diff options
Diffstat (limited to 'arch/x86/kernel/cpu/cacheinfo.c')
| -rw-r--r-- | arch/x86/kernel/cpu/cacheinfo.c | 179 |
1 files changed, 179 insertions, 0 deletions
diff --git a/arch/x86/kernel/cpu/cacheinfo.c b/arch/x86/kernel/cpu/cacheinfo.c index 66556833d7af..f4e5aa27eec6 100644 --- a/arch/x86/kernel/cpu/cacheinfo.c +++ b/arch/x86/kernel/cpu/cacheinfo.c @@ -11,15 +11,19 @@ #include <linux/slab.h> #include <linux/cacheinfo.h> #include <linux/cpu.h> +#include <linux/cpuhotplug.h> #include <linux/sched.h> #include <linux/capability.h> #include <linux/sysfs.h> #include <linux/pci.h> +#include <linux/stop_machine.h> #include <asm/cpufeature.h> #include <asm/cacheinfo.h> #include <asm/amd_nb.h> #include <asm/smp.h> +#include <asm/mtrr.h> +#include <asm/tlbflush.h> #include "cpu.h" @@ -35,6 +39,9 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map); /* Shared L2 cache maps */ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_l2c_shared_map); +/* Kernel controls MTRR and/or PAT MSRs. */ +unsigned int memory_caching_control __ro_after_init; + struct _cache_table { unsigned char descriptor; char cache_type; @@ -1040,3 +1047,175 @@ int populate_cache_leaves(unsigned int cpu) return 0; } + +/* + * Disable and enable caches. Needed for changing MTRRs and the PAT MSR. + * + * Since we are disabling the cache don't allow any interrupts, + * they would run extremely slow and would only increase the pain. + * + * The caller must ensure that local interrupts are disabled and + * are reenabled after cache_enable() has been called. + */ +static unsigned long saved_cr4; +static DEFINE_RAW_SPINLOCK(cache_disable_lock); + +void cache_disable(void) __acquires(cache_disable_lock) +{ + unsigned long cr0; + + /* + * Note that this is not ideal + * since the cache is only flushed/disabled for this CPU while the + * MTRRs are changed, but changing this requires more invasive + * changes to the way the kernel boots + */ + + raw_spin_lock(&cache_disable_lock); + + /* Enter the no-fill (CD=1, NW=0) cache mode and flush caches. */ + cr0 = read_cr0() | X86_CR0_CD; + write_cr0(cr0); + + /* + * Cache flushing is the most time-consuming step when programming + * the MTRRs. Fortunately, as per the Intel Software Development + * Manual, we can skip it if the processor supports cache self- + * snooping. + */ + if (!static_cpu_has(X86_FEATURE_SELFSNOOP)) + wbinvd(); + + /* Save value of CR4 and clear Page Global Enable (bit 7) */ + if (cpu_feature_enabled(X86_FEATURE_PGE)) { + saved_cr4 = __read_cr4(); + __write_cr4(saved_cr4 & ~X86_CR4_PGE); + } + + /* Flush all TLBs via a mov %cr3, %reg; mov %reg, %cr3 */ + count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL); + flush_tlb_local(); + + if (cpu_feature_enabled(X86_FEATURE_MTRR)) + mtrr_disable(); + + /* Again, only flush caches if we have to. */ + if (!static_cpu_has(X86_FEATURE_SELFSNOOP)) + wbinvd(); +} + +void cache_enable(void) __releases(cache_disable_lock) +{ + /* Flush TLBs (no need to flush caches - they are disabled) */ + count_vm_tlb_event(NR_TLB_LOCAL_FLUSH_ALL); + flush_tlb_local(); + + if (cpu_feature_enabled(X86_FEATURE_MTRR)) + mtrr_enable(); + + /* Enable caches */ + write_cr0(read_cr0() & ~X86_CR0_CD); + + /* Restore value of CR4 */ + if (cpu_feature_enabled(X86_FEATURE_PGE)) + __write_cr4(saved_cr4); + + raw_spin_unlock(&cache_disable_lock); +} + +static void cache_cpu_init(void) +{ + unsigned long flags; + + local_irq_save(flags); + cache_disable(); + + if (memory_caching_control & CACHE_MTRR) + mtrr_generic_set_state(); + + if (memory_caching_control & CACHE_PAT) + pat_cpu_init(); + + cache_enable(); + local_irq_restore(flags); +} + +static bool cache_aps_delayed_init = true; + +void set_cache_aps_delayed_init(bool val) +{ + cache_aps_delayed_init = val; +} + +bool get_cache_aps_delayed_init(void) +{ + return cache_aps_delayed_init; +} + +static int cache_rendezvous_handler(void *unused) +{ + if (get_cache_aps_delayed_init() || !cpu_online(smp_processor_id())) + cache_cpu_init(); + + return 0; +} + +void __init cache_bp_init(void) +{ + mtrr_bp_init(); + pat_bp_init(); + + if (memory_caching_control) + cache_cpu_init(); +} + +void cache_bp_restore(void) +{ + if (memory_caching_control) + cache_cpu_init(); +} + +static int cache_ap_init(unsigned int cpu) +{ + if (!memory_caching_control || get_cache_aps_delayed_init()) + return 0; + + /* + * Ideally we should hold mtrr_mutex here to avoid MTRR entries + * changed, but this routine will be called in CPU boot time, + * holding the lock breaks it. + * + * This routine is called in two cases: + * + * 1. very early time of software resume, when there absolutely + * isn't MTRR entry changes; + * + * 2. CPU hotadd time. We let mtrr_add/del_page hold cpuhotplug + * lock to prevent MTRR entry changes + */ + stop_machine_from_inactive_cpu(cache_rendezvous_handler, NULL, + cpu_callout_mask); + + return 0; +} + +/* + * Delayed cache initialization for all AP's + */ +void cache_aps_init(void) +{ + if (!memory_caching_control || !get_cache_aps_delayed_init()) + return; + + stop_machine(cache_rendezvous_handler, NULL, cpu_online_mask); + set_cache_aps_delayed_init(false); +} + +static int __init cache_ap_register(void) +{ + cpuhp_setup_state_nocalls(CPUHP_AP_CACHECTRL_STARTING, + "x86/cachectrl:starting", + cache_ap_init, NULL); + return 0; +} +core_initcall(cache_ap_register); |