From ac15e00b1efe705b66a36d1a6a9db7f6ed524c43 Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 31 Oct 2011 09:22:22 +0000 Subject: ARM: restart: move reboot failure handing into machine_restart() Move the failure to reboot into machine_restart() to always catch this condition, even if a platform decides to hook the restarting via arm_pm_restart(). Acked-by: Nicolas Pitre Acked-by: Will Deacon Acked-by: H Hartley Sweeten Acked-by: Tony Lindgren Signed-off-by: Russell King --- arch/arm/kernel/process.c | 20 +++++++++----------- 1 file changed, 9 insertions(+), 11 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 75316f0dd02..3bda1c37977 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -114,18 +114,8 @@ void arm_machine_restart(char mode, const char *cmd) /* Push out any further dirty data, and ensure cache is empty */ flush_cache_all(); - /* - * Now call the architecture specific reboot code. - */ + /* Now call the architecture specific reboot code. */ arch_reset(mode, cmd); - - /* - * Whoops - the architecture was unable to reboot. - * Tell the user! - */ - mdelay(1000); - printk("Reboot failed -- System halted\n"); - while (1); } /* @@ -250,7 +240,15 @@ void machine_power_off(void) void machine_restart(char *cmd) { machine_shutdown(); + arm_pm_restart(reboot_mode, cmd); + + /* Give a grace period for failure to restart of 1s */ + mdelay(1000); + + /* Whoops - the platform was unable to reboot. Tell the user! */ + printk("Reboot failed -- System halted\n"); + while (1); } void __show_regs(struct pt_regs *regs) -- cgit v1.2.3-18-g5258 From 5aafec15bdc54cf0722696c95091d7bd674bfcad Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 1 Nov 2011 10:15:27 +0000 Subject: ARM: restart: remove argument to setup_mm_for_reboot() setup_mm_for_reboot() doesn't make use of its argument, so remove it. Acked-by: Nicolas Pitre Acked-by: Will Deacon Acked-by: H Hartley Sweeten Acked-by: Tony Lindgren Signed-off-by: Russell King --- arch/arm/kernel/process.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 3bda1c37977..4181738452f 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -57,7 +57,7 @@ static const char *isa_modes[] = { "ARM" , "Thumb" , "Jazelle", "ThumbEE" }; -extern void setup_mm_for_reboot(char mode); +extern void setup_mm_for_reboot(void); static volatile int hlt_counter; @@ -103,7 +103,7 @@ void arm_machine_restart(char mode, const char *cmd) * we may need it to insert some 1:1 mappings so that * soft boot works. */ - setup_mm_for_reboot(mode); + setup_mm_for_reboot(); /* Clean and invalidate caches */ flush_cache_all(); -- cgit v1.2.3-18-g5258 From e879c862fb81b986095ae7a4676b2281c2f97957 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 1 Nov 2011 13:16:26 +0000 Subject: ARM: restart: only perform setup for restart when soft-restarting MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We only need to set the system up for a soft-restart if we're going to be doing a soft-restart. Provide a new function (soft_restart()) which does the setup and final call for this, and make platforms use it. Eliminate the call to setup_restart() from the default handler. This means that platforms arch_reset() function is no longer called with the page tables prepared for a soft-restart, and caches will still be enabled. Acked-by: Nicolas Pitre Acked-by: Will Deacon Acked-by: H Hartley Sweeten Acked-by: Kukjin Kim Acked-by: Sascha Hauer Acked-by: Viresh Kumar Acked-by: Krzysztof Ha■asa Acked-by: Paul Mundt Acked-by: Richard Purdie Acked-by: Wan ZongShun Acked-by: Eric Miao Signed-off-by: Russell King --- arch/arm/kernel/process.