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linux/arch/powerpc/kernel/process.c
Sam bobroff 96d0161086 powerpc: Correct DSCR during TM context switch 
Correct the DSCR SPR becoming temporarily corrupted if a task is
context switched during a transaction.

The problem occurs while suspending the task and is caused by saving
the DSCR to thread.dscr after it has already been set to the CPU's
default value:

__switch_to() calls __switch_to_tm()
	which calls tm_reclaim_task()
	which calls tm_reclaim_thread()
	which calls tm_reclaim()
		where the DSCR is set to the CPU's default
__switch_to() calls _switch()
		where thread.dscr is set to the DSCR

When the task is resumed, it's transaction will be doomed (as usual)
and the DSCR SPR will be corrupted, although the checkpointed value
will be correct. Therefore the DSCR will be immediately corrected by
the transaction aborting, unless it has been suspended. In that case
the incorrect value can be seen by the task until it resumes the
transaction.

The fix is to treat the DSCR similarly to the TAR and save it early
in __switch_to().

A program exposing the problem is added to the kernel self tests as:
tools/testing/selftests/powerpc/tm/tm-resched-dscr.

Signed-off-by: Sam Bobroff <sam.bobroff@au1.ibm.com>
CC: <stable@vger.kernel.org> [v3.10+]
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2014-06-11 17:02:56 +10:00

1671 lines
43 KiB
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/*
* Derived from "arch/i386/kernel/process.c"
* Copyright (C) 1995 Linus Torvalds
*
* Updated and modified by Cort Dougan (cort@cs.nmt.edu) and
* Paul Mackerras (paulus@cs.anu.edu.au)
*
* PowerPC version
* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version
* 2 of the License, or (at your option) any later version.
*/
#include <linux/errno.h>
#include <linux/sched.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/stddef.h>
#include <linux/unistd.h>
#include <linux/ptrace.h>
#include <linux/slab.h>
#include <linux/user.h>
#include <linux/elf.h>
#include <linux/prctl.h>
#include <linux/init_task.h>
#include <linux/export.h>
#include <linux/kallsyms.h>
#include <linux/mqueue.h>
#include <linux/hardirq.h>
#include <linux/utsname.h>
#include <linux/ftrace.h>
#include <linux/kernel_stat.h>
#include <linux/personality.h>
#include <linux/random.h>
#include <linux/hw_breakpoint.h>
#include <asm/pgtable.h>
#include <asm/uaccess.h>
#include <asm/io.h>
#include <asm/processor.h>
#include <asm/mmu.h>
#include <asm/prom.h>
#include <asm/machdep.h>
#include <asm/time.h>
#include <asm/runlatch.h>
#include <asm/syscalls.h>
#include <asm/switch_to.h>
#include <asm/tm.h>
#include <asm/debug.h>
#ifdef CONFIG_PPC64
#include <asm/firmware.h>
#endif
#include <asm/code-patching.h>
#include <linux/kprobes.h>
#include <linux/kdebug.h>
/* Transactional Memory debug */
#ifdef TM_DEBUG_SW
#define TM_DEBUG(x...) printk(KERN_INFO x)
#else
#define TM_DEBUG(x...) do { } while(0)
#endif
extern unsigned long _get_SP(void);
#ifndef CONFIG_SMP
struct task_struct *last_task_used_math = NULL;
struct task_struct *last_task_used_altivec = NULL;
struct task_struct *last_task_used_vsx = NULL;
struct task_struct *last_task_used_spe = NULL;
#endif
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
void giveup_fpu_maybe_transactional(struct task_struct *tsk)
{
/*
* If we are saving the current thread's registers, and the
* thread is in a transactional state, set the TIF_RESTORE_TM
* bit so that we know to restore the registers before
* returning to userspace.
*/
if (tsk == current && tsk->thread.regs &&
MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
!test_thread_flag(TIF_RESTORE_TM)) {
tsk->thread.tm_orig_msr = tsk->thread.regs->msr;
set_thread_flag(TIF_RESTORE_TM);
}
giveup_fpu(tsk);
}
void giveup_altivec_maybe_transactional(struct task_struct *tsk)
{
/*
* If we are saving the current thread's registers, and the
* thread is in a transactional state, set the TIF_RESTORE_TM
* bit so that we know to restore the registers before
* returning to userspace.
*/
if (tsk == current && tsk->thread.regs &&
MSR_TM_ACTIVE(tsk->thread.regs->msr) &&
!test_thread_flag(TIF_RESTORE_TM)) {
tsk->thread.tm_orig_msr = tsk->thread.regs->msr;
set_thread_flag(TIF_RESTORE_TM);
}
giveup_altivec(tsk);
}
#else
#define giveup_fpu_maybe_transactional(tsk) giveup_fpu(tsk)
#define giveup_altivec_maybe_transactional(tsk) giveup_altivec(tsk)
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
#ifdef CONFIG_PPC_FPU
/*
* Make sure the floating-point register state in the
* the thread_struct is up to date for task tsk.
*/
void flush_fp_to_thread(struct task_struct *tsk)
{
if (tsk->thread.regs) {
/*
* We need to disable preemption here because if we didn't,
* another process could get scheduled after the regs->msr
* test but before we have finished saving the FP registers
* to the thread_struct. That process could take over the
* FPU, and then when we get scheduled again we would store
* bogus values for the remaining FP registers.
*/
preempt_disable();
if (tsk->thread.regs->msr & MSR_FP) {
#ifdef CONFIG_SMP
/*
* This should only ever be called for current or
* for a stopped child process. Since we save away
* the FP register state on context switch on SMP,
* there is something wrong if a stopped child appears
* to still have its FP state in the CPU registers.
*/
BUG_ON(tsk != current);
#endif
giveup_fpu_maybe_transactional(tsk);
}
preempt_enable();
}
}
EXPORT_SYMBOL_GPL(flush_fp_to_thread);
#endif /* CONFIG_PPC_FPU */
void enable_kernel_fp(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_FP))
giveup_fpu_maybe_transactional(current);
else
giveup_fpu(NULL); /* just enables FP for kernel */
#else
giveup_fpu_maybe_transactional(last_task_used_math);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_fp);
#ifdef CONFIG_ALTIVEC
void enable_kernel_altivec(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_VEC))
giveup_altivec_maybe_transactional(current);
else
giveup_altivec_notask();
#else
giveup_altivec_maybe_transactional(last_task_used_altivec);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_altivec);
/*
* Make sure the VMX/Altivec register state in the
* the thread_struct is up to date for task tsk.
