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Commit 7502ff99 authored by Stéphane Eranian's avatar Stéphane Eranian Committed by David Mosberger
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[PATCH] ia64: fix critical perfmon2 bugs 

This patch fixes the following issues:

- fix a nasty corner case by which a task could inherit psr.pp/psr.up
  that could be stale by the time it runs. psr.pp/psr.up bits must be
  cleared on fork and inherited on execve(). Test case provided by
  John Levon.

- mask interrupts when locking the pfm stat structure. We don't want
  to take PMU interrupts in the middle of this kind of critical
  section.

- fix a bug in pfm_close() for context which use asynchronous
  notifications.  You cannot call fasync_helper() with interrupts
  disabled because it reenables them. There was no real danger of
  moving the call outside our critical section.

- fix a bug in in pfm_flush_pmds() where you can leave the freeze bit
  set in the pmc saved state.

- updated dump_pmu_state()

- cleanup the BUG_ON() usage
parent fe6f0598
Hide whitespace changes
Inline Side-by-side
Showing with 124 additions and 84 deletions
arch/ia64/kernel/perfmon.c
View file @ 7502ff99
......@@ -202,8 +202,8 @@
#define GET_PMU_OWNER() pfm_get_cpu_var(pmu_owner)
#define GET_PMU_CTX() pfm_get_cpu_var(pmu_ctx)
#define LOCK_PFS() spin_lock(&pfm_sessions.pfs_lock)
#define UNLOCK_PFS() spin_unlock(&pfm_sessions.pfs_lock)
#define LOCK_PFS(g) spin_lock_irqsave(&pfm_sessions.pfs_lock, g)
#define UNLOCK_PFS(g) spin_unlock_irqrestore(&pfm_sessions.pfs_lock, g)
#define PFM_REG_RETFLAG_SET(flags, val) do { flags &= ~PFM_REG_RETFL_MASK; flags |= (val); } while(0)
......@@ -618,6 +618,7 @@ static struct file_system_type pfm_fs_type = {
.get_sb = pfmfs_get_sb,
.kill_sb = kill_anon_super,
};
DEFINE_PER_CPU(unsigned long, pfm_syst_info);
DEFINE_PER_CPU(struct task_struct *, pmu_owner);
DEFINE_PER_CPU(pfm_context_t *, pmu_ctx);
......@@ -634,6 +635,8 @@ static struct file_operations pfm_file_ops;
static void pfm_lazy_save_regs (struct task_struct *ta);
#endif
void dump_pmu_state(const char *);
/*
* the HP simulator must be first because
* CONFIG_IA64_HP_SIM is independent of CONFIG_MCKINLEY or CONFIG_ITANIUM
......@@ -1283,10 +1286,11 @@ pfm_unregister_buffer_fmt(pfm_uuid_t uuid)
static int
pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
{
unsigned long flags;
/*
* validy checks on cpu_mask have been done upstream
*/
LOCK_PFS();
LOCK_PFS(flags);
DPRINT(("in sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
pfm_sessions.pfs_sys_sessions,
......@@ -1325,7 +1329,7 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
is_syswide,
cpu));
UNLOCK_PFS();
UNLOCK_PFS(flags);
return 0;
......@@ -1334,7 +1338,7 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
pfm_sessions.pfs_sys_session[cpu]->pid,
smp_processor_id()));
abort:
UNLOCK_PFS();
UNLOCK_PFS(flags);
return -EBUSY;
......@@ -1343,11 +1347,11 @@ pfm_reserve_session(struct task_struct *task, int is_syswide, unsigned int cpu)
static int
pfm_unreserve_session(pfm_context_t *ctx, int is_syswide, unsigned int cpu)
{
unsigned long flags;
/*
* validy checks on cpu_mask have been done upstream
*/
LOCK_PFS();
LOCK_PFS(flags);
DPRINT(("in sys_sessions=%u task_sessions=%u dbregs=%u syswide=%d cpu=%u\n",
pfm_sessions.pfs_sys_sessions,
......@@ -1380,7 +1384,7 @@ pfm_unreserve_session(pfm_context_t *ctx, int is_syswide, unsigned int cpu)
is_syswide,
cpu));
UNLOCK_PFS();
UNLOCK_PFS(flags);
return 0;
}
......@@ -1655,7 +1659,7 @@ pfm_ioctl(struct inode *inode, struct file *file, unsigned int cmd, unsigned lon
}
/*
* context is locked when coming here
* context is locked when coming here and interrupts are disabled
*/
static inline int
pfm_do_fasync(int fd, struct file *filp, pfm_context_t *ctx, int on)
......@@ -1789,6 +1793,7 @@ pfm_syswide_cleanup_other_cpu(pfm_context_t *ctx)
* even if the task itself is in the middle of being ctxsw out.
