cachepc-linux

Fork of AMDESE/linux with modifications for CachePC side-channel attack
git clone https://git.sinitax.com/sinitax/cachepc-linux
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rtas-rtc.c (2732B)

      1// SPDX-License-Identifier: GPL-2.0
      2#include <linux/kernel.h>
      3#include <linux/time.h>
      4#include <linux/timer.h>
      5#include <linux/init.h>
      6#include <linux/rtc.h>
      7#include <linux/delay.h>
      8#include <linux/ratelimit.h>
      9#include <asm/rtas.h>
     10#include <asm/time.h>
     11
     12
     13#define MAX_RTC_WAIT 5000	/* 5 sec */
     14
     15time64_t __init rtas_get_boot_time(void)
     16{
     17	int ret[8];
     18	int error;
     19	unsigned int wait_time;
     20	u64 max_wait_tb;
     21
     22	max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
     23	do {
     24		error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
     25
     26		wait_time = rtas_busy_delay_time(error);
     27		if (wait_time) {
     28			/* This is boot time so we spin. */
     29			udelay(wait_time*1000);
     30		}
     31	} while (wait_time && (get_tb() < max_wait_tb));
     32
     33	if (error != 0) {
     34		printk_ratelimited(KERN_WARNING
     35				   "error: reading the clock failed (%d)\n",
     36				   error);
     37		return 0;
     38	}
     39
     40	return mktime64(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
     41}
     42
     43/* NOTE: get_rtc_time will get an error if executed in interrupt context
     44 * and if a delay is needed to read the clock.  In this case we just
     45 * silently return without updating rtc_tm.
     46 */
     47void rtas_get_rtc_time(struct rtc_time *rtc_tm)
     48{
     49        int ret[8];
     50	int error;
     51	unsigned int wait_time;
     52	u64 max_wait_tb;
     53
     54	max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
     55	do {
     56		error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
     57
     58		wait_time = rtas_busy_delay_time(error);
     59		if (wait_time) {
     60			if (in_interrupt()) {
     61				memset(rtc_tm, 0, sizeof(struct rtc_time));
     62				printk_ratelimited(KERN_WARNING
     63						   "error: reading clock "
     64						   "would delay interrupt\n");
     65				return;	/* delay not allowed */
     66			}
     67			msleep(wait_time);
     68		}
     69	} while (wait_time && (get_tb() < max_wait_tb));
     70
     71	if (error != 0) {
     72		printk_ratelimited(KERN_WARNING
     73				   "error: reading the clock failed (%d)\n",
     74				   error);
     75		return;
     76        }
     77
     78	rtc_tm->tm_sec = ret[5];
     79	rtc_tm->tm_min = ret[4];
     80	rtc_tm->tm_hour = ret[3];
     81	rtc_tm->tm_mday = ret[2];
     82	rtc_tm->tm_mon = ret[1] - 1;
     83	rtc_tm->tm_year = ret[0] - 1900;
     84}
     85
     86int rtas_set_rtc_time(struct rtc_time *tm)
     87{
     88	int error, wait_time;
     89	u64 max_wait_tb;
     90
     91	max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
     92	do {
     93	        error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
     94				  tm->tm_year + 1900, tm->tm_mon + 1,
     95				  tm->tm_mday, tm->tm_hour, tm->tm_min,
     96				  tm->tm_sec, 0);
     97
     98		wait_time = rtas_busy_delay_time(error);
     99		if (wait_time) {
    100			if (in_interrupt())
    101				return 1;	/* probably decrementer */
    102			msleep(wait_time);
    103		}
    104	} while (wait_time && (get_tb() < max_wait_tb));
    105
    106	if (error != 0)
    107		printk_ratelimited(KERN_WARNING
    108				   "error: setting the clock failed (%d)\n",
    109				   error);
    110
    111        return 0;
    112}