unsigned long get_tm_stackpointer(struct pt_regs *regs)
{
/* When in an active transaction that takes a signal, we need to be
* careful with the stack. It's possible that the stack has moved back
* up after the tbegin. The obvious case here is when the tbegin is
* called inside a function that returns before a tend. In this case,
* the stack is part of the checkpointed transactional memory state.
* If we write over this non transactionally or in suspend, we are in
* trouble because if we get a tm abort, the program counter and stack
* pointer will be back at the tbegin but our in memory stack won't be
* valid anymore.
*
* To avoid this, when taking a signal in an active transaction, we
* need to use the stack pointer from the checkpointed state, rather
* than the speculated state. This ensures that the signal context
* (written tm suspended) will be written below the stack required for
* the rollback. The transaction is aborted becuase of the treclaim,
* so any memory written between the tbegin and the signal will be
* rolled back anyway.
*
* For signals taken in non-TM or suspended mode, we use the
* normal/non-checkpointed stack pointer.
*/
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (MSR_TM_ACTIVE(regs->msr)) {
tm_enable();
tm_reclaim(¤t->thread, regs->msr, TM_CAUSE_SIGNAL);
if (MSR_TM_TRANSACTIONAL(regs->msr))
return current->thread.ckpt_regs.gpr[1];
}
#endif
return regs->gpr[1];
}
static long restore_tm_sigcontexts(struct pt_regs *regs,
struct sigcontext __user *sc,
struct sigcontext __user *tm_sc)
{
#ifdef CONFIG_ALTIVEC
elf_vrreg_t __user *v_regs, *tm_v_regs;
#endif
unsigned long err = 0;
unsigned long msr;
#ifdef CONFIG_VSX
int i;
#endif
/* copy the GPRs */
err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
err |= __copy_from_user(¤t->thread.ckpt_regs, sc->gp_regs,
sizeof(regs->gpr));
/*
* TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
* TEXASR was set by the signal delivery reclaim, as was TFIAR.
* Users doing anything abhorrent like thread-switching w/ signals for
* TM-Suspended code will have to back TEXASR/TFIAR up themselves.
* For the case of getting a signal and simply returning from it,
* we don't need to re-copy them here.
*/
err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
err |= __get_user(current->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
/* get MSR separately, transfer the LE bit if doing signal return */
err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
/* pull in MSR TM from user context */
regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK);
/* pull in MSR LE from user context */
regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
/* The following non-GPR non-FPR non-VR state is also checkpointed: */
err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
err |= __get_user(current->thread.ckpt_regs.ctr,
&sc->gp_regs[PT_CTR]);
err |= __get_user(current->thread.ckpt_regs.link,
&sc->gp_regs[PT_LNK]);
err |= __get_user(current->thread.ckpt_regs.xer,
&sc->gp_regs[PT_XER]);
err |= __get_user(current->thread.ckpt_regs.ccr,
&sc->gp_regs[PT_CCR]);
/* These regs are not checkpointed; they can go in 'regs'. */
err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
/*
* Do this before updating the thread state in
* current->thread.fpr/vr. That way, if we get preempted
* and another task grabs the FPU/Altivec, it won't be
* tempted to save the current CPU state into the thread_struct
* and corrupt what we are writing there.
*/
discard_lazy_cpu_state();
/*
* Force reload of FP/VEC.
* This has to be done before copying stuff into current->thread.fpr/vr
* for the reasons explained in the previous comment.
*/
regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
#ifdef CONFIG_ALTIVEC
err |= __get_user(v_regs, &sc->v_regs);
err |= __get_user(tm_v_regs, &tm_sc->v_regs);
if (err)
return err;
if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
return -EFAULT;
if (tm_v_regs && !access_ok(VERIFY_READ,
tm_v_regs, 34 * sizeof(vector128)))
return -EFAULT;
/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
err |= __copy_from_user(¤t->thread.vr_state, v_regs,
33 * sizeof(vector128));
err |= __copy_from_user(¤t->thread.transact_vr, tm_v_regs,
33 * sizeof(vector128));
}
else if (current->thread.used_vr) {
memset(¤t->thread.vr_state, 0, 33 * sizeof(vector128));
memset(¤t->thread.transact_vr, 0, 33 * sizeof(vector128));
}
/* Always get VRSAVE back */
if (v_regs != NULL && tm_v_regs != NULL) {
err |= __get_user(current->thread.vrsave,
(u32 __user *)&v_regs[33]);
err |= __get_user(current->thread.transact_vrsave,
(u32 __user *)&tm_v_regs[33]);
}
else {
current->thread.vrsave = 0;
current->thread.transact_vrsave = 0;
}
if (cpu_has_feature(CPU_FTR_ALTIVEC))
mtspr(SPRN_VRSAVE, current->thread.vrsave);
#endif /* CONFIG_ALTIVEC */
/* restore floating point */
err |= copy_fpr_from_user(current, &sc->fp_regs);
err |= copy_transact_fpr_from_user(current, &tm_sc->fp_regs);
#ifdef CONFIG_VSX
/*
* Get additional VSX data. Update v_regs to point after the
* VMX data. Copy VSX low doubleword from userspace to local
* buffer for formatting, then into the taskstruct.
