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MIPS: OCTEON: Improve _machine_halt implementation. 

As noted by Wladislav Wiebe:
   $ halt
   ..
   Sent SIGKILL to all processes
   Requesting system halt
   [66.729373] System halted.
   [66.733244]
   [66.734761] =====================================
   [66.739473] [ BUG: lock held at task exit time! ]
   [66.744188] 3.8.7-0-sampleversion-fct #49 Tainted: G           O
   [66.750202] -------------------------------------
   [66.754913] init/21479 is exiting with locks still held!
   [66.760234] 1 lock held by init/21479:
   [66.763990]  #0:  (reboot_mutex){+.+...}, at: [<ffffffff801776c8>] SyS_reboot+0xe0/0x218
   [66.772165]
   [66.772165] stack backtrace:
   [66.776532] Call Trace:
   [66.778992] [<ffffffff805780a8>] dump_stack+0x8/0x34
   [66.783972] [<ffffffff801618b0>] do_exit+0x610/0xa70
   [66.788948] [<ffffffff801777a8>] SyS_reboot+0x1c0/0x218
   [66.794186] [<ffffffff8013d6a4>] handle_sys64+0x44/0x64

This is an alternative fix to the one sent by Wladislav.  We kill the
watchdog for each CPU and then spin in WAIT with interrupts disabled.
This is the lowest power mode for the OCTEON.  If we were to spin with
interrupts enabled, we would get a continual stream of warning messages
and backtraces from the lockup detector, so I chose to disable
interrupts.

Signed-off-by: David Daney <david.daney@cavium.com>
Cc: Maxim Uvarov <muvarov@gmail.com>
Cc: Wladislav Wiebe <wladislav.kw@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: David Daney <david.daney@cavium.com>
Patchwork: https://patchwork.linux-mips.org/patch/5324/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
This commit is contained in:
David Daney 2013-05-24 16:23:02 +00:00 committed by Ralf Baechle
parent 406b5ee222
commit 38c3c0f673
1 changed files with 9 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

15
arch/mips/cavium-octeon/setup.c
View File

@ -428,13 +428,16 @@ static void octeon_restart(char *command)
*/
static void octeon_kill_core(void *arg)
{
mb();
if (octeon_is_simulation()) {
/* The simulator needs the watchdog to stop for dead cores */
cvmx_write_csr(CVMX_CIU_WDOGX(cvmx_get_core_num()), 0);
if (octeon_is_simulation())
/* A break instruction causes the simulator stop a core */
asm volatile ("sync\nbreak");
}
asm volatile ("break" ::: "memory");
local_irq_disable();
/* Disable watchdog on this core. */
cvmx_write_csr(CVMX_CIU_WDOGX(cvmx_get_core_num()), 0);
/* Spin in a low power mode. */
while (true)
asm volatile ("wait" ::: "memory");
}