Messages in this thread Patch in this message | | | From | Rusty Russell <> | Subject | Hotplug CPU Boot Change 2/2 | Date | Thu, 18 Jul 2002 14:21:59 +1000 |
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.... And this fixes up x86.
Name: Hot-plug CPU Boot Rewrite for i386 Author: Rusty Russell Status: Tested 2.5.25, dual SMP Depends: Hotcpu/hotcpu-boot.patch.gz
D: This modifies the i386 boot sequence to "plug in" CPUs one at a D: time. This is the minimal change to make it work (the CPUs are D: brought up as normal during the "smp_prepare_cpus()" probe phase).
diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/apic.c working-2.5.25-hotcpu/arch/i386/kernel/apic.c --- linux-2.5.25/arch/i386/kernel/apic.c Thu Jun 20 01:28:47 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/apic.c Mon Jul 15 18:23:12 2002 @@ -798,9 +798,9 @@ apic_write_around(APIC_TMICT, clocks/APIC_DIVISOR); } -void setup_APIC_timer(void * data) +static void setup_APIC_timer(unsigned int clocks) { - unsigned int clocks = (unsigned int) data, slice, t0, t1; + unsigned int slice, t0, t1; unsigned long flags; int delta; @@ -926,7 +926,7 @@ int dont_use_local_apic_timer __initdata = 0; -void __init setup_APIC_clocks (void) +void __init setup_boot_APIC_clock(void) { /* Disabled by DMI scan or kernel option? */ if (dont_use_local_apic_timer) @@ -941,12 +941,16 @@ /* * Now set up the timer for real. */ - setup_APIC_timer((void *)calibration_result); + setup_APIC_timer(calibration_result); __sti(); +} - /* and update all other cpus */ - smp_call_function(setup_APIC_timer, (void *)calibration_result, 1, 1); +void __init setup_secondary_APIC_clock(void) +{ + __cli(); /* FIXME: Do we need this? --RR */ + setup_APIC_timer(calibration_result); + __sti(); } void __init disable_APIC_timer(void) @@ -1178,7 +1182,7 @@ if (!skip_ioapic_setup && nr_ioapics) setup_IO_APIC(); #endif - setup_APIC_clocks(); + setup_boot_APIC_clock(); return 0; } diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/apm.c working-2.5.25-hotcpu/arch/i386/kernel/apm.c --- linux-2.5.25/arch/i386/kernel/apm.c Sun Jul 7 02:12:17 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/apm.c Mon Jul 15 14:42:18 2002 @@ -1587,7 +1587,7 @@ p = buf; - if ((num_online_cpus() == 1) && + if ((num_possible_cpus() == 1) && !(error = apm_get_power_status(&bx, &cx, &dx))) { ac_line_status = (bx >> 8) & 0xff; battery_status = bx & 0xff; @@ -1718,7 +1718,7 @@ } } - if (debug && (num_online_cpus() == 1)) { + if (debug && (num_possible_cpus() == 1)) { error = apm_get_power_status(&bx, &cx, &dx); if (error) printk(KERN_INFO "apm: power status not available\n"); @@ -1762,7 +1762,7 @@ pm_power_off = apm_power_off; register_sysrq_key('o', &sysrq_poweroff_op); - if (num_online_cpus() == 1) { + if (num_possible_cpus() == 1) { #if defined(CONFIG_APM_DISPLAY_BLANK) && defined(CONFIG_VT) console_blank_hook = apm_console_blank; #endif @@ -1905,9 +1905,7 @@ printk(KERN_NOTICE "apm: disabled on user request.\n"); return -ENODEV; } - /* FIXME: When boot code changes, this will need to be - deactivated when/if a CPU comes up --RR */ - if ((num_online_cpus() > 1) && !power_off) { + if ((num_possible_cpus() > 1) && !power_off) { printk(KERN_NOTICE "apm: disabled - APM is not SMP safe.