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SubjectRe: [PATCH 07/18] x86 idle: clarify AMD erratum 400 workaround
On Sat, Apr 02, 2011 at 02:22:49AM -0400, Len Brown wrote:
> From: Len Brown <len.brown@intel.com>
>
> The workaround for AMD erratum 400 uses the term "c1e" suggesting:
> 1. All AMD processors with AMD C1E are involved
> 2. Any Intel processors with Intel C1E are involved.
>
> Both are false.
>
> Replace occurrences if "c1e" with "amd_e400" in the code to
> clarify that it is specific to AMD processors with AMD erratum 400.
>
> This patch is text-substitution only, with no functional change.
>
> cc: x86@kernel.org
> cc: Hans Rosenfeld <hans.rosenfeld@amd.com>
> cc: Andreas Herrmann <andreas.herrmann3@amd.com>
> Signed-off-by: Len Brown <len.brown@intel.com>
> ---
> arch/x86/include/asm/acpi.h | 2 +-
> arch/x86/include/asm/idle.h | 2 +-
> arch/x86/include/asm/processor.h | 4 ++--
> arch/x86/kernel/cpu/common.c | 2 +-
> arch/x86/kernel/process.c | 38 +++++++++++++++++++-------------------
> arch/x86/kernel/smpboot.c | 2 +-
> drivers/acpi/processor_idle.c | 2 +-
> 7 files changed, 26 insertions(+), 26 deletions(-)
>
> diff --git a/arch/x86/include/asm/acpi.h b/arch/x86/include/asm/acpi.h
> index 4ea15ca..ae5bc1a 100644
> --- a/arch/x86/include/asm/acpi.h
> +++ b/arch/x86/include/asm/acpi.h
> @@ -138,7 +138,7 @@ static inline unsigned int acpi_processor_cstate_check(unsigned int max_cstate)
> boot_cpu_data.x86_model <= 0x05 &&
> boot_cpu_data.x86_mask < 0x0A)
> return 1;
> - else if (c1e_detected)
> + else if (amd_e400_detected)
> return 1;
> else
> return max_cstate;
> diff --git a/arch/x86/include/asm/idle.h b/arch/x86/include/asm/idle.h
> index 38d8737..f49253d7 100644
> --- a/arch/x86/include/asm/idle.h
> +++ b/arch/x86/include/asm/idle.h
> @@ -16,6 +16,6 @@ static inline void enter_idle(void) { }
> static inline void exit_idle(void) { }
> #endif /* CONFIG_X86_64 */
>
> -void c1e_remove_cpu(int cpu);
> +void amd_e400_remove_cpu(int cpu);
>
> #endif /* _ASM_X86_IDLE_H */
> diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
> index 45636ce..a8c5fed 100644
> --- a/arch/x86/include/asm/processor.h
> +++ b/arch/x86/include/asm/processor.h
> @@ -758,10 +758,10 @@ static inline void __sti_mwait(unsigned long eax, unsigned long ecx)
> extern void mwait_idle_with_hints(unsigned long eax, unsigned long ecx);
>
> extern void select_idle_routine(const struct cpuinfo_x86 *c);
> -extern void init_c1e_mask(void);
> +extern void init_amd_e400_mask(void);
>
> extern unsigned long boot_option_idle_override;
> -extern bool c1e_detected;
> +extern bool amd_e400_detected;
>
> enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_NOMWAIT,
> IDLE_POLL, IDLE_FORCE_MWAIT};
> diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
> index 1d59834..30ce74c 100644
> --- a/arch/x86/kernel/cpu/common.c
> +++ b/arch/x86/kernel/cpu/common.c
> @@ -887,7 +887,7 @@ static void vgetcpu_set_mode(void)
> void __init identify_boot_cpu(void)
> {
> identify_cpu(&boot_cpu_data);
> - init_c1e_mask();
> + init_amd_e400_mask();
> #ifdef CONFIG_X86_32
> sysenter_setup();
> enable_sep_cpu();
> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
> index 1f64501..1c45a9c 100644
> --- a/arch/x86/kernel/process.c
> +++ b/arch/x86/kernel/process.c
> @@ -540,45 +540,45 @@ int mwait_usable(const struct cpuinfo_x86 *c)
> return (edx & MWAIT_EDX_C1);
> }
>
> -bool c1e_detected;
> -EXPORT_SYMBOL(c1e_detected);
> +bool amd_e400_detected;
> +EXPORT_SYMBOL(amd_e400_detected);
>
> -static cpumask_var_t c1e_mask;
> +static cpumask_var_t amd_e400_mask;

