Applied. thanks, -Len On Monday 25 September 2006 19:28, akpm@xxxxxxxx wrote: > From: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx> > > Background: > Newer Intel processors (eg: Core Duo), support processor native C-state using > mwait instructions. > Refer: Intel Architecture Software Developer's Manual > http://www.intel.com/design/Pentium4/manuals/253668.htm > > Platform firmware exports the support for Native C-state to OS using > ACPI _PDC and _CST methods. > Refer: Intel Processor Vendor-Specific ACPI: Interface Specification > http://www.intel.com/technology/iapc/acpi/downloads/302223.htm > > With Processor Native C-state, we use 'mwait' instruction on the processor > to enter different C-states (C1, C2, C3). We won't use the special IO > ports to enter C-state and no SMM mode etc required to enter C-state. > Overall this will mean better C-state support. > > One major advantage of using mwait for all C-states is, with this and > "treat interrupt as break event" feature of mwait, we can now get accurate > timing for the time spent in C1, C2, .. states. > > The patch below adds support for both i386 and x86-64 kernels. > > Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@xxxxxxxxx> > Signed-off-by: Andrew Morton <akpm@xxxxxxxx> > --- > > arch/i386/kernel/acpi/cstate.c | 122 ++++++++++++++++++++++++++++++- > arch/i386/kernel/process.c | 22 +++-- > arch/x86_64/kernel/process.c | 22 +++-- > drivers/acpi/processor_idle.c | 97 +++++++++++++++--------- > include/acpi/pdc_intel.h | 9 +- > include/acpi/processor.h | 18 ++++ > include/asm-i386/processor.h | 2 > include/asm-x86_64/processor.h | 2 > 8 files changed, 240 insertions(+), 54 deletions(-) > > diff -puN arch/i386/kernel/acpi/cstate.c~acpi-mwait-c-state-fixes arch/i386/kernel/acpi/cstate.c > --- a/arch/i386/kernel/acpi/cstate.c~acpi-mwait-c-state-fixes > +++ a/arch/i386/kernel/acpi/cstate.c > @@ -10,6 +10,7 @@ > #include <linux/module.h> > #include <linux/init.h> > #include <linux/acpi.h> > +#include <linux/cpu.h> > > #include <acpi/processor.h> > #include <asm/acpi.h> > @@ -41,5 +42,124 @@ void acpi_processor_power_init_bm_check( > flags->bm_check = 1; > } > } > - > EXPORT_SYMBOL(acpi_processor_power_init_bm_check); > + > +/* The code below handles cstate entry with monitor-mwait pair on Intel*/ > + > +struct cstate_entry_s { > + struct { > + unsigned int eax; > + unsigned int ecx; > + } states[ACPI_PROCESSOR_MAX_POWER]; > +}; > +static struct cstate_entry_s *cpu_cstate_entry; /* per CPU ptr */ > + > +static short mwait_supported[ACPI_PROCESSOR_MAX_POWER]; > + > +#define MWAIT_SUBSTATE_MASK (0xf) > +#define MWAIT_SUBSTATE_SIZE (4) > + > +#define CPUID_MWAIT_LEAF (5) > +#define CPUID5_ECX_EXTENSIONS_SUPPORTED (0x1) > +#define CPUID5_ECX_INTERRUPT_BREAK (0x2) > + > +#define MWAIT_ECX_INTERRUPT_BREAK (0x1) > + > +#define NATIVE_CSTATE_BEYOND_HALT (2) > + > +int acpi_processor_ffh_cstate_probe(unsigned int cpu, > + struct acpi_processor_cx *cx, struct acpi_power_register *reg) > +{ > + struct cstate_entry_s *percpu_entry; > + struct cpuinfo_x86 *c = cpu_data + cpu; > + > + cpumask_t saved_mask; > + int retval; > + unsigned int eax, ebx, ecx, edx; > + unsigned int edx_part; > + unsigned int cstate_type; /* C-state type and not ACPI C-state type */ > + unsigned int num_cstate_subtype; > + > + if (!cpu_cstate_entry || c->cpuid_level < CPUID_MWAIT_LEAF ) > + return -1; > + > + if (reg->bit_offset != NATIVE_CSTATE_BEYOND_HALT) > + return -1; > + > + percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu); > + percpu_entry->states[cx->index].eax = 0; > + percpu_entry->states[cx->index].ecx = 0; > + > + /* Make sure we are running on right CPU */ > + saved_mask = current->cpus_allowed; > + retval = set_cpus_allowed(current, cpumask_of_cpu(cpu)); > + if (retval) > + return -1; > + > + cpuid(CPUID_MWAIT_LEAF, &eax, &ebx, &ecx, &edx); > + > + /* Check whether this particular cx_type (in CST) is supported or not */ > + cstate_type = (cx->address >> MWAIT_SUBSTATE_SIZE) + 1; > + edx_part = edx >> (cstate_type * MWAIT_SUBSTATE_SIZE); > + num_cstate_subtype = edx_part & MWAIT_SUBSTATE_MASK; > + > + retval = 0; > + if (num_cstate_subtype < (cx->address & MWAIT_SUBSTATE_MASK)) { > + retval = -1; > + goto out; > + } > + > + /* mwait ecx extensions INTERRUPT_BREAK should be supported for C2/C3 */ > + if (!(ecx & CPUID5_ECX_EXTENSIONS_SUPPORTED) || > + !(ecx & CPUID5_ECX_INTERRUPT_BREAK)) { > + retval = -1; > + goto out; > + } > + percpu_entry->states[cx->index].ecx = MWAIT_ECX_INTERRUPT_BREAK; > + > + /* Use the hint in CST */ > + percpu_entry->states[cx->index].eax = cx->address; > + > + if (!mwait_supported[cstate_type]) { > + mwait_supported[cstate_type] = 1; > + printk(KERN_DEBUG "Monitor-Mwait will be used to enter C-%d " > + "state\n", cx->type); > + } > + > +out: > + set_cpus_allowed(current, saved_mask); > + return retval; > +} > +EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_probe); > + > +void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cx) > +{ > + unsigned int cpu = smp_processor_id(); > + struct cstate_entry_s *percpu_entry; > + > + percpu_entry = per_cpu_ptr(cpu_cstate_entry, cpu); > + mwait_idle_with_hints(percpu_entry->states[cx->index].eax, > + percpu_entry->states[cx->index].ecx); > +} > +EXPORT_SYMBOL_GPL(acpi_processor_ffh_cstate_enter); > + > +static int __init ffh_cstate_init(void) > +{ > + struct cpuinfo_x86 *c = &boot_cpu_data; > + if (c->x86_vendor != X86_VENDOR_INTEL) > + return -1; > + > + cpu_cstate_entry = alloc_percpu(struct cstate_entry_s); > + return 0; > +} > + > +static void __exit ffh_cstate_exit(void) > +{ > + if (cpu_cstate_entry) { > + free_percpu(cpu_cstate_entry); > + cpu_cstate_entry = NULL; > + } > +} > + > +arch_initcall(ffh_cstate_init); > +__exitcall(ffh_cstate_exit); > diff -puN arch/i386/kernel/process.c~acpi-mwait-c-state-fixes arch/i386/kernel/process.c > --- a/arch/i386/kernel/process.c~acpi-mwait-c-state-fixes > +++ a/arch/i386/kernel/process.c > @@ -235,20 +235,28 @@ EXPORT_SYMBOL_GPL(cpu_idle_wait); > * We execute MONITOR against need_resched and enter optimized wait state > * through MWAIT. Whenever someone changes need_resched, we would be woken > * up from MWAIT (without an IPI). > + * > + * New with Core Duo processors, MWAIT can take some hints based on CPU > + * capability. > */ > -static void mwait_idle(void) > +void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) > { > - local_irq_enable(); > - > - while (!need_resched()) { > + if (!need_resched()) { > __monitor((void *)¤t_thread_info()->flags, 0, 0); > smp_mb(); > - if (need_resched()) > - break; > - __mwait(0, 0); > + if (!need_resched()) > + __mwait(eax, ecx); > } > } > > +/* Default MONITOR/MWAIT with no hints, used for default C1 state */ > +static void mwait_idle(void) > +{ > + local_irq_enable(); > + while (!need_resched()) > + mwait_idle_with_hints(0, 0); > +} > + > void __devinit select_idle_routine(const struct cpuinfo_x86 *c) > { > if (cpu_has(c, X86_FEATURE_MWAIT)) { > diff -puN arch/x86_64/kernel/process.c~acpi-mwait-c-state-fixes arch/x86_64/kernel/process.c > --- a/arch/x86_64/kernel/process.c~acpi-mwait-c-state-fixes > +++ a/arch/x86_64/kernel/process.c > @@ -235,20 +235,28 @@ void cpu_idle (void) > * We execute MONITOR against need_resched and enter optimized wait state > * through MWAIT. Whenever someone changes need_resched, we would be woken > * up from MWAIT (without an IPI). > + * > + * New with Core Duo processors, MWAIT can take some hints based on CPU > + * capability. > */ > -static void mwait_idle(void) > +void mwait_idle_with_hints(unsigned long eax, unsigned long ecx) > { > - local_irq_enable(); > - > - while (!need_resched()) { > + if (!need_resched()) { > __monitor((void *)¤t_thread_info()->flags, 0, 0); > smp_mb(); > - if (need_resched()) > - break; > - __mwait(0, 0); > + if (!need_resched()) > + __mwait(eax, ecx); > } > } > > +/* Default MONITOR/MWAIT with no hints, used for default C1 state */ > +static void mwait_idle(void) > +{ > + local_irq_enable(); > + while (!need_resched()) > + mwait_idle_with_hints(0,0); > +} > + > void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c) > { > static int printed; > diff -puN drivers/acpi/processor_idle.c~acpi-mwait-c-state-fixes drivers/acpi/processor_idle.c > --- a/drivers/acpi/processor_idle.c~acpi-mwait-c-state-fixes > +++ a/drivers/acpi/processor_idle.c > @@ -218,6 +218,23 @@ static void acpi_safe_halt(void) > > static atomic_t c3_cpu_count; > > +/* Common C-state entry for C2, C3, .. */ > +static void acpi_cstate_enter(struct acpi_processor_cx *cstate) > +{ > + if (cstate->space_id == ACPI_CSTATE_FFH) { > + /* Call into architectural FFH based C-state */ > + acpi_processor_ffh_cstate_enter(cstate); > + } else { > + int unused; > + /* IO port based C-state */ > + inb(cstate->address); > + /* Dummy wait op - must do something useless after P_LVL2 read > + because chipsets cannot guarantee that STPCLK# signal > + gets asserted in time to freeze execution properly. */ > + unused = inl(acpi_fadt.xpm_tmr_blk.address); > + } > +} > + > static void acpi_processor_idle(void) > { > struct acpi_processor *pr = NULL; > @@ -360,11 +377,7 @@ static void acpi_processor_idle(void) > /* Get start time (ticks) */ > t1 = inl(acpi_fadt.xpm_tmr_blk.address); > /* Invoke C2 */ > - inb(cx->address); > - /* Dummy wait op - must do something useless after P_LVL2 read > - because chipsets cannot guarantee that STPCLK# signal > - gets asserted in time to freeze execution properly. */ > - t2 = inl(acpi_fadt.xpm_tmr_blk.address); > + acpi_cstate_enter(cx); > /* Get end time (ticks) */ > t2 = inl(acpi_fadt.xpm_tmr_blk.address); > > @@ -400,9 +413,7 @@ static void acpi_processor_idle(void) > /* Get start time (ticks) */ > t1 = inl(acpi_fadt.xpm_tmr_blk.address); > /* Invoke C3 */ > - inb(cx->address); > - /* Dummy wait op (see above) */ > - t2 = inl(acpi_fadt.xpm_tmr_blk.address); > + acpi_cstate_enter(cx); > /* Get end time (ticks) */ > t2 = inl(acpi_fadt.xpm_tmr_blk.address); > if (pr->flags.bm_check) { > @@ -624,20 +635,16 @@ static int acpi_processor_get_power_info > return 0; > } > > -static int acpi_processor_get_power_info_default_c1(struct acpi_processor *pr) > +static int acpi_processor_get_power_info_default(struct acpi_processor *pr) > { > - > - /* Zero initialize all the C-states info. */ > - memset(pr->power.states, 0, sizeof(pr->power.states)); > - > - /* set the first C-State to C1 */ > - pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; > - > - /* the C0 state only exists as a filler in our array, > - * and all processors need to support C1 */ > + if (!pr->power.states[ACPI_STATE_C1].valid) { > + /* set the first C-State to C1 */ > + /* all processors need to support C1 */ > + pr->power.states[ACPI_STATE_C1].type = ACPI_STATE_C1; > + pr->power.states[ACPI_STATE_C1].valid = 1; > + } > + /* the C0 state only exists as a filler in our array */ > pr->power.states[ACPI_STATE_C0].valid = 1; > - pr->power.states[ACPI_STATE_C1].valid = 1; > - > return 0; > } > > @@ -654,12 +661,7 @@ static int acpi_processor_get_power_info > if (nocst) > return -ENODEV; > > - current_count = 1; > - > - /* Zero initialize C2 onwards and prepare for fresh CST lookup */ > - for (i = 2; i < ACPI_PROCESSOR_MAX_POWER; i++) > - memset(&(pr->power.states[i]), 0, > - sizeof(struct acpi_processor_cx)); > + current_count = 0; > > status = acpi_evaluate_object(pr->handle, "_CST", NULL, &buffer); > if (ACPI_FAILURE(status)) { > @@ -714,22 +716,39 @@ static int acpi_processor_get_power_info > (reg->space_id != ACPI_ADR_SPACE_FIXED_HARDWARE)) > continue; > > - cx.address = (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) ? > - 0 : reg->address; > - > /* There should be an easy way to extract an integer... */ > obj = (union acpi_object *)&(element->package.elements[1]); > if (obj->type != ACPI_TYPE_INTEGER) > continue; > > cx.type = obj->integer.value; > + /* > + * Some buggy BIOSes won't list C1 in _CST - > + * Let acpi_processor_get_power_info_default() handle them later > + */ > + if (i == 1 && cx.type != ACPI_STATE_C1) > + current_count++; > > - if ((cx.type != ACPI_STATE_C1) && > - (reg->space_id != ACPI_ADR_SPACE_SYSTEM_IO)) > - continue; > + cx.address = reg->address; > + cx.index = current_count + 1; > > - if ((cx.type < ACPI_STATE_C2) || (cx.type > ACPI_STATE_C3)) > - continue; > + cx.space_id = ACPI_CSTATE_SYSTEMIO; > + if (reg->space_id == ACPI_ADR_SPACE_FIXED_HARDWARE) { > + if (acpi_processor_ffh_cstate_probe > + (pr->id, &cx, reg) == 0) { > + cx.space_id = ACPI_CSTATE_FFH; > + } else if (cx.type != ACPI_STATE_C1) { > + /* > + * C1 is a special case where FIXED_HARDWARE > + * can be handled in non-MWAIT way as well. > + * In that case, save this _CST entry info. > + * That is, we retain space_id of SYSTEM_IO for > + * halt based C1. > + * Otherwise, ignore this info and continue. > + */ > + continue; > + } > + } > > obj = (union acpi_object *)&(element->package.elements[2]); > if (obj->type != ACPI_TYPE_INTEGER) > @@ -934,12 +953,18 @@ static int acpi_processor_get_power_info > /* NOTE: the idle thread may not be running while calling > * this function */ > > - /* Adding C1 state */ > - acpi_processor_get_power_info_default_c1(pr); > + /* Zero initialize all the C-states info. */ > + memset(pr->power.states, 0, sizeof(pr->power.states)); > + > result = acpi_processor_get_power_info_cst(pr); > if (result == -ENODEV) > acpi_processor_get_power_info_fadt(pr); > > + if (result) > + return result; > + > + acpi_processor_get_power_info_default(pr); > + > pr->power.count = acpi_processor_power_verify(pr); > > /* > diff -puN include/acpi/pdc_intel.h~acpi-mwait-c-state-fixes include/acpi/pdc_intel.h > --- a/include/acpi/pdc_intel.h~acpi-mwait-c-state-fixes > +++ a/include/acpi/pdc_intel.h > @@ -13,6 +13,7 @@ > #define ACPI_PDC_SMP_C_SWCOORD (0x0040) > #define ACPI_PDC_SMP_T_SWCOORD (0x0080) > #define ACPI_PDC_C_C1_FFH (0x0100) > +#define ACPI_PDC_C_C2C3_FFH (0x0200) > > #define ACPI_PDC_EST_CAPABILITY_SMP (ACPI_PDC_SMP_C1PT | \ > ACPI_PDC_C_C1_HALT | \ > @@ -23,8 +24,10 @@ > ACPI_PDC_SMP_P_SWCOORD | \ > ACPI_PDC_P_FFH) > > -#define ACPI_PDC_C_CAPABILITY_SMP (ACPI_PDC_SMP_C2C3 | \ > - ACPI_PDC_SMP_C1PT | \ > - ACPI_PDC_C_C1_HALT) > +#define ACPI_PDC_C_CAPABILITY_SMP (ACPI_PDC_SMP_C2C3 | \ > + ACPI_PDC_SMP_C1PT | \ > + ACPI_PDC_C_C1_HALT | \ > + ACPI_PDC_C_C1_FFH | \ > + ACPI_PDC_C_C2C3_FFH) > > #endif /* __PDC_INTEL_H__ */ > diff -puN include/acpi/processor.h~acpi-mwait-c-state-fixes include/acpi/processor.h > --- a/include/acpi/processor.h~acpi-mwait-c-state-fixes > +++ a/include/acpi/processor.h > @@ -29,6 +29,9 @@ > #define DOMAIN_COORD_TYPE_SW_ANY 0xfd > #define DOMAIN_COORD_TYPE_HW_ALL 0xfe > > +#define ACPI_CSTATE_SYSTEMIO (0) > +#define ACPI_CSTATE_FFH (1) > + > /* Power Management */ > > struct acpi_processor_cx; > @@ -58,6 +61,8 @@ struct acpi_processor_cx { > u8 valid; > u8 type; > u32 address; > + u8 space_id; > + u8 index; > u32 latency; > u32 latency_ticks; > u32 power; > @@ -206,6 +211,9 @@ void arch_acpi_processor_init_pdc(struct > #ifdef ARCH_HAS_POWER_INIT > void acpi_processor_power_init_bm_check(struct acpi_processor_flags *flags, > unsigned int cpu); > +int acpi_processor_ffh_cstate_probe(unsigned int cpu, > + struct acpi_processor_cx *cx, struct acpi_power_register *reg); > +void acpi_processor_ffh_cstate_enter(struct acpi_processor_cx *cstate); > #else > static inline void acpi_processor_power_init_bm_check(struct > acpi_processor_flags > @@ -214,6 +222,16 @@ static inline void acpi_processor_power_ > flags->bm_check = 1; > return; > } > +static inline int acpi_processor_ffh_cstate_probe(unsigned int cpu, > + struct acpi_processor_cx *cx, struct acpi_power_register *reg) > +{ > + return -1; > +} > +static inline void acpi_processor_ffh_cstate_enter( > + struct acpi_processor_cx *cstate) > +{ > + return; > +} > #endif > > /* in processor_perflib.c */ > diff -puN include/asm-i386/processor.h~acpi-mwait-c-state-fixes include/asm-i386/processor.h > --- a/include/asm-i386/processor.h~acpi-mwait-c-state-fixes > +++ a/include/asm-i386/processor.h > @@ -312,6 +312,8 @@ static inline void __mwait(unsigned long > : :"a" (eax), "c" (ecx)); > } > > +extern void mwait_idle_with_hints(unsigned long eax, unsigned long ecx); > + > /* from system description table in BIOS. Mostly for MCA use, but > others may find it useful. */ > extern unsigned int machine_id; > diff -puN include/asm-x86_64/processor.h~acpi-mwait-c-state-fixes include/asm-x86_64/processor.h > --- a/include/asm-x86_64/processor.h~acpi-mwait-c-state-fixes > +++ a/include/asm-x86_64/processor.h > @@ -475,6 +475,8 @@ static inline void __mwait(unsigned long > : :"a" (eax), "c" (ecx)); > } > > +extern void mwait_idle_with_hints(unsigned long eax, unsigned long ecx); > + > #define stack_current() \ > ({ \ > struct thread_info *ti; \ > _ > - > To unsubscribe from this list: send the line "unsubscribe linux-acpi" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