*/
static int pfm_context_unload(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs);
static int
pfm_close(struct inode *inode, struct file *filp)
{
......@@ -1803,10 +1808,6 @@ pfm_close(struct inode *inode, struct file *filp)
int free_possible = 1;
int state, is_system;
{ u64 psr = pfm_get_psr();
BUG_ON((psr & IA64_PSR_I) == 0UL);
}
DPRINT(("pfm_close called private=%p\n", filp->private_data));
if (!inode) {
......@@ -1815,7 +1816,7 @@ pfm_close(struct inode *inode, struct file *filp)
}
if (PFM_IS_FILE(filp) == 0) {
printk(KERN_ERR "perfmon: pfm_close: bad magic [%d]\n", current->pid);
DPRINT(("bad magic for [%d]\n", current->pid));
return -EBADF;
}
......@@ -1824,6 +1825,23 @@ pfm_close(struct inode *inode, struct file *filp)
printk(KERN_ERR "perfmon: pfm_close: NULL ctx [%d]\n", current->pid);
return -EBADF;
}
/*
* remove our file from the async queue, if we use this mode.
* This can be done without the context being protected. We come
* here when the context has become unreacheable by other tasks.
*
* We may still have active monitoring at this point and we may
* end up in pfm_overflow_handler(). However, fasync_helper()
* operates with interrupts disabled and it cleans up the
* queue. If the PMU handler is called prior to entering
* fasync_helper() then it will send a signal. If it is
* invoked after, it will find an empty queue and no
* signal will be sent. In both case, we are safe
*/
if (filp->f_flags & FASYNC) {
DPRINT(("[%d] cleaning up async_queue=%p\n", current->pid, ctx->ctx_async_queue));
pfm_do_fasync (-1, filp, ctx, 0);
}
PROTECT_CTX(ctx, flags);
......@@ -1832,24 +1850,17 @@ pfm_close(struct inode *inode, struct file *filp)
task = PFM_CTX_TASK(ctx);
/*
* remove our file from the async queue, if we use it
*/
if (filp->f_flags & FASYNC) {
DPRINT(("[%d] before async_queue=%p\n", current->pid, ctx->ctx_async_queue));
pfm_do_fasync (-1, filp, ctx, 0);
DPRINT(("[%d] after async_queue=%p\n", current->pid, ctx->ctx_async_queue));
}
regs = ia64_task_regs(task);
DPRINT(("[%d] ctx_state=%d\n", current->pid, state));
DPRINT(("[%d] ctx_state=%d is_current=%d\n",
current->pid, state,
task == current ? 1 : 0));
if (state == PFM_CTX_UNLOADED || state == PFM_CTX_TERMINATED) {
goto doit;
}
regs = ia64_task_regs(task);
/*
* context still loaded/masked and self monitoring,
* we stop/unload and we destroy right here
......@@ -1898,12 +1909,11 @@ pfm_close(struct inode *inode, struct file *filp)
ctx->ctx_state = PFM_CTX_TERMINATED;
DPRINT(("[%d] ctx_state=%d\n", current->pid, state));
DPRINT(("[%d] ctx_state=%d\n", current->pid, ctx->ctx_state));
}
goto doit;
}
/*
* The task is currently blocked or will block after an overflow.
