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Merge branch 'sparc64-jump-to-boot-prom'

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Vijay Kumar says:

====================
sparc64: Jump to boot prom from console on panic

V3 changes:
  - patch 02/04: Added SERIAL_SUNHV conditional group for
    sunhv_migrate_hvcons_irq in smp_send_stop().
V2 changes:
 -  Added cover letter patch

Currently Stop-A (L1A) does not make the kernel switch to OBP on panic. This
patchset addresses this issue. Also, now we can cause a jump to OBP by sending
'break' twice from sunhv console. On bare metal, one can send a break by
typing Esc + 'B' + Sysrq (or whatever). On LDOM, press Ctrl + ] in telnet,
and then "send break" at the telnet prompt.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2017-02-23 08:27:30 -08:00
commit 0d88b86694
5 changed files with 34 additions and 4 deletions
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9
Documentation/sparc/console.txt Normal file
View File

@ -0,0 +1,9 @@
Steps for sending 'break' on sunhv console:
===========================================
On Baremetal:
1. press Esc + 'B'
On LDOM:
1. press Ctrl + ']'
2. telnet> send break

5
arch/sparc/include/asm/setup.h
View File

@ -59,8 +59,11 @@ extern atomic_t dcpage_flushes;
extern atomic_t dcpage_flushes_xcall;
extern int sysctl_tsb_ratio;
#endif
#ifdef CONFIG_SERIAL_SUNHV
void sunhv_migrate_hvcons_irq(int cpu);
#endif
#endif
void sun_do_break(void);
extern int stop_a_enabled;
extern int scons_pwroff;

9
arch/sparc/kernel/smp_64.c
View File

@ -1443,6 +1443,7 @@ void __irq_entry smp_receive_signal_client(int irq, struct pt_regs *regs)
static void stop_this_cpu(void *dummy)
{
set_cpu_online(smp_processor_id(), false);
prom_stopself();
}
@ -1451,9 +1452,15 @@ void smp_send_stop(void)
int cpu;
if (tlb_type == hypervisor) {
int this_cpu = smp_processor_id();
#ifdef CONFIG_SERIAL_SUNHV
sunhv_migrate_hvcons_irq(this_cpu);
#endif
for_each_online_cpu(cpu) {
if (cpu == smp_processor_id())
if (cpu == this_cpu)
continue;
set_cpu_online(cpu, false);
#ifdef CONFIG_SUN_LDOMS
if (ldom_domaining_enabled) {
unsigned long hv_err;

12
drivers/tty/serial/sunhv.c
View File

@ -116,7 +116,7 @@ static int receive_chars_getchar(struct uart_port *port)
static int receive_chars_read(struct uart_port *port)
{
int saw_console_brk = 0;
static int saw_console_brk;
int limit = 10000;
while (limit-- > 0) {
@ -128,6 +128,9 @@ static int receive_chars_read(struct uart_port *port)
bytes_read = 0;
if (stat == CON_BREAK) {
if (saw_console_brk)
sun_do_break();
if (uart_handle_break(port))
continue;
saw_console_brk = 1;
@ -151,6 +154,7 @@ static int receive_chars_read(struct uart_port *port)
if (port->sysrq != 0 && *con_read_page) {
for (i = 0; i < bytes_read; i++)
uart_handle_sysrq_char(port, con_read_page[i]);
saw_console_brk = 0;
}
if (port->state == NULL)
@ -398,6 +402,12 @@ static struct uart_driver sunhv_reg = {
static struct uart_port *sunhv_port;
void sunhv_migrate_hvcons_irq(int cpu)
{
/* Migrate hvcons irq to param cpu */
irq_force_affinity(sunhv_port->irq, cpumask_of(cpu));
}
/* Copy 's' into the con_write_page, decoding "\n" into
* "\r\n" along the way. We have to return two lengths
* because the caller needs to know how much to advance

3
kernel/panic.c
View File

@ -273,7 +273,8 @@ void panic(const char *fmt, ...)
extern int stop_a_enabled;
/* Make sure the user can actually press Stop-A (L1-A) */
stop_a_enabled = 1;
pr_emerg("Press Stop-A (L1-A) to return to the boot prom\n");
pr_emerg("Press Stop-A (L1-A) from sun keyboard or send break\n"
"twice on console to return to the boot prom\n");
}
#endif
#if defined(CONFIG_S390)