From ad3b6993b9c5482e8a2ec5aed181538c921fdcbd Mon Sep 17 00:00:00 2001 From: Russell King Date: Mon, 15 Nov 2010 09:42:08 +0000 Subject: ARM: SMP: pass an ipi number to smp_cross_call() This allows us to use smp_cross_call() to trigger a number of different software generated interrupts, rather than combining them all on one SGI. Recover the SGI number via do_IPI. Reviewed-by: Catalin Marinas Signed-off-by: Russell King --- arch/arm/mach-realview/include/mach/smp.h | 4 ++-- arch/arm/mach-realview/platsmp.c | 2 +- 2 files changed, 3 insertions(+), 3 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-realview/include/mach/smp.h b/arch/arm/mach-realview/include/mach/smp.h index d3cd265cb058..d1aa70415a4e 100644 --- a/arch/arm/mach-realview/include/mach/smp.h +++ b/arch/arm/mach-realview/include/mach/smp.h @@ -7,9 +7,9 @@ /* * We use IRQ1 as the IPI */ -static inline void smp_cross_call(const struct cpumask *mask) +static inline void smp_cross_call(const struct cpumask *mask, int ipi) { - gic_raise_softirq(mask, 1); + gic_raise_softirq(mask, ipi); } #endif diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index 009265818d55..af3d9093390b 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -116,7 +116,7 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) * Use smp_cross_call() for this, since there's little * point duplicating the code here */ - smp_cross_call(cpumask_of(cpu)); + smp_cross_call(cpumask_of(cpu), 1); timeout = jiffies + (1 * HZ); while (time_before(jiffies, timeout)) { -- cgit v1.2.3 From bbc3d14e9aca023bb98e580aa1c9350af8effdb1 Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 3 Dec 2010 10:42:58 +0000 Subject: ARM: SMP: move CPU number sanity checks to smp_init_cpus() Ensure that the number of CPUs is sanity checked before setting the number of possible CPUs. This avoids any chance of overflowing the cpu_possible bitmap. Signed-off-by: Russell King --- arch/arm/mach-omap2/omap-smp.c | 21 +++++++++++---------- arch/arm/mach-realview/platsmp.c | 20 ++++++++++---------- arch/arm/mach-ux500/platsmp.c | 26 +++++++++++++------------- 3 files changed, 34 insertions(+), 33 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c index 56a8bce247c8..3c87468ce9cb 100644 --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -120,16 +120,6 @@ void __init smp_init_cpus(void) ncores = get_core_count(); - for (i = 0; i < ncores; i++) - set_cpu_possible(i, true); -} - -void __init smp_prepare_cpus(unsigned int max_cpus) -{ - unsigned int ncores = get_core_count(); - unsigned int cpu = smp_processor_id(); - int i; - /* sanity check */ if (ncores == 0) { printk(KERN_ERR @@ -144,6 +134,17 @@ void __init smp_prepare_cpus(unsigned int max_cpus) ncores, NR_CPUS); ncores = NR_CPUS; } + + for (i = 0; i < ncores; i++) + set_cpu_possible(i, true); +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + unsigned int ncores = num_possible_cpus(); + unsigned int cpu = smp_processor_id(); + int i; + smp_store_cpu_info(cpu); /* diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index af3d9093390b..108e92f9746b 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -160,16 +160,6 @@ void __init smp_init_cpus(void) { unsigned int i, ncores = get_core_count(); - for (i = 0; i < ncores; i++) - set_cpu_possible(i, true); -} - -void __init smp_prepare_cpus(unsigned int max_cpus) -{ - unsigned int ncores = get_core_count(); - unsigned int cpu = smp_processor_id(); - int i; - /* sanity check */ if (ncores == 0) { printk(KERN_ERR @@ -186,6 +176,16 @@ void __init smp_prepare_cpus(unsigned int max_cpus) ncores = NR_CPUS; } + for (i = 0; i < ncores; i++) + set_cpu_possible(i, true); +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + unsigned int ncores = num_possible_cpus(); + unsigned int cpu = smp_processor_id(); + int i; + smp_store_cpu_info(cpu); /* diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index b8987bd21249..a51962b7579b 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -128,16 +128,6 @@ void __init smp_init_cpus(void) { unsigned int i, ncores = get_core_count(); - for (i = 0; i < ncores; i++) - set_cpu_possible(i, true); -} - -void __init smp_prepare_cpus(unsigned int max_cpus) -{ - unsigned int ncores = get_core_count(); - unsigned int cpu = smp_processor_id(); - int i; - /* sanity check */ if (ncores == 0) { printk(KERN_ERR @@ -145,14 +135,24 @@ void __init smp_prepare_cpus(unsigned int max_cpus) ncores = 1; } - if (ncores > num_possible_cpus()) { + if (ncores > NR_CPUS) { printk(KERN_WARNING "U8500: no. of cores (%d) greater than configured " "maximum of %d - clipping\n", - ncores, num_possible_cpus()); - ncores = num_possible_cpus(); + ncores, NR_CPUS); + ncores = NR_CPUS; } + for (i = 0; i < ncores; i++) + set_cpu_possible(i, true); +} + +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + unsigned int ncores = num_possible_cpus(); + unsigned int cpu = smp_processor_id(); + int i; + smp_store_cpu_info(cpu); /* -- cgit v1.2.3 From 8975b6c0fdd57e061f4d1040163778ceaf340ad8 Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 3 Dec 2010 19:29:53 +0000 Subject: ARM: SMP: Clean up ncores sanity checks scu_get_core_count() never returns zero cores, so we don't need to check and correct if ncores is zero. Tegra was missing the check against NR_CPUS, leading to a potential bitfield overflow if this becomes the case. Signed-off-by: Russell King --- arch/arm/mach-omap2/omap-smp.c | 6 ------ arch/arm/mach-realview/platsmp.c | 7 ------- arch/arm/mach-s5pv310/platsmp.c | 7 ------- arch/arm/mach-tegra/platsmp.c | 6 ++++++ arch/arm/mach-ux500/platsmp.c | 6 ------ arch/arm/mach-vexpress/platsmp.c | 7 ------- 6 files changed, 6 insertions(+), 33 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c index 3c87468ce9cb..5f10f38354ae 100644 --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -121,12 +121,6 @@ void __init smp_init_cpus(void) ncores = get_core_count(); /* sanity check */ - if (ncores == 0) { - printk(KERN_ERR - "OMAP4: strange core count of 0? Default to 1\n"); - ncores = 1; - } - if (ncores > NR_CPUS) { printk(KERN_WARNING "OMAP4: no. of cores (%d) greater than configured " diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index 108e92f9746b..13116cd37639 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -161,13 +161,6 @@ void __init smp_init_cpus(void) unsigned int i, ncores = get_core_count(); /* sanity check */ - if (ncores == 0) { - printk(KERN_ERR - "Realview: strange CM count of 0? Default to 1\n"); - - ncores = 1; - } - if (ncores > NR_CPUS) { printk(KERN_WARNING "Realview: no. of cores (%d) greater than configured " diff --git a/arch/arm/mach-s5pv310/platsmp.c b/arch/arm/mach-s5pv310/platsmp.c index d474426f37b7..560ada83b0b1 100644 --- a/arch/arm/mach-s5pv310/platsmp.c +++ b/arch/arm/mach-s5pv310/platsmp.c @@ -130,13 +130,6 @@ void __init smp_init_cpus(void) ncores = scu_base ? scu_get_core_count(scu_base) : 1; /* sanity check */ - if (ncores == 0) { - printk(KERN_ERR - "S5PV310: strange CM count of 0? Default to 1\n"); - - ncores = 1; - } - if (ncores > NR_CPUS) { printk(KERN_WARNING "S5PV310: no. of cores (%d) greater than configured " diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c index 1c0fd92cab39..5b194dd815a8 100644 --- a/arch/arm/mach-tegra/platsmp.c +++ b/arch/arm/mach-tegra/platsmp.c @@ -117,6 +117,12 @@ void __init smp_init_cpus(void) { unsigned int i, ncores = scu_get_core_count(scu_base); + if (ncores > NR_CPUS) { + printk(KERN_ERR "Tegra: no. of cores (%u) greater than configured (%u), clipping\n", + ncores, NR_CPUS); + ncores = NR_CPUS; + } + for (i = 0; i < ncores; i++) cpu_set(i, cpu_possible_map); } diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index a51962b7579b..e31024e3a7cc 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -129,12 +129,6 @@ void __init smp_init_cpus(void) unsigned int i, ncores = get_core_count(); /* sanity check */ - if (ncores == 0) { - printk(KERN_ERR - "U8500: strange CM count of 0? Default to 1\n"); - ncores = 1; - } - if (ncores > NR_CPUS) { printk(KERN_WARNING "U8500: no. of cores (%d) greater than configured " diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c index 276f916014c1..b5a758683668 100644 --- a/arch/arm/mach-vexpress/platsmp.c +++ b/arch/arm/mach-vexpress/platsmp.c @@ -124,13 +124,6 @@ void __init smp_init_cpus(void) ncores = scu_base ? scu_get_core_count(scu_base) : 1; /* sanity check */ - if (ncores == 0) { - printk(KERN_ERR - "vexpress: strange CM count of 0? Default to 1\n"); - - ncores = 1; - } - if (ncores > NR_CPUS) { printk(KERN_WARNING "vexpress: no. of cores (%d) greater than configured " -- cgit v1.2.3 From fd778f0ad7dda1108281410ddca0d07936256d3c Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 2 Dec 2010 18:09:37 +0000 Subject: ARM: SMP: get rid of get_core_count() We don't need this small function as well as scu_get_core_count() Signed-off-by: Russell King --- arch/arm/mach-omap2/omap-smp.c | 12 +----------- arch/arm/mach-realview/platsmp.c | 13 ++++--------- arch/arm/mach-ux500/platsmp.c | 9 +++------ 3 files changed, 8 insertions(+), 26 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c index 5f10f38354ae..405a8fc53308 100644 --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -29,16 +29,6 @@ /* SCU base address */ static void __iomem *scu_base; -/* - * Use SCU config register to count number of cores - */ -static inline unsigned int get_core_count(void) -{ - if (scu_base) - return scu_get_core_count(scu_base); - return 1; -} - static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) @@ -118,7 +108,7 @@ void __init smp_init_cpus(void) scu_base = ioremap(OMAP44XX_SCU_BASE, SZ_256); BUG_ON(!scu_base); - ncores = get_core_count(); + ncores = scu_get_core_count(scu_base); /* sanity check */ if (ncores > NR_CPUS) { diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index 13116cd37639..6595e875fb2f 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -50,14 +50,6 @@ static void __iomem *scu_base_addr(void) return (void __iomem *)0; } -static inline unsigned int get_core_count(void) -{ - void __iomem *scu_base = scu_base_addr(); - if (scu_base) - return scu_get_core_count(scu_base); - return 1; -} - static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) @@ -158,7 +150,10 @@ static void __init poke_milo(void) */ void __init smp_init_cpus(void) { - unsigned int i, ncores = get_core_count(); + void __iomem *scu_base = scu_base_addr(); + unsigned int i, ncores; + + ncores = scu_base ? scu_get_core_count(scu_base) : 1; /* sanity check */ if (ncores > NR_CPUS) { diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index e31024e3a7cc..fd40fa175913 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -28,11 +28,6 @@ */ volatile int __cpuinitdata pen_release = -1; -static unsigned int __init get_core_count(void) -{ - return scu_get_core_count(__io_address(UX500_SCU_BASE)); -} - static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) @@ -126,7 +121,9 @@ static void __init wakeup_secondary(void) */ void __init smp_init_cpus(void) { - unsigned int i, ncores = get_core_count(); + unsigned int i, ncores; + + ncores = scu_get_core_count(__io_address(UX500_SCU_BASE)); /* sanity check */ if (ncores > NR_CPUS) { -- cgit v1.2.3 From aec66ba1f75c2030cf66f5a21d1c81aa83aa5d95 Mon Sep 17 00:00:00 2001 From: Russell King Date: Thu, 2 Dec 2010 19:10:01 +0000 Subject: ARM: SMP: get rid of references to poke_milo and Milo Milo is an old boot loader, which is no longer relevant for these platforms. References to it are misleading. Move the code out of poke_milo(), and remove references to milo in comments. Signed-off-by: Russell King --- arch/arm/mach-realview/platsmp.c | 44 +++++++++++----------------------------- arch/arm/mach-tegra/platsmp.c | 7 ------- 2 files changed, 12 insertions(+), 39 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index 6595e875fb2f..ef3cc86f5140 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -99,14 +99,9 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) flush_cache_all(); /* - * XXX - * - * This is a later addition to the booting protocol: the - * bootMonitor now puts secondary cores into WFI, so - * poke_milo() no longer gets the cores moving; we need - * to send a soft interrupt to wake the secondary core. - * Use smp_cross_call() for this, since there's little - * point duplicating the code here + * Send the secondary CPU a soft interrupt, thereby causing + * the boot monitor to read the system wide flags register, + * and branch to the address found there. */ smp_cross_call(cpumask_of(cpu), 1); @@ -128,22 +123,6 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) return pen_release != -1 ? -ENOSYS : 0; } -static void __init poke_milo(void) -{ - /* nobody is to be released from the pen yet */ - pen_release = -1; - - /* - * Write the address of secondary startup into the system-wide flags - * register. The BootMonitor waits for this register to become - * non-zero. - */ - __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)), - __io_address(REALVIEW_SYS_FLAGSSET)); - - mb(); -} - /* * Initialise the CPU possible map early - this describes the CPUs * which may be present or become present in the system. @@ -189,13 +168,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); - /* - * Initialise the SCU if there are more than one CPU and let - * them know where to start. Note that, on modern versions of - * MILO, the "poke" doesn't actually do anything until each - * individual core is sent a soft interrupt to get it out of - * WFI - */ if (max_cpus > 1) { /* * Enable the local timer or broadcast device for the @@ -204,6 +176,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus) percpu_timer_setup(); scu_enable(scu_base_addr()); - poke_milo(); + + /* + * Write the address of secondary startup into the + * system-wide flags register. The BootMonitor waits + * until it receives a soft interrupt, and then the + * secondary CPU branches to this address. + */ + __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)), + __io_address(REALVIEW_SYS_FLAGSSET)); } } diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c index 5b194dd815a8..66d0634e7a96 100644 --- a/arch/arm/mach-tegra/platsmp.c +++ b/arch/arm/mach-tegra/platsmp.c @@ -148,13 +148,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); - /* - * Initialise the SCU if there are more than one CPU and let - * them know where to start. Note that, on modern versions of - * MILO, the "poke" doesn't actually do anything until each - * individual core is sent a soft interrupt to get it out of - * WFI - */ if (max_cpus > 1) { percpu_timer_setup(); scu_enable(scu_base); -- cgit v1.2.3 From 05c74a6cbcfb416286a947668ba32f63d99fe74a Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 3 Dec 2010 11:09:48 +0000 Subject: ARM: SMP: