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Commit 253f29a4 authored by Brian Gerst's avatar Brian Gerst Committed by Ingo Molnar
Browse files

x86: pass in pt_regs pointer for syscalls that need it 



Some syscalls need to access the pt_regs structure, either to copy
user register state or to modifiy it.  This patch adds stubs to load
the address of the pt_regs struct into the %eax register, and changes
the syscalls to regparm(1) to receive the pt_regs pointer as the
first argument.

Signed-off-by: default avatarBrian Gerst <brgerst@gmail.com>
Acked-by: default avatarTejun Heo <tj@kernel.org>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent aa78bcfa

arch/x86/include/asm/linkage.h

+7 −0
Original line number Original line Diff line number Diff line
@@ -17,6 +17,13 @@ 
 */

 */

#define asmregparm __attribute__((regparm(3)))

#define asmregparm __attribute__((regparm(3)))





/*

 * For syscalls that need a pointer to the pt_regs struct (ie. fork).

 * The regs pointer is passed in %eax as the first argument.  The

 * remaining function arguments remain on the stack.

 */

#define ptregscall __attribute__((regparm(1)))



/*

/*

 * Make sure the compiler doesn't do anything stupid with the

 * Make sure the compiler doesn't do anything stupid with the

 * arguments on the stack - they are owned by the *caller*, not

 * arguments on the stack - they are owned by the *caller*, not

arch/x86/include/asm/syscalls.h

+15 −10
Original line number Original line Diff line number Diff line
@@ -29,21 +29,26 @@ asmlinkage int sys_get_thread_area(struct user_desc __user *); 
/* X86_32 only */

/* X86_32 only */

#ifdef CONFIG_X86_32

#ifdef CONFIG_X86_32

/* kernel/process_32.c */

/* kernel/process_32.c */

asmlinkage int sys_fork(struct pt_regs);

ptregscall int sys_fork(struct pt_regs *);

asmlinkage int sys_clone(struct pt_regs);

ptregscall int sys_clone(struct pt_regs *, unsigned long,

asmlinkage int sys_vfork(struct pt_regs);

			 unsigned long, int __user *,

asmlinkage int sys_execve(struct pt_regs);

			 unsigned long, int __user *);

ptregscall int sys_vfork(struct pt_regs *);

ptregscall int sys_execve(struct pt_regs *, char __user *,

			  char __user * __user *,

			  char __user * __user *);





/* kernel/signal_32.c */

/* kernel/signal_32.c */

asmlinkage int sys_sigsuspend(int, int, old_sigset_t);

asmlinkage int sys_sigsuspend(int, int, old_sigset_t);

asmlinkage int sys_sigaction(int, const struct old_sigaction __user *,

asmlinkage int sys_sigaction(int, const struct old_sigaction __user *,

			     struct old_sigaction __user *);

			     struct old_sigaction __user *);

asmlinkage int sys_sigaltstack(unsigned long);

ptregscall int sys_sigaltstack(struct pt_regs *, const stack_t __user *,

asmlinkage unsigned long sys_sigreturn(unsigned long);

			       stack_t __user *);

asmlinkage int sys_rt_sigreturn(unsigned long);

ptregscall unsigned long sys_sigreturn(struct pt_regs *);

ptregscall int sys_rt_sigreturn(struct pt_regs *);





/* kernel/ioport.c */

/* kernel/ioport.c */

asmlinkage long sys_iopl(unsigned long);

ptregscall long sys_iopl(struct pt_regs *, unsigned int);





/* kernel/sys_i386_32.c */

/* kernel/sys_i386_32.c */

asmlinkage long sys_mmap2(unsigned long, unsigned long, unsigned long,

asmlinkage long sys_mmap2(unsigned long, unsigned long, unsigned long,
@@ -59,8 +64,8 @@ struct oldold_utsname; 
asmlinkage int sys_olduname(struct oldold_utsname __user *);

asmlinkage int sys_olduname(struct oldold_utsname __user *);





/* kernel/vm86_32.c */

/* kernel/vm86_32.c */

asmlinkage int sys_vm86old(struct pt_regs);

ptregscall int sys_vm86old(struct pt_regs *, struct vm86_struct __user *);

asmlinkage int sys_vm86(struct pt_regs);

ptregscall int sys_vm86(struct pt_regs *, unsigned long, unsigned long);





#else /* CONFIG_X86_32 */

#else /* CONFIG_X86_32 */

arch/x86/kernel/entry_32.S

+20 −0
Original line number Original line Diff line number Diff line
@@ -697,6 +697,26 @@ syscall_badsys: 
END(syscall_badsys)

END(syscall_badsys)

	CFI_ENDPROC

	CFI_ENDPROC





/*

 * System calls that need a pt_regs pointer.

