[GitHub/mt8127/android_kernel_alcatel_ttab.git] / arch / x86_64 / ia32 / syscall32.c

/* 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>

extern unsigned char syscall32_syscall[], syscall32_syscall_end[];
extern unsigned char syscall32_sysenter[], syscall32_sysenter_end[];
extern int sysctl_vsyscall32;

char *syscall32_page; 
static int use_sysenter = -1;

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, GFP_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"); 
 	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);
  	}	
	return 0;
} 
	
__initcall(init_syscall32); 

/* May not be __init: called during resume */
void syscall32_cpu_init(void)
{
	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);
}
Commit	Line	Data
1da177e4 LT	1	/* Copyright 2002,2003 Andi Kleen, SuSE Labs */
	2
	3	/* vsyscall handling for 32bit processes. Map a stub page into it
	4	on demand because 32bit cannot reach the kernel's fixmaps */
	5
	6	#include <linux/mm.h>
	7	#include <linux/string.h>
	8	#include <linux/kernel.h>
	9	#include <linux/gfp.h>
	10	#include <linux/init.h>
	11	#include <linux/stringify.h>
1e014410	12	#include <linux/security.h>
1da177e4 LT	13	#include <asm/proto.h>
	14	#include <asm/tlbflush.h>
	15	#include <asm/ia32_unistd.h>
	16
1da177e4 LT	17	extern unsigned char syscall32_syscall[], syscall32_syscall_end[];
	18	extern unsigned char syscall32_sysenter[], syscall32_sysenter_end[];
	19	extern int sysctl_vsyscall32;
	20
	21	char *syscall32_page;
	22	static int use_sysenter = -1;
	23
1e014410 AK	24	static struct page *
	25	syscall32_nopage(struct vm_area_struct vma, unsigned long adr, int type)
	26	{
	27	struct page *p = virt_to_page(adr - vma->vm_start + syscall32_page);
	28	get_page(p);
	29	return p;
1da177e4 LT	30	}
1da177e4 LT	31
1e014410 AK	32	/* Prevent VMA merging */
1e014410 AK	33	static void syscall32_vma_close(struct vm_area_struct *vma)
1da177e4	34	{
1e014410 AK	35	}
	36
	37	static struct vm_operations_struct syscall32_vm_ops = {
	38	.close = syscall32_vma_close,
	39	.nopage = syscall32_nopage,
	40	};
	41
	42	struct linux_binprm;
	43
	44	/* Setup a VMA at program startup for the vsyscall page */
	45	int syscall32_setup_pages(struct linux_binprm *bprm, int exstack)
	46	{
	47	int npages = (VSYSCALL32_END - VSYSCALL32_BASE) >> PAGE_SHIFT;
	48	struct vm_area_struct *vma;
	49	struct mm_struct *mm = current->mm;
9fb1759a	50	int ret;
1e014410	51
e94b1766	52	vma = kmem_cache_alloc(vm_area_cachep, GFP_KERNEL);
1e014410 AK	53	if (!vma)
1e014410 AK	54	return -ENOMEM;
1e014410 AK	55
	56	memset(vma, 0, sizeof(struct vm_area_struct));
	57	/* Could randomize here */
	58	vma->vm_start = VSYSCALL32_BASE;
	59	vma->vm_end = VSYSCALL32_END;
	60	/* MAYWRITE to allow gdb to COW and set breakpoints */
2fd4ef85	61	vma->vm_flags = VM_READ\|VM_EXEC\|VM_MAYREAD\|VM_MAYEXEC\|VM_MAYWRITE;
1e014410 AK	62	vma->vm_flags \|= mm->def_flags;
	63	vma->vm_page_prot = protection_map[vma->vm_flags & 7];
	64	vma->vm_ops = &syscall32_vm_ops;
	65	vma->vm_mm = mm;
	66
	67	down_write(&mm->mmap_sem);
9fb1759a SS	68	if ((ret = insert_vm_struct(mm, vma))) {
	69	up_write(&mm->mmap_sem);
	70	kmem_cache_free(vm_area_cachep, vma);
	71	return ret;
	72	}
1e014410 AK	73	mm->total_vm += npages;
	74	up_write(&mm->mmap_sem);
	75	return 0;
1da177e4 LT	76	}
	77
	78	static int __init init_syscall32(void)
	79	{
	80	syscall32_page = (void *)get_zeroed_page(GFP_KERNEL);
	81	if (!syscall32_page)
	82	panic("Cannot allocate syscall32 page");
1da177e4 LT	83	if (use_sysenter > 0) {
	84	memcpy(syscall32_page, syscall32_sysenter,
	85	syscall32_sysenter_end - syscall32_sysenter);
	86	} else {
	87	memcpy(syscall32_page, syscall32_syscall,
	88	syscall32_syscall_end - syscall32_syscall);
	89	}
	90	return 0;
	91	}
	92
	93	__initcall(init_syscall32);
	94
	95	/* May not be __init: called during resume */
	96	void syscall32_cpu_init(void)
	97	{
	98	if (use_sysenter < 0)
	99	use_sysenter = (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL);
	100
	101	/* Load these always in case some future AMD CPU supports
	102	SYSENTER from compat mode too. */
	103	checking_wrmsrl(MSR_IA32_SYSENTER_CS, (u64)__KERNEL_CS);
	104	checking_wrmsrl(MSR_IA32_SYSENTER_ESP, 0ULL);
	105	checking_wrmsrl(MSR_IA32_SYSENTER_EIP, (u64)ia32_sysenter_target);
	106
	107	wrmsrl(MSR_CSTAR, ia32_cstar_target);
	108	}