* we must force it to wakeup to get out of the
......@@ -3482,6 +3492,7 @@ int
pfm_use_debug_registers(struct task_struct *task)
{
pfm_context_t *ctx = task->thread.pfm_context;
unsigned long flags;
int ret = 0;
if (pmu_conf.use_rr_dbregs == 0) return 0;
......@@ -3503,7 +3514,7 @@ pfm_use_debug_registers(struct task_struct *task)
*/
if (ctx && ctx->ctx_fl_using_dbreg == 1) return -1;
LOCK_PFS();
LOCK_PFS(flags);
/*
* We cannot allow setting breakpoints when system wide monitoring
......@@ -3519,7 +3530,7 @@ pfm_use_debug_registers(struct task_struct *task)
pfm_sessions.pfs_sys_use_dbregs,
task->pid, ret));
UNLOCK_PFS();
UNLOCK_PFS(flags);
return ret;
}
......@@ -3535,11 +3546,12 @@ pfm_use_debug_registers(struct task_struct *task)
int
pfm_release_debug_registers(struct task_struct *task)
{
unsigned long flags;
int ret;
if (pmu_conf.use_rr_dbregs == 0) return 0;
LOCK_PFS();
LOCK_PFS(flags);
if (pfm_sessions.pfs_ptrace_use_dbregs == 0) {
printk(KERN_ERR "perfmon: invalid release for [%d] ptrace_use_dbregs=0\n", task->pid);
ret = -1;
......@@ -3547,7 +3559,7 @@ pfm_release_debug_registers(struct task_struct *task)
pfm_sessions.pfs_ptrace_use_dbregs--;
ret = 0;
}
UNLOCK_PFS();
UNLOCK_PFS(flags);
return ret;
}
......@@ -3723,7 +3735,6 @@ pfm_debug(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
memset(pfm_stats, 0, sizeof(pfm_stats));
for(m=0; m < NR_CPUS; m++) pfm_stats[m].pfm_ovfl_intr_cycles_min = ~0UL;
}
return 0;
}
......@@ -3735,6 +3746,7 @@ pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_
{
struct thread_struct *thread = NULL;
pfarg_dbreg_t *req = (pfarg_dbreg_t *)arg;
unsigned long flags;
dbreg_t dbreg;
unsigned int rnum;
int first_time;
......@@ -3793,7 +3805,7 @@ pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_
* written after the context is loaded
*/
if (is_loaded) {
LOCK_PFS();
LOCK_PFS(flags);
if (first_time && is_system) {
if (pfm_sessions.pfs_ptrace_use_dbregs)
......@@ -3801,7 +3813,7 @@ pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_
else
pfm_sessions.pfs_sys_use_dbregs++;
}
UNLOCK_PFS();
UNLOCK_PFS(flags);
}
if (ret != 0) return ret;
......@@ -3902,11 +3914,11 @@ pfm_write_ibr_dbr(int mode, pfm_context_t *ctx, void *arg, int count, struct pt_
* in case it was our first attempt, we undo the global modifications
*/
if (first_time) {
LOCK_PFS();
LOCK_PFS(flags);
if (ctx->ctx_fl_system) {
pfm_sessions.pfs_sys_use_dbregs--;
}
UNLOCK_PFS();
UNLOCK_PFS(flags);
ctx->ctx_fl_using_dbreg = 0;
}
/*
......@@ -3959,7 +3971,11 @@ pfm_stop(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
