8 files changed, 15 insertions, 140 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 363e348bff9b..109ee45cf20d 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -1039,16 +1039,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         Claim all unknown PCI IDE storage controllers.
 
         idle=           [X86]
-                        Format: idle=poll, idle=mwait, idle=halt, idle=nomwait
+                        Format: idle=poll, idle=halt, idle=nomwait
                         Poll forces a polling idle loop that can slightly
                         improve the performance of waking up a idle CPU, but
                         will use a lot of power and make the system run hot.
                         Not recommended.
-                        idle=mwait: On systems which support MONITOR/MWAIT but
-                        the kernel chose to not use it because it doesn't save
-                        as much power as a normal idle loop, use the
-                        MONITOR/MWAIT idle loop anyways. Performance should be
-                        the same as idle=poll.
                         idle=halt: Halt is forced to be used for CPU idle.
                         In such case C2/C3 won't be used again.
                         idle=nomwait: Disable mwait for CPU C-states
@@ -1886,10 +1881,6 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
                         wfi(ARM) instruction doesn't work correctly and not to
                         use it. This is also useful when using JTAG debugger.
 
-        no-hlt          [BUGS=X86-32] Tells the kernel that the hlt
-                        instruction doesn't work correctly and not to
-                        use it.
-
         no_file_caps    Tells the kernel not to honor file capabilities.  The
                         only way then for a file to be executed with privilege
                         is to be setuid root or executed by root.
diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h
index 888184b2fc85..b9e7d279f8ef 100644
--- a/arch/x86/include/asm/processor.h
+++ b/arch/x86/include/asm/processor.h
@@ -89,7 +89,6 @@ struct cpuinfo_x86 {
         char                    wp_works_ok;    /* It doesn't on 386's */
 
         /* Problems on some 486Dx4's and old 386's: */
-        char                    hlt_works_ok;
         char                    hard_math;
         char                    rfu;
         char                    fdiv_bug;
@@ -165,15 +164,6 @@ DECLARE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info);
 
 extern const struct seq_operations cpuinfo_op;
 
-static inline int hlt_works(int cpu)
-{
-#ifdef CONFIG_X86_32
-        return cpu_data(cpu).hlt_works_ok;
-#else
-        return 1;
-#endif
-}
-
 #define cache_line_size()       (boot_cpu_data.x86_cache_alignment)
 
 extern void cpu_detect(struct cpuinfo_x86 *c);
@@ -725,7 +715,7 @@ extern unsigned long		boot_option_idle_override;
 extern bool                     amd_e400_c1e_detected;
 
 enum idle_boot_override {IDLE_NO_OVERRIDE=0, IDLE_HALT, IDLE_NOMWAIT,
-                         IDLE_POLL, IDLE_FORCE_MWAIT};
+                         IDLE_POLL};
 
 extern void enable_sep_cpu(void);
 extern int sysenter_setup(void);
@@ -998,7 +988,11 @@ extern unsigned long arch_align_stack(unsigned long sp);
 extern void free_init_pages(char *what, unsigned long begin, unsigned long end);
 
 void default_idle(void);
-bool set_pm_idle_to_default(void);
+#ifdef  CONFIG_XEN
+bool xen_set_default_idle(void);
+#else
+#define xen_set_default_idle 0
+#endif
 
 void stop_this_cpu(void *dummy);
 
diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
index 92dfec986a48..af6455e3fcc9 100644
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -17,15 +17,6 @@
 #include <asm/paravirt.h>
 #include <asm/alternative.h>
 
-static int __init no_halt(char *s)
-{
-        WARN_ONCE(1, "\"no-hlt\" is deprecated, please use \"idle=poll\"\n");
-        boot_cpu_data.hlt_works_ok = 0;
-        return 1;
-}
-
-__setup("no-hlt", no_halt);
-
 static int __init no_387(char *s)
 {
         boot_cpu_data.hard_math = 0;
@@ -89,23 +80,6 @@ static void __init check_fpu(void)
                 pr_warn("Hmm, FPU with FDIV bug\n");
 }
 
