Commit 3add42c2 authored by Al Viro's avatar Al Viro
Browse files

x86: get rid of get_user_ex() in restore_sigcontext() 



Just do copyin into a local struct and be done with that - we are
on a shallow stack here.

[reworked by tglx, removing the macro horrors while we are touching that]

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent 978727ca

arch/x86/kernel/signal.c

+36 −50
Original line number Diff line number Diff line
@@ -47,24 +47,6 @@ 
#include <asm/sigframe.h>

#include <asm/signal.h>



#define COPY(x)			do {			\

	get_user_ex(regs->x, &sc->x);			\

} while (0)



#define GET_SEG(seg)		({			\

	unsigned short tmp;				\

	get_user_ex(tmp, &sc->seg);			\

	tmp;						\

})



#define COPY_SEG(seg)		do {			\

	regs->seg = GET_SEG(seg);			\

} while (0)



#define COPY_SEG_CPL3(seg)	do {			\

	regs->seg = GET_SEG(seg) | 3;			\

} while (0)



#ifdef CONFIG_X86_64

/*

 * If regs->ss will cause an IRET fault, change it.  Otherwise leave it
@@ -92,53 +74,58 @@ static void force_valid_ss(struct pt_regs *regs) 
	    ar != (AR_DPL3 | AR_S | AR_P | AR_TYPE_RWDATA_EXPDOWN))

		regs->ss = __USER_DS;

}

# define CONTEXT_COPY_SIZE	offsetof(struct sigcontext, reserved1)

#else

# define CONTEXT_COPY_SIZE	sizeof(struct sigcontext)

#endif



static int restore_sigcontext(struct pt_regs *regs,

			      struct sigcontext __user *sc,

			      struct sigcontext __user *usc,

			      unsigned long uc_flags)

{

	unsigned long buf_val;

	void __user *buf;

	unsigned int tmpflags;

	unsigned int err = 0;

	struct sigcontext sc;



	/* Always make any pending restarted system calls return -EINTR */

	current->restart_block.fn = do_no_restart_syscall;



	get_user_try {

	if (copy_from_user(&sc, usc, CONTEXT_COPY_SIZE))

		return -EFAULT;



#ifdef CONFIG_X86_32

		set_user_gs(regs, GET_SEG(gs));

		COPY_SEG(fs);

		COPY_SEG(es);

		COPY_SEG(ds);

	set_user_gs(regs, sc.gs);

	regs->fs = sc.fs;

	regs->es = sc.es;

	regs->ds = sc.ds;

#endif /* CONFIG_X86_32 */



		COPY(di); COPY(si); COPY(bp); COPY(sp); COPY(bx);

		COPY(dx); COPY(cx); COPY(ip); COPY(ax);

	regs->bx = sc.bx;

	regs->cx = sc.cx;

	regs->dx = sc.dx;

	regs->si = sc.si;

	regs->di = sc.di;

	regs->bp = sc.bp;

	regs->ax = sc.ax;

	regs->sp = sc.sp;

	regs->ip = sc.ip;



#ifdef CONFIG_X86_64

		COPY(r8);

		COPY(r9);

		COPY(r10);

		COPY(r11);

		COPY(r12);

		COPY(r13);

		COPY(r14);

		COPY(r15);

	regs->r8 = sc.r8;

	regs->r9 = sc.r9;

	regs->r10 = sc.r10;

	regs->r11 = sc.r11;

	regs->r12 = sc.r12;

	regs->r13 = sc.r13;

	regs->r14 = sc.r14;

	regs->r15 = sc.r15;

#endif /* CONFIG_X86_64 */



		COPY_SEG_CPL3(cs);

		COPY_SEG_CPL3(ss);



		get_user_ex(tmpflags, &sc->flags);

		regs->flags = (regs->flags & ~FIX_EFLAGS) | (tmpflags & FIX_EFLAGS);

		regs->orig_ax = -1;		/* disable syscall checks */

	/* Get CS/SS and force CPL3 */

	regs->cs = sc.cs | 0x03;

	regs->ss = sc.ss | 0x03;



		get_user_ex(buf_val, &sc->fpstate);

		buf = (void __user *)buf_val;

	} get_user_catch(err);

	regs->flags = (regs->flags & ~FIX_EFLAGS) | (sc.flags & FIX_EFLAGS);

	/* disable syscall checks */

	regs->orig_ax = -1;



#ifdef CONFIG_X86_64

	/*
@@ -149,9 +136,8 @@ static int restore_sigcontext(struct pt_regs *regs, 
		force_valid_ss(regs);

#endif



	err |= fpu__restore_sig(buf, IS_ENABLED(CONFIG_X86_32));



	return err;

	return fpu__restore_sig((void __user *)sc.fpstate,

			       IS_ENABLED(CONFIG_X86_32));

}



int setup_sigcontext(struct sigcontext __user *sc, void __user *fpstate,

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