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authorLinus Torvalds <torvalds@linux-foundation.org>2019-11-02 11:00:26 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-11-02 11:00:26 -0700
commit969a5197da89454c41d95e2404e2e9d91ad73ba6 (patch)
treebcecf84affacc307f8a3ab2c3d740d18cd916783
parent1204c70d9dcba31164f78ad5d8c88c42335d51f8 (diff)
parent3d7efa4edd07be5c5c3ffa95ba63e97e070e1f3f (diff)
Merge tag 's390-5.4-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux
Pull s390 fixes from Vasily Gorbik: - Fix cpu idle time accounting - Fix stack unwinder case when both pt_regs and sp are specified - Fix information leak via cmm timeout proc handler * tag 's390-5.4-6' of git://git.kernel.org/pub/scm/linux/kernel/git/s390/linux: s390/idle: fix cpu idle time calculation s390/unwind: fix mixing regs and sp s390/cmm: fix information leak in cmm_timeout_handler()
-rw-r--r--arch/s390/include/asm/unwind.h1
-rw-r--r--arch/s390/kernel/idle.c29
-rw-r--r--arch/s390/kernel/unwind_bc.c18
-rw-r--r--arch/s390/mm/cmm.c12
4 files changed, 42 insertions, 18 deletions
diff --git a/arch/s390/include/asm/unwind.h b/arch/s390/include/asm/unwind.h
index d827b5b9a32c..eaaefeceef6f 100644
--- a/arch/s390/include/asm/unwind.h
+++ b/arch/s390/include/asm/unwind.h
@@ -35,6 +35,7 @@ struct unwind_state {
struct task_struct *task;
struct pt_regs *regs;
unsigned long sp, ip;
+ bool reuse_sp;
int graph_idx;
bool reliable;
bool error;
diff --git a/arch/s390/kernel/idle.c b/arch/s390/kernel/idle.c
index b9d8fe45737a..8f8456816d83 100644
--- a/arch/s390/kernel/idle.c
+++ b/arch/s390/kernel/idle.c
@@ -69,18 +69,26 @@ DEVICE_ATTR(idle_count, 0444, show_idle_count, NULL);
static ssize_t show_idle_time(struct device *dev,
struct device_attribute *attr, char *buf)
{
+ unsigned long long now, idle_time, idle_enter, idle_exit, in_idle;
struct s390_idle_data *idle = &per_cpu(s390_idle, dev->id);
- unsigned long long now, idle_time, idle_enter, idle_exit;
unsigned int seq;
do {
- now = get_tod_clock();
seq = read_seqcount_begin(&idle->seqcount);
idle_time = READ_ONCE(idle->idle_time);
idle_enter = READ_ONCE(idle->clock_idle_enter);
idle_exit = READ_ONCE(idle->clock_idle_exit);
} while (read_seqcount_retry(&idle->seqcount, seq));
- idle_time += idle_enter ? ((idle_exit ? : now) - idle_enter) : 0;
+ in_idle = 0;
+ now = get_tod_clock();
+ if (idle_enter) {
+ if (idle_exit) {
+ in_idle = idle_exit - idle_enter;
+ } else if (now > idle_enter) {
+ in_idle = now - idle_enter;
+ }
+ }
+ idle_time += in_idle;
return sprintf(buf, "%llu\n", idle_time >> 12);
}
DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
@@ -88,17 +96,24 @@ DEVICE_ATTR(idle_time_us, 0444, show_idle_time, NULL);
u64 arch_cpu_idle_time(int cpu)
{
struct s390_idle_data *idle = &per_cpu(s390_idle, cpu);
- unsigned long long now, idle_enter, idle_exit;
+ unsigned long long now, idle_enter, idle_exit, in_idle;
unsigned int seq;
do {
- now = get_tod_clock();
seq = read_seqcount_begin(&idle->seqcount);