*/
if (v_regs && ((msr & MSR_VSX) != 0)) {
v_regs += ELF_NVRREG;
tm_v_regs += ELF_NVRREG;
err |= copy_vsx_from_user(current, v_regs);
err |= copy_transact_vsx_from_user(current, tm_v_regs);
} else {
for (i = 0; i < 32 ; i++) {
current->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
current->thread.transact_fp.fpr[i][TS_VSRLOWOFFSET] = 0;
}
}
#endif
tm_enable();
/* Make sure the transaction is marked as failed */
current->thread.tm_texasr |= TEXASR_FS;
/* This loads the checkpointed FP/VEC state, if used */
tm_recheckpoint(¤t->thread, msr);
/* This loads the speculative FP/VEC state, if used */
if (msr & MSR_FP) {
do_load_up_transact_fpu(¤t->thread);
regs->msr |= (MSR_FP | current->thread.fpexc_mode);
}
#ifdef CONFIG_ALTIVEC
if (msr & MSR_VEC) {
do_load_up_transact_altivec(¤t->thread);
regs->msr |= MSR_VEC;
}
#endif
return err;
}
static long restore_tm_sigcontexts(struct task_struct *tsk,
struct sigcontext __user *sc,
struct sigcontext __user *tm_sc)
{
#ifdef CONFIG_ALTIVEC
elf_vrreg_t __user *v_regs, *tm_v_regs;
#endif
unsigned long err = 0;
unsigned long msr;
struct pt_regs *regs = tsk->thread.regs;
#ifdef CONFIG_VSX
int i;
#endif
BUG_ON(tsk != current);
if (tm_suspend_disabled)
return -EINVAL;
/* copy the GPRs */
err |= __copy_from_user(regs->gpr, tm_sc->gp_regs, sizeof(regs->gpr));
err |= __copy_from_user(&tsk->thread.ckpt_regs, sc->gp_regs,
sizeof(regs->gpr));
/*
* TFHAR is restored from the checkpointed 'wound-back' ucontext's NIP.
* TEXASR was set by the signal delivery reclaim, as was TFIAR.
* Users doing anything abhorrent like thread-switching w/ signals for
* TM-Suspended code will have to back TEXASR/TFIAR up themselves.
* For the case of getting a signal and simply returning from it,
* we don't need to re-copy them here.
*/
err |= __get_user(regs->nip, &tm_sc->gp_regs[PT_NIP]);
err |= __get_user(tsk->thread.tm_tfhar, &sc->gp_regs[PT_NIP]);
/* get MSR separately, transfer the LE bit if doing signal return */
err |= __get_user(msr, &sc->gp_regs[PT_MSR]);
/* Don't allow reserved mode. */
if (MSR_TM_RESV(msr))
return -EINVAL;
/* pull in MSR TS bits from user context */
regs->msr = (regs->msr & ~MSR_TS_MASK) | (msr & MSR_TS_MASK);
/*
* Ensure that TM is enabled in regs->msr before we leave the signal
* handler. It could be the case that (a) user disabled the TM bit
* through the manipulation of the MSR bits in uc_mcontext or (b) the
* TM bit was disabled because a sufficient number of context switches
* happened whilst in the signal handler and load_tm overflowed,
* disabling the TM bit. In either case we can end up with an illegal
* TM state leading to a TM Bad Thing when we return to userspace.