*/
void flush_altivec_to_thread(struct task_struct *tsk)
{
if (tsk->thread.regs) {
preempt_disable();
if (tsk->thread.regs->msr & MSR_VEC) {
#ifdef CONFIG_SMP
BUG_ON(tsk != current);
#endif
giveup_altivec_maybe_transactional(tsk);
}
preempt_enable();
}
}
EXPORT_SYMBOL_GPL(flush_altivec_to_thread);
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
#if 0
/* not currently used, but some crazy RAID module might want to later */
void enable_kernel_vsx(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_VSX))
giveup_vsx(current);
else
giveup_vsx(NULL); /* just enable vsx for kernel - force */
#else
giveup_vsx(last_task_used_vsx);
#endif /* CONFIG_SMP */
}
EXPORT_SYMBOL(enable_kernel_vsx);
#endif
void giveup_vsx(struct task_struct *tsk)
{
giveup_fpu_maybe_transactional(tsk);
giveup_altivec_maybe_transactional(tsk);
__giveup_vsx(tsk);
}
void flush_vsx_to_thread(struct task_struct *tsk)
{
if (tsk->thread.regs) {
preempt_disable();
if (tsk->thread.regs->msr & MSR_VSX) {
#ifdef CONFIG_SMP
BUG_ON(tsk != current);
#endif
giveup_vsx(tsk);
}
preempt_enable();
}
}
EXPORT_SYMBOL_GPL(flush_vsx_to_thread);
#endif /* CONFIG_VSX */
#ifdef CONFIG_SPE
void enable_kernel_spe(void)
{
WARN_ON(preemptible());
#ifdef CONFIG_SMP
if (current->thread.regs && (current->thread.regs->msr & MSR_SPE))
giveup_spe(current);
else
giveup_spe(NULL); /* just enable SPE for kernel - force */
#else
giveup_spe(last_task_used_spe);
#endif /* __SMP __ */
}
EXPORT_SYMBOL(enable_kernel_spe);
void flush_spe_to_thread(struct task_struct *tsk)
{
if (tsk->thread.regs) {
preempt_disable();
if (tsk->thread.regs->msr & MSR_SPE) {
#ifdef CONFIG_SMP
BUG_ON(tsk != current);
#endif
tsk->thread.spefscr = mfspr(SPRN_SPEFSCR);
giveup_spe(tsk);
}
preempt_enable();
}
}
#endif /* CONFIG_SPE */
#ifndef CONFIG_SMP
/*
* If we are doing lazy switching of CPU state (FP, altivec or SPE),
* and the current task has some state, discard it.
*/
void discard_lazy_cpu_state(void)
{
preempt_disable();
if (last_task_used_math == current)
last_task_used_math = NULL;
#ifdef CONFIG_ALTIVEC
if (last_task_used_altivec == current)
last_task_used_altivec = NULL;
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
if (last_task_used_vsx == current)
last_task_used_vsx = NULL;
#endif /* CONFIG_VSX */
#ifdef CONFIG_SPE
if (last_task_used_spe == current)
last_task_used_spe = NULL;
#endif
preempt_enable();
}
#endif /* CONFIG_SMP */
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
void do_send_trap(struct pt_regs *regs, unsigned long address,
unsigned long error_code, int signal_code, int breakpt)
{
siginfo_t info;
current->thread.trap_nr = signal_code;
if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
11, SIGSEGV) == NOTIFY_STOP)
return;
/* Deliver the signal to userspace */
info.si_signo = SIGTRAP;
info.si_errno = breakpt; /* breakpoint or watchpoint id */
info.si_code = signal_code;
info.si_addr = (void __user *)address;
force_sig_info(SIGTRAP, &info, current);
}
#else /* !CONFIG_PPC_ADV_DEBUG_REGS */
void do_break (struct pt_regs *regs, unsigned long address,
unsigned long error_code)
{
siginfo_t info;
current->thread.trap_nr = TRAP_HWBKPT;
if (notify_die(DIE_DABR_MATCH, "dabr_match", regs, error_code,
11, SIGSEGV) == NOTIFY_STOP)
return;
if (debugger_break_match(regs))
return;
/* Clear the breakpoint */
hw_breakpoint_disable();
/* Deliver the signal to userspace */
info.si_signo = SIGTRAP;
info.si_errno = 0;
info.si_code = TRAP_HWBKPT;
info.si_addr = (void __user *)address;
force_sig_info(SIGTRAP, &info, current);
}
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
static DEFINE_PER_CPU(struct arch_hw_breakpoint, current_brk);
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
/*
* Set the debug registers back to their default "safe" values.
*/
static void set_debug_reg_defaults(struct thread_struct *thread)
{
thread->debug.iac1 = thread->debug.iac2 = 0;
#if CONFIG_PPC_ADV_DEBUG_IACS > 2
thread->debug.iac3 = thread->debug.iac4 = 0;
#endif
thread->debug.dac1 = thread->debug.dac2 = 0;
#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
thread->debug.dvc1 = thread->debug.dvc2 = 0;
#endif
thread->debug.dbcr0 = 0;
#ifdef CONFIG_BOOKE
/*
* Force User/Supervisor bits to b11 (user-only MSR[PR]=1)
*/
thread->debug.dbcr1 = DBCR1_IAC1US | DBCR1_IAC2US |
DBCR1_IAC3US | DBCR1_IAC4US;
/*
* Force Data Address Compare User/Supervisor bits to be User-only
* (0b11 MSR[PR]=1) and set all other bits in DBCR2 register to be 0.
*/
thread->debug.dbcr2 = DBCR2_DAC1US | DBCR2_DAC2US;
#else
thread->debug.dbcr1 = 0;
#endif
}
static void prime_debug_regs(struct debug_reg *debug)
{
/*
* We could have inherited MSR_DE from userspace, since
* it doesn't get cleared on exception entry. Make sure
* MSR_DE is clear before we enable any debug events.
*/
mtmsr(mfmsr() & ~MSR_DE);
mtspr(SPRN_IAC1, debug->iac1);
mtspr(SPRN_IAC2, debug->iac2);
#if CONFIG_PPC_ADV_DEBUG_IACS > 2
mtspr(SPRN_IAC3, debug->iac3);
mtspr(SPRN_IAC4, debug->iac4);
#endif
mtspr(SPRN_DAC1, debug->dac1);
mtspr(SPRN_DAC2, debug->dac2);
#if CONFIG_PPC_ADV_DEBUG_DVCS > 0
mtspr(SPRN_DVC1, debug->dvc1);
mtspr(SPRN_DVC2, debug->dvc2);
#endif
mtspr(SPRN_DBCR0, debug->dbcr0);
mtspr(SPRN_DBCR1, debug->dbcr1);
#ifdef CONFIG_BOOKE
mtspr(SPRN_DBCR2, debug->dbcr2);
#endif
}
/*
* Unless neither the old or new thread are making use of the
* debug registers, set the debug registers from the values
* stored in the new thread.
