blob: 1affe15bed76be23997bb3f3ab202c60f73b6521 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
|
/* SPDX-License-Identifier: GPL-2.0-only */
#include <console/console.h>
#include <cpu/x86/lapic.h>
#include <delay.h>
#include <halt.h>
/**
* Sending INIT IPI to self is equivalent of asserting #INIT with a bit of
* delay.
* An undefined number of instruction cycles will complete. All global locks
* must be released before INIT IPI and no printk is allowed after this.
* De-asserting INIT IPI is a no-op on later Intel CPUs.
*
* If you set DEBUG_HALT_SELF to 1, printk's after INIT IPI are enabled
* but running thread may halt without releasing the lock and effectively
* deadlock other CPUs.
*/
#define DEBUG_HALT_SELF 0
#if DEBUG_HALT_SELF
#define dprintk(LEVEL, args...) do { printk(LEVEL, ##args); } while (0)
#else
#define dprintk(LEVEL, args...) do { } while (0)
#endif
static void wait_for_ipi_completion_without_printk(const int timeout_ms)
{
int loops = timeout_ms * 10;
uint32_t send_status;
/* wait for the ipi send to finish */
dprintk(BIOS_SPEW, "Waiting for send to finish...\n");
do {
dprintk(BIOS_SPEW, "+");
udelay(100);
send_status = lapic_busy();
} while (send_status && (--loops > 0));
if (send_status)
dprintk(BIOS_ERR, "timed out\n");
}
/**
* Normally this function is defined in lapic.h as an always inline function
* that just keeps the CPU in a hlt() loop. This does not work on all CPUs.
* I think all hyperthreading CPUs might need this version, but I could only
* verify this on the Intel Core Duo
*/
void stop_this_cpu(void)
{
const int timeout_100ms = 100;
unsigned long id = lapicid();
printk(BIOS_DEBUG, "CPU %ld going down...\n", id);
/* send an LAPIC INIT to myself */
lapic_send_ipi_self(LAPIC_INT_LEVELTRIG | LAPIC_INT_ASSERT | LAPIC_DM_INIT);
wait_for_ipi_completion_without_printk(timeout_100ms);
mdelay(10);
dprintk(BIOS_SPEW, "Deasserting INIT.\n");
/* Deassert the LAPIC INIT */
lapic_send_ipi_self(LAPIC_INT_LEVELTRIG | LAPIC_DM_INIT);
wait_for_ipi_completion_without_printk(timeout_100ms);
halt();
}
|