consolidate the common parts of smp_prepare_cpus() There is a certain amount of smp_prepare_cpus() which doesn't belong in the platform support code - that is, code which is invariant to the SMP implementation. Move this code into arch/arm/kernel/smp.c, and add a platform_ prefix to the original function. Signed-off-by: Russell King --- arch/arm/include/asm/smp.h | 9 ++++---- arch/arm/kernel/smp.c | 49 +++++++++++++++++++++++++++++++--------- arch/arm/mach-omap2/omap-smp.c | 33 ++++++--------------------- arch/arm/mach-realview/platsmp.c | 41 +++++++++------------------------ arch/arm/mach-s5pv310/platsmp.c | 35 ++++++---------------------- arch/arm/mach-tegra/platsmp.c | 18 ++------------- arch/arm/mach-ux500/platsmp.c | 24 +++----------------- arch/arm/mach-vexpress/platsmp.c | 43 ++++++++--------------------------- 8 files changed, 83 insertions(+), 169 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/include/asm/smp.h b/arch/arm/include/asm/smp.h index f93d0a637016..96ed521f2408 100644 --- a/arch/arm/include/asm/smp.h +++ b/arch/arm/include/asm/smp.h @@ -45,10 +45,6 @@ asmlinkage void do_IPI(int ipinr, struct pt_regs *regs); */ extern void smp_init_cpus(void); -/* - * Move global data into per-processor storage. - */ -extern void smp_store_cpu_info(unsigned int cpuid); /* * Raise an IPI cross call on CPUs in callmap. @@ -72,6 +68,11 @@ asmlinkage void secondary_start_kernel(void); */ extern void platform_secondary_init(unsigned int cpu); +/* + * Initialize cpu_possible map, and enable coherency + */ +extern void platform_smp_prepare_cpus(unsigned int); + /* * Initial data for bringing up a secondary CPU. */ diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index 64f2d198c764..c66f2d3f65d3 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -281,6 +281,17 @@ void __ref cpu_die(void) } #endif /* CONFIG_HOTPLUG_CPU */ +/* + * Called by both boot and secondaries to move global data into + * per-processor storage. + */ +static void __cpuinit smp_store_cpu_info(unsigned int cpuid) +{ + struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); + + cpu_info->loops_per_jiffy = loops_per_jiffy; +} + /* * This is the secondary CPU boot entry. We're using this CPUs * idle thread stack, but a set of temporary page tables. @@ -339,17 +350,6 @@ asmlinkage void __cpuinit secondary_start_kernel(void) cpu_idle(); } -/* - * Called by both boot and secondaries to move global data into - * per-processor storage. - */ -void __cpuinit smp_store_cpu_info(unsigned int cpuid) -{ - struct cpuinfo_arm *cpu_info = &per_cpu(cpu_data, cpuid); - - cpu_info->loops_per_jiffy = loops_per_jiffy; -} - void __init smp_cpus_done(unsigned int max_cpus) { int cpu; @@ -372,6 +372,33 @@ void __init smp_prepare_boot_cpu(void) per_cpu(cpu_data, cpu).idle = current; } +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + unsigned int ncores = num_possible_cpus(); + + smp_store_cpu_info(smp_processor_id()); + + /* + * are we trying to boot more cores than exist? + */ + if (max_cpus > ncores) + max_cpus = ncores; + + if (max_cpus > 1) { + /* + * Enable the local timer or broadcast device for the + * boot CPU, but only if we have more than one CPU. + */ + percpu_timer_setup(); + + /* + * Initialise the SCU if there are more than one CPU + * and let them know where to start. + */ + platform_smp_prepare_cpus(max_cpus); + } +} + void arch_send_call_function_ipi_mask(const struct cpumask *mask) { smp_cross_call(mask, IPI_CALL_FUNC); diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c index 405a8fc53308..3c3d6796c97c 100644 --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -21,7 +21,6 @@ #include #include -#include #include #include #include @@ -123,20 +122,10 @@ void __init smp_init_cpus(void) set_cpu_possible(i, true); } -void __init smp_prepare_cpus(unsigned int max_cpus) +void __init platform_smp_prepare_cpus(unsigned int max_cpus) { - unsigned int ncores = num_possible_cpus(); - unsigned int cpu = smp_processor_id(); int i; - smp_store_cpu_info(cpu); - - /* - * are we trying to boot more cores than exist? - */ - if (max_cpus > ncores) - max_cpus = ncores; - /* * Initialise the present map, which describes the set of CPUs * actually populated at the present time. @@ -144,18 +133,10 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); - if (max_cpus > 1) { - /* - * Enable the local timer or broadcast device for the - * boot CPU, but only if we have more than one CPU. - */ - percpu_timer_setup(); - - /* - * Initialise the SCU and wake up the secondary core using - * wakeup_secondary(). - */ - scu_enable(scu_base); - wakeup_secondary(); - } + /* + * Initialise the SCU and wake up the secondary core using + * wakeup_secondary(). + */ + scu_enable(scu_base); + wakeup_secondary(); } diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index ef3cc86f5140..380562cd6580 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -19,7 +19,6 @@ #include #include #include -#include #include #include @@ -147,20 +146,10 @@ void __init smp_init_cpus(void) set_cpu_possible(i, true); } -void __init smp_prepare_cpus(unsigned int max_cpus) +void __init platform_smp_prepare_cpus(unsigned int max_cpus) { - unsigned int ncores = num_possible_cpus(); - unsigned int cpu = smp_processor_id(); int i; - smp_store_cpu_info(cpu); - - /* - * are we trying to boot more cores than exist? - */ - if (max_cpus > ncores) - max_cpus = ncores; - /* * Initialise the present map, which describes the set of CPUs * actually populated at the present time. @@ -168,22 +157,14 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); - if (max_cpus > 1) { - /* - * Enable the local timer or broadcast device for the - * boot CPU, but only if we have more than one CPU. - */ - percpu_timer_setup(); - - scu_enable(scu_base_addr()); - - /* - * Write the address of secondary startup into the - * system-wide flags register. The BootMonitor waits - * until it receives a soft interrupt, and then the - * secondary CPU branches to this address. - */ - __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)), - __io_address(REALVIEW_SYS_FLAGSSET)); - } + scu_enable(scu_base_addr()); + + /* + * Write the address of secondary startup into the + * system-wide flags register. The BootMonitor waits + * until it receives a soft interrupt, and then the + * secondary CPU branches to this address. + */ + __raw_writel(BSYM(virt_to_phys(realview_secondary_startup)), + __io_address(REALVIEW_SYS_FLAGSSET)); } diff --git a/arch/arm/mach-s5pv310/platsmp.c b/arch/arm/mach-s5pv310/platsmp.c index 560ada83b0b1..51c44d4c9890 100644 --- a/arch/arm/mach-s5pv310/platsmp.c +++ b/arch/arm/mach-s5pv310/platsmp.c @@ -22,7 +22,6 @@ #include #include -#include #include #include @@ -142,18 +141,10 @@ void __init smp_init_cpus(void) set_cpu_possible(i, true); } -void __init smp_prepare_cpus(unsigned int max_cpus) +void __init platform_smp_prepare_cpus(unsigned int max_cpus) { - unsigned int ncores = num_possible_cpus(); - unsigned int cpu = smp_processor_id(); int i; - smp_store_cpu_info(cpu); - - /* are we trying to boot more cores than exist? */ - if (max_cpus > ncores) - max_cpus = ncores; - /* * Initialise the present map, which describes the set of CPUs * actually populated at the present time. @@ -161,25 +152,13 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); + scu_enable(scu_base_addr()); + /* - * Initialise the SCU if there