*/
void switch_booke_debug_regs(struct debug_reg *new_debug)
{
if ((current->thread.debug.dbcr0 & DBCR0_IDM)
|| (new_debug->dbcr0 & DBCR0_IDM))
prime_debug_regs(new_debug);
}
EXPORT_SYMBOL_GPL(switch_booke_debug_regs);
#else /* !CONFIG_PPC_ADV_DEBUG_REGS */
#ifndef CONFIG_HAVE_HW_BREAKPOINT
static void set_debug_reg_defaults(struct thread_struct *thread)
{
thread->hw_brk.address = 0;
thread->hw_brk.type = 0;
set_breakpoint(&thread->hw_brk);
}
#endif /* !CONFIG_HAVE_HW_BREAKPOINT */
#endif /* CONFIG_PPC_ADV_DEBUG_REGS */
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
{
mtspr(SPRN_DAC1, dabr);
#ifdef CONFIG_PPC_47x
isync();
#endif
return 0;
}
#elif defined(CONFIG_PPC_BOOK3S)
static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
{
mtspr(SPRN_DABR, dabr);
if (cpu_has_feature(CPU_FTR_DABRX))
mtspr(SPRN_DABRX, dabrx);
return 0;
}
#else
static inline int __set_dabr(unsigned long dabr, unsigned long dabrx)
{
return -EINVAL;
}
#endif
static inline int set_dabr(struct arch_hw_breakpoint *brk)
{
unsigned long dabr, dabrx;
dabr = brk->address | (brk->type & HW_BRK_TYPE_DABR);
dabrx = ((brk->type >> 3) & 0x7);
if (ppc_md.set_dabr)
return ppc_md.set_dabr(dabr, dabrx);
return __set_dabr(dabr, dabrx);
}
static inline int set_dawr(struct arch_hw_breakpoint *brk)
{
unsigned long dawr, dawrx, mrd;
dawr = brk->address;
dawrx = (brk->type & (HW_BRK_TYPE_READ | HW_BRK_TYPE_WRITE)) \
<< (63 - 58); //* read/write bits */
dawrx |= ((brk->type & (HW_BRK_TYPE_TRANSLATE)) >> 2) \
<< (63 - 59); //* translate */
dawrx |= (brk->type & (HW_BRK_TYPE_PRIV_ALL)) \
>> 3; //* PRIM bits */
/* dawr length is stored in field MDR bits 48:53. Matches range in
doublewords (64 bits) baised by -1 eg. 0b000000=1DW and
0b111111=64DW.
brk->len is in bytes.
This aligns up to double word size, shifts and does the bias.
*/
mrd = ((brk->len + 7) >> 3) - 1;
dawrx |= (mrd & 0x3f) << (63 - 53);
if (ppc_md.set_dawr)
return ppc_md.set_dawr(dawr, dawrx);
mtspr(SPRN_DAWR, dawr);
mtspr(SPRN_DAWRX, dawrx);
return 0;
}
void __set_breakpoint(struct arch_hw_breakpoint *brk)
{
__get_cpu_var(current_brk) = *brk;
if (cpu_has_feature(CPU_FTR_DAWR))
set_dawr(brk);
else
set_dabr(brk);
}
void set_breakpoint(struct arch_hw_breakpoint *brk)
{
preempt_disable();
__set_breakpoint(brk);
preempt_enable();
}
#ifdef CONFIG_PPC64
DEFINE_PER_CPU(struct cpu_usage, cpu_usage_array);
#endif
static inline bool hw_brk_match(struct arch_hw_breakpoint *a,
struct arch_hw_breakpoint *b)
{
if (a->address != b->address)
return false;
if (a->type != b->type)
return false;
if (a->len != b->len)
return false;
return true;
}
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
static void tm_reclaim_thread(struct thread_struct *thr,
struct thread_info *ti, uint8_t cause)
{
unsigned long msr_diff = 0;
/*
* If FP/VSX registers have been already saved to the
* thread_struct, move them to the transact_fp array.
* We clear the TIF_RESTORE_TM bit since after the reclaim
* the thread will no longer be transactional.
*/
if (test_ti_thread_flag(ti, TIF_RESTORE_TM)) {
msr_diff = thr->tm_orig_msr & ~thr->regs->msr;
if (msr_diff & MSR_FP)
memcpy(&thr->transact_fp, &thr->fp_state,
sizeof(struct thread_fp_state));
if (msr_diff & MSR_VEC)
memcpy(&thr->transact_vr, &thr->vr_state,
sizeof(struct thread_vr_state));
clear_ti_thread_flag(ti, TIF_RESTORE_TM);
msr_diff &= MSR_FP | MSR_VEC | MSR_VSX | MSR_FE0 | MSR_FE1;
}
tm_reclaim(thr, thr->regs->msr, cause);
/* Having done the reclaim, we now have the checkpointed
* FP/VSX values in the registers. These might be valid
* even if we have previously called enable_kernel_fp() or
* flush_fp_to_thread(), so update thr->regs->msr to
* indicate their current validity.
*/
thr->regs->msr |= msr_diff;
}
void tm_reclaim_current(uint8_t cause)
{
tm_enable();
tm_reclaim_thread(&current->thread, current_thread_info(), cause);
}
static inline void tm_reclaim_task(struct task_struct *tsk)
{
/* We have to work out if we're switching from/to a task that's in the
* middle of a transaction.
*
* In switching we need to maintain a 2nd register state as
* oldtask->thread.ckpt_regs. We tm_reclaim(oldproc); this saves the
* checkpointed (tbegin) state in ckpt_regs and saves the transactional
* (current) FPRs into oldtask->thread.transact_fpr[].
*
* We also context switch (save) TFHAR/TEXASR/TFIAR in here.
*/
struct thread_struct *thr = &tsk->thread;
if (!thr->regs)
return;
if (!MSR_TM_ACTIVE(thr->regs->msr))
goto out_and_saveregs;
/* Stash the original thread MSR, as giveup_fpu et al will
* modify it. We hold onto it to see whether the task used
* FP & vector regs. If the TIF_RESTORE_TM flag is set,
* tm_orig_msr is already set.
*/
if (!test_ti_thread_flag(task_thread_info(tsk), TIF_RESTORE_TM))
thr->tm_orig_msr = thr->regs->msr;
TM_DEBUG("--- tm_reclaim on pid %d (NIP=%lx, "
"ccr=%lx, msr=%lx, trap=%lx)\n",
tsk->pid, thr->regs->nip,
thr->regs->ccr, thr->regs->msr,
thr->regs->trap);
tm_reclaim_thread(thr, task_thread_info(tsk), TM_CAUSE_RESCHED);
TM_DEBUG("--- tm_reclaim on pid %d complete\n",
tsk->pid);
out_and_saveregs:
/* Always save the regs here, even if a transaction's not active.
