13 files changed, 418 insertions, 12 deletions

diff --git a/arch/sh/kernel/Makefile b/arch/sh/kernel/Makefile
index 0e2148f63e7e..5da88a43d350 100644
--- a/arch/sh/kernel/Makefile
+++ b/arch/sh/kernel/Makefile
@@ -9,6 +9,7 @@ obj-y	:= process.o signal.o entry.o traps.o irq.o \
         io.o io_generic.o sh_ksyms.o syscalls.o
 
 obj-y                           += cpu/ timers/
+obj-$(CONFIG_VSYSCALL)          += vsyscall/
 
 obj-$(CONFIG_SMP)               += smp.o
 obj-$(CONFIG_CF_ENABLER)        += cf-enabler.o
diff --git a/arch/sh/kernel/process.c b/arch/sh/kernel/process.c
index 630ec1af2483..0b1d5dd7a93b 100644
--- a/arch/sh/kernel/process.c
+++ b/arch/sh/kernel/process.c
@@ -355,7 +355,7 @@ struct task_struct *__switch_to(struct task_struct *prev, struct task_struct *ne
         else if (next->thread.ubc_pc && next->mm) {
                 int asid = 0;
 #ifdef CONFIG_MMU
-                asid |= next->mm->context & MMU_CONTEXT_ASID_MASK;
+                asid |= next->mm->context.id & MMU_CONTEXT_ASID_MASK;
 #endif
                 ubc_set_tracing(asid, next->thread.ubc_pc);
         } else {
diff --git a/arch/sh/kernel/signal.c b/arch/sh/kernel/signal.c
index 2f1c9545b49f..5213f5bc6ce0 100644
--- a/arch/sh/kernel/signal.c
+++ b/arch/sh/kernel/signal.c
@@ -8,7 +8,6 @@
  *  SuperH version:  Copyright (C) 1999, 2000  Niibe Yutaka & Kaz Kojima
  *
  */
-
 #include <linux/sched.h>
 #include <linux/mm.h>
 #include <linux/smp.h>
@@ -21,6 +20,7 @@
 #include <linux/unistd.h>
 #include <linux/stddef.h>
 #include <linux/tty.h>
+#include <linux/elf.h>
 #include <linux/personality.h>
 #include <linux/binfmts.h>
 
@@ -29,8 +29,6 @@
 #include <asm/pgtable.h>
 #include <asm/cacheflush.h>
 
-#undef DEBUG
-
 #define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))
 
 /*
@@ -312,6 +310,11 @@ get_sigframe(struct k_sigaction *ka, unsigned long sp, size_t frame_size)
         return (void __user *)((sp - frame_size) & -8ul);
 }
 
