diff options
| -rw-r--r-- | arch/arc/Kconfig | 11 | ||||
| -rw-r--r-- | arch/arc/include/asm/smp.h | 8 | ||||
| -rw-r--r-- | arch/arc/kernel/head.S | 26 | ||||
| -rw-r--r-- | arch/arc/kernel/setup.c | 48 | ||||
| -rw-r--r-- | arch/arc/kernel/smp.c | 124 | ||||
| -rw-r--r-- | arch/arc/plat-arcfpga/smp.c | 12 |
6 files changed, 121 insertions, 108 deletions
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 5438cab..9be30c8 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -409,17 +409,6 @@ config ARC_DBG_TLB_MISS_COUNT Counts number of I and D TLB Misses and exports them via Debugfs The counters can be cleared via Debugfs as well -config CMDLINE_UBOOT - bool "Support U-boot kernel command line passing" - default n - help - If you are using U-boot (www.denx.de) and wish to pass the kernel - command line from the U-boot environment to the Linux kernel then - switch this option on. - ARC U-boot will setup the cmdline in RAM/flash and set r2 to point - to it. kernel startup code will append this to DeviceTree - /bootargs provided cmdline args. - config ARC_BUILTIN_DTB_NAME string "Built in DTB" help diff --git a/arch/arc/include/asm/smp.h b/arch/arc/include/asm/smp.h index eefc29f..5d06eee 100644 --- a/arch/arc/include/asm/smp.h +++ b/arch/arc/include/asm/smp.h @@ -46,14 +46,14 @@ extern int smp_ipi_irq_setup(int cpu, int irq); * * @info: SoC SMP specific info for /proc/cpuinfo etc * @cpu_kick: For Master to kickstart a cpu (optionally at a PC) - * @ipi_send: To send IPI to a @cpumask - * @ips_clear: To clear IPI received by @cpu at @irq + * @ipi_send: To send IPI to a @cpu + * @ips_clear: To clear IPI received at @irq */ struct plat_smp_ops { const char *info; void (*cpu_kick)(int cpu, unsigned long pc); - void (*ipi_send)(void *callmap); - void (*ipi_clear)(int cpu, int irq); + void (*ipi_send)(int cpu); + void (*ipi_clear)(int irq); }; /* TBD: stop exporting it for direct population by platform */ diff --git a/arch/arc/kernel/head.S b/arch/arc/kernel/head.S index 2c878e9..9919972 100644 --- a/arch/arc/kernel/head.S +++ b/arch/arc/kernel/head.S @@ -49,25 +49,13 @@ stext: st.ab 0, [r5,4] brlt r5, r6, 1b -#ifdef CONFIG_CMDLINE_UBOOT - ; support for bootloader provided cmdline - ; If cmdline passed by u-boot, then - ; r0 = 1 (because ATAGS parsing, now retired, used to use 0) - ; r1 = magic number (board identity) - ; r2 = addr of cmdline string (somewhere in memory/flash) - - brne r0, 1, .Lother_bootup_chores ; u-boot didn't pass cmdline - breq r2, 0, .Lother_bootup_chores ; or cmdline is NULL - - mov r5, @command_line -1: - ldb.ab r6, [r2, 1] - breq r6, 0, .Lother_bootup_chores - b.d 1b - stb.ab r6, [r5, 1] -#endif - -.Lother_bootup_chores: + ; Uboot - kernel ABI + ; r0 = [0] No uboot interaction, [1] cmdline in r2, [2] DTB in r2 + ; r1 = magic number (board identity, unused as of now + ; r2 = pointer to uboot provided cmdline or external DTB in mem + ; These are handled later in setup_arch() + st r0, [@uboot_tag] + st r2, [@uboot_arg] ; Identify if running on ISS vs Silicon ; IDENTITY Reg [ 3 2 1 0 ] diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c index 643eae4..119dddb 100644 --- a/arch/arc/kernel/setup.c +++ b/arch/arc/kernel/setup.c @@ -29,7 +29,10 @@ int running_on_hw = 1; /* vs. on ISS */ -char __initdata command_line[COMMAND_LINE_SIZE]; +/* Part of U-boot ABI: see head.S */ +int __initdata uboot_tag; +char __initdata *uboot_arg; + const struct machine_desc *machine_desc; struct task_struct *_current_task[NR_CPUS]; /* For stack switching */ @@ -311,19 +314,40 @@ void setup_processor(void) arc_chk_fpu(); } +static