are more than one CPU and let - * them know where to start. + * Write the address of secondary startup into the + * system-wide flags register. The boot monitor waits + * until it receives a soft interrupt, and then the + * secondary CPU branches to this address. */ - if (max_cpus > 1) { - /* - * Enable the local timer or broadcast device for the - * boot CPU, but only if we have more than one CPU. - */ - percpu_timer_setup(); - - scu_enable(scu_base_addr()); - - /* - * Write the address of secondary startup into the - * system-wide flags register. The boot monitor waits - * until it receives a soft interrupt, and then the - * secondary CPU branches to this address. - */ __raw_writel(BSYM(virt_to_phys(s5pv310_secondary_startup)), S5P_VA_SYSRAM); - } } diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c index 66d0634e7a96..b66a0c2d990d 100644 --- a/arch/arm/mach-tegra/platsmp.c +++ b/arch/arm/mach-tegra/platsmp.c @@ -22,7 +22,6 @@ #include #include #include -#include #include #include @@ -127,20 +126,10 @@ void __init smp_init_cpus(void) cpu_set(i, cpu_possible_map); } -void __init smp_prepare_cpus(unsigned int max_cpus) +void __init platform_smp_prepare_cpus(unsigned int max_cpus) { - unsigned int ncores = scu_get_core_count(scu_base); - unsigned int cpu = smp_processor_id(); int i; - smp_store_cpu_info(cpu); - - /* - * are we trying to boot more cores than exist? - */ - if (max_cpus > ncores) - max_cpus = ncores; - /* * Initialise the present map, which describes the set of CPUs * actually populated at the present time. @@ -148,8 +137,5 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); - if (max_cpus > 1) { - percpu_timer_setup(); - scu_enable(scu_base); - } + scu_enable(scu_base); } diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index fd40fa175913..458a288981cb 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -18,7 +18,6 @@ #include #include -#include #include #include @@ -138,20 +137,10 @@ void __init smp_init_cpus(void) set_cpu_possible(i, true); } -void __init smp_prepare_cpus(unsigned int max_cpus) +void __init platform_smp_prepare_cpus(unsigned int max_cpus) { - unsigned int ncores = num_possible_cpus(); - unsigned int cpu = smp_processor_id(); int i; - smp_store_cpu_info(cpu); - - /* - * are we trying to boot more cores than exist? - */ - if (max_cpus > ncores) - max_cpus = ncores; - /* * Initialise the present map, which describes the set of CPUs * actually populated at the present time. @@ -159,13 +148,6 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); - if (max_cpus > 1) { - /* - * Enable the local timer or broadcast device for the - * boot CPU, but only if we have more than one CPU. - */ - percpu_timer_setup(); - scu_enable(__io_address(UX500_SCU_BASE)); - wakeup_secondary(); - } + scu_enable(__io_address(UX500_SCU_BASE)); + wakeup_secondary(); } diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c index b5a758683668..a0341d14ff2a 100644 --- a/arch/arm/mach-vexpress/platsmp.c +++ b/arch/arm/mach-vexpress/platsmp.c @@ -17,7 +17,6 @@ #include #include -#include #include #include @@ -136,20 +135,10 @@ void __init smp_init_cpus(void) set_cpu_possible(i, true); } -void __init smp_prepare_cpus(unsigned int max_cpus) +void __init platform_smp_prepare_cpus(unsigned int max_cpus) { - unsigned int ncores = num_possible_cpus(); - unsigned int cpu = smp_processor_id(); int i; - smp_store_cpu_info(cpu); - - /* - * are we trying to boot more cores than exist? - */ - if (max_cpus > ncores) - max_cpus = ncores; - /* * Initialise the present map, which describes the set of CPUs * actually populated at the present time. @@ -157,27 +146,15 @@ void __init smp_prepare_cpus(unsigned int max_cpus) for (i = 0; i < max_cpus; i++) set_cpu_present(i, true); + scu_enable(scu_base_addr()); + /* - * Initialise the SCU if there are more than one CPU and let - * them know where to start. + * Write the address of secondary startup into the + * system-wide flags register. The boot monitor waits + * until it receives a soft interrupt, and then the + * secondary CPU branches to this address. */ - if (max_cpus > 1) { - /* - * Enable the local timer or broadcast device for the - * boot CPU, but only if we have more than one CPU. - */ - percpu_timer_setup(); - - scu_enable(scu_base_addr()); - - /* - * Write the address of secondary startup into the - * system-wide flags register. The boot monitor waits - * until it receives a soft interrupt, and then the - * secondary CPU branches to this address. - */ - writel(~0, MMIO_P2V(V2M_SYS_FLAGSCLR)); - writel(BSYM(virt_to_phys(vexpress_secondary_startup)), - MMIO_P2V(V2M_SYS_FLAGSSET)); - } + writel(~0, MMIO_P2V(V2M_SYS_FLAGSCLR)); + writel(BSYM(virt_to_phys(vexpress_secondary_startup)), + MMIO_P2V(V2M_SYS_FLAGSSET)); } -- cgit v1.2.3 From 2c0136dba4e43b0916ccc9ecc7f11e6d6b73f046 Mon Sep 17 00:00:00 2001 From: Russell King Date: Fri, 3 Dec 2010 15:00:49 +0000 Subject: ARM: SMP: consolidate trace_hardirqs_off() into common SMP code All platforms call trace_hardirqs_off() in their secondary startup code, so move this into the core SMP code - it doesn't need to be in the per-platform code. Signed-off-by: Russell King --- arch/arm/kernel/smp.c | 1 + arch/arm/mach-omap2/omap-smp.c | 2 -- arch/arm/mach-realview/platsmp.c | 2 -- arch/arm/mach-s5pv310/platsmp.c | 2 -- arch/arm/mach-tegra/platsmp.c | 2 -- arch/arm/mach-ux500/platsmp.c | 2 -- arch/arm/mach-vexpress/platsmp.c | 2 -- 7 files changed, 1 insertion(+), 12 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index c66f2d3f65d3..a30c4094db3a 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -317,6 +317,7 @@ asmlinkage void __cpuinit secondary_start_kernel(void) cpu_init(); preempt_disable(); + trace_hardirqs_off(); /* * Give the platform a chance to do its own initialisation. diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c index 3c3d6796c97c..9fed631ba046 100644 --- a/arch/arm/mach-omap2/omap-smp.c +++ b/arch/arm/mach-omap2/omap-smp.c @@ -32,8 +32,6 @@ static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { - trace_hardirqs_off(); - /* * If any interrupts are already enabled for the primary * core (e.g. timer irq), then they will not have been enabled diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index 380562cd6580..226c63102a00 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -53,8 +53,6 @@ static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { - trace_hardirqs_off(); - /* * if any interrupts are already enabled for the primary * core (e.g. timer irq), then they will not have been enabled diff --git a/arch/arm/mach-s5pv310/platsmp.c b/arch/arm/mach-s5pv310/platsmp.c index 51c44d4c9890..18aaf5f54033 100644 --- a/arch/arm/mach-s5pv310/platsmp.c +++ b/arch/arm/mach-s5pv310/platsmp.c @@ -46,8 +46,6 @@ static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { - trace_hardirqs_off(); - /* * if any interrupts are already enabled for the primary * core (e.g. timer irq), then they will not have been enabled diff --git a/arch/arm/mach-tegra/platsmp.c b/arch/arm/mach-tegra/platsmp.c index b66a0c2d990d..c729cd72cc3b 100644 --- a/arch/arm/mach-tegra/platsmp.c +++ b/arch/arm/mach-tegra/platsmp.c @@ -40,8 +40,6 @@ static void __iomem *scu_base = IO_ADDRESS(TEGRA_ARM_PERIF_BASE); void __cpuinit platform_secondary_init(unsigned int cpu) { - trace_hardirqs_off(); - /* * if any interrupts are already enabled for