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 4181738452f..1e8b3e2de7a 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -92,7 +92,7 @@ static int __init hlt_setup(char *__unused) __setup("nohlt", nohlt_setup); __setup("hlt", hlt_setup); -void arm_machine_restart(char mode, const char *cmd) +void soft_restart(unsigned long addr) { /* Disable interrupts first */ local_irq_disable(); @@ -114,7 +114,16 @@ void arm_machine_restart(char mode, const char *cmd) /* Push out any further dirty data, and ensure cache is empty */ flush_cache_all(); - /* Now call the architecture specific reboot code. */ + cpu_reset(addr); +} + +void arm_machine_restart(char mode, const char *cmd) +{ + /* Disable interrupts first */ + local_irq_disable(); + local_fiq_disable(); + + /* Call the architecture specific reboot code. */ arch_reset(mode, cmd); } -- cgit v1.2.3-18-g5258 From 11ed0ba1754841316d4095478944300acf19acc3 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 14 Nov 2011 17:24:58 +0100 Subject: ARM: 7161/1: errata: no automatic store buffer drain This patch implements a workaround for PL310 erratum 769419. On revisions of the PL310 prior to r3p2, the Store Buffer does not automatically drain. This can cause normal, non-cacheable writes to be retained when the memory system is idle, leading to suboptimal I/O performance for drivers using coherent DMA. This patch adds an optional wmb() call to the cpu_idle loop. On systems with an outer cache, this causes an explicit flush of the store buffer. Cc: stable@vger.kernel.org Acked-by: Catalin Marinas Tested-by: Marc Zyngier Signed-off-by: Will Deacon Signed-off-by: Russell King --- arch/arm/kernel/process.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 75316f0dd02..3d0c6fb74ae 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -192,6 +192,9 @@ void cpu_idle(void) #endif local_irq_disable(); +#ifdef CONFIG_PL310_ERRATA_769419 + wmb(); +#endif if (hlt_counter) { local_irq_enable(); cpu_relax(); -- cgit v1.2.3-18-g5258 From 280f06774afedf849f0b34248ed6aff57d0f6908 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Fri, 7 Oct 2011 18:22:06 +0200 Subject: nohz: Separate out irq exit and idle loop dyntick logic The tick_nohz_stop_sched_tick() function, which tries to delay the next timer tick as long as possible, can be called from two places: - From the idle loop to start the dytick idle mode - From interrupt exit if we have interrupted the dyntick idle mode, so that we reprogram the next tick event in case the irq changed some internal state that requires this action. There are only few minor differences between both that are handled by that function, driven by the ts->inidle cpu variable and the inidle parameter. The whole guarantees that we only update the dyntick mode on irq exit if we actually interrupted the dyntick idle mode, and that we enter in RCU extended quiescent state from idle loop entry only. Split this function into: - tick_nohz_idle_enter(), which sets ts->inidle to 1, enters dynticks idle mode unconditionally if it can, and enters into RCU extended quiescent state. - tick_nohz_irq_exit() which only updates the dynticks idle mode when ts->inidle is set (ie: if tick_nohz_idle_enter() has been called). To maintain symmetry, tick_nohz_restart_sched_tick() has been renamed into tick_nohz_idle_exit(). This simplifies the code and micro-optimize the irq exit path (no need for local_irq_save there). This also prepares for the split between dynticks and rcu extended quiescent state logics. We'll need this split to further fix illegal uses of RCU in extended quiescent states in the idle loop. Signed-off-by: Frederic Weisbecker Cc: Mike Frysinger Cc: Guan Xuetao Cc: David Miller Cc: Chris Metcalf Cc: Hans-Christian Egtvedt Cc: Ralf Baechle Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: H. Peter Anvin Cc: Russell King Cc: Paul Mackerras Cc: Heiko Carstens Cc: Paul Mundt Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- arch/arm/kernel/process.