From 767bf7e7a1e82a81c59778348d156993d0a6175d Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 1 Apr 2015 16:20:39 +0100 Subject: ARM: fix broken hibernation Normally, when a CPU wants to clear a cache line to zero in the external L2 cache, it would generate bus cycles to write each word as it would do with any other data access. However, a Cortex A9 connected to a L2C-310 has a specific feature where the CPU can detect this operation, and signal that it wants to zero an entire cache line. This feature, known as Full Line of Zeros (FLZ), involves a non-standard AXI signalling mechanism which only the L2C-310 can properly interpret. There are separate enable bits in both the L2C-310 and the Cortex A9 - the L2C-310 needs to be enabled and have the FLZ enable bit set in the auxiliary control register before the Cortex A9 has this feature enabled. Unfortunately, the suspend code was not respecting this - it's not obvious from the code: swsusp_arch_suspend() cpu_suspend() /* saves the Cortex A9 auxiliary control register */ arch_save_image() soft_restart() /* turns off FLZ in Cortex A9, and disables L2C */ cpu_resume() /* restores the Cortex A9 registers, inc auxcr */ At this point, we end up with the L2C disabled, but the Cortex A9 with FLZ enabled - which means any memset() or zeroing of a full cache line will fail to take effect. A similar issue exists in the resume path, but it's slightly more complex: swsusp_arch_suspend() cpu_suspend() /* saves the Cortex A9 auxiliary control register */ arch_save_image() /* image with A9 auxcr saved */ ... swsusp_arch_resume() call_with_stack() arch_restore_image() /* restores image with A9 auxcr saved above */ soft_restart() /* turns off FLZ in Cortex A9, and disables L2C */ cpu_resume() /* restores the Cortex A9 registers, inc auxcr */ Again, here we end up with the L2C disabled, but Cortex A9 FLZ enabled. There's no need to turn off the L2C in either of these two paths; there are benefits from not doing so - for example, the page copies will be faster with the L2C enabled. Hence, fix this by providing a variant of soft_restart() which can be used without turning the L2 cache controller off, and use it in both of these paths to keep the L2C enabled across the respective resume transitions. Fixes: 8ef418c7178f ("ARM: l2c: trial at enabling some Cortex-A9 optimisations") Reported-by: Sean Cross Tested-by: Sean Cross Signed-off-by: Russell King --- arch/arm/kernel/hibernate.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'arch/arm/kernel/hibernate.c') diff --git a/arch/arm/kernel/hibernate.c b/arch/arm/kernel/hibernate.c index c4cc50e58c13..cfb354ff2a60 100644 --- a/arch/arm/kernel/hibernate.c +++ b/arch/arm/kernel/hibernate.c @@ -22,6 +22,7 @@ #include #include #include +#include "reboot.h" int pfn_is_nosave(unsigned long pfn) { @@ -61,7 +62,7 @@ static int notrace arch_save_image(unsigned long unused) ret = swsusp_save(); if (ret == 0) - soft_restart(virt_to_phys(cpu_resume)); + _soft_restart(virt_to_phys(cpu_resume), false); return ret; } @@ -86,7 +87,7 @@ static void notrace arch_restore_image(void *unused) for (pbe = restore_pblist; pbe; pbe = pbe->next) copy_page(pbe->orig_address, pbe->address); - soft_restart(virt_to_phys(cpu_resume)); + _soft_restart(virt_to_phys(cpu_resume), false); } static u64 resume_stack[PAGE_SIZE/2/sizeof(u64)] __nosavedata; -- cgit From 045ab94e10ee17038066d71abc8fdce719ab56f9 Mon Sep 17 00:00:00 2001 From: Russell King Date: Wed, 1 Apr 2015 17:02:45 +0100 Subject: ARM: move reboot code to arch/arm/kernel/reboot.c Move shutdown and reboot related code to a separate file, out of process.c. This helps to avoid polluting process.c with non-process related code. Signed-off-by: Russell King --- arch/arm/kernel/Makefile | 2 +- arch/arm/kernel/hibernate.c | 1 - arch/arm/kernel/process.c | 149 +----------------------------------------- arch/arm/kernel/reboot.c | 155 ++++++++++++++++++++++++++++++++++++++++++++ arch/arm/kernel/reboot.h | 1 + 5 files changed, 158 insertions(+), 150 deletions(-) create mode 100644 arch/arm/kernel/reboot.c (limited to 'arch/arm/kernel/hibernate.c') diff --git a/arch/arm/kernel/Makefile b/arch/arm/kernel/Makefile index 1c1cdfa566ac..b6544abe2f5e 100644 --- a/arch/arm/kernel/Makefile +++ b/arch/arm/kernel/Makefile @@ -16,7 +16,7 @@ CFLAGS_REMOVE_return_address.o = -pg # Object file lists. obj-y := elf.o entry-common.o irq.o opcodes.o \ - process.o ptrace.o return_address.o \ + process.o ptrace.o reboot.o return_address.o \ setup.o signal.o sigreturn_codes.o \ stacktrace.o sys_arm.o time.o traps.o diff --git a/arch/arm/kernel/hibernate.c b/arch/arm/kernel/hibernate.c index cfb354ff2a60..a71501ff6f18 100644 --- a/arch/arm/kernel/hibernate.c +++ b/arch/arm/kernel/hibernate.c @@ -100,7 +100,6 @@ static u64 resume_stack[PAGE_SIZE/2/sizeof(u64)] __nosavedata; */ int swsusp_arch_resume(void) { - extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); call_with_stack(arch_restore_image, 0, resume_stack + ARRAY_SIZE(resume_stack)); return 0; diff --git a/arch/arm/kernel/process.c b/arch/arm/kernel/process.c index 2bf1a162defb..f810a6cc3790 100644 --- a/arch/arm/kernel/process.c +++ b/arch/arm/kernel/process.c @@ -17,12 +17,9 @@ #include #include #include -#include -#include #include #include #include -#include #include #include #include @@ -31,17 +28,14 @@ #include #include #include -#include -#include -#include #include #include #include #include #include #include -#include "reboot.h" +#include #ifdef CONFIG_CC_STACKPROTECTOR #include @@ -60,74 +54,6 @@ static const char *isa_modes[] __maybe_unused = { "ARM" , "Thumb" , "Jazelle", "ThumbEE" }; -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) -{ - phys_reset_t phys_reset; - - /* Take out a flat memory mapping. */ - setup_mm_for_reboot(); - - /* Clean and invalidate caches */ - flush_cache_all(); - - /* Turn off caching */ - cpu_proc_fin(); - - /* Push out any further dirty data, and ensure cache is empty */ - flush_cache_all(); - - /* 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, bool disable_l2) -{ - u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); - - /* Disable interrupts first */ - raw_local_irq_disable(); - local_fiq_disable(); - - /* Disable the L2 if we're the last man standing. */ - if (disable_l2) - 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 soft_restart(unsigned long addr) -{ - _soft_restart(addr, num_online_cpus() == 1); -} - -/* - * Function pointers to optional machine specific functions - */ -void (*pm_power_off)(void); -EXPORT_SYMBOL(pm_power_off); - -void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); - /* * This is our default idle handler. */ @@ -172,79 +98,6 @@ void arch_cpu_idle_dead(void) } #endif -/* - * Called by kexec, immediately prior to machine_kexec(). - * - * This must completely disable all secondary CPUs; simply causing those CPUs - * to execute e.g. a RAM-based pin loop is not sufficient. This allows the - * kexec'd kernel to use any and all RAM as it sees fit, without having to - * avoid any code or data used by any SW CPU pin loop. The CPU hotplug - * functionality embodied in disable_nonboot_cpus() to achieve this. - */ -void machine_shutdown(void) -{ - disable_nonboot_cpus(); -} - -/* - * Halting simply requires that the secondary CPUs stop performing any - * activity (executing tasks, handling interrupts). smp_send_stop() - * achieves this. - */ -void machine_halt(void) -{ - local_irq_disable(); - smp_send_stop(); - - local_irq_disable(); - while (1); -} - -/* - * Power-off simply requires that the secondary CPUs stop performing any - * activity (executing tasks, handling interrupts). smp_send_stop() - * achieves this. When the system power is turned off, it will take all CPUs - * with it. - */ -void machine_power_off(void) -{ - local_irq_disable(); - smp_send_stop(); - - if (pm_power_off) - pm_power_off(); -} - -/* - * Restart requires that the secondary CPUs stop performing any activity - * while the primary CPU resets the system. Systems with a single CPU can - * use soft_restart() as their machine descriptor's .restart hook, since that - * will cause the only available CPU to reset. Systems with multiple CPUs must - * provide a HW restart implementation, to ensure that all CPUs reset at once. - * This is required so that any code running after reset on the primary CPU - * doesn't have to co-ordinate with other CPUs to ensure they aren't still - * executing pre-reset code, and using RAM that the primary CPU's code wishes - * to use. Implementing such co-ordination would be essentially impossible. - */ -void machine_restart(char *cmd) -{ - local_irq_disable(); - smp_send_stop(); - - if (arm_pm_restart) - arm_pm_restart(reboot_mode, cmd); - else - do_kernel_restart(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"); - local_irq_disable(); - while (1); -} - void __show_regs(struct pt_regs *regs) { unsigned long flags; diff --git a/arch/arm/kernel/reboot.c b/arch/arm/kernel/reboot.c new file mode 100644 index 000000000000..1a4d232796be --- /dev/null +++ b/arch/arm/kernel/reboot.c @@ -0,0 +1,155 @@ +/* + * Copyright (C) 1996-2000 Russell King - Converted to ARM. + * Original Copyright (C) 1995 Linus Torvalds + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ +#include +#include +#include + +#include +#include + +#include "reboot.h" + +typedef void (*phys_reset_t)(unsigned long); + +/* + * Function pointers to optional machine specific functions + */ +void (*arm_pm_restart)(enum reboot_mode reboot_mode, const char *cmd); +void (*pm_power_off)(void); +EXPORT_SYMBOL(pm_power_off); + +/* + * 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) +{ + phys_reset_t phys_reset; + + /* Take out a flat memory mapping. */ + setup_mm_for_reboot(); + + /* Clean and invalidate caches */ + flush_cache_all(); + + /* Turn off caching */ + cpu_proc_fin(); + + /* Push out any further dirty data, and ensure cache is empty */ + flush_cache_all(); + + /* 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, bool disable_l2) +{ + u64 *stack = soft_restart_stack + ARRAY_SIZE(soft_restart_stack); + + /* Disable interrupts first */ + raw_local_irq_disable(); + local_fiq_disable(); + + /* Disable the L2 if we're the last man standing. */ + if (disable_l2) + 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 soft_restart(unsigned long addr) +{ + _soft_restart(addr, num_online_cpus() == 1); +} + +/* + * Called by kexec, immediately prior to machine_kexec(). + * + * This must completely disable all secondary CPUs; simply causing those CPUs + * to execute e.g. a RAM-based pin loop is not sufficient. This allows the + * kexec'd kernel to use any and all RAM as it sees fit, without having to + * avoid any code or data used by any SW CPU pin loop. The CPU hotplug + * functionality embodied in disable_nonboot_cpus() to achieve this. + */ +void machine_shutdown(void) +{ + disable_nonboot_cpus(); +} + +/* + * Halting simply requires that the secondary CPUs stop performing any + * activity (executing tasks, handling interrupts). smp_send_stop() + * achieves this. + */ +void machine_halt(void) +{ + local_irq_disable(); + smp_send_stop(); + + local_irq_disable(); + while (1); +} + +/* + * Power-off simply requires that the secondary CPUs stop performing any + * activity (executing tasks, handling interrupts). smp_send_stop() + * achieves this. When the system power is turned off, it will take all CPUs + * with it. + */ +void machine_power_off(void) +{ + local_irq_disable(); + smp_send_stop(); + + if (pm_power_off) + pm_power_off(); +} + +/* + * Restart requires that the secondary CPUs stop performing any activity + * while the primary CPU resets the system. Systems with a single CPU can + * use soft_restart() as their machine descriptor's .restart hook, since that + * will cause the only available CPU to reset. Systems with multiple CPUs must + * provide a HW restart implementation, to ensure that all CPUs reset at once. + * This is required so that any code running after reset on the primary CPU + * doesn't have to co-ordinate with other CPUs to ensure they aren't still + * executing pre-reset code, and using RAM that the primary CPU's code wishes + * to use. Implementing such co-ordination would be essentially impossible. + */ +void machine_restart(char *cmd) +{ + local_irq_disable(); + smp_send_stop(); + + if (arm_pm_restart) + arm_pm_restart(reboot_mode, cmd); + else + do_kernel_restart(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"); + local_irq_disable(); + while (1); +} diff --git a/arch/arm/kernel/reboot.h b/arch/arm/kernel/reboot.h index c87f05816d6b..bf7a0b1f076e 100644 --- a/arch/arm/kernel/reboot.h +++ b/arch/arm/kernel/reboot.h @@ -1,6 +1,7 @@ #ifndef REBOOT_H #define REBOOT_H +extern void call_with_stack(void (*fn)(void *), void *arg, void *sp); extern void _soft_restart(unsigned long addr, bool disable_l2); #endif -- cgit