DPRINT(("[%d] should be running on CPU%d\n", current->pid, ctx->ctx_cpu));
return -EBUSY;
}
DPRINT(("current [%d] task [%d] ctx_state=%d is_system=%d\n",
current->pid,
PFM_CTX_TASK(ctx)->pid,
state,
is_system));
/*
* in system mode, we need to update the PMU directly
* and the user level state of the caller, which may not
......@@ -4157,6 +4173,7 @@ pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
struct task_struct *task;
struct thread_struct *thread;
struct pfm_context_t *old;
unsigned long flags;
#ifndef CONFIG_SMP
struct task_struct *owner_task = NULL;
#endif
......@@ -4217,7 +4234,7 @@ pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
DPRINT(("load_pid [%d] task is debugged, cannot load range restrictions\n", req->load_pid));
goto error;
}
LOCK_PFS();
LOCK_PFS(flags);
if (is_system) {
if (pfm_sessions.pfs_ptrace_use_dbregs) {
......@@ -4230,7 +4247,7 @@ pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
}
}
UNLOCK_PFS();
UNLOCK_PFS(flags);
if (ret) goto error;
}
......@@ -4377,9 +4394,9 @@ pfm_context_load(pfm_context_t *ctx, void *arg, int count, struct pt_regs *regs)
* we must undo the dbregs setting (for system-wide)
*/
if (ret && set_dbregs) {
LOCK_PFS();
LOCK_PFS(flags);
pfm_sessions.pfs_sys_use_dbregs--;
UNLOCK_PFS();
UNLOCK_PFS(flags);
}
/*
* release task, there is now a link with the context
......@@ -4605,11 +4622,14 @@ pfm_exit_thread(struct task_struct *task)
printk(KERN_ERR "perfmon: pfm_exit_thread [%d] unexpected state=%d\n", task->pid, state);
break;
}
UNPROTECT_CTX(ctx, flags);
{ u64 psr = pfm_get_psr();
BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
BUG_ON(GET_PMU_OWNER());
BUG_ON(ia64_psr(regs)->up);
BUG_ON(ia64_psr(regs)->pp);
}
UNPROTECT_CTX(ctx, flags);
/*
* All memory free operations (especially for vmalloc'ed memory)
......@@ -5488,7 +5508,7 @@ pfm_proc_info(char *page)
char *p = page;
struct list_head * pos;
pfm_buffer_fmt_t * entry;
unsigned long psr;
unsigned long psr, flags;
int online_cpus = 0;
int i;
......@@ -5528,7 +5548,7 @@ pfm_proc_info(char *page)
}
}
LOCK_PFS();
LOCK_PFS(flags);
p += sprintf(p, "proc_sessions : %u\n"
"sys_sessions : %u\n"
"sys_use_dbregs : %u\n"
......@@ -5537,7 +5557,7 @@ pfm_proc_info(char *page)
pfm_sessions.pfs_sys_sessions,
pfm_sessions.pfs_sys_use_dbregs,
pfm_sessions.pfs_ptrace_use_dbregs);
UNLOCK_PFS();
UNLOCK_PFS(flags);
spin_lock(&pfm_buffer_fmt_lock);
......@@ -5712,10 +5732,6 @@ pfm_save_regs(struct task_struct *task)
*/
ctx->ctx_saved_psr_up = psr & IA64_PSR_UP;
{ u64 foo = pfm_get_psr();
BUG_ON(foo & ((IA64_PSR_UP|IA64_PSR_PP)));
}
/*
* release ownership of this PMU.
