When building a signal or a ucontext, we can incorrectly set the MSR_VEC
bit of the kernel pt_regs->msr before returning to userspace if the task
-ever- used VMX.
This can lead to funny result if that stack used it in the past, then
"lost" it (ie. it wasn't enabled after a context switch for example)
and then called get_context. It can end up with VMX enabled and the
registers containing values from some other task.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
#ifdef CONFIG_ALTIVEC
elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
#endif
#ifdef CONFIG_ALTIVEC
elf_vrreg_t __user *v_regs = (elf_vrreg_t __user *)(((unsigned long)sc->vmx_reserve + 15) & ~0xful);
#endif
+ unsigned long msr = regs->msr;
long err = 0;
flush_fp_to_thread(current);
long err = 0;
flush_fp_to_thread(current);
/* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
* contains valid data.
*/
/* set MSR_VEC in the MSR value in the frame to indicate that sc->v_reg)
* contains valid data.
*/
}
/* We always copy to/from vrsave, it's 0 if we don't have or don't
* use altivec.
}
/* We always copy to/from vrsave, it's 0 if we don't have or don't
* use altivec.
err |= __put_user(&sc->gp_regs, &sc->regs);
WARN_ON(!FULL_REGS(regs));
err |= __copy_to_user(&sc->gp_regs, regs, GP_REGS_SIZE);
err |= __put_user(&sc->gp_regs, &sc->regs);
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 |= __copy_to_user(&sc->fp_regs, ¤t->thread.fpr, FP_REGS_SIZE);
err |= __put_user(signr, &sc->signal);
err |= __put_user(handler, &sc->handler);
err |= __copy_to_user(&sc->fp_regs, ¤t->thread.fpr, FP_REGS_SIZE);
err |= __put_user(signr, &sc->signal);
err |= __put_user(handler, &sc->handler);