This commit was manufactured by cvs2svn to create branch 'vserver'.

[linux-2.6.git] / arch / x86_64 / ia32 / syscall32-xen.c

diff --git a/arch/x86_64/ia32/syscall32-xen.c b/arch/x86_64/ia32/syscall32-xen.c
new file mode 100644 (file)
index 0000000..e99a6f7
--- /dev/null
+++ b/arch/x86_64/ia32/syscall32-xen.c
@@ -0,0 +1,128 @@
+/* Copyright 2002,2003 Andi Kleen, SuSE Labs */
+
+/* vsyscall handling for 32bit processes. Map a stub page into it 
+   on demand because 32bit cannot reach the kernel's fixmaps */
+
+#include <linux/mm.h>
+#include <linux/string.h>
+#include <linux/kernel.h>
+#include <linux/gfp.h>
+#include <linux/init.h>
+#include <linux/stringify.h>
+#include <linux/security.h>
+#include <asm/proto.h>
+#include <asm/tlbflush.h>
+#include <asm/ia32_unistd.h>
+
+#ifdef USE_INT80
+extern unsigned char syscall32_int80[], syscall32_int80_end[];
+#endif
+extern unsigned char syscall32_syscall[], syscall32_syscall_end[];
+extern unsigned char syscall32_sysenter[], syscall32_sysenter_end[];
+extern int sysctl_vsyscall32;
+
+char *syscall32_page; 
+#ifndef USE_INT80
+static int use_sysenter = -1;
+#endif
+
+static struct page *
+syscall32_nopage(struct vm_area_struct *vma, unsigned long adr, int *type)
+{
+       struct page *p = virt_to_page(adr - vma->vm_start + syscall32_page);
+       get_page(p);
+       return p;
+}
+
+/* Prevent VMA merging */
+static void syscall32_vma_close(struct vm_area_struct *vma)
+{
+}
+
+static struct vm_operations_struct syscall32_vm_ops = {
+       .close = syscall32_vma_close,
+       .nopage = syscall32_nopage,
+};
+
+struct linux_binprm;
+
+/* Setup a VMA at program startup for the vsyscall page */
+int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
+{
+       int npages = (VSYSCALL32_END - VSYSCALL32_BASE) >> PAGE_SHIFT;
+       struct vm_area_struct *vma;
+       struct mm_struct *mm = current->mm;
+       int ret;
+
+       vma = kmem_cache_alloc(vm_area_cachep, SLAB_KERNEL);
+       if (!vma)
+               return -ENOMEM;
+
+       memset(vma, 0, sizeof(struct vm_area_struct));
+       /* Could randomize here */
+       vma->vm_start = VSYSCALL32_BASE;
+       vma->vm_end = VSYSCALL32_END;
+       /* 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 = &syscall32_vm_ops;
+       vma->vm_mm = mm;
+
+       down_write(&mm->mmap_sem);
+       if ((ret = insert_vm_struct(mm, vma))) {
+               up_write(&mm->mmap_sem);
+               kmem_cache_free(vm_area_cachep, vma);
+               return ret;
+       }
+       mm->total_vm += npages;
+       up_write(&mm->mmap_sem);
+       return 0;
+}
+
+static int __init init_syscall32(void)
+{ 
+       syscall32_page = (void *)get_zeroed_page(GFP_KERNEL); 
+       if (!syscall32_page) 
+               panic("Cannot allocate syscall32 page"); 
+
+#ifdef USE_INT80
+       /*
+        * At this point we use int 0x80.
+        */
+       memcpy(syscall32_page, syscall32_int80,
+              syscall32_int80_end - syscall32_int80);
+#else
+       if (use_sysenter > 0) {
+               memcpy(syscall32_page, syscall32_sysenter,
+                      syscall32_sysenter_end - syscall32_sysenter);
+       } else {
+               memcpy(syscall32_page, syscall32_syscall,
+                      syscall32_syscall_end - syscall32_syscall);
+       }       
+#endif
+       return 0;
+} 
+
+/*
+ * This must be done early in case we have an initrd containing 32-bit
+ * binaries (e.g., hotplug). This could be pushed upstream to arch/x86_64.
+ */    
+core_initcall(init_syscall32); 
+
+/* May not be __init: called during resume */
+void syscall32_cpu_init(void)
+{
+#ifndef USE_INT80
+       if (use_sysenter < 0)
+               use_sysenter = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL);
+
+       /* Load these always in case some future AMD CPU supports
+          SYSENTER from compat mode too. */
+       checking_wrmsrl(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
+       checking_wrmsrl(MSR_IA32_SYSENTER_ESP, 0ULL);
+       checking_wrmsrl(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
+
+       wrmsrl(MSR_CSTAR, ia32_cstar_target);
+#endif
+}