* PM interrupts are masked, so nothing
......@@ -5771,6 +5787,8 @@ pfm_save_regs(struct task_struct *task)
*/
psr = pfm_get_psr();
BUG_ON(foo & (IA64_PSR_I));
/*
* stop monitoring:
* This is the last instruction which may generate an overflow
......@@ -5785,12 +5803,6 @@ pfm_save_regs(struct task_struct *task)
*/
ctx->ctx_saved_psr_up = psr & IA64_PSR_UP;
#if 1
{ u64 foo = pfm_get_psr();
BUG_ON(foo & (IA64_PSR_I));
BUG_ON(foo & ((IA64_PSR_UP|IA64_PSR_PP)));
}
#endif
return;
save_error:
printk(KERN_ERR "perfmon: pfm_save_regs CPU%d [%d] NULL context PM_VALID=%ld\n",
......@@ -5805,11 +5817,9 @@ pfm_lazy_save_regs (struct task_struct *task)
struct thread_struct *t;
unsigned long flags;
#if 1
{ u64 foo = pfm_get_psr();
BUG_ON(foo & IA64_PSR_UP);
{ u64 psr = pfm_get_psr();
BUG_ON(psr & IA64_PSR_UP);
}
#endif
ctx = PFM_GET_CTX(task);
t = &task->thread;
......@@ -5851,7 +5861,7 @@ pfm_lazy_save_regs (struct task_struct *task)
/*
* unfreeze PMU if had pending overflows
*/
if (t->pmcs[0] & ~1UL) pfm_unfreeze_pmu();
if (t->pmcs[0] & ~0x1UL) pfm_unfreeze_pmu();
/*
* now get can unmask PMU interrupts, they will
......@@ -5900,10 +5910,8 @@ pfm_load_regs (struct task_struct *task)
flags = pfm_protect_ctx_ctxsw(ctx);
psr = pfm_get_psr();
#if 1
BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
BUG_ON(psr & IA64_PSR_I);
#endif
if (unlikely(ctx->ctx_state == PFM_CTX_ZOMBIE)) {
struct pt_regs *regs = ia64_task_regs(task);
......@@ -6060,10 +6068,8 @@ pfm_load_regs (struct task_struct *task)
t = &task->thread;
psr = pfm_get_psr();
#if 1
BUG_ON(psr & (IA64_PSR_UP|IA64_PSR_PP));
BUG_ON(psr & IA64_PSR_I);
#endif
/*
* we restore ALL the debug registers to avoid picking up
......@@ -6218,7 +6224,7 @@ pfm_flush_pmds(struct task_struct *task, pfm_context_t *ctx)
/*
* clear whatever overflow status bits there were
*/
task->thread.pmcs[0] &= ~0x1;
task->thread.pmcs[0] = 0;
}
ovfl_val = pmu_conf.ovfl_val;
/*
......@@ -6400,6 +6406,11 @@ pfm_init_percpu (void)
pfm_clear_psr_pp();
pfm_clear_psr_up();
/*
* we run with the PMU not frozen at all times
*/
pfm_unfreeze_pmu();
if (smp_processor_id() == 0)
register_percpu_irq(IA64_PERFMON_VECTOR, &perfmon_irqaction);
......@@ -6427,49 +6438,75 @@ pfm_init_percpu (void)
if (PMD_IS_IMPL(i) == 0) continue;
ia64_set_pmd(i, 0UL);
}
/*
* we run with the PMU not frozen at all times
*/
pfm_unfreeze_pmu();
}
/*
* used for debug purposes only
*/
void
dump_pmu_state(void)
dump_pmu_state(const char *from)
{
struct task_struct *task;
struct thread_struct *t;
struct pt_regs *regs;
pfm_context_t *ctx;
unsigned long psr;
int i;
unsigned long psr, dcr, info, flags;
int i, this_cpu;
local_irq_save(flags);
printk("current [%d] %s\n", current->pid, current->comm);
this_cpu = smp_processor_id();
regs = ia64_task_regs(current);
info = PFM_CPUINFO_GET();
dcr = ia64_getreg(_IA64_REG_CR_DCR);