inline int is_kernel(unsigned long addr) +{ + if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end) + return 1; + return 0; +} + void __init setup_arch(char **cmdline_p) { - /* This also populates @boot_command_line from /bootargs */ - machine_desc = setup_machine_fdt(__dtb_start); - if (!machine_desc) - panic("Embedded DT invalid\n"); - - /* Append any u-boot provided cmdline */ -#ifdef CONFIG_CMDLINE_UBOOT - /* Add a whitespace seperator between the 2 cmdlines */ - strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); - strlcat(boot_command_line, command_line, COMMAND_LINE_SIZE); -#endif + /* make sure that uboot passed pointer to cmdline/dtb is valid */ + if (uboot_tag && is_kernel((unsigned long)uboot_arg)) + panic("Invalid uboot arg\n"); + + /* See if u-boot passed an external Device Tree blob */ + machine_desc = setup_machine_fdt(uboot_arg); /* uboot_tag == 2 */ + if (!machine_desc) { + /* No, so try the embedded one */ + machine_desc = setup_machine_fdt(__dtb_start); + if (!machine_desc) + panic("Embedded DT invalid\n"); + + /* + * If we are here, it is established that @uboot_arg didn't + * point to DT blob. Instead if u-boot says it is cmdline, + * Appent to embedded DT cmdline. + * setup_machine_fdt() would have populated @boot_command_line + */ + if (uboot_tag == 1) { + /* Ensure a whitespace between the 2 cmdlines */ + strlcat(boot_command_line, " ", COMMAND_LINE_SIZE); + strlcat(boot_command_line, uboot_arg, + COMMAND_LINE_SIZE); + } + } /* Save unparsed command line copy for /proc/cmdline */ *cmdline_p = boot_command_line; diff --git a/arch/arc/kernel/smp.c b/arch/arc/kernel/smp.c index c2f9ebb..40859e5 100644 --- a/arch/arc/kernel/smp.c +++ b/arch/arc/kernel/smp.c @@ -197,51 +197,65 @@ int __init setup_profiling_timer(unsigned int multiplier) /* Inter Processor Interrupt Handling */ /*****************************************************************************/ -/* - * structures for inter-processor calls - * A Collection of single bit ipi messages - * - */ - -/* - * TODO_rajesh investigate tlb message types. - * IPI Timer not needed because each ARC has an individual Interrupting Timer - */ enum ipi_msg_type { - IPI_NOP = 0, + IPI_EMPTY = 0, IPI_RESCHEDULE = 1, IPI_CALL_FUNC, - IPI_CPU_STOP + IPI_CPU_STOP, }; -struct ipi_data { - unsigned long bits; -}; +/* + * In arches with IRQ for each msg type (above), receiver can use IRQ-id to + * figure out what msg was sent. For those which don't (ARC has dedicated IPI + * IRQ), the msg-type needs to be conveyed via per-cpu data + */ -static DEFINE_PER_CPU(struct ipi_data, ipi_data); +static DEFINE_PER_CPU(unsigned long, ipi_data); -static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg) +static void ipi_send_msg_one(int cpu, enum ipi_msg_type msg) { + unsigned long __percpu *ipi_data_ptr = per_cpu_ptr(&ipi_data, cpu); + unsigned long old, new; unsigned long flags; - unsigned int cpu; + + pr_debug("%d Sending msg [%d] to %d\n", smp_processor_id(), msg, cpu); local_irq_save(flags); - for_each_cpu(cpu, callmap) { - struct ipi_data *ipi = &per_cpu(ipi_data, cpu); - set_bit(msg, &ipi->bits); - } + /* + * Atomically write new msg bit (in case others are writing too), + * and read back old value + */ + do { + new = old = *ipi_data_ptr; + new |= 1U << msg; + } while (cmpxchg(ipi_data_ptr, old, new) != old); - /* Call the platform specific cross-CPU call function */ - if (plat_smp_ops.ipi_send) - plat_smp_ops.ipi_send((void *)callmap); + /* + * Call the platform specific IPI kick function, but avoid if possible: + * Only do so if there's no pending msg from other concurrent sender(s). + * Otherwise, recevier will see this msg as well when it takes the + * IPI corresponding to that msg. This is true, even if it is already in + * IPI handler, because !