+/* These symbols are defined with the addresses in the vsyscall page.
+   See vsyscall-trapa.S.  */
+extern void __user __kernel_sigreturn;
+extern void __user __kernel_rt_sigreturn;
+
 static int setup_frame(int sig, struct k_sigaction *ka,
                         sigset_t *set, struct pt_regs *regs)
 {
@@ -340,6 +343,10 @@ static int setup_frame(int sig, struct k_sigaction *ka,
            already in userspace.  */
         if (ka->sa.sa_flags & SA_RESTORER) {
                 regs->pr = (unsigned long) ka->sa.sa_restorer;
+#ifdef CONFIG_VSYSCALL
+        } else if (likely(current->mm->context.vdso)) {
+                regs->pr = VDSO_SYM(&__kernel_sigreturn);
+#endif
         } else {
                 /* Generate return code (system call to sigreturn) */
                 err |= __put_user(MOVW(7), &frame->retcode[0]);
@@ -416,6 +423,10 @@ static int setup_rt_frame(int sig, struct k_sigaction *ka, siginfo_t *info,
            already in userspace.  */
         if (ka->sa.sa_flags & SA_RESTORER) {
                 regs->pr = (unsigned long) ka->sa.sa_restorer;
+#ifdef CONFIG_VSYSCALL
+        } else if (likely(current->mm->context.vdso)) {
+                regs->pr = VDSO_SYM(&__kernel_rt_sigreturn);
+#endif
         } else {
                 /* Generate return code (system call to rt_sigreturn) */
                 err |= __put_user(MOVW(7), &frame->retcode[0]);
diff --git a/arch/sh/kernel/vsyscall/Makefile b/arch/sh/kernel/vsyscall/Makefile
new file mode 100644
index 000000000000..4bbce1cfa359
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/Makefile
@@ -0,0 +1,36 @@
+obj-y += vsyscall.o vsyscall-syscall.o
+
+$(obj)/vsyscall-syscall.o: \
+        $(foreach F,trapa,$(obj)/vsyscall-$F.so)
+
+# Teach kbuild about targets
+targets += $(foreach F,trapa,vsyscall-$F.o vsyscall-$F.so)
+targets += vsyscall-note.o vsyscall.lds
+
+# The DSO images are built using a special linker script
+quiet_cmd_syscall = SYSCALL $@
+      cmd_syscall = $(CC) -nostdlib $(SYSCFLAGS_$(@F)) \
+                           -Wl,-T,$(filter-out FORCE,$^) -o $@
+
+export CPPFLAGS_vsyscall.lds += -P -C -Ush
+
+vsyscall-flags = -shared -s -Wl,-soname=linux-gate.so.1 \
+                $(call ld-option, -Wl$(comma)--hash-style=sysv)
+
+SYSCFLAGS_vsyscall-trapa.so     = $(vsyscall-flags)
+
+$(obj)/vsyscall-trapa.so: \
+$(obj)/vsyscall-%.so: $(src)/vsyscall.lds $(obj)/vsyscall-%.o FORCE
+        $(call if_changed,syscall)
+
+# We also create a special relocatable object that should mirror the symbol
+# table and layout of the linked DSO.  With ld -R we can then refer to
+# these symbols in the kernel code rather than hand-coded addresses.
+extra-y += vsyscall-syms.o
+$(obj)/built-in.o: $(obj)/vsyscall-syms.o
+$(obj)/built-in.o: ld_flags += -R $(obj)/vsyscall-syms.o
+
+SYSCFLAGS_vsyscall-syms.o = -r
+$(obj)/vsyscall-syms.o: $(src)/vsyscall.lds \
+                        $(obj)/vsyscall-trapa.o $(obj)/vsyscall-note.o FORCE
+        $(call if_changed,syscall)
diff --git a/arch/sh/kernel/vsyscall/vsyscall-note.S b/arch/sh/kernel/vsyscall/vsyscall-note.S
new file mode 100644
index 000000000000..d4b5be4f3d5f
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall-note.S
@@ -0,0 +1,25 @@
+/*
+ * 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>
+
+#define ASM_ELF_NOTE_BEGIN(name, flags, vendor, type)                         \
+        .section name, flags;                                                 \
+        .balign 4;                                                            \
+        .long 1f - 0f;          /* name length */                             \
+        .long 3f - 2f;          /* data length */                             \
+        .long type;             /* note type */                               \
+0:      .asciz vendor;          /* vendor name */                             \
+1:      .balign 4;                                                            \
+2:
+
+#define ASM_ELF_NOTE_END                                                      \
+3:      .balign 4;              /* pad out section */                         \
+        .previous
+
+        ASM_ELF_NOTE_BEGIN(".note.kernel-version", "a", UTS_SYSNAME, 0)
+        .long LINUX_VERSION_CODE
+        ASM_ELF_NOTE_END
diff --git a/arch/sh/kernel/vsyscall/vsyscall-sigreturn.S b/arch/sh/kernel/vsyscall/vsyscall-sigreturn.S
new file mode 100644
index 000000000000..555a64f124ca
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall-sigreturn.S
@@ -0,0 +1,39 @@
+#include <asm/unistd.h>
+
+        .text
+        .balign 32
+        .globl __kernel_sigreturn
+        .type __kernel_sigreturn,@function
+__kernel_sigreturn:
+.LSTART_sigreturn:
