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// SPDX-License-Identifier: GPL-2.0
/*
* Request power readings for resources in a computing environment via
* diag 0x324. diag 0x324 stores the power readings in the power information
* block (pib).
*
* Copyright IBM Corp. 2024
*/
#define pr_fmt(fmt) "diag324: " fmt
#include <linux/fs.h>
#include <linux/gfp.h>
#include <linux/ioctl.h>
#include <linux/jiffies.h>
#include <linux/kernel.h>
#include <linux/ktime.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/timer.h>
#include <linux/types.h>
#include <linux/uaccess.h>
#include <linux/vmalloc.h>
#include <asm/diag.h>
#include <asm/sclp.h>
#include <asm/timex.h>
#include <uapi/asm/diag.h>
#include "diag_ioctl.h"
enum subcode {
DIAG324_SUBC_0 = 0,
DIAG324_SUBC_1 = 1,
DIAG324_SUBC_2 = 2,
};
enum retcode {
DIAG324_RET_SUCCESS = 0x0001,
DIAG324_RET_SUBC_NOTAVAIL = 0x0103,
DIAG324_RET_INSUFFICIENT_SIZE = 0x0104,
DIAG324_RET_READING_UNAVAILABLE = 0x0105,
};
union diag324_response {
u64 response;
struct {
u64 installed : 32;
u64 : 16;
u64 rc : 16;
} sc0;
struct {
u64 format : 16;
u64 : 16;
u64 pib_len : 16;
u64 rc : 16;
} sc1;
struct {
u64 : 48;
u64 rc : 16;
} sc2;
};
union diag324_request {
u64 request;
struct {
u64 : 32;
u64 allocated : 16;
u64 : 12;
u64 sc : 4;
} sc2;
};
struct pib {
u32 : 8;
u32 num : 8;
u32 len : 16;
u32 : 24;
u32 hlen : 8;
u64 : 64;
u64 intv;
u8 r[];
} __packed;
struct pibdata {
struct pib *pib;
ktime_t expire;
u64 sequence;
size_t len;
int rc;
};
static DEFINE_MUTEX(pibmutex);
static struct pibdata pibdata;
#define PIBWORK_DELAY (5 * NSEC_PER_SEC)
static void pibwork_handler(struct work_struct *work);
static DECLARE_DELAYED_WORK(pibwork, pibwork_handler);
static unsigned long diag324(unsigned long subcode, void *addr)
{
union register_pair rp = { .even = (unsigned long)addr };
diag_stat_inc(DIAG_STAT_X324);
asm volatile("diag %[rp],%[subcode],0x324\n"
: [rp] "+d" (rp.pair)
: [subcode] "d" (subcode)
: "memory");
return rp.odd;
}
static void pibwork_handler(struct work_struct *work)
{
struct pibdata *data = &pibdata;
ktime_t timedout;
mutex_lock(&pibmutex);
timedout = ktime_add_ns(data->expire, PIBWORK_DELAY);
if (ktime_before(ktime_get(), timedout)) {
mod_delayed_work(system_wq, &pibwork, nsecs_to_jiffies(PIBWORK_DELAY));
goto out;
}
vfree(data->pib);
data->pib = NULL;
out:
mutex_unlock(&pibmutex);
}
static void pib_update(struct pibdata *data)
{
union diag324_request req = { .sc2.sc = DIAG324_SUBC_2, .sc2.allocated = data->len };
union diag324_response res;
int rc;
memset(data->pib, 0, data->len);
res.response = diag324(req.request, data->pib);
switch (res.sc2.rc) {
case DIAG324_RET_SUCCESS:
rc = 0;
break;
case DIAG324_RET_SUBC_NOTAVAIL:
rc = -ENOENT;
break;
case DIAG324_RET_INSUFFICIENT_SIZE:
rc = -EMSGSIZE;
break;
case DIAG324_RET_READING_UNAVAILABLE:
rc = -EBUSY;
break;
default:
rc = -EINVAL;
}
data->rc = rc;
}
long diag324_pibbuf(unsigned long arg)
{
struct diag324_pib __user *udata = (struct diag324_pib __user *)arg;
struct pibdata *data = &pibdata;
static bool first = true;
u64 address;
int rc;
if (!data->len)
return -EOPNOTSUPP;
if (get_user(address, &udata->address))
return -EFAULT;
mutex_lock(&pibmutex);
rc = -ENOMEM;
if (!data->pib)
data->pib = vmalloc(data->len);
if (!data->pib)
goto out;
if (first || ktime_after(ktime_get(), data->expire)) {
pib_update(data);
data->sequence++;
data->expire = ktime_add_ns(ktime_get(), tod_to_ns(data->pib->intv));
mod_delayed_work(system_wq, &pibwork, nsecs_to_jiffies(PIBWORK_DELAY));
first = false;
}
rc = data->rc;
if (rc != 0 && rc != -EBUSY)
goto out;
rc = copy_to_user((void __user *)address, data->pib, data->pib->len);
rc |= put_user(data->sequence, &udata->sequence);
if (rc)
rc = -EFAULT;
out:
mutex_unlock(&pibmutex);
return rc;
}
long diag324_piblen(unsigned long arg)
{
struct pibdata *data = &pibdata;
if (!data->len)
return -EOPNOTSUPP;
if (put_user(data->len, (size_t __user *)arg))
return -EFAULT;
return 0;
}
static int __init diag324_init(void)
{
union diag324_response res;
unsigned long installed;
if (!sclp.has_diag324)
return -EOPNOTSUPP;
res.response = diag324(DIAG324_SUBC_0, NULL);
if (res.sc0.rc != DIAG324_RET_SUCCESS)
return -EOPNOTSUPP;
installed = res.response;
if (!test_bit_inv(DIAG324_SUBC_1, &installed))
return -EOPNOTSUPP;
if (!test_bit_inv(DIAG324_SUBC_2, &installed))
return -EOPNOTSUPP;
res.response = diag324(DIAG324_SUBC_1, NULL);
if (res.sc1.rc != DIAG324_RET_SUCCESS)
return -EOPNOTSUPP;
pibdata.len = res.sc1.pib_len;
return 0;
}
device_initcall(diag324_init);
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