* This context-switches a thread's TM info SPRs. We do it here to
* be consistent with the restore path (in recheckpoint) which
* cannot happen later in _switch().
*/
tm_save_sprs(thr);
}
extern void __tm_recheckpoint(struct thread_struct *thread,
unsigned long orig_msr);
void tm_recheckpoint(struct thread_struct *thread,
unsigned long orig_msr)
{
unsigned long flags;
/* We really can't be interrupted here as the TEXASR registers can't
* change and later in the trecheckpoint code, we have a userspace R1.
* So let's hard disable over this region.
*/
local_irq_save(flags);
hard_irq_disable();
/* The TM SPRs are restored here, so that TEXASR.FS can be set
* before the trecheckpoint and no explosion occurs.
*/
tm_restore_sprs(thread);
__tm_recheckpoint(thread, orig_msr);
local_irq_restore(flags);
}
static inline void tm_recheckpoint_new_task(struct task_struct *new)
{
unsigned long msr;
if (!cpu_has_feature(CPU_FTR_TM))
return;
/* Recheckpoint the registers of the thread we're about to switch to.
*
* If the task was using FP, we non-lazily reload both the original and
* the speculative FP register states. This is because the kernel
* doesn't see if/when a TM rollback occurs, so if we take an FP
* unavoidable later, we are unable to determine which set of FP regs
* need to be restored.
*/
if (!new->thread.regs)
return;
if (!MSR_TM_ACTIVE(new->thread.regs->msr)){
tm_restore_sprs(&new->thread);
return;
}
msr = new->thread.tm_orig_msr;
/* Recheckpoint to restore original checkpointed register state. */
TM_DEBUG("*** tm_recheckpoint of pid %d "
"(new->msr 0x%lx, new->origmsr 0x%lx)\n",
new->pid, new->thread.regs->msr, msr);
/* This loads the checkpointed FP/VEC state, if used */
tm_recheckpoint(&new->thread, msr);
/* This loads the speculative FP/VEC state, if used */
if (msr & MSR_FP) {
do_load_up_transact_fpu(&new->thread);
new->thread.regs->msr |=
(MSR_FP | new->thread.fpexc_mode);
}
#ifdef CONFIG_ALTIVEC
if (msr & MSR_VEC) {
do_load_up_transact_altivec(&new->thread);
new->thread.regs->msr |= MSR_VEC;
}
#endif
/* We may as well turn on VSX too since all the state is restored now */
if (msr & MSR_VSX)
new->thread.regs->msr |= MSR_VSX;
TM_DEBUG("*** tm_recheckpoint of pid %d complete "
"(kernel msr 0x%lx)\n",
new->pid, mfmsr());
}
static inline void __switch_to_tm(struct task_struct *prev)
{
if (cpu_has_feature(CPU_FTR_TM)) {
tm_enable();
tm_reclaim_task(prev);
}
}
/*
* This is called if we are on the way out to userspace and the
* TIF_RESTORE_TM flag is set. It checks if we need to reload
* FP and/or vector state and does so if necessary.
* If userspace is inside a transaction (whether active or
* suspended) and FP/VMX/VSX instructions have ever been enabled
* inside that transaction, then we have to keep them enabled
* and keep the FP/VMX/VSX state loaded while ever the transaction
* continues. The reason is that if we didn't, and subsequently
* got a FP/VMX/VSX unavailable interrupt inside a transaction,
* we don't know whether it's the same transaction, and thus we
* don't know which of the checkpointed state and the transactional
* state to use.
*/
void restore_tm_state(struct pt_regs *regs)
{
unsigned long msr_diff;
clear_thread_flag(TIF_RESTORE_TM);
if (!MSR_TM_ACTIVE(regs->msr))
return;
msr_diff = current->thread.tm_orig_msr & ~regs->msr;
msr_diff &= MSR_FP | MSR_VEC | MSR_VSX;
if (msr_diff & MSR_FP) {
fp_enable();
load_fp_state(&current->thread.fp_state);
regs->msr |= current->thread.fpexc_mode;
}
if (msr_diff & MSR_VEC) {
vec_enable();
load_vr_state(&current->thread.vr_state);
}
regs->msr |= msr_diff;
}
#else
#define tm_recheckpoint_new_task(new)
#define __switch_to_tm(prev)
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
struct task_struct *__switch_to(struct task_struct *prev,
struct task_struct *new)
{
struct thread_struct *new_thread, *old_thread;
struct task_struct *last;
#ifdef CONFIG_PPC_BOOK3S_64
struct ppc64_tlb_batch *batch;
#endif
WARN_ON(!irqs_disabled());
/* Back up the TAR and DSCR across context switches.
* Note that the TAR is not available for use in the kernel. (To
* provide this, the TAR should be backed up/restored on exception
* entry/exit instead, and be in pt_regs. FIXME, this should be in
* pt_regs anyway (for debug).)
* Save the TAR and DSCR here before we do treclaim/trecheckpoint as
* these will change them.
*/
save_early_sprs(&prev->thread);
__switch_to_tm(prev);
#ifdef CONFIG_SMP
/* avoid complexity of lazy save/restore of fpu
* by just saving it every time we switch out if
* this task used the fpu during the last quantum.
*
* If it tries to use the fpu again, it'll trap and
* reload its fp regs. So we don't have to do a restore
* every switch, just a save.
* -- Cort
*/
if (prev->thread.regs && (prev->thread.regs->msr & MSR_FP))
giveup_fpu(prev);
#ifdef CONFIG_ALTIVEC
/*
* If the previous thread used altivec in the last quantum
* (thus changing altivec regs) then save them.
* We used to check the VRSAVE register but not all apps
* set it, so we don't rely on it now (and in fact we need
* to save & restore VSCR even if VRSAVE == 0). -- paulus
*
* On SMP we always save/restore altivec regs just to avoid the
* complexity of changing processors.
* -- Cort
*/
if (prev->thread.regs && (prev->thread.regs->msr & MSR_VEC))
giveup_altivec(prev);
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
if (prev->thread.regs && (prev->thread.regs->msr & MSR_VSX))
/* VMX and FPU registers are already save here */
__giveup_vsx(prev);
#endif /* CONFIG_VSX */
#ifdef CONFIG_SPE
/*
* If the previous thread used spe in the last quantum
* (thus changing spe regs) then save them.
*
* On SMP we always save/restore spe regs just to avoid the
* complexity of changing processors.
