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Commit a8a4b03a authored by Madhavan Srinivasan's avatar Madhavan Srinivasan Committed by Michael Ellerman
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powerpc: Hard wire PT_SOFTE value to 1 in ptrace & signals 



We have always had softe in pt_regs, and accessible via PT_SOFTE, even
though it is not userspace state.

The value userspace sees should always be 1, because we should never
be in userspace with interrupts soft disabled.

In a subsequent patch we will be changing the semantics of the kernel
softe value, so hard wire the value to 1 to retain the existing
semantics. As far as we know nothing ever looks at it, but better safe
than sorry.

Signed-off-by: default avatarMadhavan Srinivasan <maddy@linux.vnet.ibm.com>
[mpe: Split out of larger patch, write change log]
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 7a074fc0

arch/powerpc/kernel/ptrace.c

+12 −0
Original line number Diff line number Diff line
@@ -283,6 +283,18 @@ int ptrace_get_reg(struct task_struct *task, int regno, unsigned long *data) 
	if (regno == PT_DSCR)

		return get_user_dscr(task, data);



#ifdef CONFIG_PPC64

	/*

	 * softe copies paca->soft_enabled variable state. Since soft_enabled is

	 * no more used as a flag, lets force usr to alway see the softe value as 1

	 * which means interrupts are not soft disabled.

	 */

	if (regno == PT_SOFTE) {

		*data = 1;

		return  0;

	}

#endif



	if (regno < (sizeof(struct pt_regs) / sizeof(unsigned long))) {

		*data = ((unsigned long *)task->thread.regs)[regno];

		return 0;

arch/powerpc/kernel/signal_32.c

+8 −0
Original line number Diff line number Diff line
@@ -111,12 +111,20 @@ static inline int save_general_regs(struct pt_regs *regs, 
{

	elf_greg_t64 *gregs = (elf_greg_t64 *)regs;

	int i;

	/* Force usr to alway see softe as 1 (interrupts enabled) */

	elf_greg_t64 softe = 0x1;



	WARN_ON(!FULL_REGS(regs));



	for (i = 0; i <= PT_RESULT; i ++) {

		if (i == 14 && !FULL_REGS(regs))

			i = 32;

		if ( i == PT_SOFTE) {

			if(__put_user((unsigned int)softe, &frame->mc_gregs[i]))

				return -EFAULT;

			else

				continue;

		}

		if (__put_user((unsigned int)gregs[i], &frame->mc_gregs[i]))

			return -EFAULT;

	}

arch/powerpc/kernel/signal_64.c

+3 −0
Original line number Diff line number Diff line
@@ -110,6 +110,8 @@ static long setup_sigcontext(struct sigcontext __user *sc, 
	struct pt_regs *regs = tsk->thread.regs;

	unsigned long msr = regs->msr;

	long err = 0;

	/* Force usr to alway see softe as 1 (interrupts enabled) */

	unsigned long softe = 0x1;



	BUG_ON(tsk != current);
@@ -169,6 +171,7 @@ static long setup_sigcontext(struct sigcontext __user *sc, 
	WARN_ON(!FULL_REGS(regs));

	err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);

	err |= __put_user(msr, &sc->gp_regs[PT_MSR]);

	err |= __put_user(softe, &sc->gp_regs[PT_SOFTE]);

	err |= __put_user(signr, &sc->signal);

	err |= __put_user(handler, &sc->handler);

	if (set != NULL)