\n"); return -ENODEV; } @@ -1961,9 +1959,7 @@ kernel_thread(apm, NULL, CLONE_FS | CLONE_FILES | CLONE_SIGHAND | SIGCHLD); - /* FIXME: When boot code changes, this will need to be - deactivated when/if a CPU comes up --RR */ - if (num_online_cpus() > 1) { + if (num_possible_cpus() > 1) { printk(KERN_NOTICE "apm: disabled - APM is not SMP safe (power off active).\n"); return 0; diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/mtrr.c working-2.5.25-hotcpu/arch/i386/kernel/mtrr.c --- linux-2.5.25/arch/i386/kernel/mtrr.c Thu Jun 20 01:28:47 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/mtrr.c Mon Jul 15 14:42:42 2002 @@ -1055,7 +1055,7 @@ wait_barrier_cache_disable = TRUE; wait_barrier_execute = TRUE; wait_barrier_cache_enable = TRUE; - atomic_set (&undone_count, num_online_cpus() - 1); + atomic_set (&undone_count, num_booting_cpus() - 1); /* Start the ball rolling on other CPUs */ if (smp_call_function (ipi_handler, &data, 1, 0) != 0) panic ("mtrr: timed out waiting for other CPUs\n"); @@ -1064,14 +1064,14 @@ /* Wait for all other CPUs to flush and disable their caches */ while (atomic_read (&undone_count) > 0) { rep_nop(); barrier(); } /* Set up for completion wait and then release other CPUs to change MTRRs*/ - atomic_set (&undone_count, num_online_cpus() - 1); + atomic_set (&undone_count, num_booting_cpus() - 1); wait_barrier_cache_disable = FALSE; set_mtrr_cache_disable (&ctxt); /* Wait for all other CPUs to flush and disable their caches */ while (atomic_read (&undone_count) > 0) { rep_nop(); barrier(); } /* Set up for completion wait and then release other CPUs to change MTRRs*/ - atomic_set (&undone_count, num_online_cpus() - 1); + atomic_set (&undone_count, num_booting_cpus() - 1); wait_barrier_execute = FALSE; (*set_mtrr_up) (reg, base, size, type, FALSE); /* Now wait for other CPUs to complete the function */ diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/nmi.c working-2.5.25-hotcpu/arch/i386/kernel/nmi.c --- linux-2.5.25/arch/i386/kernel/nmi.c Thu Jun 20 01:28:47 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/nmi.c Mon Jul 15 15:30:34 2002 @@ -81,6 +81,8 @@ sti(); mdelay((10*1000)/nmi_hz); // wait 10 ticks + /* FIXME: Only boot CPU is online at this stage. Check CPUs + as they come up. */ for (cpu = 0; cpu < NR_CPUS; cpu++) { if (!cpu_online(cpu)) continue; diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/arch/i386/kernel/smpboot.c working-2.5.25-hotcpu/arch/i386/kernel/smpboot.c --- linux-2.5.25/arch/i386/kernel/smpboot.c Fri Jun 21 09:41:52 2002 +++ working-2.5.25-hotcpu/arch/i386/kernel/smpboot.c Mon Jul 15 17:44:05 2002 @@ -31,7 +31,7 @@ * Maciej W. Rozycki : Bits for genuine 82489DX APICs * Martin J. Bligh : Added support for multi-quad systems * Dave Jones : Report invalid combinations of Athlon CPUs. - */ +* Rusty Russell : Hacked into shape for new "hotplug" boot process. */ #include <linux/config.h> #include <linux/init.h> @@ -53,9 +53,6 @@ /* Set if we find a B stepping CPU */ static int __initdata smp_b_stepping; -/* Setup configured maximum number of CPUs to activate */ -static int __initdata max_cpus = NR_CPUS; - /* Number of siblings per CPU package */ int smp_num_siblings = 1; int __initdata phys_proc_id[NR_CPUS]; /* Package