static int
setup_return(struct pt_regs *regs, struct ksignal *ksig,
unsigned long __user *rc, void __user *frame)
{
unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
unsigned long retcode;
int thumb = 0;
unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
cpsr |= PSR_ENDSTATE;
/*
* Maybe we need to deliver a 32-bit signal to a 26-bit task.
*/
if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
#ifdef CONFIG_ARM_THUMB
if (elf_hwcap & HWCAP_THUMB) {
/*
* The LSB of the handler determines if we're going to
* be using THUMB or ARM mode for this signal handler.
*/
thumb = handler & 1;
#if __LINUX_ARM_ARCH__ >= 6
/*
* Clear the If-Then Thumb-2 execution state. ARM spec
* requires this to be all 000s in ARM mode. Snapdragon
* S4/Krait misbehaves on a Thumb=>ARM signal transition
* without this.
*
* We must do this whenever we are running on a Thumb-2
* capable CPU, which includes ARMv6T2. However, we elect
* to do this whenever we're on an ARMv6 or later CPU for
* simplicity.
*/
cpsr &= ~PSR_IT_MASK;
#endif
if (thumb) {
cpsr |= PSR_T_BIT;
} else
cpsr &= ~PSR_T_BIT;
}
#endif
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
retcode = (unsigned long)ksig->ka.sa.sa_restorer;
} else {
unsigned int idx = thumb << 1;
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
idx += 3;
/*
* Put the sigreturn code on the stack no matter which return
* mechanism we use in order to remain ABI compliant
*/
if (__put_user(sigreturn_codes[idx], rc) ||
__put_user(sigreturn_codes[idx+1], rc+1))
return 1;
#ifdef CONFIG_MMU
if (cpsr & MODE32_BIT) {
struct mm_struct *mm = current->mm;
/*
* 32-bit code can use the signal return page
* except when the MPU has protected the vectors
* page from PL0
*/
retcode = mm->context.sigpage + signal_return_offset +
(idx << 2) + thumb;
} else
#endif
{
/*
* Ensure that the instruction cache sees
* the return code written onto the stack.
*/
flush_icache_range((unsigned long)rc,
(unsigned long)(rc + 2));
retcode = ((unsigned long)rc) + thumb;
}
}
regs->ARM_r0 = map_sig(ksig->sig);
regs->ARM_sp = (unsigned long)frame;
regs->ARM_lr = retcode;
regs->ARM_pc = handler;
regs->ARM_cpsr = cpsr;
return 0;
}
static int
setup_rt_frame(int signo, struct k_sigaction *ka, siginfo_t *info,
sigset_t *set, struct pt_regs *regs)
{
struct rt_sigframe __user *sf;
unsigned int magic = 0;
int err = 0;
sf = get_sigframe(ka, regs, sizeof(struct rt_sigframe));
if (!sf)
return 1;
/*
* w/o SA_SIGINFO, struct ucontext is partially populated (only
* uc_mcontext/uc_sigmask) for kernel's normal user state preservation
* during signal handler execution. This works for SA_SIGINFO as well
* although the semantics are now overloaded (the same reg state can be
* inspected by userland: but are they allowed to fiddle with it ?
*/
err |= stash_usr_regs(sf, regs, set);
/*
* SA_SIGINFO requires 3 args to signal handler:
* #1: sig-no (common to any handler)
* #2: struct siginfo
* #3: struct ucontext (completely populated)
*/
if (unlikely(ka->sa.sa_flags & SA_SIGINFO)) {
err |= copy_siginfo_to_user(&sf->info, info);
err |= __put_user(0, &sf->uc.uc_flags);
err |= __put_user(NULL, &sf->uc.uc_link);
err |= __save_altstack(&sf->uc.uc_stack, regs->sp);
/* setup args 2 and 3 for user mode handler */
regs->r1 = (unsigned long)&sf->info;
regs->r2 = (unsigned long)&sf->uc;
/*
* small optim to avoid unconditonally calling do_sigaltstack
* in sigreturn path, now that we only have rt_sigreturn
*/
magic = MAGIC_SIGALTSTK;
}
err |= __put_user(magic, &sf->sigret_magic);
if (err)
return err;
/* #1 arg to the user Signal handler */
regs->r0 = map_sig(signo);
/* setup PC of user space signal handler */
regs->ret = (unsigned long)ka->sa.sa_handler;
/*
* handler returns using sigreturn stub provided already by userpsace
*/
BUG_ON(!(ka->sa.sa_flags & SA_RESTORER));
regs->blink = (unsigned long)ka->sa.sa_restorer;
/* User Stack for signal handler will be above the frame just carved */
regs->sp = (unsigned long)sf;
/*
* Bug 94183, Clear the DE bit, so that when signal handler
* starts to run, it doesn't use BTA
*/
regs->status32 &= ~STATUS_DE_MASK;
regs->status32 |= STATUS_L_MASK;
return err;
}
static int
setup_return(struct pt_regs *regs, struct ksignal *ksig,
unsigned long __user *rc, void __user *frame)
{
unsigned long handler = (unsigned long)ksig->ka.sa.sa_handler;
unsigned long retcode;
int thumb = 0;
unsigned long cpsr = regs->ARM_cpsr & ~(PSR_f | PSR_E_BIT);
cpsr |= PSR_ENDSTATE;
/*
* Maybe we need to deliver a 32-bit signal to a 26-bit task.
*/
if (ksig->ka.sa.sa_flags & SA_THIRTYTWO)
cpsr = (cpsr & ~MODE_MASK) | USR_MODE;
#ifdef CONFIG_ARM_THUMB
if (elf_hwcap & HWCAP_THUMB) {
/*
* The LSB of the handler determines if we're going to
* be using THUMB or ARM mode for this signal handler.
*/
thumb = handler & 1;
if (thumb) {
cpsr |= PSR_T_BIT;
#if __LINUX_ARM_ARCH__ >= 7
/* clear the If-Then Thumb-2 execution state */
cpsr &= ~PSR_IT_MASK;
#endif
} else
cpsr &= ~PSR_T_BIT;
}
#endif
if (ksig->ka.sa.sa_flags & SA_RESTORER) {
retcode = (unsigned long)ksig->ka.sa.sa_restorer;
} else {
unsigned int idx = thumb << 1;
if (ksig->ka.sa.sa_flags & SA_SIGINFO)
idx += 3;
if (__put_user(sigreturn_codes[idx], rc) ||
__put_user(sigreturn_codes[idx+1], rc+1))
return 1;
#ifdef CONFIG_MMU
if (cpsr & MODE32_BIT) {
struct mm_struct *mm = current->mm;
/*
* 32-bit code can use the signal return page
* except when the MPU has protected the vectors
* page from PL0
*/
retcode = mm->context.sigpage + signal_return_offset +
(idx << 2) + thumb;
} else
#endif
{
/*
* Ensure that the instruction cache sees
* the return code written onto the stack.
*/
flush_icache_range((unsigned long)rc,
(unsigned long)(rc + 2));
retcode = ((unsigned long)rc) + thumb;
}
}
regs->ARM_r0 = map_sig(ksig->sig);
regs->ARM_sp = (unsigned long)frame;
regs->ARM_lr = retcode;
regs->ARM_pc = handler;
regs->ARM_cpsr = cpsr;
return 0;
}