*/
if ((prev->thread.regs && (prev->thread.regs->msr & MSR_SPE)))
giveup_spe(prev);
#endif /* CONFIG_SPE */
#else /* CONFIG_SMP */
#ifdef CONFIG_ALTIVEC
/* Avoid the trap. On smp this this never happens since
* we don't set last_task_used_altivec -- Cort
*/
if (new->thread.regs && last_task_used_altivec == new)
new->thread.regs->msr |= MSR_VEC;
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_VSX
if (new->thread.regs && last_task_used_vsx == new)
new->thread.regs->msr |= MSR_VSX;
#endif /* CONFIG_VSX */
#ifdef CONFIG_SPE
/* Avoid the trap. On smp this this never happens since
* we don't set last_task_used_spe
*/
if (new->thread.regs && last_task_used_spe == new)
new->thread.regs->msr |= MSR_SPE;
#endif /* CONFIG_SPE */
#endif /* CONFIG_SMP */
#ifdef CONFIG_PPC_ADV_DEBUG_REGS
switch_booke_debug_regs(&new->thread.debug);
#else
/*
* For PPC_BOOK3S_64, we use the hw-breakpoint interfaces that would
* schedule DABR
*/
#ifndef CONFIG_HAVE_HW_BREAKPOINT
if (unlikely(!hw_brk_match(&__get_cpu_var(current_brk), &new->thread.hw_brk)))
__set_breakpoint(&new->thread.hw_brk);
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
#endif
new_thread = &new->thread;
old_thread = &current->thread;
#ifdef CONFIG_PPC64
/*
* Collect processor utilization data per process
*/
if (firmware_has_feature(FW_FEATURE_SPLPAR)) {
struct cpu_usage *cu = &__get_cpu_var(cpu_usage_array);
long unsigned start_tb, current_tb;
start_tb = old_thread->start_tb;
cu->current_tb = current_tb = mfspr(SPRN_PURR);
old_thread->accum_tb += (current_tb - start_tb);
new_thread->start_tb = current_tb;
}
#endif /* CONFIG_PPC64 */
#ifdef CONFIG_PPC_BOOK3S_64
batch = &__get_cpu_var(ppc64_tlb_batch);
if (batch->active) {
current_thread_info()->local_flags |= _TLF_LAZY_MMU;
if (batch->index)
__flush_tlb_pending(batch);
batch->active = 0;
}
#endif /* CONFIG_PPC_BOOK3S_64 */
/*
* We can't take a PMU exception inside _switch() since there is a
* window where the kernel stack SLB and the kernel stack are out
* of sync. Hard disable here.
*/
hard_irq_disable();
tm_recheckpoint_new_task(new);
last = _switch(old_thread, new_thread);
#ifdef CONFIG_PPC_BOOK3S_64
if (current_thread_info()->local_flags & _TLF_LAZY_MMU) {
current_thread_info()->local_flags &= ~_TLF_LAZY_MMU;
batch = &__get_cpu_var(ppc64_tlb_batch);
batch->active = 1;
}
#endif /* CONFIG_PPC_BOOK3S_64 */
return last;
}
static int instructions_to_print = 16;
static void show_instructions(struct pt_regs *regs)
{
int i;
unsigned long pc = regs->nip - (instructions_to_print * 3 / 4 *
sizeof(int));
printk("Instruction dump:");
for (i = 0; i < instructions_to_print; i++) {
int instr;
if (!(i % 8))
printk("\n");
#if !defined(CONFIG_BOOKE)
/* If executing with the IMMU off, adjust pc rather
* than print XXXXXXXX.
*/
if (!(regs->msr & MSR_IR))
pc = (unsigned long)phys_to_virt(pc);
#endif
/* We use __get_user here *only* to avoid an OOPS on a
* bad address because the pc *should* only be a
* kernel address.
*/
if (!__kernel_text_address(pc) ||
__get_user(instr, (unsigned int __user *)pc)) {
printk(KERN_CONT "XXXXXXXX ");
} else {
if (regs->nip == pc)
printk(KERN_CONT "<%08x> ", instr);
else
printk(KERN_CONT "%08x ", instr);
}
pc += sizeof(int);
}
printk("\n");
}
static struct regbit {
unsigned long bit;
const char *name;
} msr_bits[] = {
#if defined(CONFIG_PPC64) && !defined(CONFIG_BOOKE)
{MSR_SF, "SF"},
{MSR_HV, "HV"},
#endif
{MSR_VEC, "VEC"},
{MSR_VSX, "VSX"},
#ifdef CONFIG_BOOKE
{MSR_CE, "CE"},
#endif
{MSR_EE, "EE"},
{MSR_PR, "PR"},
{MSR_FP, "FP"},
{MSR_ME, "ME"},
#ifdef CONFIG_BOOKE
{MSR_DE, "DE"},
#else
{MSR_SE, "SE"},
{MSR_BE, "BE"},
#endif
{MSR_IR, "IR"},
{MSR_DR, "DR"},
{MSR_PMM, "PMM"},
#ifndef CONFIG_BOOKE
{MSR_RI, "RI"},
{MSR_LE, "LE"},
#endif
{0, NULL}
};
static void printbits(unsigned long val, struct regbit *bits)
{
const char *sep = "";
printk("<");
for (; bits->bit; ++bits)
if (val & bits->bit) {
printk("%s%s", sep, bits->name);
sep = ",";
}
printk(">");
}
#ifdef CONFIG_PPC64
#define REG "%016lx"
#define REGS_PER_LINE 4
#define LAST_VOLATILE 13
#else
#define REG "%08lx"
#define REGS_PER_LINE 8
#define LAST_VOLATILE 12
#endif
void show_regs(struct pt_regs * regs)
{
int i, trap;
show_regs_print_info(KERN_DEFAULT);
printk("NIP: "REG" LR: "REG" CTR: "REG"\n",
regs->nip, regs->link, regs->ctr);
printk("REGS: %p TRAP: %04lx %s (%s)\n",
regs, regs->trap, print_tainted(), init_utsname()->release);
printk("MSR: "REG" ", regs->msr);
printbits(regs->msr, msr_bits);
printk(" CR: %08lx XER: %08lx\n", regs->ccr, regs->xer);
trap = TRAP(regs);
if ((regs->trap != 0xc00) && cpu_has_feature(CPU_FTR_CFAR))
printk("CFAR: "REG" ", regs->orig_gpr3);
if (trap == 0x200 || trap == 0x300 || trap == 0x600)
#if defined(CONFIG_4xx) || defined(CONFIG_BOOKE)
printk("DEAR: "REG" ESR: "REG" ", regs->dar, regs->dsisr);
#else
printk("DAR: "REG" DSISR: %08lx ", regs->dar, regs->dsisr);
#endif
#ifdef CONFIG_PPC64
printk("SOFTE: %ld ", regs->softe);
#endif
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (MSR_TM_ACTIVE(regs->msr))
printk("\nPACATMSCRATCH: %016llx ", get_paca()->tm_scratch);
#endif
for (i = 0; i < 32; i++) {
if ((i % REGS_PER_LINE) == 0)
printk("\nGPR%02d: ", i);
printk(REG " ", regs->gpr[i]);
if (i == LAST_VOLATILE && !FULL_REGS(regs))
break;
}
printk("\n");
#ifdef CONFIG_KALLSYMS
/*
* Lookup NIP late so we have the best change of getting the
* above info out without failing
*/
printk("NIP ["REG"] %pS\n", regs->nip, (void *)regs->nip);
printk("LR ["REG"] %pS\n", regs->link, (void *)regs->link);
#endif
show_stack(current, (unsigned long *) regs->gpr[1]);
if (!user_mode(regs))
show_instructions(regs);
}
void exit_thread(void)
{
discard_lazy_cpu_state();
}
void flush_thread(void)
{
discard_lazy_cpu_state();
#ifdef CONFIG_HAVE_HW_BREAKPOINT
flush_ptrace_hw_breakpoint(current);
#else /* CONFIG_HAVE_HW_BREAKPOINT */
set_debug_reg_defaults(&current->thread);
#endif /* CONFIG_HAVE_HW_BREAKPOINT */
}
void
release_thread(struct task_struct *t)
{
}
/*
* this gets called so that we can store coprocessor state into memory and
* copy the current task into the new thread.