idle_enter = READ_ONCE(idle->clock_idle_enter);
idle_exit = READ_ONCE(idle->clock_idle_exit);
} while (read_seqcount_retry(&idle->seqcount, seq));
-
- return cputime_to_nsecs(idle_enter ? ((idle_exit ?: now) - idle_enter) : 0);
+ in_idle = 0;
+ now = get_tod_clock();
+ if (idle_enter) {
+ if (idle_exit) {
+ in_idle = idle_exit - idle_enter;
+ } else if (now > idle_enter) {
+ in_idle = now - idle_enter;
+ }
+ }
+ return cputime_to_nsecs(in_idle);
}
void arch_cpu_idle_enter(void)
diff --git a/arch/s390/kernel/unwind_bc.c b/arch/s390/kernel/unwind_bc.c
index 8fc9daae47a2..a8204f952315 100644
--- a/arch/s390/kernel/unwind_bc.c
+++ b/arch/s390/kernel/unwind_bc.c
@@ -46,10 +46,15 @@ bool unwind_next_frame(struct unwind_state *state)
regs = state->regs;
if (unlikely(regs)) {
- sp = READ_ONCE_NOCHECK(regs->gprs[15]);
- if (unlikely(outside_of_stack(state, sp))) {
- if (!update_stack_info(state, sp))
- goto out_err;
+ if (state->reuse_sp) {
+ sp = state->sp;
+ state->reuse_sp = false;
+ } else {
+ sp = READ_ONCE_NOCHECK(regs->gprs[15]);
+ if (unlikely(outside_of_stack(state, sp))) {
+ if (!update_stack_info(state, sp))
+ goto out_err;
+ }
}
sf = (struct stack_frame *) sp;
ip = READ_ONCE_NOCHECK(sf->gprs[8]);
@@ -107,9 +112,9 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
{
struct stack_info *info = &state->stack_info;
unsigned long *mask = &state->stack_mask;
+ bool reliable, reuse_sp;
struct stack_frame *sf;
unsigned long ip;
- bool reliable;
memset(state, 0, sizeof(*state));
state->task = task;
@@ -134,10 +139,12 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
if (regs) {
ip = READ_ONCE_NOCHECK(regs->psw.addr);
reliable = true;
+ reuse_sp = true;
} else {
sf = (struct stack_frame *) sp;
ip = READ_ONCE_NOCHECK(sf->gprs[8]);
reliable = false;
+ reuse_sp = false;
}
#ifdef CONFIG_FUNCTION_GRAPH_TRACER
@@ -151,5 +158,6 @@ void __unwind_start(struct unwind_state *state, struct task_struct *task,
state->sp = sp;
state->ip = ip;
state->reliable = reliable;
+ state->reuse_sp = reuse_sp;
}
EXPORT_SYMBOL_GPL(__unwind_start);
diff --git a/arch/s390/mm/cmm.c b/arch/s390/mm/cmm.c
index 510a18299196..a51c892f14f3 100644
--- a/arch/s390/mm/cmm.c
+++ b/arch/s390/mm/cmm.c
@@ -298,16 +298,16 @@ static int cmm_timeout_handler(struct ctl_table *ctl, int write,
}
if (write) {
- len = *lenp;
- if (copy_from_user(buf, buffer,
- len > sizeof(buf) ? sizeof(buf) : len))
+ len = min(*lenp, sizeof(buf));
+ if (copy_from_user(buf, buffer, len))
return -EFAULT;
- buf[sizeof(buf) - 1] = '\0';
+ buf[len - 1] = '\0';
cmm_skip_blanks(buf, &p);
nr = simple_strtoul(p, &p, 0);
cmm_skip_blanks(p, &p);
seconds = simple_strtoul(p, &p, 0);
cmm_set_timeout(nr, seconds);
+ *ppos += *lenp;
} else {
len = sprintf(buf, "%ld %ld\n",
cmm_timeout_pages, cmm_timeout_seconds);
@@ -315,9 +315,9 @@ static int cmm_timeout_handler(struct ctl_table *ctl, int write,
len = *lenp;
if (copy_to_user(buffer, buf, len))
return -EFAULT;
+ *lenp = len;
+ *ppos += len;
}
- *lenp = len;
- *ppos += len;
return 0;
}