*/
regs->msr |= MSR_TM;
/* pull in MSR LE from user context */
regs->msr = (regs->msr & ~MSR_LE) | (msr & MSR_LE);
/* The following non-GPR non-FPR non-VR state is also checkpointed: */
err |= __get_user(regs->ctr, &tm_sc->gp_regs[PT_CTR]);
err |= __get_user(regs->link, &tm_sc->gp_regs[PT_LNK]);
err |= __get_user(regs->xer, &tm_sc->gp_regs[PT_XER]);
err |= __get_user(regs->ccr, &tm_sc->gp_regs[PT_CCR]);
err |= __get_user(tsk->thread.ckpt_regs.ctr,
&sc->gp_regs[PT_CTR]);
err |= __get_user(tsk->thread.ckpt_regs.link,
&sc->gp_regs[PT_LNK]);
err |= __get_user(tsk->thread.ckpt_regs.xer,
&sc->gp_regs[PT_XER]);
err |= __get_user(tsk->thread.ckpt_regs.ccr,
&sc->gp_regs[PT_CCR]);
/* These regs are not checkpointed; they can go in 'regs'. */
err |= __get_user(regs->trap, &sc->gp_regs[PT_TRAP]);
err |= __get_user(regs->dar, &sc->gp_regs[PT_DAR]);
err |= __get_user(regs->dsisr, &sc->gp_regs[PT_DSISR]);
err |= __get_user(regs->result, &sc->gp_regs[PT_RESULT]);
/*
* Force reload of FP/VEC.
* This has to be done before copying stuff into tsk->thread.fpr/vr
* for the reasons explained in the previous comment.
*/
regs->msr &= ~(MSR_FP | MSR_FE0 | MSR_FE1 | MSR_VEC | MSR_VSX);
#ifdef CONFIG_ALTIVEC
err |= __get_user(v_regs, &sc->v_regs);
err |= __get_user(tm_v_regs, &tm_sc->v_regs);
if (err)
return err;
if (v_regs && !access_ok(VERIFY_READ, v_regs, 34 * sizeof(vector128)))
return -EFAULT;
if (tm_v_regs && !access_ok(VERIFY_READ,
tm_v_regs, 34 * sizeof(vector128)))
return -EFAULT;
/* Copy 33 vec registers (vr0..31 and vscr) from the stack */
if (v_regs != NULL && tm_v_regs != NULL && (msr & MSR_VEC) != 0) {
err |= __copy_from_user(&tsk->thread.ckvr_state, v_regs,
33 * sizeof(vector128));
err |= __copy_from_user(&tsk->thread.vr_state, tm_v_regs,
33 * sizeof(vector128));
current->thread.used_vr = true;
}
else if (tsk->thread.used_vr) {
memset(&tsk->thread.vr_state, 0, 33 * sizeof(vector128));
memset(&tsk->thread.ckvr_state, 0, 33 * sizeof(vector128));
}
/* Always get VRSAVE back */
if (v_regs != NULL && tm_v_regs != NULL) {
err |= __get_user(tsk->thread.ckvrsave,
(u32 __user *)&v_regs[33]);
err |= __get_user(tsk->thread.vrsave,
(u32 __user *)&tm_v_regs[33]);
}
else {
tsk->thread.vrsave = 0;
tsk->thread.ckvrsave = 0;
}
if (cpu_has_feature(CPU_FTR_ALTIVEC))
mtspr(SPRN_VRSAVE, tsk->thread.vrsave);
#endif /* CONFIG_ALTIVEC */
/* restore floating point */
err |= copy_fpr_from_user(tsk, &tm_sc->fp_regs);
err |= copy_ckfpr_from_user(tsk, &sc->fp_regs);
#ifdef CONFIG_VSX
/*
* Get additional VSX data. Update v_regs to point after the
* VMX data. Copy VSX low doubleword from userspace to local
* buffer for formatting, then into the taskstruct.
*/
if (v_regs && ((msr & MSR_VSX) != 0)) {
v_regs += ELF_NVRREG;
tm_v_regs += ELF_NVRREG;
err |= copy_vsx_from_user(tsk, tm_v_regs);
err |= copy_ckvsx_from_user(tsk, v_regs);
tsk->thread.used_vsr = true;
} else {
for (i = 0; i < 32 ; i++) {
tsk->thread.fp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
tsk->thread.ckfp_state.fpr[i][TS_VSRLOWOFFSET] = 0;
}
}
#endif
tm_enable();
/* Make sure the transaction is marked as failed */
tsk->thread.tm_texasr |= TEXASR_FS;
/* This loads the checkpointed FP/VEC state, if used */
tm_recheckpoint(&tsk->thread);
msr_check_and_set(msr & (MSR_FP | MSR_VEC));
if (msr & MSR_FP) {
load_fp_state(&tsk->thread.fp_state);
regs->msr |= (MSR_FP | tsk->thread.fpexc_mode);
}
if (msr & MSR_VEC) {
load_vr_state(&tsk->thread.vr_state);
regs->msr |= MSR_VEC;
}
return err;
}