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Commit a3f61dc0 authored by Benjamin Herrenschmidt's avatar Benjamin Herrenschmidt Committed by Paul Mackerras
Browse files

[POWERPC] Merge creation of signal frame 



The code for creating signal frames was still duplicated and split
in strange ways between 32 and 64 bits, including the SA_ONSTACK
handling being in do_signal on 32 bits but inside handle_rt_signal
on 64 bits etc...

This moves the 64 bits get_sigframe() to the generic signal.c,
cleans it a bit, moves the access_ok() call done by all callers to
it as well, and adapts/cleanups the 3 different signal handling cases
to use that common function.

Signed-off-by: default avatarBenjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: default avatarPaul Mackerras <paulus@samba.org>
parent 5f9f375a

arch/powerpc/kernel/signal.c

+29 −10
Original line number Diff line number Diff line
@@ -11,6 +11,7 @@ 


#include <linux/ptrace.h>

#include <linux/signal.h>

#include <asm/uaccess.h>

#include <asm/unistd.h>



#include "signal.h"
@@ -28,6 +29,32 @@ static inline int is_32bit_task(void) 
}

#endif



/*

 * Allocate space for the signal frame

 */

void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,

			   size_t frame_size)

{

        unsigned long oldsp, newsp;



        /* Default to using normal stack */

        oldsp = regs->gpr[1];



	/* Check for alt stack */

	if ((ka->sa.sa_flags & SA_ONSTACK) &&

	    current->sas_ss_size && !on_sig_stack(oldsp))

		oldsp = (current->sas_ss_sp + current->sas_ss_size);



	/* Get aligned frame */

	newsp = (oldsp - frame_size) & ~0xFUL;



	/* Check access */

	if (!access_ok(VERIFY_WRITE, (void __user *)newsp, oldsp - newsp))

		return NULL;



        return (void __user *)newsp;

}





/*

 * Restore the user process's signal mask
@@ -130,20 +157,12 @@ int do_signal(sigset_t *oldset, struct pt_regs *regs) 
#endif



	if (is32) {

		unsigned int newsp;



		if ((ka.sa.sa_flags & SA_ONSTACK) &&

		    current->sas_ss_size && !on_sig_stack(regs->gpr[1]))

			newsp = current->sas_ss_sp + current->sas_ss_size;

		else

			newsp = regs->gpr[1];



        	if (ka.sa.sa_flags & SA_SIGINFO)

			ret = handle_rt_signal32(signr, &ka, &info, oldset,

					regs, newsp);

					regs);

		else

			ret = handle_signal32(signr, &ka, &info, oldset,

					regs, newsp);

					regs);

#ifdef CONFIG_PPC64

	} else {

		ret = handle_rt_signal64(signr, &ka, &info, oldset, regs);

arch/powerpc/kernel/signal.h

+4 −2
Original line number Diff line number Diff line
@@ -12,15 +12,17 @@ 


#define _BLOCKABLE (~(sigmask(SIGKILL) | sigmask(SIGSTOP)))



extern void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,

				  size_t frame_size);

extern void restore_sigmask(sigset_t *set);



extern int handle_signal32(unsigned long sig, struct k_sigaction *ka,

			   siginfo_t *info, sigset_t *oldset,

			   struct pt_regs *regs, unsigned long newsp);

			   struct pt_regs *regs);



extern int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,

			      siginfo_t *info, sigset_t *oldset,

			      struct pt_regs *regs, unsigned long newsp);

			      struct pt_regs *regs);



extern int handle_rt_signal64(int signr, struct k_sigaction *ka,

			      siginfo_t *info, sigset_t *set,

arch/powerpc/kernel/signal_32.c

+24 −28
Original line number Diff line number Diff line
@@ -282,14 +282,17 @@ long sys_sigaction(int sig, struct old_sigaction __user *act, 
/*

 * When we have signals to deliver, we set up on the

 * user stack, going down from the original stack pointer:

 *	a sigregs struct

 *	an ABI gap of 56 words

 *	an mcontext struct

 *	a sigcontext struct

 *	a gap of __SIGNAL_FRAMESIZE bytes

 *

 * Each of these things must be a multiple of 16 bytes in size.

 * Each of these things must be a multiple of 16 bytes in size. The following

 * structure represent all of this except the __SIGNAL_FRAMESIZE gap

 *

 */

struct sigregs {

struct sigframe {

	struct sigcontext sctx;		/* the sigcontext */

	struct mcontext	mctx;		/* all the register values */

	/*

	 * Programs using the rs6000/xcoff abi can save up to 19 gp
@@ -698,21 +701,16 @@ int compat_sys_sigaltstack(u32 __new, u32 __old, int r5, 
 */

int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka,

		siginfo_t *info, sigset_t *oldset,

		struct pt_regs *regs, unsigned long newsp)

		struct pt_regs *regs)

{

	struct rt_sigframe __user *rt_sf;

	struct mcontext __user *frame;

	unsigned long origsp = newsp;

	unsigned long newsp = 0;



	/* Set up Signal Frame */

	/* Put a Real Time Context onto stack */

	newsp -= sizeof(*rt_sf);

	rt_sf = (struct rt_sigframe __user *)newsp;