 */

#define PTREGSCALL(name) \

	ALIGN; \

ptregs_##name: \

	leal 4(%esp),%eax; \

	jmp sys_##name;



PTREGSCALL(iopl)

PTREGSCALL(fork)

PTREGSCALL(clone)

PTREGSCALL(vfork)

PTREGSCALL(execve)

PTREGSCALL(sigaltstack)

PTREGSCALL(sigreturn)

PTREGSCALL(rt_sigreturn)

PTREGSCALL(vm86)

PTREGSCALL(vm86old)



.macro FIXUP_ESPFIX_STACK

.macro FIXUP_ESPFIX_STACK

	/* since we are on a wrong stack, we cant make it a C code :( */

	/* since we are on a wrong stack, we cant make it a C code :( */

	PER_CPU(gdt_page, %ebx)

	PER_CPU(gdt_page, %ebx)

arch/x86/kernel/ioport.c

+1 −3
Original line number Original line Diff line number Diff line
@@ -131,10 +131,8 @@ static int do_iopl(unsigned int level, struct pt_regs *regs) 
}

}





#ifdef CONFIG_X86_32

#ifdef CONFIG_X86_32

asmlinkage long sys_iopl(unsigned long regsp)

ptregscall long sys_iopl(struct pt_regs *regs, unsigned int level)

{

{

	struct pt_regs *regs = (struct pt_regs *)&regsp;

	unsigned int level = regs->bx;

	struct thread_struct *t = &current->thread;

	struct thread_struct *t = &current->thread;

	int rc;

	int rc;

arch/x86/kernel/process_32.c

+14 −21
Original line number Original line Diff line number Diff line
@@ -603,24 +603,18 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) 
	return prev_p;

	return prev_p;

}

}





asmlinkage int sys_fork(struct pt_regs regs)

ptregscall int sys_fork(struct pt_regs *regs)

{

{

	return do_fork(SIGCHLD, regs.sp, &regs, 0, NULL, NULL);

	return do_fork(SIGCHLD, regs->sp, regs, 0, NULL, NULL);

}

}





asmlinkage int sys_clone(struct pt_regs regs)

ptregscall int sys_clone(struct pt_regs *regs, unsigned long clone_flags,

			 unsigned long newsp, int __user *parent_tidptr,

			 unsigned long unused, int __user *child_tidptr)

{

{

	unsigned long clone_flags;

	unsigned long newsp;

	int __user *parent_tidptr, *child_tidptr;



	clone_flags = regs.bx;

	newsp = regs.cx;

	parent_tidptr = (int __user *)regs.dx;

	child_tidptr = (int __user *)regs.di;

	if (!newsp)

	if (!newsp)

		newsp = regs.sp;

		newsp = regs->sp;

	return do_fork(clone_flags, newsp, &regs, 0, parent_tidptr, child_tidptr);

	return do_fork(clone_flags, newsp, regs, 0, parent_tidptr, child_tidptr);

}

}





/*

/*
@@ -633,27 +627,26 @@ asmlinkage int sys_clone(struct pt_regs regs) 
 * do not have enough call-clobbered registers to hold all

 * do not have enough call-clobbered registers to hold all

 * the information you need.

 * the information you need.

 */

 */

asmlinkage int sys_vfork(struct pt_regs regs)

ptregscall int sys_vfork(struct pt_regs *regs)

{

{

	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs.sp, &regs, 0, NULL, NULL);

	return do_fork(CLONE_VFORK | CLONE_VM | SIGCHLD, regs->sp, regs, 0, NULL, NULL);

}

}





/*

/*

 * sys_execve() executes a new program.

 * sys_execve() executes a new program.

 */

 */

asmlinkage int sys_execve(struct pt_regs regs)

ptregscall int sys_execve(struct pt_regs *regs, char __user *u_filename,

			  char __user * __user *argv,

			  char __user * __user *envp)

{

{

	int error;

	int error;

	char *filename;

	char *filename;





	filename = getname((char __user *) regs.bx);

	filename = getname(u_filename);

	error = PTR_ERR(filename);

	error = PTR_ERR(filename);

	if (IS_ERR(filename))

	if (IS_ERR(filename))

		goto out;

		goto out;

	error = do_execve(filename,

	error = do_execve(filename, argv, envp, regs);

			(char __user * __user *) regs.cx,

			(char __user * __user *) regs.dx,

			&regs);

	if (error == 0) {

	if (error == 0) {

		/* Make sure we don't return using sysenter.. */

		/* Make sure we don't return using sysenter.. */

		set_thread_flag(TIF_IRET);

		set_thread_flag(TIF_IRET);