From 38c3c0f6733bec1d1841915a9a82d2c324362686 Mon Sep 17 00:00:00 2001 From: David Daney Date: Fri, 24 May 2013 16:23:02 +0000 Subject: [PATCH] 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: [] SyS_reboot+0xe0/0x218 [66.772165] [66.772165] stack backtrace: [66.776532] Call Trace: [66.778992] [] dump_stack+0x8/0x34 [66.783972] [] do_exit+0x610/0xa70 [66.788948] [] SyS_reboot+0x1c0/0x218 [66.794186] [] 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 Cc: Maxim Uvarov Cc: Wladislav Wiebe Cc: linux-mips@linux-mips.org Cc: David Daney Patchwork: https://patchwork.linux-mips.org/patch/5324/ Signed-off-by: Ralf Baechle --- arch/mips/cavium-octeon/setup.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/arch/mips/cavium-octeon/setup.c b/arch/mips/cavium-octeon/setup.c index b0baa299f899..01b1b3f94feb 100644 --- a/arch/mips/cavium-octeon/setup.c +++ b/arch/mips/cavium-octeon/setup.c @@ -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"); } -- 2.30.2