*/
int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
{
flush_fp_to_thread(src);
flush_altivec_to_thread(src);
flush_vsx_to_thread(src);
flush_spe_to_thread(src);
/*
* Flush TM state out so we can copy it. __switch_to_tm() does this
* flush but it removes the checkpointed state from the current CPU and
* transitions the CPU out of TM mode. Hence we need to call
* tm_recheckpoint_new_task() (on the same task) to restore the
* checkpointed state back and the TM mode.
*/
__switch_to_tm(src);
tm_recheckpoint_new_task(src);
*dst = *src;
clear_task_ebb(dst);
return 0;
}
/*
* Copy a thread..
*/
extern unsigned long dscr_default; /* defined in arch/powerpc/kernel/sysfs.c */
int copy_thread(unsigned long clone_flags, unsigned long usp,
unsigned long arg, struct task_struct *p)
{
struct pt_regs *childregs, *kregs;
extern void ret_from_fork(void);
extern void ret_from_kernel_thread(void);
void (*f)(void);
unsigned long sp = (unsigned long)task_stack_page(p) + THREAD_SIZE;
/* Copy registers */
sp -= sizeof(struct pt_regs);
childregs = (struct pt_regs *) sp;
if (unlikely(p->flags & PF_KTHREAD)) {
struct thread_info *ti = (void *)task_stack_page(p);
memset(childregs, 0, sizeof(struct pt_regs));
childregs->gpr[1] = sp + sizeof(struct pt_regs);
/* function */
if (usp)
childregs->gpr[14] = ppc_function_entry((void *)usp);
#ifdef CONFIG_PPC64
clear_tsk_thread_flag(p, TIF_32BIT);
childregs->softe = 1;
#endif
childregs->gpr[15] = arg;
p->thread.regs = NULL; /* no user register state */
ti->flags |= _TIF_RESTOREALL;
f = ret_from_kernel_thread;
} else {
struct pt_regs *regs = current_pt_regs();
CHECK_FULL_REGS(regs);
*childregs = *regs;
if (usp)
childregs->gpr[1] = usp;
p->thread.regs = childregs;
childregs->gpr[3] = 0; /* Result from fork() */
if (clone_flags & CLONE_SETTLS) {
#ifdef CONFIG_PPC64
if (!is_32bit_task())
childregs->gpr[13] = childregs->gpr[6];
else
#endif
childregs->gpr[2] = childregs->gpr[6];
}
f = ret_from_fork;
}
sp -= STACK_FRAME_OVERHEAD;
/*
* The way this works is that at some point in the future
* some task will call _switch to switch to the new task.
* That will pop off the stack frame created below and start
* the new task running at ret_from_fork. The new task will
* do some house keeping and then return from the fork or clone
* system call, using the stack frame created above.
*/
((unsigned long *)sp)[0] = 0;
sp -= sizeof(struct pt_regs);
kregs = (struct pt_regs *) sp;
sp -= STACK_FRAME_OVERHEAD;
p->thread.ksp = sp;
#ifdef CONFIG_PPC32
p->thread.ksp_limit = (unsigned long)task_stack_page(p) +
_ALIGN_UP(sizeof(struct thread_info), 16);
#endif
#ifdef CONFIG_HAVE_HW_BREAKPOINT
p->thread.ptrace_bps[0] = NULL;
#endif
p->thread.fp_save_area = NULL;
#ifdef CONFIG_ALTIVEC
p->thread.vr_save_area = NULL;
#endif
#ifdef CONFIG_PPC_STD_MMU_64
if (mmu_has_feature(MMU_FTR_SLB)) {
unsigned long sp_vsid;
unsigned long llp = mmu_psize_defs[mmu_linear_psize].sllp;
if (mmu_has_feature(MMU_FTR_1T_SEGMENT))
sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_1T)
<< SLB_VSID_SHIFT_1T;
else
sp_vsid = get_kernel_vsid(sp, MMU_SEGSIZE_256M)
<< SLB_VSID_SHIFT;
sp_vsid |= SLB_VSID_KERNEL | llp;
p->thread.ksp_vsid = sp_vsid;
}
#endif /* CONFIG_PPC_STD_MMU_64 */
#ifdef CONFIG_PPC64
if (cpu_has_feature(CPU_FTR_DSCR)) {
p->thread.dscr_inherit = current->thread.dscr_inherit;
p->thread.dscr = current->thread.dscr;
}
if (cpu_has_feature(CPU_FTR_HAS_PPR))
p->thread.ppr = INIT_PPR;
#endif
kregs->nip = ppc_function_entry(f);
return 0;
}
/*
* Set up a thread for executing a new program
*/
void start_thread(struct pt_regs *regs, unsigned long start, unsigned long sp)
{
#ifdef CONFIG_PPC64
unsigned long load_addr = regs->gpr[2]; /* saved by ELF_PLAT_INIT */
#endif
/*
* If we exec out of a kernel thread then thread.regs will not be
* set. Do it now.
*/
if (!current->thread.regs) {
struct pt_regs *regs = task_stack_page(current) + THREAD_SIZE;
current->thread.regs = regs - 1;
}
memset(regs->gpr, 0, sizeof(regs->gpr));
regs->ctr = 0;
regs->link = 0;
regs->xer = 0;
regs->ccr = 0;
regs->gpr[1] = sp;
/*
* We have just cleared all the nonvolatile GPRs, so make
* FULL_REGS(regs) return true. This is necessary to allow
* ptrace to examine the thread immediately after exec.