@old means it has not yet dequeued the msg(s) + * so @new msg can be a free-loader + */ + if (plat_smp_ops.ipi_send && !old) + plat_smp_ops.ipi_send(cpu); local_irq_restore(flags); } +static void ipi_send_msg(const struct cpumask *callmap, enum ipi_msg_type msg) +{ + unsigned int cpu; + + for_each_cpu(cpu, callmap) + ipi_send_msg_one(cpu, msg); +} + void smp_send_reschedule(int cpu) { - ipi_send_msg(cpumask_of(cpu), IPI_RESCHEDULE); + ipi_send_msg_one(cpu, IPI_RESCHEDULE); } void smp_send_stop(void) @@ -254,7 +268,7 @@ void smp_send_stop(void) void arch_send_call_function_single_ipi(int cpu) { - ipi_send_msg(cpumask_of(cpu), IPI_CALL_FUNC); + ipi_send_msg_one(cpu, IPI_CALL_FUNC); } void arch_send_call_function_ipi_mask(const struct cpumask *mask) @@ -265,33 +279,29 @@ void arch_send_call_function_ipi_mask(const struct cpumask *mask) /* * ipi_cpu_stop - handle IPI from smp_send_stop() */ -static void ipi_cpu_stop(unsigned int cpu) +static void ipi_cpu_stop(void) { machine_halt(); } -static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi, int cpu) +static inline void __do_IPI(unsigned long msg) { - unsigned long msg = 0; + switch (msg) { + case IPI_RESCHEDULE: + scheduler_ipi(); + break; - do { - msg = find_next_bit(ops, BITS_PER_LONG, msg+1); + case IPI_CALL_FUNC: + generic_smp_call_function_interrupt(); + break; - switch (msg) { - case IPI_RESCHEDULE: - scheduler_ipi(); - break; - - case IPI_CALL_FUNC: - generic_smp_call_function_interrupt(); - break; - - case IPI_CPU_STOP: - ipi_cpu_stop(cpu); - break; - } - } while (msg < BITS_PER_LONG); + case IPI_CPU_STOP: + ipi_cpu_stop(); + break; + default: + pr_warn("IPI with unexpected msg %ld\n", msg); + } } /* @@ -300,19 +310,25 @@ static inline void __do_IPI(unsigned long *ops, struct ipi_data *ipi, int cpu) */ irqreturn_t do_IPI(int irq, void *dev_id) { - int cpu = smp_processor_id(); - struct ipi_data *ipi = &per_cpu(ipi_data, cpu); - unsigned long ops; + unsigned long pending; + + pr_debug("IPI [%ld] received on cpu %d\n", + *this_cpu_ptr(&ipi_data), smp_processor_id()); if (plat_smp_ops.ipi_clear) - plat_smp_ops.ipi_clear(cpu, irq); + plat_smp_ops.ipi_clear(irq); /* - * XXX: is this loop really needed - * And do we need to move ipi_clean inside + * "dequeue" the msg corresponding to this IPI (and possibly other + * piggybacked msg from elided IPIs: see ipi_send_msg_one() above) */ - while ((ops = xchg(&ipi->bits, 0)) != 0) - __do_IPI(&ops, ipi, cpu); + pending = xchg(this_cpu_ptr(&ipi_data), 0); + + do { + unsigned long msg = __ffs(pending); + __do_IPI(msg); + pending &= ~(1U << msg); + } while (pending); return IRQ_HANDLED; } diff --git a/arch/arc/plat-arcfpga/smp.c b/arch/arc/plat-arcfpga/smp.c index 91b5534..8a12741 100644 --- a/arch/arc/plat-arcfpga/smp.c +++ b/arch/arc/plat-arcfpga/smp.c @@ -88,18 +88,14 @@ void iss_model_init_smp(unsigned int cpu) smp_ipi_irq_setup(cpu, IDU_INTERRUPT_0 + cpu); } -static void iss_model_ipi_send(void *arg) +static void iss_model_ipi_send(int cpu) { - struct cpumask *callmap = arg; - unsigned int cpu; - - for_each_cpu(cpu, callmap) - idu_irq_assert(cpu); + idu_irq_assert(cpu); } -static void iss_model_ipi_clear(int cpu, int irq) +static void iss_model_ipi_clear(int irq) { - idu_irq_clear(IDU_INTERRUPT_0 + cpu); + idu_irq_clear(IDU_INTERRUPT_0 + smp_processor_id()); } void iss_model_init_early_smp(void) |