+        mov.w   1f, r3
+        trapa   #0x10
+        or      r0, r0
+        or      r0, r0
+        or      r0, r0
+        or      r0, r0
+        or      r0, r0
+
+1:      .short  __NR_sigreturn
+.LEND_sigreturn:
+        .size __kernel_sigreturn,.-.LSTART_sigreturn
+
+        .balign 32
+        .globl __kernel_rt_sigreturn
+        .type __kernel_rt_sigreturn,@function
+__kernel_rt_sigreturn:
+.LSTART_rt_sigreturn:
+        mov.w   1f, r3
+        trapa   #0x10
+        or      r0, r0
+        or      r0, r0
+        or      r0, r0
+        or      r0, r0
+        or      r0, r0
+
+1:      .short  __NR_rt_sigreturn
+.LEND_rt_sigreturn:
+        .size __kernel_rt_sigreturn,.-.LSTART_rt_sigreturn
+
+        .section .eh_frame,"a",@progbits
+        .previous
diff --git a/arch/sh/kernel/vsyscall/vsyscall-syscall.S b/arch/sh/kernel/vsyscall/vsyscall-syscall.S
new file mode 100644
index 000000000000..c2ac7f0282b3
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall-syscall.S
@@ -0,0 +1,10 @@
+#include <linux/init.h>
+
+__INITDATA
+
+        .globl vsyscall_trapa_start, vsyscall_trapa_end
+vsyscall_trapa_start:
+        .incbin "arch/sh/kernel/vsyscall/vsyscall-trapa.so"
+vsyscall_trapa_end:
+
+__FINIT
diff --git a/arch/sh/kernel/vsyscall/vsyscall-trapa.S b/arch/sh/kernel/vsyscall/vsyscall-trapa.S
new file mode 100644
index 000000000000..3b6eb34c43fa
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall-trapa.S
@@ -0,0 +1,42 @@
+        .text
+        .globl __kernel_vsyscall
+        .type __kernel_vsyscall,@function
+__kernel_vsyscall:
+.LSTART_vsyscall:
+        /* XXX: We'll have to do something here once we opt to use the vDSO
+         * page for something other than the signal trampoline.. as well as
+         * fill out .eh_frame -- PFM. */
+.LEND_vsyscall:
+        .size __kernel_vsyscall,.-.LSTART_vsyscall
+        .previous
+
+        .section .eh_frame,"a",@progbits
+.LCIE:
+        .ualong .LCIE_end - .LCIE_start
+.LCIE_start:
+        .ualong 0               /* CIE ID */
+        .byte   0x1             /* Version number */
+        .string "zRS"           /* NUL-terminated augmentation string */
+        .uleb128 0x1            /* Code alignment factor */
+        .sleb128 -4             /* Data alignment factor */
+        .byte   0x11            /* Return address register column */
+                                /* Augmentation length and data (none) */
+        .byte   0xc             /* DW_CFA_def_cfa */
+        .uleb128 0xf            /* r15 */
+        .uleb128 0x0            /* offset 0 */
+
+        .align 2
+.LCIE_end:
+
+        .ualong .LFDE_end-.LFDE_start   /* Length FDE */
+.LFDE_start:
+        .ualong .LCIE                   /* CIE pointer */
+        .ualong .LSTART_vsyscall-.      /* start address */
+        .ualong .LEND_vsyscall-.LSTART_vsyscall
+        .uleb128 0
+        .align 2
+.LFDE_end:
+        .previous
+
+/* Get the common code for the sigreturn entry points */
+#include "vsyscall-sigreturn.S"
diff --git a/arch/sh/kernel/vsyscall/vsyscall.c b/arch/sh/kernel/vsyscall/vsyscall.c
new file mode 100644
index 000000000000..075d6cc1a2d7
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall.c
@@ -0,0 +1,150 @@
+/*
+ * arch/sh/kernel/vsyscall.c
+ *
+ *  Copyright (C) 2006 Paul Mundt
+ *
+ * vDSO randomization
+ * Copyright(C) 2005-2006, Red Hat, Inc., Ingo Molnar
+ *
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License.  See the file "COPYING" in the main directory of this archive
+ * for more details.
+ */
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/gfp.h>
+#include <linux/module.h>
+#include <linux/elf.h>
+
+/*
+ * Should the kernel map a VDSO page into processes and pass its
+ * address down to glibc upon exec()?
+ */
+unsigned int __read_mostly vdso_enabled = 1;
+EXPORT_SYMBOL_GPL(vdso_enabled);
+
+static int __init vdso_setup(char *s)
+{
+        vdso_enabled = simple_strtoul(s, NULL, 0);
+        return 1;
+}
+__setup("vdso=", vdso_setup);
+
+/*
+ * These symbols are defined by vsyscall.o to mark the bounds
+ * of the ELF DSO images included therein.
+ */
+extern const char vsyscall_trapa_start, vsyscall_trapa_end;
+static void *syscall_page;
+
+int __init vsyscall_init(void)
+{
+        syscall_page = (void *)get_zeroed_page(GFP_ATOMIC);
+
+        /*
+         * XXX: Map this page to a fixmap entry if we get around
+         * to adding the page to ELF core dumps
+         */
+
+        memcpy(syscall_page,
+               &vsyscall_trapa_start,
+               &vsyscall_trapa_end - &vsyscall_trapa_start);
+
+        return 0;
+}
+
+static struct page *syscall_vma_nopage(struct vm_area_struct *vma,