*/
regs->trap &= ~1UL;
#ifdef CONFIG_PPC32
regs->mq = 0;
regs->nip = start;
regs->msr = MSR_USER;
#else
if (!is_32bit_task()) {
unsigned long entry;
if (is_elf2_task()) {
/* Look ma, no function descriptors! */
entry = start;
/*
* Ulrich says:
* The latest iteration of the ABI requires that when
* calling a function (at its global entry point),
* the caller must ensure r12 holds the entry point
* address (so that the function can quickly
* establish addressability).
*/
regs->gpr[12] = start;
/* Make sure that's restored on entry to userspace. */
set_thread_flag(TIF_RESTOREALL);
} else {
unsigned long toc;
/* start is a relocated pointer to the function
* descriptor for the elf _start routine. The first
* entry in the function descriptor is the entry
* address of _start and the second entry is the TOC
* value we need to use.
*/
__get_user(entry, (unsigned long __user *)start);
__get_user(toc, (unsigned long __user *)start+1);
/* Check whether the e_entry function descriptor entries
* need to be relocated before we can use them.
*/
if (load_addr != 0) {
entry += load_addr;
toc += load_addr;
}
regs->gpr[2] = toc;
}
regs->nip = entry;
regs->msr = MSR_USER64;
} else {
regs->nip = start;
regs->gpr[2] = 0;
regs->msr = MSR_USER32;
}
#endif
discard_lazy_cpu_state();
#ifdef CONFIG_VSX
current->thread.used_vsr = 0;
#endif
memset(&current->thread.fp_state, 0, sizeof(current->thread.fp_state));
current->thread.fp_save_area = NULL;
#ifdef CONFIG_ALTIVEC
memset(&current->thread.vr_state, 0, sizeof(current->thread.vr_state));
current->thread.vr_state.vscr.u[3] = 0x00010000; /* Java mode disabled */
current->thread.vr_save_area = NULL;
current->thread.vrsave = 0;
current->thread.used_vr = 0;
#endif /* CONFIG_ALTIVEC */
#ifdef CONFIG_SPE
memset(current->thread.evr, 0, sizeof(current->thread.evr));
current->thread.acc = 0;
current->thread.spefscr = 0;
current->thread.used_spe = 0;
#endif /* CONFIG_SPE */
#ifdef CONFIG_PPC_TRANSACTIONAL_MEM
if (cpu_has_feature(CPU_FTR_TM))
regs->msr |= MSR_TM;
current->thread.tm_tfhar = 0;
current->thread.tm_texasr = 0;
current->thread.tm_tfiar = 0;
#endif /* CONFIG_PPC_TRANSACTIONAL_MEM */
}
#define PR_FP_ALL_EXCEPT (PR_FP_EXC_DIV | PR_FP_EXC_OVF | PR_FP_EXC_UND \
| PR_FP_EXC_RES | PR_FP_EXC_INV)
int set_fpexc_mode(struct task_struct *tsk, unsigned int val)
{
struct pt_regs *regs = tsk->thread.regs;
/* This is a bit hairy. If we are an SPE enabled processor
* (have embedded fp) we store the IEEE exception enable flags in
* fpexc_mode. fpexc_mode is also used for setting FP exception
* mode (asyn, precise, disabled) for 'Classic' FP. */
if (val & PR_FP_EXC_SW_ENABLE) {
#ifdef CONFIG_SPE
if (cpu_has_feature(CPU_FTR_SPE)) {
/*
* When the sticky exception bits are set
* directly by userspace, it must call prctl
* with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
* in the existing prctl settings) or
* PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
* the bits being set). <fenv.h> functions
* saving and restoring the whole
* floating-point environment need to do so
* anyway to restore the prctl settings from
* the saved environment.
*/
tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
tsk->thread.fpexc_mode = val &
(PR_FP_EXC_SW_ENABLE | PR_FP_ALL_EXCEPT);
return 0;
} else {
return -EINVAL;
}
#else
return -EINVAL;
#endif
}
/* on a CONFIG_SPE this does not hurt us. The bits that
* __pack_fe01 use do not overlap with bits used for
* PR_FP_EXC_SW_ENABLE. Additionally, the MSR[FE0,FE1] bits
* on CONFIG_SPE implementations are reserved so writing to
* them does not change anything */
if (val > PR_FP_EXC_PRECISE)
return -EINVAL;
tsk->thread.fpexc_mode = __pack_fe01(val);
if (regs != NULL && (regs->msr & MSR_FP) != 0)
regs->msr = (regs->msr & ~(MSR_FE0|MSR_FE1))
| tsk->thread.fpexc_mode;
return 0;
}
int get_fpexc_mode(struct task_struct *tsk, unsigned long adr)
{
unsigned int val;
if (tsk->thread.fpexc_mode & PR_FP_EXC_SW_ENABLE)
#ifdef CONFIG_SPE
if (cpu_has_feature(CPU_FTR_SPE)) {
/*
* When the sticky exception bits are set
* directly by userspace, it must call prctl
* with PR_GET_FPEXC (with PR_FP_EXC_SW_ENABLE
* in the existing prctl settings) or
* PR_SET_FPEXC (with PR_FP_EXC_SW_ENABLE in
* the bits being set). <fenv.h> functions
* saving and restoring the whole
* floating-point environment need to do so
* anyway to restore the prctl settings from
* the saved environment.
*/
tsk->thread.spefscr_last = mfspr(SPRN_SPEFSCR);
val = tsk->thread.fpexc_mode;
} else
return -EINVAL;
#else
return -EINVAL;
#endif
else
val = __unpack_fe01(tsk->thread.fpexc_mode);
return put_user(val, (unsigned int __user *) adr);
}
int set_endian(struct task_struct *tsk, unsigned int val)
{
struct pt_regs *regs = tsk->thread.regs;
if ((val == PR_ENDIAN_LITTLE && !cpu_has_feature(CPU_FTR_REAL_LE)) ||
(val == PR_ENDIAN_PPC_LITTLE && !cpu_has_feature(CPU_FTR_PPC_LE)))
return -EINVAL;
if (regs == NULL)
return -EINVAL;
if (val == PR_ENDIAN_BIG)
regs->msr &= ~MSR_LE;
else if (val == PR_ENDIAN_LITTLE || val == PR_ENDIAN_PPC_LITTLE)
regs->msr |= MSR_LE;
else
return -EINVAL;
return 0;
}
int get_endian(struct task_struct *tsk, unsigned long adr)
{
struct pt_regs *regs = tsk->thread.regs;
unsigned int val;
if (!cpu_has_feature(CPU_FTR_PPC_LE) &&
!cpu_has_feature(CPU_FTR_REAL_LE))
return -EINVAL;
if (regs == NULL)
return -EINVAL;
if (regs->msr & MSR_LE) {
if (cpu_has_feature(CPU_FTR_REAL_LE))
val = PR_ENDIAN_LITTLE;
else
val = PR_ENDIAN_PPC_LITTLE;
} else
val = PR_ENDIAN_BIG;
return put_user(val, (unsigned int __user *)adr);
}
int set_unalign_ctl(struct task_struct *tsk, unsigned int val)
{
tsk->thread.align_ctl = val;
return 0;
}
int get_unalign_ctl(struct task_struct *tsk, unsigned long adr)
{
return put_user(tsk->thread.align_ctl, (unsigned int __user *)adr);
}
static inline int valid_irq_stack(unsigned long sp, struct task_struct *p,
unsigned long nbytes)
{
unsigned long stack_page;
unsigned long cpu = task_cpu(p);
/*
* Avoid crashing if the stack has overflowed and corrupted
* task_cpu(p), which is in the thread_info struct.