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 3d0c6fb74ae..3f1f8daf703 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -183,7 +183,7 @@ void cpu_idle(void) /* endless idle loop with no priority at all */ while (1) { - tick_nohz_stop_sched_tick(1); + tick_nohz_idle_enter(); leds_event(led_idle_start); while (!need_resched()) { #ifdef CONFIG_HOTPLUG_CPU @@ -213,7 +213,7 @@ void cpu_idle(void) } } leds_event(led_idle_end); - tick_nohz_restart_sched_tick(); + tick_nohz_idle_exit(); preempt_enable_no_resched(); schedule(); preempt_disable(); -- cgit v1.2.3-18-g5258 From 2bbb6817c0ac1b5f2a68d720f364f98eeb1ac4fd Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Sat, 8 Oct 2011 16:01:00 +0200 Subject: nohz: Allow rcu extended quiescent state handling seperately from tick stop It is assumed that rcu won't be used once we switch to tickless mode and until we restart the tick. However this is not always true, as in x86-64 where we dereference the idle notifiers after the tick is stopped. To prepare for fixing this, add two new APIs: tick_nohz_idle_enter_norcu() and tick_nohz_idle_exit_norcu(). If no use of RCU is made in the idle loop between tick_nohz_enter_idle() and tick_nohz_exit_idle() calls, the arch must instead call the new *_norcu() version such that the arch doesn't need to call rcu_idle_enter() and rcu_idle_exit(). Otherwise the arch must call tick_nohz_enter_idle() and tick_nohz_exit_idle() and also call explicitly: - rcu_idle_enter() after its last use of RCU before the CPU is put to sleep. - rcu_idle_exit() before the first use of RCU after the CPU is woken up. Signed-off-by: Frederic Weisbecker Cc: Mike Frysinger Cc: Guan Xuetao Cc: David Miller Cc: Chris Metcalf Cc: Hans-Christian Egtvedt Cc: Ralf Baechle Cc: Paul E. McKenney Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: H. Peter Anvin Cc: Russell King Cc: Paul Mackerras Cc: Heiko Carstens Cc: Paul Mundt Signed-off-by: Paul E. McKenney --- arch/arm/kernel/process.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 3f1f8daf703..47e34c09127 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -183,7 +183,7 @@ void cpu_idle(void) /* endless idle loop with no priority at all */ while (1) { - tick_nohz_idle_enter(); + tick_nohz_idle_enter_norcu(); leds_event(led_idle_start); while (!need_resched()) { #ifdef CONFIG_HOTPLUG_CPU @@ -213,7 +213,7 @@ void cpu_idle(void) } } leds_event(led_idle_end); - tick_nohz_idle_exit(); + tick_nohz_idle_exit_norcu(); preempt_enable_no_resched(); schedule(); preempt_disable(); -- cgit v1.2.3-18-g5258 From 1268fbc746ea1cd279886a740dcbad4ba5232225 Mon Sep 17 00:00:00 2001 From: Frederic Weisbecker Date: Thu, 17 Nov 2011 18:48:14 +0100 Subject: nohz: Remove tick_nohz_idle_enter_norcu() / tick_nohz_idle_exit_norcu() Those two APIs were provided to optimize the calls of tick_nohz_idle_enter() and rcu_idle_enter() into a single irq disabled section. This way no interrupt happening in-between would needlessly process any RCU job. Now we are talking about an optimization for which benefits have yet to be measured. Let's start simple and completely decouple idle rcu and dyntick idle logics to simplify. Signed-off-by: Frederic Weisbecker Cc: Ingo Molnar Cc: Thomas Gleixner Cc: Peter Zijlstra Reviewed-by: Josh Triplett Signed-off-by: Paul E. McKenney --- arch/arm/kernel/process.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 47e34c09127..e8e8fe505df 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -183,7 +183,8 @@ void cpu_idle(void) /* endless idle loop with no priority at all */ while (1) { - tick_nohz_idle_enter_norcu(); + tick_nohz_idle_enter(); + rcu_idle_enter(); leds_event(led_idle_start); while (!need_resched()) { #ifdef CONFIG_HOTPLUG_CPU @@ -213,7 +214,8 @@ void cpu_idle(void) } } leds_event(led_idle_end); - tick_nohz_idle_exit_norcu(); + rcu_idle_exit(); + tick_nohz_idle_exit(); preempt_enable_no_resched(); schedule(); preempt_disable(); -- cgit v1.2.3-18-g5258 From 290130a17718c1451bb8a77a5e2510e0279bd5f3 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Mon, 6 Jun 2011 12:28:54 +0100 Subject: ARM: reset: implement soft_restart for jumping to a physical address Tools such as kexec and CPU hotplug require a way to reset the processor and branch to some code in physical space. This requires various bits of jiggery pokery with the caches and MMU which, when it goes wrong, tends to lock up the system. This patch fleshes out the soft_restart implementation so that it branches to the reset code using the identity mapping. This requires us to change to a temporary