	/* create a stack frame for the caller of the handler */

	newsp -= __SIGNAL_FRAMESIZE + 16;



	if (!access_ok(VERIFY_WRITE, (void __user *)newsp, origsp - newsp))

	rt_sf = get_sigframe(ka, regs, sizeof(*rt_sf));

	if (unlikely(rt_sf == NULL))

		goto badframe;



	/* Put the siginfo & fill in most of the ucontext */
@@ -742,8 +740,12 @@ int handle_rt_signal32(unsigned long sig, struct k_sigaction *ka, 


	current->thread.fpscr.val = 0;	/* turn off all fp exceptions */



	/* create a stack frame for the caller of the handler */

	newsp = ((unsigned long)rt_sf) - (__SIGNAL_FRAMESIZE + 16);

	if (put_user(regs->gpr[1], (u32 __user *)newsp))

		goto badframe;



	/* Fill registers for signal handler */

	regs->gpr[1] = newsp;

	regs->gpr[3] = sig;

	regs->gpr[4] = (unsigned long) &rt_sf->info;
@@ -988,26 +990,17 @@ int sys_debug_setcontext(struct ucontext __user *ctx, 
 * OK, we're invoking a handler

 */

int handle_signal32(unsigned long sig, struct k_sigaction *ka,

		siginfo_t *info, sigset_t *oldset, struct pt_regs *regs,

		unsigned long newsp)

		    siginfo_t *info, sigset_t *oldset, struct pt_regs *regs)

{

	struct sigcontext __user *sc;

	struct sigregs __user *frame;

	unsigned long origsp = newsp;

	struct sigframe __user *frame;

	unsigned long newsp = 0;



	/* Set up Signal Frame */

	newsp -= sizeof(struct sigregs);

	frame = (struct sigregs __user *) newsp;



	/* Put a sigcontext on the stack */

	newsp -= sizeof(*sc);

	sc = (struct sigcontext __user *) newsp;



	/* create a stack frame for the caller of the handler */

	newsp -= __SIGNAL_FRAMESIZE;



	if (!access_ok(VERIFY_WRITE, (void __user *) newsp, origsp - newsp))

	frame = get_sigframe(ka, regs, sizeof(*frame));

	if (unlikely(frame == NULL))

		goto badframe;

	sc = (struct sigcontext __user *) &frame->sctx;



#if _NSIG != 64

#error "Please adjust handle_signal()"
@@ -1019,7 +1012,7 @@ int handle_signal32(unsigned long sig, struct k_sigaction *ka, 
#else

	    || __put_user(oldset->sig[1], &sc->_unused[3])

#endif

	    || __put_user(to_user_ptr(frame), &sc->regs)

	    || __put_user(to_user_ptr(&frame->mctx), &sc->regs)

	    || __put_user(sig, &sc->signal))

		goto badframe;
@@ -1035,8 +1028,11 @@ int handle_signal32(unsigned long sig, struct k_sigaction *ka, 


	current->thread.fpscr.val = 0;	/* turn off all fp exceptions */



	/* create a stack frame for the caller of the handler */

	newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;

	if (put_user(regs->gpr[1], (u32 __user *)newsp))

		goto badframe;



	regs->gpr[1] = newsp;

	regs->gpr[3] = sig;

	regs->gpr[4] = (unsigned long) sc;

arch/powerpc/kernel/signal_64.c

+2 −22
Original line number Diff line number Diff line
@@ -195,25 +195,6 @@ static long restore_sigcontext(struct pt_regs *regs, sigset_t *set, int sig, 
	return err;

}



/*

 * Allocate space for the signal frame

 */

static inline void __user * get_sigframe(struct k_sigaction *ka, struct pt_regs *regs,

				  size_t frame_size)

{

        unsigned long newsp;



        /* Default to using normal stack */

        newsp = regs->gpr[1];



	if ((ka->sa.sa_flags & SA_ONSTACK) && current->sas_ss_size) {

		if (! on_sig_stack(regs->gpr[1]))

			newsp = (current->sas_ss_sp + current->sas_ss_size);

	}



        return (void __user *)((newsp - frame_size) & -16ul);

}



/*

 * Setup the trampoline code on the stack

 */
@@ -348,8 +329,7 @@ int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info, 
	long err = 0;



	frame = get_sigframe(ka, regs, sizeof(*frame));



	if (!access_ok(VERIFY_WRITE, frame, sizeof(*frame)))

	if (unlikely(frame == NULL))

		goto badframe;



	err |= __put_user(&frame->info, &frame->pinfo);
@@ -386,7 +366,7 @@ int handle_rt_signal64(int signr, struct k_sigaction *ka, siginfo_t *info, 
	funct_desc_ptr = (func_descr_t __user *) ka->sa.sa_handler;



	/* Allocate a dummy caller frame for the signal handler. */

	newsp = (unsigned long)frame - __SIGNAL_FRAMESIZE;

	newsp = ((unsigned long)frame) - __SIGNAL_FRAMESIZE;

	err |= put_user(regs->gpr[1], (unsigned long __user *)newsp);



	/* Set up "regs" so we "return" to the signal handler. */