*/
if (cpu < NR_CPUS && cpu_possible(cpu)) {
stack_page = (unsigned long) hardirq_ctx[cpu];
if (sp >= stack_page + sizeof(struct thread_struct)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
stack_page = (unsigned long) softirq_ctx[cpu];
if (sp >= stack_page + sizeof(struct thread_struct)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
}
return 0;
}
int validate_sp(unsigned long sp, struct task_struct *p,
unsigned long nbytes)
{
unsigned long stack_page = (unsigned long)task_stack_page(p);
if (sp >= stack_page + sizeof(struct thread_struct)
&& sp <= stack_page + THREAD_SIZE - nbytes)
return 1;
return valid_irq_stack(sp, p, nbytes);
}
EXPORT_SYMBOL(validate_sp);
unsigned long get_wchan(struct task_struct *p)
{
unsigned long ip, sp;
int count = 0;
if (!p || p == current || p->state == TASK_RUNNING)
return 0;
sp = p->thread.ksp;
if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
return 0;
do {
sp = *(unsigned long *)sp;
if (!validate_sp(sp, p, STACK_FRAME_OVERHEAD))
return 0;
if (count > 0) {
ip = ((unsigned long *)sp)[STACK_FRAME_LR_SAVE];
if (!in_sched_functions(ip))
return ip;
}
} while (count++ < 16);
return 0;
}
static int kstack_depth_to_print = CONFIG_PRINT_STACK_DEPTH;
void show_stack(struct task_struct *tsk, unsigned long *stack)
{
unsigned long sp, ip, lr, newsp;
int count = 0;
int firstframe = 1;
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
int curr_frame = current->curr_ret_stack;
extern void return_to_handler(void);
unsigned long rth = (unsigned long)return_to_handler;
unsigned long mrth = -1;
#ifdef CONFIG_PPC64
extern void mod_return_to_handler(void);
rth = *(unsigned long *)rth;
mrth = (unsigned long)mod_return_to_handler;
mrth = *(unsigned long *)mrth;
#endif
#endif
sp = (unsigned long) stack;
if (tsk == NULL)
tsk = current;
if (sp == 0) {
if (tsk == current)
asm("mr %0,1" : "=r" (sp));
else
sp = tsk->thread.ksp;
}
lr = 0;
printk("Call Trace:\n");
do {
if (!validate_sp(sp, tsk, STACK_FRAME_OVERHEAD))
return;
stack = (unsigned long *) sp;
newsp = stack[0];
ip = stack[STACK_FRAME_LR_SAVE];
if (!firstframe || ip != lr) {
printk("["REG"] ["REG"] %pS", sp, ip, (void *)ip);
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
if ((ip == rth || ip == mrth) && curr_frame >= 0) {
printk(" (%pS)",
(void *)current->ret_stack[curr_frame].ret);
curr_frame--;
}
#endif
if (firstframe)
printk(" (unreliable)");
printk("\n");
}
firstframe = 0;
/*
* See if this is an exception frame.
* We look for the "regshere" marker in the current frame.
*/
if (validate_sp(sp, tsk, STACK_INT_FRAME_SIZE)
&& stack[STACK_FRAME_MARKER] == STACK_FRAME_REGS_MARKER) {
struct pt_regs *regs = (struct pt_regs *)
(sp + STACK_FRAME_OVERHEAD);
lr = regs->link;
printk("--- Exception: %lx at %pS\n LR = %pS\n",
regs->trap, (void *)regs->nip, (void *)lr);
firstframe = 1;
}
sp = newsp;
} while (count++ < kstack_depth_to_print);
}
#ifdef CONFIG_PPC64
/* Called with hard IRQs off */
void notrace __ppc64_runlatch_on(void)
{
struct thread_info *ti = current_thread_info();
unsigned long ctrl;
ctrl = mfspr(SPRN_CTRLF);
ctrl |= CTRL_RUNLATCH;
mtspr(SPRN_CTRLT, ctrl);
ti->local_flags |= _TLF_RUNLATCH;
}
/* Called with hard IRQs off */
void notrace __ppc64_runlatch_off(void)
{
struct thread_info *ti = current_thread_info();
unsigned long ctrl;
ti->local_flags &= ~_TLF_RUNLATCH;
ctrl = mfspr(SPRN_CTRLF);
ctrl &= ~CTRL_RUNLATCH;
mtspr(SPRN_CTRLT, ctrl);
}
#endif /* CONFIG_PPC64 */
unsigned long arch_align_stack(unsigned long sp)
{
if (!(current->personality & ADDR_NO_RANDOMIZE) && randomize_va_space)
sp -= get_random_int() & ~PAGE_MASK;
return sp & ~0xf;
}
static inline unsigned long brk_rnd(void)
{
unsigned long rnd = 0;
/* 8MB for 32bit, 1GB for 64bit */
if (is_32bit_task())
rnd = (long)(get_random_int() % (1<<(23-PAGE_SHIFT)));
else
rnd = (long)(get_random_int() % (1<<(30-PAGE_SHIFT)));
return rnd << PAGE_SHIFT;
}
unsigned long arch_randomize_brk(struct mm_struct *mm)
{
unsigned long base = mm->brk;
unsigned long ret;
#ifdef CONFIG_PPC_STD_MMU_64
/*
* If we are using 1TB segments and we are allowed to randomise
* the heap, we can put it above 1TB so it is backed by a 1TB
* segment. Otherwise the heap will be in the bottom 1TB
* which always uses 256MB segments and this may result in a
* performance penalty.
*/
if (!is_32bit_task() && (mmu_highuser_ssize == MMU_SEGSIZE_1T))
base = max_t(unsigned long, mm->brk, 1UL << SID_SHIFT_1T);
#endif
ret = PAGE_ALIGN(base + brk_rnd());
if (ret < mm->brk)
return mm->brk;
return ret;
}
unsigned long randomize_et_dyn(unsigned long base)
{
unsigned long ret = PAGE_ALIGN(base + brk_rnd());
if (ret < base)
return base;
return ret;
}
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