stack, held within the kernel image as a static array, to avoid conflicting with the new view of memory. Signed-off-by: Will Deacon --- arch/arm/kernel/process.c | 50 +++++++++++++++++++++++++++++++++++++---------- 1 file changed, 40 insertions(+), 10 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index eeb3e16c604..423bb201945 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -92,17 +92,23 @@ static int __init hlt_setup(char *__unused) __setup("nohlt", nohlt_setup); __setup("hlt", hlt_setup); -void soft_restart(unsigned long addr) +extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); +typedef void (*phys_reset_t)(unsigned long); + +/* + * A temporary stack to use for CPU reset. This is static so that we + * don't clobber it with the identity mapping. When running with this + * stack, any references to the current task *will not work* so you + * should really do as little as possible before jumping to your reset + * code. + */ +static u64 soft_restart_stack[16]; + +static void __soft_restart(void *addr) { - /* Disable interrupts first */ - local_irq_disable(); - local_fiq_disable(); + phys_reset_t phys_reset; - /* - * Tell the mm system that we are going to reboot - - * we may need it to insert some 1:1 mappings so that - * soft boot works. - */ + /* Take out a flat memory mapping. */ setup_mm_for_reboot(); /* Clean and invalidate caches */ @@ -114,7 +120,31 @@ void soft_restart(unsigned long addr) /* Push out any further dirty data, and ensure cache is empty */ flush_cache_all(); - cpu_reset(addr); + /* Switch to the identity mapping. */ + phys_reset = (phys_reset_t)(unsigned long)virt_to_phys(cpu_reset); + phys_reset((unsigned long)addr); + + /* Should never get here. */ + BUG(); +} + +void soft_restart(unsigned long addr) +{ + u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); + + /* Disable interrupts first */ + local_irq_disable(); + local_fiq_disable(); + + /* Disable the L2 if we're the last man standing. */ + if (num_online_cpus() == 1) + outer_disable(); + + /* Change to the new stack and continue with the reset. */ + call_with_stack(__soft_restart, (void *)addr, (void *)stack); + + /* Should never get here. */ + BUG(); } void arm_machine_restart(char mode, const char *cmd) -- cgit v1.2.3-18-g5258 From f88b8979d26615ce68772cebc85c3b556571afca Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 5 Nov 2011 21:30:00 +0000 Subject: ARM: restart: remove the now empty arch_reset() Remove the now empty arch_reset() from all the mach/system.h includes, and remove its callsite. Remove arm_machine_restart() as this function no longer does anything useful. For samsung platforms, remove the include of mach/system-reset.h and plat/system-reset.h from their respective mach/system.h headers as these just define their arch_reset functions. As a result, the s3c2410 and plat-samsung system-reset.h files are no longer referenced, so remove these files entirely. Acked-by: Nicolas Pitre Acked-by: H Hartley Sweeten Acked-by: Jamie Iles Acked-by: Tony Lindgren Acked-by: Linus Walleij Signed-off-by: Russell King --- arch/arm/kernel/process.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) (limited to 'arch/arm/kernel/process.c') diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index eeb3e16c604..17859ce4e7b 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -117,14 +117,8 @@ void soft_restart(unsigned long addr) cpu_reset(addr); } -void arm_machine_restart(char mode, const char *cmd) +static void null_restart(char mode, const char *cmd) { - /* Disable interrupts first */ - local_irq_disable(); - local_fiq_disable(); - - /* Call the architecture specific reboot code. */ - arch_reset(mode, cmd); } /* @@ -133,7 +127,7 @@ void arm_machine_restart(char mode, const char *cmd) void (*pm_power_off)(void); EXPORT_SYMBOL(pm_power_off); -void (*arm_pm_restart)(char str, const char *cmd) = arm_machine_restart; +void (*arm_pm_restart)(char str, const char *cmd) = null_restart; EXPORT_SYMBOL_GPL(arm_pm_restart); static void do_nothing(void *unused) -- cgit v1.2.3-18-g5258