ID of each logical CPU */ @@ -64,7 +61,8 @@ unsigned long cpu_online_map; static volatile unsigned long cpu_callin_map; -static volatile unsigned long cpu_callout_map; +volatile unsigned long cpu_callout_map; +static unsigned long smp_commenced_mask; /* Per CPU bogomips and other parameters */ struct cpuinfo_x86 cpu_data[NR_CPUS] __cacheline_aligned; @@ -73,33 +71,6 @@ int smp_threads_ready; /* - * Setup routine for controlling SMP activation - * - * Command-line option of "nosmp" or "maxcpus=0" will disable SMP - * activation entirely (the MPS table probe still happens, though). - * - * Command-line option of "maxcpus=<NUM>", where <NUM> is an integer - * greater than 0, limits the maximum number of CPUs activated in - * SMP mode to <NUM>. - */ - -static int __init nosmp(char *str) -{ - max_cpus = 0; - return 1; -} - -__setup("nosmp", nosmp); - -static int __init maxcpus(char *str) -{ - get_option(&str, &max_cpus); - return 1; -} - -__setup("maxcpus=", maxcpus); - -/* * Trampoline 80x86 program as an array. */ @@ -139,7 +110,7 @@ * a given CPU */ -void __init smp_store_cpu_info(int id) +static void __init smp_store_cpu_info(int id) { struct cpuinfo_x86 *c = cpu_data + id; @@ -193,29 +164,6 @@ } /* - * Architecture specific routine called by the kernel just before init is - * fired off. This allows the BP to have everything in order [we hope]. - * At the end of this all the APs will hit the system scheduling and off - * we go. Each AP will load the system gdt's and jump through the kernel - * init into idle(). At this point the scheduler will one day take over - * and give them jobs to do. smp_callin is a standard routine - * we use to track CPUs as they power up. - */ - -static atomic_t smp_commenced = ATOMIC_INIT(0); - -void __init smp_commence(void) -{ - /* - * Lets the callins below out of their loop. - */ - Dprintk("Setting commenced=1, go go go\n"); - - wmb(); - atomic_set(&smp_commenced,1); -} - -/* * TSC synchronization. * * We first check wether all CPUs have their TSC's synchronized, @@ -268,7 +216,7 @@ unsigned long one_usec; int buggy = 0; - printk("checking TSC synchronization across CPUs: "); + printk("checking TSC synchronization across %u CPUs: ", num_booting_cpus()); one_usec = ((1<<30)/fast_gettimeoffset_quotient)*(1<<2); @@ -289,7 +237,7 @@ /* * all APs synchronize but they loop on '== num_cpus' */ - while (atomic_read(&tsc_count_start) != num_online_cpus()-1) + while (atomic_read(&tsc_count_start) != num_booting_cpus()-1) mb(); atomic_set(&tsc_count_stop, 0); wmb(); @@ -308,7 +256,7 @@ /* * Wait for all APs to leave the synchronization point: */ - while (atomic_read(&tsc_count_stop) != num_online_cpus()-1) + while (atomic_read(&tsc_count_stop) != num_booting_cpus()-1) mb(); atomic_set(&tsc_count_start, 0); wmb(); @@ -317,16 +265,16 @@ sum = 0; for (i = 0; i < NR_CPUS; i++) { - if (cpu_online(i)) { + if (test_bit(i, &cpu_callout_map)) { t0 = tsc_values[i]; sum += t0; } } - avg = div64(sum, num_online_cpus()); + avg = div64(sum, num_booting_cpus()); sum = 0; for (i = 0; i < NR_CPUS; i++) { - if (!cpu_online(i)) + if (!test_bit(i, &cpu_callout_map)) continue; delta = tsc_values[i] - avg; if (delta < 0) @@ -359,7 +307,7 @@ int i; /* - * num_online_cpus is not necessarily