the primary * core (e.g. timer irq), then they will not have been enabled diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index 458a288981cb..ddedbc80c41f 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -31,8 +31,6 @@ static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { - trace_hardirqs_off(); - /* * if any interrupts are already enabled for the primary * core (e.g. timer irq), then they will not have been enabled diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c index a0341d14ff2a..d7e0cb994e9d 100644 --- a/arch/arm/mach-vexpress/platsmp.c +++ b/arch/arm/mach-vexpress/platsmp.c @@ -43,8 +43,6 @@ static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) { - trace_hardirqs_off(); - /* * if any interrupts are already enabled for the primary * core (e.g. timer irq), then they will not have been enabled -- cgit v1.2.3 From 3c030beabf937b1d3b4ecaedfd1fb2f1e2aa0c70 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 30 Nov 2010 11:07:35 +0000 Subject: ARM: CPU hotplug: move cpu_killed completion to core code We always need to wait for the dying CPU to reach a safe state before taking it down, irrespective of the requirements of the platform. Move the completion code into the ARM SMP hotplug code rather than having each platform re-implement this. Signed-off-by: Russell King --- arch/arm/kernel/smp.c | 14 +++++++++++++- arch/arm/mach-omap2/omap-hotplug.c | 8 ++------ arch/arm/mach-realview/hotplug.c | 8 +------- arch/arm/mach-s5pv310/hotplug.c | 8 +------- arch/arm/mach-tegra/hotplug.c | 8 +------- arch/arm/mach-ux500/hotplug.c | 8 +------- 6 files changed, 19 insertions(+), 35 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c index a30c4094db3a..8c81ff9b3732 100644 --- a/arch/arm/kernel/smp.c +++ b/arch/arm/kernel/smp.c @@ -24,6 +24,7 @@ #include #include #include +#include #include #include @@ -238,12 +239,20 @@ int __cpu_disable(void) return 0; } +static DECLARE_COMPLETION(cpu_died); + /* * called on the thread which is asking for a CPU to be shutdown - * waits until shutdown has completed, or it is timed out. */ void __cpu_die(unsigned int cpu) { + if (!wait_for_completion_timeout(&cpu_died, msecs_to_jiffies(5000))) { + pr_err("CPU%u: cpu didn't die\n", cpu); + return; + } + printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); + if (!platform_cpu_kill(cpu)) printk("CPU%u: unable to kill\n", cpu); } @@ -263,9 +272,12 @@ void __ref cpu_die(void) local_irq_disable(); idle_task_exit(); + /* Tell __cpu_die() that this CPU is now safe to dispose of */ + complete(&cpu_died); + /* * actual CPU shutdown procedure is at least platform (if not - * CPU) specific + * CPU) specific. */ platform_cpu_die(cpu); diff --git a/arch/arm/mach-omap2/omap-hotplug.c b/arch/arm/mach-omap2/omap-hotplug.c index 6cee456ca542..ace979d74bfc 100644 --- a/arch/arm/mach-omap2/omap-hotplug.c +++ b/arch/arm/mach-omap2/omap-hotplug.c @@ -17,16 +17,13 @@ #include #include #include -#include #include #include -static DECLARE_COMPLETION(cpu_killed); - int platform_cpu_kill(unsigned int cpu) { - return wait_for_completion_timeout(&cpu_killed, 5000); + return 1; } /* @@ -42,8 +39,7 @@ void platform_cpu_die(unsigned int cpu) this_cpu, cpu); BUG(); } - pr_notice("CPU%u: shutdown\n", cpu); - complete(&cpu_killed); + flush_cache_all(); dsb(); diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c index f95521a5e5ce..7d58c16c83a7 100644 --- a/arch/arm/mach-realview/hotplug.c +++ b/arch/arm/mach-realview/hotplug.c @@ -11,14 +11,11 @@ #include #include #include -#include #include extern volatile int pen_release; -static DECLARE_COMPLETION(cpu_killed); - static inline void cpu_enter_lowpower(void) { unsigned int v; @@ -95,7 +92,7 @@ static inline void platform_do_lowpower(unsigned int cpu) int platform_cpu_kill(unsigned int cpu) { - return wait_for_completion_timeout(&cpu_killed, 5000); + return 1; } /* @@ -115,9 +112,6 @@ void platform_cpu_die(unsigned int cpu) } #endif - printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); - complete(&cpu_killed); - /* * we're ready for shutdown now, so do it */ diff --git a/arch/arm/mach-s5pv310/hotplug.c b/arch/arm/mach-s5pv310/hotplug.c index 03652c3605f6..d7be70ac7536 100644 --- a/arch/arm/mach-s5pv310/hotplug.c +++ b/arch/arm/mach-s5pv310/hotplug.c @@ -13,14 +13,11 @@ #include #include #include -#include #include extern volatile int pen_release; -static DECLARE_COMPLETION(cpu_killed); - static inline void cpu_enter_lowpower(void) { unsigned int v; @@ -98,7 +95,7 @@ static inline void platform_do_lowpower(unsigned int cpu) int platform_cpu_kill(unsigned int cpu) { - return wait_for_completion_timeout(&cpu_killed, 5000); + return 1; } /* @@ -118,9 +115,6 @@ void platform_cpu_die(unsigned int cpu) } #endif - printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); - complete(&cpu_killed); - /* * we're ready for shutdown now, so do it */ diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c index 8e7f115aa21e..ecaa41ce4976 100644 --- a/arch/arm/mach-tegra/hotplug.c +++ b/arch/arm/mach-tegra/hotplug.c @@ -11,12 +11,9 @@ #include #include #include -#include #include -static DECLARE_COMPLETION(cpu_killed); - static inline void cpu_enter_lowpower(void) { unsigned int v; @@ -94,7 +91,7 @@ static inline void platform_do_lowpower(unsigned int cpu) int platform_cpu_kill(unsigned int cpu) { - return wait_for_completion_timeout(&cpu_killed, 5000); + return 1; } /* @@ -114,9 +111,6 @@ void platform_cpu_die(unsigned int cpu) } #endif - printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); - complete(&cpu_killed); - /* * we're ready for shutdown now, so do it */ diff --git a/arch/arm/mach-ux500/hotplug.c b/arch/arm/mach-ux500/hotplug.c index b782a03024be..7a4890b96e5c 100644 --- a/arch/arm/mach-ux500/hotplug.c +++ b/arch/arm/mach-ux500/hotplug.c @@ -11,14 +11,11 @@ #include #include #include -#include #include extern volatile int pen_release; -static DECLARE_COMPLETION(cpu_killed); - static inline void platform_do_lowpower(unsigned int cpu) { flush_cache_all(); @@ -38,7 +35,7 @@ static inline void platform_do_lowpower(unsigned int cpu) int platform_cpu_kill(unsigned int cpu) { - return wait_for_completion_timeout(&cpu_killed, 5000); + return 1; } /* @@ -58,9 +55,6 @@ void platform_cpu_die(unsigned int cpu) } #endif - printk(KERN_NOTICE "CPU%u: shutdown\n", cpu); - complete(&cpu_killed); - /* directly enter low power state, skipping secure registers */ platform_do_lowpower(cpu); } -- cgit v1.2.3 From bbc81fd4327f9ed4480b05981e38acd48b1d184a Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 30 Nov 2010 11:12:30 +0000 Subject: ARM: CPU hotplug: remove bug checks in platform_cpu_die() platform_cpu_die() is entered from the CPU's own idle thread, which can not be migrated to other CPUs. Moreover, the 'cpu' argument comes from the thread info, which will always be the 'current' CPU. So remove this useless bug check. Signed-off-by: Russell King --- arch/arm/mach-omap2/omap-hotplug.c | 8 -------- arch/arm/mach-realview/hotplug.c | 10 ---------- arch/arm/mach-s5pv310/hotplug.c | 10 ---------- arch/arm/mach-tegra/hotplug.c | 10 ---------- arch/arm/mach-ux500/hotplug.c | 10 ---------- 5 files changed, 48 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-omap2/omap-hotplug.c b/arch/arm/mach-omap2/omap-hotplug.c index ace979d74bfc..4976b9393e49 100644 --- a/arch/arm/mach-omap2/omap-hotplug.c +++ b/arch/arm/mach-omap2/omap-hotplug.c @@ -32,14 +32,6 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { - unsigned int this_cpu = hard_smp_processor_id(); - - if (cpu != this_cpu) { - pr_crit("platform_cpu_die running on %u, should be %u\n", - this_cpu, cpu); - BUG(); - } - flush_cache_all(); dsb(); diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c index 7d58c16c83a7..e06572e6c490 100644 --- a/arch/arm/mach-realview/hotplug.c +++ b/arch/arm/mach-realview/hotplug.c @@ -102,16 +102,6 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { -#ifdef DEBUG - unsigned int this_cpu = hard_smp_processor_id(); - - if (cpu != this_cpu) { - printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n", - this_cpu, cpu); - BUG(); - } -#endif - /* * we're ready for shutdown now, so do it */ diff --git a/arch/arm/mach-s5pv310/hotplug.c b/arch/arm/mach-s5pv310/hotplug.c index d7be70ac7536..ea951ef6ea54 100644 --- a/arch/arm/mach-s5pv310/hotplug.c +++ b/arch/arm/mach-s5pv310/hotplug.c @@ -105,16 +105,6 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { -#ifdef DEBUG - unsigned int this_cpu = hard_smp_processor_id(); - - if (cpu != this_cpu) { - printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n", - this_cpu, cpu); - BUG(); - } -#endif - /* * we're ready for shutdown now, so do it */ diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c index ecaa41ce4976..a5eeb9126645 100644 --- a/arch/arm/mach-tegra/hotplug.c +++ b/arch/arm/mach-tegra/hotplug.c @@ -101,16 +101,6 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { -#ifdef DEBUG - unsigned int this_cpu = hard_smp_processor_id(); - - if (cpu != this_cpu) { - printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n", - this_cpu, cpu); - BUG(); - } -#endif - /* * we're ready for shutdown now, so do it */ diff --git a/arch/arm/mach-ux500/hotplug.c b/arch/arm/mach-ux500/hotplug.c index 7a4890b96e5c..dd8037ebccf8 100644 --- a/arch/arm/mach-ux500/hotplug.c +++ b/arch/arm/mach-ux500/hotplug.c @@ -45,16 +45,6 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { -#ifdef DEBUG - unsigned int this_cpu = hard_smp_processor_id(); - - if (cpu != this_cpu) { - printk(KERN_CRIT "Eek! platform_cpu_die running on %u, should be %u\n", - this_cpu, cpu); - BUG(); - } -#endif - /* directly enter low power state, skipping secure registers */ platform_do_lowpower(cpu); } -- cgit v1.2.3 From 86e62b93368cffca9111996e3ed9e5b7bf6f0af3 Mon Sep 17 00:00:00 2001 From: Russell King Date: Tue, 30 Nov 2010 18:24:57 +0000 Subject: ARM: SMP: remove smp_mpidr.h With "ARM: CPU hotplug: remove bug checks in platform_cpu_die()", we now do not use hard_smp_processor_id(), we no longer need to read the hardware processor ID. Remove the include providing this function. Signed-off-by: Russell King --- arch/arm/include/asm/smp_mpidr.h | 17 ----------------- arch/arm/mach-realview/include/mach/smp.h | 1 - arch/arm/mach-s5pv310/include/mach/smp.h | 1 - arch/arm/mach-tegra/include/mach/smp.h | 1 - arch/arm/mach-ux500/include/mach/smp.h | 1 - arch/arm/mach-vexpress/include/mach/smp.h | 1 - arch/arm/plat-omap/include/plat/smp.h | 1 - 7 files changed, 23 deletions(-) delete mode 100644 arch/arm/include/asm/smp_mpidr.h (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/include/asm/smp_mpidr.h b/arch/arm/include/asm/smp_mpidr.h deleted file mode 100644 index 6a9307d64900..000000000000 --- a/arch/arm/include/asm/smp_mpidr.h +++ /dev/null @@ -1,17 +0,0 @@ -#ifndef ASMARM_SMP_MIDR_H -#define ASMARM_SMP_MIDR_H - -#define hard_smp_processor_id() \ - ({ \ - unsigned int cpunum; \ - __asm__("\n" \ - "1: mrc p15, 0, %0, c0, c0, 5\n" \ - " .pushsection \".alt.smp.init\", \"a\"\n"\ - " .long 1b\n" \ - " mov %0, #0\n" \ - " .popsection" \ - : "=r" (cpunum)); \ - cpunum &= 0x0F; \ - }) - -#endif diff --git a/arch/arm/mach-realview/include/mach/smp.h b/arch/arm/mach-realview/include/mach/smp.h index d1aa70415a4e..c8221b38ee7c 100644 --- a/arch/arm/mach-realview/include/mach/smp.h +++ b/arch/arm/mach-realview/include/mach/smp.h @@ -2,7 +2,6 @@ #define ASMARM_ARCH_SMP_H #include -#include /* * We use IRQ1 as the IPI diff --git a/arch/arm/mach-s5pv310/include/mach/smp.h b/arch/arm/mach-s5pv310/include/mach/smp.h index 2897747bcb07..77e5a841f741 100644 --- a/arch/arm/mach-s5pv310/include/mach/smp.h +++ b/arch/arm/mach-s5pv310/include/mach/smp.h @@ -7,7 +7,6 @@ #define ASM_ARCH_SMP_H __FILE__ #include -#include extern void __iomem *gic_cpu_base_addr; diff --git a/arch/arm/mach-tegra/include/mach/smp.h b/arch/arm/mach-tegra/include/mach/smp.h index d1aa70415a4e..c8221b38ee7c 100644 --- a/arch/arm/mach-tegra/include/mach/smp.h +++ b/arch/arm/mach-tegra/include/mach/smp.h @@ -2,7 +2,6 @@ #define ASMARM_ARCH_SMP_H #include -#include /* * We use IRQ1 as the IPI diff --git a/arch/arm/mach-ux500/include/mach/smp.h b/arch/arm/mach-ux500/include/mach/smp.h index bd57c50a5b86..ca2b15b1b3b1 100644 --- a/arch/arm/mach-ux500/include/mach/smp.h +++ b/arch/arm/mach-ux500/include/mach/smp.h @@ -10,7 +10,6 @@ #define ASMARM_ARCH_SMP_H #include -#include /* This is required to wakeup the secondary core */ extern void u8500_secondary_startup(void); diff --git a/arch/arm/mach-vexpress/include/mach/smp.h b/arch/arm/mach-vexpress/include/mach/smp.h index 721be0f0311d..4c05e4a9713a 100644 --- a/arch/arm/mach-vexpress/include/mach/smp.h +++ b/arch/arm/mach-vexpress/include/mach/smp.h @@ -2,7 +2,6 @@ #define __MACH_SMP_H #include -#include /* * We use IRQ1 as the IPI diff --git a/arch/arm/plat-omap/include/plat/smp.h b/arch/arm/plat-omap/include/plat/smp.h index e5541e5388be..7a10257909ef 100644 --- a/arch/arm/plat-omap/include/plat/smp.h +++ b/arch/arm/plat-omap/include/plat/smp.h @@ -18,7 +18,6 @@ #define OMAP_ARCH_SMP_H #include -#include /* Needed for secondary core boot */ extern void omap_secondary_startup(void); -- cgit v1.2.3 From 3705ff6da538aff6dba535e2e9cbcbb9456d0d53 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sat, 18 Dec 2010 10:53:12 +0000 Subject: ARM: Fix subtle race in CPU pen_release hotplug code There is a subtle race in the CPU hotplug code, where a CPU which has been offlined can online itself before being requested, which results in things going astray on the next online/offline cycle. What happens in the normal online/offline/online cycle is: CPU0 CPU3 requests boot of CPU3 pen_release = 3 flush cache line checks pen_release, reads 3 starts boot pen_release = -1 ... requests CPU3 offline ... ... dies ... checks pen_release, reads -1 requests boot of CPU3 pen_release = 3 flush cache line checks pen_release, reads 3 starts boot pen_release = -1 However, as the write of -1 of pen_release is not fully flushed back to memory, and the checking of pen_release is done with caches disabled, this allows CPU3 the opportunity to read the old value of pen_release: CPU0 CPU3 requests boot of CPU3 pen_release = 3 flush cache line checks pen_release, reads 3 starts boot pen_release = -1 ... requests CPU3 offline ... ... dies ... checks pen_release, reads 3 starts boot pen_release = -1 requests boot of CPU3 pen_release = 3 flush cache line Fix this by grouping the write of pen_release along with its cache line flushing code to ensure that any update to pen_release is always pushed out to physical memory. Signed-off-by: Russell King --- arch/arm/mach-realview/platsmp.c | 19 +++++++++++++++---- arch/arm/mach-s5pv310/platsmp.c | 20 +++++++++++++++----- arch/arm/mach-ux500/platsmp.c | 22 +++++++++++++++------- arch/arm/mach-vexpress/platsmp.c | 20 +++++++++++++++----- 4 files changed, 60 insertions(+), 21 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-realview/platsmp.c b/arch/arm/mach-realview/platsmp.c index 226c63102a00..bb8d6c4e4315 100644 --- a/arch/arm/mach-realview/platsmp.c +++ b/arch/arm/mach-realview/platsmp.c @@ -36,6 +36,19 @@ extern void realview_secondary_startup(void); */ volatile int __cpuinitdata pen_release = -1; +/* + * Write pen_release in a way that is guaranteed to be visible to all + * observers, irrespective of whether they're taking part in coherency + * or not. This is necessary for the hotplug code to work reliably. + */ +static void write_pen_release(int val) +{ + pen_release = val; + smp_wmb(); + __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); + outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); +} + static void __iomem *scu_base_addr(void) { if (machine_is_realview_eb_mp()) @@ -64,8 +77,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu) * let the primary processor know we're out of the * pen, then head off into the C entry point */ - pen_release = -1; - smp_wmb(); + write_pen_release(-1); /* * Synchronise with the boot thread. @@ -92,8 +104,7 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) * Note that "pen_release" is the hardware CPU ID, whereas * "cpu" is Linux's internal ID. */ - pen_release = cpu; - flush_cache_all(); + write_pen_release(cpu); /* * Send the secondary CPU a soft interrupt, thereby causing diff --git a/arch/arm/mach-s5pv310/platsmp.c b/arch/arm/mach-s5pv310/platsmp.c index 18aaf5f54033..98c04748ed84 100644 --- a/arch/arm/mach-s5pv310/platsmp.c +++ b/arch/arm/mach-s5pv310/platsmp.c @@ -37,6 +37,19 @@ extern void s5pv310_secondary_startup(void); volatile int __cpuinitdata pen_release = -1; +/* + * Write pen_release in a way that is guaranteed to be visible to all + * observers, irrespective of whether they're taking part in coherency + * or not. This is necessary for the hotplug code to work reliably. + */ +static void write_pen_release(int val) +{ + pen_release = val; + smp_wmb(); + __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); + outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); +} + static void __iomem *scu_base_addr(void) { return (void __iomem *)(S5P_VA_SCU); @@ -57,8 +70,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu) * let the primary processor know we're out of the * pen, then head off into the C entry point */ - pen_release = -1; - smp_wmb(); + write_pen_release(-1); /* * Synchronise with the boot thread. @@ -85,9 +97,7 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) * Note that "pen_release" is the hardware CPU ID, whereas * "cpu" is Linux's internal ID. */ - pen_release = cpu; - __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); - outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); + write_pen_release(cpu); /* * Send the secondary CPU a soft interrupt, thereby causing diff --git a/arch/arm/mach-ux500/platsmp.c b/arch/arm/mach-ux500/platsmp.c index ddedbc80c41f..f71175a766d7 100644 --- a/arch/arm/mach-ux500/platsmp.c +++ b/arch/arm/mach-ux500/platsmp.c @@ -27,6 +27,19 @@ */ volatile int __cpuinitdata pen_release = -1; +/* + * Write pen_release in a way that is guaranteed to be visible to all + * observers, irrespective of whether they're taking part in coherency + * or not. This is necessary for the hotplug code to work reliably. + */ +static void write_pen_release(int val) +{ + pen_release = val; + smp_wmb(); + __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); + outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); +} + static DEFINE_SPINLOCK(boot_lock); void __cpuinit platform_secondary_init(unsigned int cpu) @@ -42,7 +55,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu) * let the primary processor know we're out of the * pen, then head off into the C entry point */ - pen_release = -1; + write_pen_release(-1); /* * Synchronise with the boot thread. @@ -66,9 +79,7 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) * the holding pen - release it, then wait for it to flag * that it has been released by resetting pen_release. */ - pen_release = cpu; - __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); - outer_clean_range(__pa(&pen_release), __pa(&pen_release) + 1); + write_pen_release(cpu); smp_cross_call(cpumask_of(cpu), 1); @@ -89,9 +100,6 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) static void __init wakeup_secondary(void) { - /* nobody is to be released from the pen yet */ - pen_release = -1; - /* * write the address of secondary startup into the backup ram register * at offset 0x1FF4, then write the magic number 0xA1FEED01 to the diff --git a/arch/arm/mach-vexpress/platsmp.c b/arch/arm/mach-vexpress/platsmp.c index d7e0cb994e9d..8ce9fef29555 100644 --- a/arch/arm/mach-vexpress/platsmp.c +++ b/arch/arm/mach-vexpress/platsmp.c @@ -34,6 +34,19 @@ extern void vexpress_secondary_startup(void); */ volatile int __cpuinitdata pen_release = -1; +/* + * Write pen_release in a way that is guaranteed to be visible to all + * observers, irrespective of whether they're taking part in coherency + * or not. This is necessary for the hotplug code to work reliably. + */ +static void write_pen_release(int val) +{ + pen_release = val; + smp_wmb(); + __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); + outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); +} + static void __iomem *scu_base_addr(void) { return MMIO_P2V(A9_MPCORE_SCU); @@ -54,8 +67,7 @@ void __cpuinit platform_secondary_init(unsigned int cpu) * let the primary processor know we're out of the * pen, then head off into the C entry point */ - pen_release = -1; - smp_wmb(); + write_pen_release(-1); /* * Synchronise with the boot thread. @@ -80,9 +92,7 @@ int __cpuinit boot_secondary(unsigned int cpu, struct task_struct *idle) * since we haven't sent them a soft interrupt, they shouldn't * be there. */ - pen_release = cpu; - __cpuc_flush_dcache_area((void *)&pen_release, sizeof(pen_release)); - outer_clean_range(__pa(&pen_release), __pa(&pen_release + 1)); + write_pen_release(cpu); /* * Send the secondary CPU a soft interrupt, thereby causing -- cgit v1.2.3 From d4450261e546953c4a1ce8b48e29164a57c6ed33 Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 19 Dec 2010 11:30:43 +0000 Subject: ARM: CPU hotplug: fix reporting of spurious wakeups The original scheme for reporting spurious wakeups was broken - it tried to use printk() from a context which wasn't coherent with the other CPUs, which risks corrupting the printk() data. Fix this by noting the number spurious wakeups, and only report them when we are properly woken - when we will be coherent with the rest of the system. Signed-off-by: Russell King --- arch/arm/mach-realview/hotplug.c | 20 +++++++++++--------- arch/arm/mach-s5pv310/hotplug.c | 20 +++++++++++--------- arch/arm/mach-tegra/hotplug.c | 20 +++++++++++--------- 3 files changed, 33 insertions(+), 27 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c index e06572e6c490..b6387cfe7044 100644 --- a/arch/arm/mach-realview/hotplug.c +++ b/arch/arm/mach-realview/hotplug.c @@ -53,7 +53,7 @@ static inline void cpu_leave_lowpower(void) : "cc"); } -static inline void platform_do_lowpower(unsigned int