+                                       unsigned long address, int *type)
+{
+        unsigned long offset = address - vma->vm_start;
+        struct page *page;
+
+        if (address < vma->vm_start || address > vma->vm_end)
+                return NOPAGE_SIGBUS;
+
+        page = virt_to_page(syscall_page + offset);
+
+        get_page(page);
+
+        return page;
+}
+
+/* Prevent VMA merging */
+static void syscall_vma_close(struct vm_area_struct *vma)
+{
+}
+
+static struct vm_operations_struct syscall_vm_ops = {
+        .nopage = syscall_vma_nopage,
+        .close  = syscall_vma_close,
+};
+
+/* Setup a VMA at program startup for the vsyscall page */
+int arch_setup_additional_pages(struct linux_binprm *bprm,
+                                int executable_stack)
+{
+        struct vm_area_struct *vma;
+        struct mm_struct *mm = current->mm;
+        unsigned long addr;
+        int ret;
+
+        down_write(&mm->mmap_sem);
+        addr = get_unmapped_area(NULL, 0, PAGE_SIZE, 0, 0);
+        if (IS_ERR_VALUE(addr)) {
+                ret = addr;
+                goto up_fail;
+        }
+
+        vma = kmem_cache_zalloc(vm_area_cachep, SLAB_KERNEL);
+        if (!vma) {
+                ret = -ENOMEM;
+                goto up_fail;
+        }
+
+        vma->vm_start = addr;
+        vma->vm_end = addr + PAGE_SIZE;
+        /* MAYWRITE to allow gdb to COW and set breakpoints */
+        vma->vm_flags = VM_READ|VM_EXEC|VM_MAYREAD|VM_MAYEXEC|VM_MAYWRITE;
+        vma->vm_flags |= mm->def_flags;
+        vma->vm_page_prot = protection_map[vma->vm_flags & 7];
+        vma->vm_ops = &syscall_vm_ops;
+        vma->vm_mm = mm;
+
+        ret = insert_vm_struct(mm, vma);
+        if (unlikely(ret)) {
+                kmem_cache_free(vm_area_cachep, vma);
+                goto up_fail;
+        }
+
+        current->mm->context.vdso = (void *)addr;
+
+        mm->total_vm++;
+up_fail:
+        up_write(&mm->mmap_sem);
+        return ret;
+}
+
+const char *arch_vma_name(struct vm_area_struct *vma)
+{
+        if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)
+                return "[vdso]";
+
+        return NULL;
+}
+
+struct vm_area_struct *get_gate_vma(struct task_struct *task)
+{
+        return NULL;
+}
+
+int in_gate_area(struct task_struct *task, unsigned long address)
+{
+        return 0;
+}
+
+int in_gate_area_no_task(unsigned long address)
+{
+        return 0;
+}
diff --git a/arch/sh/kernel/vsyscall/vsyscall.lds.S b/arch/sh/kernel/vsyscall/vsyscall.lds.S
new file mode 100644
index 000000000000..b13c3d439fee
--- /dev/null
+++ b/arch/sh/kernel/vsyscall/vsyscall.lds.S
@@ -0,0 +1,74 @@
+/*
+ * Linker script for vsyscall DSO.  The vsyscall page is an ELF shared
+ * object prelinked to its virtual address, and with only one read-only
+ * segment (that fits in one page).  This script controls its layout.
+ */
+#include <asm/asm-offsets.h>
+
+#ifdef CONFIG_CPU_LITTLE_ENDIAN
+OUTPUT_FORMAT("elf32-sh-linux", "elf32-sh-linux", "elf32-sh-linux")
+#else
+OUTPUT_FORMAT("elf32-shbig-linux", "elf32-shbig-linux", "elf32-shbig-linux")
+#endif
+OUTPUT_ARCH(sh)
+
+/* The ELF entry point can be used to set the AT_SYSINFO value.  */
+ENTRY(__kernel_vsyscall);
+
+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) }
+
+  /* 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.  */
+  . = 0x400;
+
+  .text           : { *(.text) }                :text =0x90909090
+  .note           : { *(.note.*) }              :text :note
+  .eh_frame_hdr   : { *(.eh_frame_hdr) }        :text :eh_frame_hdr
+  .eh_frame       : { KEEP (*(.eh_frame)) }     :text
+  .dynamic        : { *(.dynamic) }             :text :dynamic
+  .useless        : {
+        *(.got.plt) *(.got)
+        *(.data .data.* .gnu.linkonce.d.*)
+        *(.dynbss)
+        *(.bss .bss.* .gnu.linkonce.b.*)
+  }                                             :text
+}
+
+/*
+ * 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 FILEHDR PHDRS FLAGS(5); /* PF_R|PF_X */
+  dynamic PT_DYNAMIC FLAGS(4); /* PF_R */
+  note PT_NOTE FLAGS(4); /* PF_R */
+  eh_frame_hdr 0x6474e550; /* PT_GNU_EH_FRAME, but ld doesn't match the name */
+}
+
+/*
+ * This controls what symbols we export from the DSO.
+ */
+VERSION
+{
+  LINUX_2.6 {
+    global:
+        __kernel_vsyscall;
+        __kernel_sigreturn;
+        __kernel_rt_sigreturn;
+
+    local: *;
+  };
+}
diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig
index b445d02075e8..9dd606464d23 100644
--- a/arch/sh/mm/Kconfig
+++ b/arch/sh/mm/Kconfig
@@ -223,6 +223,19 @@ config 32BIT
           32-bits through the SH-4A PMB. If this is not set, legacy
           29-bit physical addressing will be used.
 
