this adds the AT_SYSINFO_EHDR in a new user-visible header
asm/auxvec.h; this is consistent with other architectures.

Signed-off-by: Nathan Lynch <nathan_lynch@mentor.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

diff --git a/arch/arm/include/asm/Kbuild b/arch/arm/include/asm/Kbuild
index fe74c0d..eb0f43f 100644 (file)
--- a/arch/arm/include/asm/Kbuild
+++ b/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

diff --git a/arch/arm/include/asm/auxvec.h b/arch/arm/include/asm/auxvec.h
new file mode 100644 (file)
index 0000000..fbd388c
--- /dev/null
+++ b/arch/arm/include/asm/auxvec.h
@@ -0,0 +1 @@
+#include <uapi/asm/auxvec.h>

diff --git a/arch/arm/include/asm/elf.h b/arch/arm/include/asm/elf.h
index afb9caf..ac3f17f 100644 (file)
--- a/arch/arm/include/asm/elf.h
+++ b/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..
@@ -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);

diff --git a/arch/arm/include/asm/mmu.h b/arch/arm/include/asm/mmu.h
index 64fd151..a5b4742 100644 (file)
--- a/arch/arm/include/asm/mmu.h
+++ b/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

diff --git a/arch/arm/include/asm/vdso.h b/arch/arm/include/asm/vdso.h
new file mode 100644 (file)
index 0000000..d0295f1
--- /dev/null
+++ b/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 */

diff --git a/arch/arm/include/asm/vdso_datapage.h b/arch/arm/include/asm/vdso_datapage.h
new file mode 100644 (file)
index 0000000..9be2594
--- /dev/null
+++ b/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 */

diff --git a/arch/arm/include/uapi/asm/Kbuild b/arch/arm/include/uapi/asm/Kbuild
index 70a1c9d..a1c05f9 100644 (file)
--- a/arch/arm/include/uapi/asm/Kbuild
+++ b/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

diff --git a/arch/arm/include/uapi/asm/auxvec.h b/arch/arm/include/uapi/asm/auxvec.h
new file mode 100644 (file)
index 0000000..cb02a76
--- /dev/null
+++ b/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