if (info == 0 && ia64_psr(regs)->pp == 0 && (dcr & IA64_DCR_PP) == 0) {
local_irq_restore(flags);
return;
}
printk("CPU%d from %s() current [%d] iip=0x%lx %s\n",
this_cpu,
from,
current->pid,
regs->cr_iip,
current->comm);
task = GET_PMU_OWNER();
ctx = GET_PMU_CTX();
printk("owner [%d] ctx=%p\n", task ? task->pid : -1, ctx);
printk("->CPU%d owner [%d] ctx=%p\n", this_cpu, task ? task->pid : -1, ctx);
psr = pfm_get_psr();
printk("psr.pp=%ld psr.up=%ld\n", (psr >> IA64_PSR_PP_BIT) &0x1UL, (psr >> IA64_PSR_PP_BIT)&0x1UL);
printk("->CPU%d pmc0=0x%lx psr.pp=%d psr.up=%d dcr.pp=%d syst_info=0x%lx user_psr.up=%d user_psr.pp=%d\n",
this_cpu,
ia64_get_pmc(0),
psr & IA64_PSR_PP ? 1 : 0,
psr & IA64_PSR_UP ? 1 : 0,
dcr & IA64_DCR_PP ? 1 : 0,
info,
ia64_psr(regs)->up,
ia64_psr(regs)->pp);
ia64_psr(regs)->up = 0;
ia64_psr(regs)->pp = 0;
t = &current->thread;
for (i=1; PMC_IS_LAST(i) == 0; i++) {
if (PMC_IS_IMPL(i) == 0) continue;
printk("pmc[%d]=0x%lx tpmc=0x%lx\n", i, ia64_get_pmc(i), t->pmcs[i]);
printk("->CPU%d pmc[%d]=0x%lx thread_pmc[%d]=0x%lx\n", this_cpu, i, ia64_get_pmc(i), i, t->pmcs[i]);
}
for (i=1; PMD_IS_LAST(i) == 0; i++) {
if (PMD_IS_IMPL(i) == 0) continue;
printk("pmd[%d]=0x%lx tpmd=0x%lx\n", i, ia64_get_pmd(i), t->pmds[i]);
printk("->CPU%d pmd[%d]=0x%lx thread_pmd[%d]=0x%lx\n", this_cpu, i, ia64_get_pmd(i), i, t->pmds[i]);
}
if (ctx) {
printk("ctx_state=%d vaddr=%p addr=%p fd=%d ctx_task=[%d] saved_psr_up=0x%lx\n",
printk("->CPU%d ctx_state=%d vaddr=%p addr=%p fd=%d ctx_task=[%d] saved_psr_up=0x%lx\n",
this_cpu,
ctx->ctx_state,
ctx->ctx_smpl_vaddr,
ctx->ctx_smpl_hdr,
......@@ -6477,6 +6514,7 @@ dump_pmu_state(void)
ctx->ctx_msgq_tail,
ctx->ctx_saved_psr_up);
}
local_irq_restore(flags);
}
/*
......@@ -6499,10 +6537,8 @@ pfm_inherit(struct task_struct *task, struct pt_regs *regs)
PFM_SET_WORK_PENDING(task, 0);
/*
* restore default psr settings
* the psr bits are already set properly in copy_threads()
*/
ia64_psr(regs)->pp = ia64_psr(regs)->up = 0;
ia64_psr(regs)->sp = 1;
}
#else /* !CONFIG_PERFMON */
asmlinkage long
......
arch/ia64/kernel/process.c
View file @ 7502ff99
......@@ -353,9 +353,13 @@ copy_thread (int nr, unsigned long clone_flags,
/* copy parts of thread_struct: */
p->thread.ksp = (unsigned long) child_stack - 16;
/* stop some PSR bits from being inherited: */
/* stop some PSR bits from being inherited.
* the psr.up/psr.pp bits must be cleared on fork but inherited on execve()
* therefore we must specify them explicitly here and not include them in
* IA64_PSR_BITS_TO_CLEAR.
*/
child_ptregs->cr_ipsr = ((child_ptregs->cr_ipsr | IA64_PSR_BITS_TO_SET)
& ~IA64_PSR_BITS_TO_CLEAR);
& ~(IA64_PSR_BITS_TO_CLEAR | IA64_PSR_PP | IA64_PSR_UP));
/*
* NOTE: The calling convention considers all floating point
......
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