+config VSYSCALL
+        bool "Support vsyscall page"
+        depends on MMU
+        default y
+        help
+          This will enable support for the kernel mapping a vDSO page
+          in process space, and subsequently handing down the entry point
+          to the libc through the ELF auxiliary vector.
+
+          From the kernel side this is used for the signal trampoline.
+          For systems with an MMU that can afford to give up a page,
+          (the default value) say Y.
+
 choice
         prompt "HugeTLB page size"
         depends on HUGETLB_PAGE && CPU_SH4 && MMU
diff --git a/arch/sh/mm/init.c b/arch/sh/mm/init.c
index ad182b31d846..7154d1ce9785 100644
--- a/arch/sh/mm/init.c
+++ b/arch/sh/mm/init.c
@@ -286,6 +286,9 @@ void __init mem_init(void)
                 initsize >> 10);
 
         p3_cache_init();
+
+        /* Initialize the vDSO */
+        vsyscall_init();
 }
 
 void free_initmem(void)
diff --git a/arch/sh/mm/tlb-flush.c b/arch/sh/mm/tlb-flush.c
index fd7e42bcaa40..73ec7f6084fa 100644
--- a/arch/sh/mm/tlb-flush.c
+++ b/arch/sh/mm/tlb-flush.c
@@ -14,12 +14,12 @@
 