Actually, the correct name should be IMHO

amd_e400_c1e_mask


>
> -void c1e_remove_cpu(int cpu)
> +void amd_e400_remove_cpu(int cpu)
> {
> - if (c1e_mask != NULL)
> - cpumask_clear_cpu(cpu, c1e_mask);
> + if (amd_e400_mask != NULL)
> + cpumask_clear_cpu(cpu, amd_e400_mask);
> }
>
> /*
> - * C1E aware idle routine. We check for C1E active in the interrupt
> + * AMD Erratum 400 aware idle routine. We check for C1E active in the interrupt
> * pending message MSR. If we detect C1E, then we handle it the same
> * way as C3 power states (local apic timer and TSC stop)
> */
> -static void c1e_idle(void)
> +static void amd_e400_idle(void)
> {
> if (need_resched())
> return;
>
> - if (!c1e_detected) {
> + if (!amd_e400_detected) {
> u32 lo, hi;
>
> rdmsr(MSR_K8_INT_PENDING_MSG, lo, hi);
>
> if (lo & K8_INTP_C1E_ACTIVE_MASK) {
> - c1e_detected = true;
> + amd_e400_detected = true;

Hmm, c1e_detected is still the correct name since those two bits in
the INT_PENDING MSR mean simply that the system can either generate an
IO read or an SMI to enter C1E irrespective of E400. So I'd leave it
c1e_detected.

The function name amd_e400_idle() OTOH looks fine to me since we denote
that this is a special idle routine for CPUs affected by E400.

> if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
> mark_tsc_unstable("TSC halt in AMD C1E");
> printk(KERN_INFO "System has AMD C1E enabled\n");
> }
> }
>
> - if (c1e_detected) {
> + if (amd_e400_detected) {
> int cpu = smp_processor_id();
>
> - if (!cpumask_test_cpu(cpu, c1e_mask)) {
> - cpumask_set_cpu(cpu, c1e_mask);
> + if (!cpumask_test_cpu(cpu, amd_e400_mask)) {
> + cpumask_set_cpu(cpu, amd_e400_mask);
> /*
> * Force broadcast so ACPI can not interfere.
> */
> @@ -621,17 +621,17 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
> pm_idle = mwait_idle;
> } else if (cpu_has_amd_erratum(amd_erratum_400)) {
> /* E400: APIC timer interrupt does not wake up CPU from C1e */
> - printk(KERN_INFO "using C1E aware idle routine\n");
> - pm_idle = c1e_idle;
> + printk(KERN_INFO "using E400 aware idle routine\n");
> + pm_idle = amd_e400_idle;
> } else
> pm_idle = default_idle;
> }
>
> -void __init init_c1e_mask(void)
> +void __init init_amd_e400_mask(void)

Same here, init_amd_e400_c1e_mask.

> {
> - /* If we're using c1e_idle, we need to allocate c1e_mask. */
> - if (pm_idle == c1e_idle)
> - zalloc_cpumask_var(&c1e_mask, GFP_KERNEL);
> + /* If we're using amd_e400_idle, we need to allocate amd_e400_mask. */
> + if (pm_idle == amd_e400_idle)
> + zalloc_cpumask_var(&amd_e400_mask, GFP_KERNEL);
> }
>
> static int __init idle_setup(char *str)
> diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
> index 08776a9..2c33633 100644
> --- a/arch/x86/kernel/smpboot.c
> +++ b/arch/x86/kernel/smpboot.c
> @@ -1379,7 +1379,7 @@ void play_dead_common(void)
> {
> idle_task_exit();
> reset_lazy_tlbstate();
> - c1e_remove_cpu(raw_smp_processor_id());
> + amd_e400_remove_cpu(raw_smp_processor_id());
>
> mb();
> /* Ack it */
> diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
> index d615b7d..53d9f10 100644
> --- a/drivers/acpi/processor_idle.c
> +++ b/drivers/acpi/processor_idle.c
> @@ -161,7 +161,7 @@ static void lapic_timer_check_state(int state, struct acpi_processor *pr,
> if (cpu_has(&cpu_data(pr->id), X86_FEATURE_ARAT))
> return;
>
> - if (c1e_detected)
> + if (amd_e400_detected)
> type = ACPI_STATE_C1;
>
> /*
> --
> 1.7.5.rc0

Thanks.

--
Regards/Gruss,
Boris.


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