Revision 61bf318eac2c13356f7bd1c6a05421ef504ccc8a authored by Sergei Trofimovich on 13 March 2021, 05:08:27 UTC, committed by Linus Torvalds on 13 March 2021, 19:27:31 UTC
In https://bugs.gentoo.org/769614 Dmitry noticed that `ptrace(PTRACE_GET_SYSCALL_INFO)` does not return error sign properly. The bug is in mismatch between get/set errors: static inline long syscall_get_error(struct task_struct *task, struct pt_regs *regs) { return regs->r10 == -1 ? regs->r8:0; } static inline long syscall_get_return_value(struct task_struct *task, struct pt_regs *regs) { return regs->r8; } static inline void syscall_set_return_value(struct task_struct *task, struct pt_regs *regs, int error, long val) { if (error) { /* error < 0, but ia64 uses > 0 return value */ regs->r8 = -error; regs->r10 = -1; } else { regs->r8 = val; regs->r10 = 0; } } Tested on v5.10 on rx3600 machine (ia64 9040 CPU). Link: https://lkml.kernel.org/r/20210221002554.333076-2-slyfox@gentoo.org Link: https://bugs.gentoo.org/769614 Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org> Reported-by: Dmitry V. Levin <ldv@altlinux.org> Reviewed-by: Dmitry V. Levin <ldv@altlinux.org> Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1 parent 0ceb1ac
governor_simpleondemand.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/drivers/devfreq/governor_simpleondemand.c
*
* Copyright (C) 2011 Samsung Electronics
* MyungJoo Ham <myungjoo.ham@samsung.com>
*/
#include <linux/errno.h>
#include <linux/module.h>
#include <linux/devfreq.h>
#include <linux/math64.h>
#include "governor.h"
/* Default constants for DevFreq-Simple-Ondemand (DFSO) */
#define DFSO_UPTHRESHOLD (90)
#define DFSO_DOWNDIFFERENCTIAL (5)
static int devfreq_simple_ondemand_func(struct devfreq *df,
unsigned long *freq)
{
int err;
struct devfreq_dev_status *stat;
unsigned long long a, b;
unsigned int dfso_upthreshold = DFSO_UPTHRESHOLD;
unsigned int dfso_downdifferential = DFSO_DOWNDIFFERENCTIAL;
struct devfreq_simple_ondemand_data *data = df->data;
err = devfreq_update_stats(df);
if (err)
return err;
stat = &df->last_status;
if (data) {
if (data->upthreshold)
dfso_upthreshold = data->upthreshold;
if (data->downdifferential)
dfso_downdifferential = data->downdifferential;
}
if (dfso_upthreshold > 100 ||
dfso_upthreshold < dfso_downdifferential)
return -EINVAL;
/* Assume MAX if it is going to be divided by zero */
if (stat->total_time == 0) {
*freq = DEVFREQ_MAX_FREQ;
return 0;
}
/* Prevent overflow */
if (stat->busy_time >= (1 << 24) || stat->total_time >= (1 << 24)) {
stat->busy_time >>= 7;
stat->total_time >>= 7;
}
/* Set MAX if it's busy enough */
if (stat->busy_time * 100 >
stat->total_time * dfso_upthreshold) {
*freq = DEVFREQ_MAX_FREQ;
return 0;
}
/* Set MAX if we do not know the initial frequency */
if (stat->current_frequency == 0) {
*freq = DEVFREQ_MAX_FREQ;
return 0;
}
/* Keep the current frequency */
if (stat->busy_time * 100 >
stat->total_time * (dfso_upthreshold - dfso_downdifferential)) {
*freq = stat->current_frequency;
return 0;
}
/* Set the desired frequency based on the load */
a = stat->busy_time;
a *= stat->current_frequency;
b = div_u64(a, stat->total_time);
b *= 100;
b = div_u64(b, (dfso_upthreshold - dfso_downdifferential / 2));
*freq = (unsigned long) b;
return 0;
}
static int devfreq_simple_ondemand_handler(struct devfreq *devfreq,
unsigned int event, void *data)
{
switch (event) {
case DEVFREQ_GOV_START:
devfreq_monitor_start(devfreq);
break;
case DEVFREQ_GOV_STOP:
devfreq_monitor_stop(devfreq);
break;
case DEVFREQ_GOV_UPDATE_INTERVAL:
devfreq_update_interval(devfreq, (unsigned int *)data);
break;
case DEVFREQ_GOV_SUSPEND:
devfreq_monitor_suspend(devfreq);
break;
case DEVFREQ_GOV_RESUME:
devfreq_monitor_resume(devfreq);
break;
default:
break;
}
return 0;
}
static struct devfreq_governor devfreq_simple_ondemand = {
.name = DEVFREQ_GOV_SIMPLE_ONDEMAND,
.attrs = DEVFREQ_GOV_ATTR_POLLING_INTERVAL
| DEVFREQ_GOV_ATTR_TIMER,
.get_target_freq = devfreq_simple_ondemand_func,
.event_handler = devfreq_simple_ondemand_handler,
};
static int __init devfreq_simple_ondemand_init(void)
{
return devfreq_add_governor(&devfreq_simple_ondemand);
}
subsys_initcall(devfreq_simple_ondemand_init);
static void __exit devfreq_simple_ondemand_exit(void)
{
int ret;
ret = devfreq_remove_governor(&devfreq_simple_ondemand);
if (ret)
pr_err("%s: failed remove governor %d\n", __func__, ret);
return;
}
module_exit(devfreq_simple_ondemand_exit);
MODULE_LICENSE("GPL");
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