 void flush_tlb_page(struct vm_area_struct *vma, unsigned long page)
 {
-        if (vma->vm_mm && vma->vm_mm->context != NO_CONTEXT) {
+        if (vma->vm_mm && vma->vm_mm->context.id != NO_CONTEXT) {
                 unsigned long flags;
                 unsigned long asid;
                 unsigned long saved_asid = MMU_NO_ASID;
 
-                asid = vma->vm_mm->context & MMU_CONTEXT_ASID_MASK;
+                asid = vma->vm_mm->context.id & MMU_CONTEXT_ASID_MASK;
                 page &= PAGE_MASK;
 
                 local_irq_save(flags);
@@ -39,20 +39,21 @@ void flush_tlb_range(struct vm_area_struct *vma, unsigned long start,
 {
         struct mm_struct *mm = vma->vm_mm;
 
-        if (mm->context != NO_CONTEXT) {
+        if (mm->context.id != NO_CONTEXT) {
                 unsigned long flags;
                 int size;
 
                 local_irq_save(flags);
                 size = (end - start + (PAGE_SIZE - 1)) >> PAGE_SHIFT;
                 if (size > (MMU_NTLB_ENTRIES/4)) { /* Too many TLB to flush */
-                        mm->context = NO_CONTEXT;
+                        mm->context.id = NO_CONTEXT;
                         if (mm == current->mm)
                                 activate_context(mm);
                 } else {
-                        unsigned long asid = mm->context&MMU_CONTEXT_ASID_MASK;
+                        unsigned long asid;
                         unsigned long saved_asid = MMU_NO_ASID;
 
+                        asid = mm->context.id & MMU_CONTEXT_ASID_MASK;
                         start &= PAGE_MASK;
                         end += (PAGE_SIZE - 1);
                         end &= PAGE_MASK;
@@ -81,9 +82,10 @@ void flush_tlb_kernel_range(unsigned long start, unsigned long end)
         if (size > (MMU_NTLB_ENTRIES/4)) { /* Too many TLB to flush */
                 flush_tlb_all();
         } else {
-                unsigned long asid = init_mm.context&MMU_CONTEXT_ASID_MASK;
+                unsigned long asid;
                 unsigned long saved_asid = get_asid();
 
+                asid = init_mm.context.id & MMU_CONTEXT_ASID_MASK;
                 start &= PAGE_MASK;
                 end += (PAGE_SIZE - 1);
                 end &= PAGE_MASK;
@@ -101,11 +103,11 @@ void flush_tlb_mm(struct mm_struct *mm)
 {
         /* Invalidate all TLB of this process. */
         /* Instead of invalidating each TLB, we get new MMU context. */
-        if (mm->context != NO_CONTEXT) {
+        if (mm->context.id != NO_CONTEXT) {
                 unsigned long flags;
 
                 local_irq_save(flags);
-                mm->context = NO_CONTEXT;
+                mm->context.id = NO_CONTEXT;
                 if (mm == current->mm)
                         activate_context(mm);
                 local_irq_restore(flags);