known at the time + * Not every cpu is online at the time * this gets called, so we first wait for the BP to * finish SMP initialization: */ @@ -367,7 +315,7 @@ for (i = 0; i < NR_LOOPS; i++) { atomic_inc(&tsc_count_start); - while (atomic_read(&tsc_count_start) != num_online_cpus()) + while (atomic_read(&tsc_count_start) != num_booting_cpus()) mb(); rdtscll(tsc_values[smp_processor_id()]); @@ -375,7 +323,7 @@ write_tsc(0, 0); atomic_inc(&tsc_count_stop); - while (atomic_read(&tsc_count_stop) != num_online_cpus()) mb(); + while (atomic_read(&tsc_count_stop) != num_booting_cpus()) mb(); } } #undef NR_LOOPS @@ -403,7 +351,7 @@ */ phys_id = GET_APIC_ID(apic_read(APIC_ID)); cpuid = smp_processor_id(); - if (test_and_set_bit(cpuid, &cpu_online_map)) { + if (test_bit(cpuid, &cpu_callin_map)) { printk("huh, phys CPU#%d, CPU#%d already present??\n", phys_id, cpuid); BUG(); @@ -501,15 +449,17 @@ */ cpu_init(); smp_callin(); - while (!atomic_read(&smp_commenced)) + while (!test_bit(smp_processor_id(), &smp_commenced_mask)) rep_nop(); + setup_secondary_APIC_clock(); enable_APIC_timer(); /* * low-memory mappings have been cleared, flush them from * the local TLBs too. */ local_flush_tlb(); - + set_bit(smp_processor_id(), &cpu_online_map); + wmb(); return cpu_idle(); } @@ -943,7 +893,6 @@ unmap_cpu_to_boot_apicid(cpu, apicid); clear_bit(cpu, &cpu_callout_map); /* was set here (do_boot_cpu()) */ clear_bit(cpu, &cpu_initialized); /* was set by cpu_init() */ - clear_bit(cpu, &cpu_online_map); /* was set in smp_callin() */ cpucount--; } @@ -1015,7 +964,7 @@ int cpu_sibling_map[NR_CPUS] __cacheline_aligned; -void __init smp_boot_cpus(void) +static void __init smp_boot_cpus(unsigned int max_cpus) { int apicid, cpu, bit; @@ -1057,6 +1006,7 @@ * We have the boot CPU online for sure. */ set_bit(0, &cpu_online_map); + set_bit(0, &cpu_callout_map); boot_cpu_logical_apicid = logical_smp_processor_id(); map_cpu_to_boot_apicid(0, boot_cpu_apicid); @@ -1073,11 +1023,11 @@ #ifndef CONFIG_VISWS io_apic_irqs = 0; #endif - cpu_online_map = phys_cpu_present_map = 1; + phys_cpu_present_map = 1; if (APIC_init_uniprocessor()) printk(KERN_NOTICE "Local APIC not detected." " Using dummy APIC emulation.\n"); - goto smp_done; + return; } /* @@ -1102,8 +1052,8 @@ #ifndef CONFIG_VISWS io_apic_irqs = 0; #endif - cpu_online_map = phys_cpu_present_map = 1; - goto smp_done; + phys_cpu_present_map = 1; + return; } verify_local_APIC(); @@ -1117,8 +1067,8 @@ #ifndef CONFIG_VISWS io_apic_irqs = 0; #endif - cpu_online_map = phys_cpu_present_map = 1; - goto smp_done; + phys_cpu_present_map = 1; + return; } connect_bsp_APIC(); @@ -1190,7 +1140,7 @@ } else { unsigned long bogosum = 0; for (cpu = 0; cpu < NR_CPUS; cpu++) - if (cpu_online_map & (1<<cpu)) + if (cpu_callout_map & (1<<cpu)) bogosum += cpu_data[cpu].loops_per_jiffy; printk(KERN_INFO "Total of %d processors activated (%lu.%02lu BogoMIPS).