cpu) +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) { /* * there is no power-control hardware on this platform, so all @@ -77,16 +77,13 @@ static inline void platform_do_lowpower(unsigned int cpu) } /* - * getting here, means that we have come out of WFI without + * Getting here, means that we have come out of WFI without * having been woken up - this shouldn't happen * - * The trouble is, letting people know about this is not really - * possible, since we are currently running incoherently, and - * therefore cannot safely call printk() or anything else + * Just note it happening - when we're woken, we can report + * its occurrence. */ -#ifdef DEBUG - printk("CPU%u: spurious wakeup call\n", cpu); -#endif + (*spurious)++; } } @@ -102,17 +99,22 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { + int spurious = 0; + /* * we're ready for shutdown now, so do it */ cpu_enter_lowpower(); - platform_do_lowpower(cpu); + platform_do_lowpower(cpu, &spurious); /* * bring this CPU back into the world of cache * coherency, and then restore interrupts */ cpu_leave_lowpower(); + + if (spurious) + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); } int platform_cpu_disable(unsigned int cpu) diff --git a/arch/arm/mach-s5pv310/hotplug.c b/arch/arm/mach-s5pv310/hotplug.c index ea951ef6ea54..951ba6d63d21 100644 --- a/arch/arm/mach-s5pv310/hotplug.c +++ b/arch/arm/mach-s5pv310/hotplug.c @@ -56,7 +56,7 @@ static inline void cpu_leave_lowpower(void) : "cc"); } -static inline void platform_do_lowpower(unsigned int cpu) +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) { /* * there is no power-control hardware on this platform, so all @@ -80,16 +80,13 @@ static inline void platform_do_lowpower(unsigned int cpu) } /* - * getting here, means that we have come out of WFI without + * Getting here, means that we have come out of WFI without * having been woken up - this shouldn't happen * - * The trouble is, letting people know about this is not really - * possible, since we are currently running incoherently, and - * therefore cannot safely call printk() or anything else + * Just note it happening - when we're woken, we can report + * its occurrence. */ -#ifdef DEBUG - printk(KERN_WARN "CPU%u: spurious wakeup call\n", cpu); -#endif + (*spurious)++; } } @@ -105,17 +102,22 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { + int spurious = 0; + /* * we're ready for shutdown now, so do it */ cpu_enter_lowpower(); - platform_do_lowpower(cpu); + platform_do_lowpower(cpu, &spurious); /* * bring this CPU back into the world of cache * coherency, and then restore interrupts */ cpu_leave_lowpower(); + + if (spurious) + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); } int platform_cpu_disable(unsigned int cpu) diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c index a5eeb9126645..17faf777af23 100644 --- a/arch/arm/mach-tegra/hotplug.c +++ b/arch/arm/mach-tegra/hotplug.c @@ -52,7 +52,7 @@ static inline void cpu_leave_lowpower(void) : "cc"); } -static inline void platform_do_lowpower(unsigned int cpu) +static inline void platform_do_lowpower(unsigned int cpu, int *spurious) { /* * there is no power-control hardware on this platform, so all @@ -76,16 +76,13 @@ static inline void platform_do_lowpower(unsigned int cpu) /*}*/ /* - * getting here, means that we have come out of WFI without + * Getting here, means that we have come out of WFI without * having been woken up - this shouldn't happen * - * The trouble is, letting people know about this is not really - * possible, since we are currently running incoherently, and - * therefore cannot safely call printk() or anything else + * Just note it happening - when we're woken, we can report + * its occurrence. */ -#ifdef DEBUG - printk(KERN_WARN "CPU%u: spurious wakeup call\n", cpu); -#endif + (*spurious)++; } } @@ -101,17 +98,22 @@ int platform_cpu_kill(unsigned int cpu) */ void platform_cpu_die(unsigned int cpu) { + int spurious = 0; + /* * we're ready for shutdown now, so do it */ cpu_enter_lowpower(); - platform_do_lowpower(cpu); + platform_do_lowpower(cpu, &spurious); /* * bring this CPU back into the world of cache * coherency, and then restore interrupts */ cpu_leave_lowpower(); + + if (spurious) + pr_warn("CPU%u: %u spurious wakeup calls\n", cpu, spurious); } int platform_cpu_disable(unsigned int cpu) -- cgit v1.2.3 From e3d9c625f5e4158014e041f492b46e38ad10987e Mon Sep 17 00:00:00 2001 From: Russell King Date: Sun, 19 Dec 2010 11:36:33 +0000 Subject: ARM: CPU hotplug: fix hard-coded control register constants Use the definition we've provided in asm/system.h rather than numeric constants. Signed-off-by: Russell King --- arch/arm/mach-realview/hotplug.c | 8 ++++---- arch/arm/mach-s5pv310/hotplug.c | 8 ++++---- arch/arm/mach-tegra/hotplug.c | 8 ++++---- 3 files changed, 12 insertions(+), 12 deletions(-) (limited to 'arch/arm/mach-realview') diff --git a/arch/arm/mach-realview/hotplug.c b/arch/arm/mach-realview/hotplug.c index b6387cfe7044..a87523d095e6 100644 --- a/arch/arm/mach-realview/hotplug.c +++ b/arch/arm/mach-realview/hotplug.c @@ -31,10 +31,10 @@ static inline void cpu_enter_lowpower(void) " bic %0, %0, #0x20\n" " mcr p15, 0, %0, c1, c0, 1\n" " mrc p15, 0, %0, c1, c0, 0\n" - " bic %0, %0, #0x04\n" + " bic %0, %0, %2\n" " mcr p15, 0, %0, c1, c0, 0\n" : "=&r" (v) - : "r" (0) + : "r" (0), "Ir" (CR_C) : "cc"); } @@ -43,13 +43,13 @@ static inline void cpu_leave_lowpower(void) unsigned int v; asm volatile( "mrc p15, 0, %0, c1, c0, 0\n" - " orr %0, %0, #0x04\n" + " orr %0, %0, %1\n" " mcr p15, 0, %0, c1, c0, 0\n" " mrc p15, 0, %0, c1, c0, 1\n" " orr %0, %0, #0x20\n" " mcr p15, 0, %0, c1, c0, 1\n" : "=&r" (v) - : + : "Ir" (CR_C) : "cc"); } diff --git a/arch/arm/mach-s5pv310/hotplug.c b/arch/arm/mach-s5pv310/hotplug.c index 951ba6d63d21..afa5392d9fc0 100644 --- a/arch/arm/mach-s5pv310/hotplug.c +++ b/arch/arm/mach-s5pv310/hotplug.c @@ -30,13 +30,13 @@ static inline void cpu_enter_lowpower(void) * Turn off coherency */ " mrc p15, 0, %0, c1, c0, 1\n" - " bic %0, %0, #0x20\n" + " bic %0, %0, %2\n" " mcr p15, 0, %0, c1, c0, 1\n" " mrc p15, 0, %0, c1, c0, 0\n" " bic %0, %0, #0x04\n" " mcr p15, 0, %0, c1, c0, 0\n" : "=&r" (v) - : "r" (0) + : "r" (0), "Ir" (CR_C) : "cc"); } @@ -46,13 +46,13 @@ static inline void cpu_leave_lowpower(void) asm volatile( "mrc p15, 0, %0, c1, c0, 0\n" - " orr %0, %0, #0x04\n" + " orr %0, %0, %1\n" " mcr p15, 0, %0, c1, c0, 0\n" " mrc p15, 0, %0, c1, c0, 1\n" " orr %0, %0, #0x20\n" " mcr p15, 0, %0, c1, c0, 1\n" : "=&r" (v) - : + : "Ir" (CR_C) : "cc"); } diff --git a/arch/arm/mach-tegra/hotplug.c b/arch/arm/mach-tegra/hotplug.c index 17faf777af23..a5cb1ce76ff2 100644 --- a/arch/arm/mach-tegra/hotplug.c +++ b/arch/arm/mach-tegra/hotplug.c @@ -26,13 +26,13 @@ static inline void cpu_enter_lowpower(void) * Turn off coherency */ " mrc p15, 0, %0, c1, c0, 1\n" - " bic %0, %0, #0x20\n" + " bic %0, %0, %2\n" " mcr p15, 0, %0, c1, c0, 1\n" " mrc p15, 0, %0, c1, c0, 0\n" " bic %0, %0, #0x04\n" " mcr p15, 0, %0, c1, c0, 0\n" : "=&r" (v) - : "r" (0) + : "r" (0), "Ir" (CR_C) : "cc"); } @@ -42,13 +42,13 @@ static inline void cpu_leave_lowpower(void) asm volatile( "mrc p15, 0, %0, c1, c0, 0\n" - " orr %0, %0, #0x04\n" + " orr %0, %0, %1\n" " mcr p15, 0, %0, c1, c0, 0\n" " mrc p15, 0, %0, c1, c0, 1\n" " orr %0, %0, #0x20\n" " mcr p15, 0, %0, c1, c0, 1\n" : "=&r" (v) - : + : "Ir" (CR_C) : "cc"); } -- cgit v1.2.3