\n", cpucount+1, @@ -1213,10 +1163,10 @@ for (cpu = 0; cpu < NR_CPUS; cpu++) { int i; - if (!cpu_online(cpu)) continue; + if (!test_bit(cpu, &cpu_callout_map)) continue; for (i = 0; i < NR_CPUS; i++) { - if (i == cpu || !cpu_online(i)) + if (i == cpu || !test_bit(i, &cpu_callout_map)) continue; if (phys_proc_id[cpu] == phys_proc_id[i]) { cpu_sibling_map[cpu] = i; @@ -1240,17 +1190,40 @@ setup_IO_APIC(); #endif - /* - * Set up all local APIC timers in the system: - */ - setup_APIC_clocks(); + setup_boot_APIC_clock(); /* * Synchronize the TSC with the AP */ if (cpu_has_tsc && cpucount) synchronize_tsc_bp(); +} -smp_done: +/* These are wrappers to interface to the new boot process. Someone + who understands all this stuff should rewrite it properly. --RR 15/Jul/02 */ +void __init smp_prepare_cpus(unsigned int max_cpus) +{ + smp_boot_cpus(max_cpus); +} + +int __devinit __cpu_up(unsigned int cpu) +{ + /* This only works at boot for x86. See "rewrite" above. */ + if (test_bit(cpu, &smp_commenced_mask)) + return -ENOSYS; + + /* In case one didn't come up */ + if (!test_bit(cpu, &cpu_callin_map)) + return -EIO; + + /* Unleash the CPU! */ + set_bit(cpu, &smp_commenced_mask); + while (!test_bit(cpu, &cpu_online_map)) + mb(); + return 0; +} + +void __init smp_cpus_done(unsigned int max_cpus) +{ zap_low_mappings(); } diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/include/asm-i386/apic.h working-2.5.25-hotcpu/include/asm-i386/apic.h --- linux-2.5.25/include/asm-i386/apic.h Mon Apr 15 11:47:44 2002 +++ working-2.5.25-hotcpu/include/asm-i386/apic.h Mon Jul 15 18:22:21 2002 @@ -76,7 +76,8 @@ extern void setup_local_APIC (void); extern void init_apic_mappings (void); extern void smp_local_timer_interrupt (struct pt_regs * regs); -extern void setup_APIC_clocks (void); +extern void setup_boot_APIC_clock (void); +extern void setup_secondary_APIC_clock (void); extern void setup_apic_nmi_watchdog (void); extern inline void nmi_watchdog_tick (struct pt_regs * regs); extern int APIC_init_uniprocessor (void); diff -urN -I \$.*\$ --exclude TAGS -X /home/rusty/current-dontdiff --minimal linux-2.5.25/include/asm-i386/smp.h working-2.5.25-hotcpu/include/asm-i386/smp.h --- linux-2.5.25/include/asm-i386/smp.h Thu Jun 20 01:28:51 2002 +++ working-2.5.25-hotcpu/include/asm-i386/smp.h Mon Jul 15 14:46:12 2002 @@ -79,19 +79,13 @@ extern volatile int logical_apicid_to_cpu[MAX_APICID]; /* - * General functions that each host system must provide. - */ - -extern void smp_boot_cpus(void); -extern void smp_store_cpu_info(int id); /* Store per CPU info (like the initial udelay numbers */ - -/* * This function is needed by all SMP systems. It must _always_ be valid * from the initial startup. We map APIC_BASE very early in page_setup(), * so this is correct in the x86 case. */ #define smp_processor_id() (current_thread_info()->cpu) +#define cpu_possible(cpu) (phys_cpu_present_map & (1<<(cpu))) #define cpu_online(cpu) (cpu_online_map & (1<<(cpu))) extern inline unsigned int num_online_cpus(void) @@ -117,6 +111,13 @@ { /* we don't want to mark this access volatile - bad code generation */ return GET_APIC_LOGICAL_ID(*(unsigned long *)(APIC_BASE+APIC_LDR)); +} + +extern volatile unsigned long cpu_callout_map; +/* We don't mark CPUs online until __cpu_up(), so we need another measure */ +static inline int num_booting_cpus(void) +{ + return hweight32(cpu_callout_map); } #endif /* !__ASSEMBLY__ */ -- Anyone who quotes me in their sig is an idiot. -- Rusty Russell. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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