-static void __init check_hlt(void)
-{
-        if (boot_cpu_data.x86 >= 5 || paravirt_enabled())
-                return;
-
-        pr_info("Checking 'hlt' instruction... ");
-        if (!boot_cpu_data.hlt_works_ok) {
-                pr_cont("disabled\n");
-                return;
-        }
-        halt();
-        halt();
-        halt();
-        halt();
-        pr_cont("OK\n");
-}
-
 /*
  * Check whether we are able to run this kernel safely on SMP.
  *
@@ -129,7 +103,6 @@ void __init check_bugs(void)
         print_cpu_info(&boot_cpu_data);
 #endif
         check_config();
-        check_hlt();
         init_utsname()->machine[1] =
                 '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86);
         alternative_instructions();
diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c
index 3286a92e662a..e280253f6f94 100644
--- a/arch/x86/kernel/cpu/proc.c
+++ b/arch/x86/kernel/cpu/proc.c
@@ -28,7 +28,6 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
 {
         seq_printf(m,
                    "fdiv_bug\t: %s\n"
-                   "hlt_bug\t\t: %s\n"
                    "f00f_bug\t: %s\n"
                    "coma_bug\t: %s\n"
                    "fpu\t\t: %s\n"
@@ -36,7 +35,6 @@ static void show_cpuinfo_misc(struct seq_file *m, struct cpuinfo_x86 *c)
                    "cpuid level\t: %d\n"
                    "wp\t\t: %s\n",
                    c->fdiv_bug ? "yes" : "no",
-                   c->hlt_works_ok ? "no" : "yes",
                    c->f00f_bug ? "yes" : "no",
                    c->coma_bug ? "yes" : "no",
                    c->hard_math ? "yes" : "no",
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index ceb05db59be1..b11719ea2f7b 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -390,7 +390,8 @@ void default_idle(void)
 EXPORT_SYMBOL(default_idle);
 #endif
 
-bool set_pm_idle_to_default(void)
+#ifdef CONFIG_XEN
+bool xen_set_default_idle(void)
 {
         bool ret = !!x86_idle;
 
@@ -398,6 +399,7 @@ bool set_pm_idle_to_default(void)
 
         return ret;
 }
+#endif
 void stop_this_cpu(void *dummy)
 {
         local_irq_disable();
@@ -407,31 +409,8 @@ void stop_this_cpu(void *dummy)
         set_cpu_online(smp_processor_id(), false);
         disable_local_APIC();
 
-        for (;;) {
-                if (hlt_works(smp_processor_id()))
-                        halt();
-        }
-}
-
-/* Default MONITOR/MWAIT with no hints, used for default C1 state */
-static void mwait_idle(void)
-{
-        if (!need_resched()) {
-                trace_power_start_rcuidle(POWER_CSTATE, 1, smp_processor_id());
-                trace_cpu_idle_rcuidle(1, smp_processor_id());
-                if (this_cpu_has(X86_FEATURE_CLFLUSH_MONITOR))
-                        clflush((void *)&current_thread_info()->flags);
-
-                __monitor((void *)&current_thread_info()->flags, 0, 0);
-                smp_mb();
-                if (!need_resched())
-                        __sti_mwait(0, 0);
-                else
-                        local_irq_enable();
-                trace_power_end_rcuidle(smp_processor_id());
-                trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
-        } else
-                local_irq_enable();
+        for (;;)
+                halt();
 }
 
 /*
@@ -450,53 +429,6 @@ static void poll_idle(void)
         trace_cpu_idle_rcuidle(PWR_EVENT_EXIT, smp_processor_id());
 }
 
-/*
- * mwait selection logic:
- *
- * It depends on the CPU. For AMD CPUs that support MWAIT this is
- * wrong. Family 0x10 and 0x11 CPUs will enter C1 on HLT. Powersavings
- * then depend on a clock divisor and current Pstate of the core. If
- * all cores of a processor are in halt state (C1) the processor can
- * enter the C1E (C1 enhanced) state. If mwait is used this will never
- * happen.
- *
- * idle=mwait overrides this decision and forces the usage of mwait.
- */
-
-#define MWAIT_INFO                      0x05
-#define MWAIT_ECX_EXTENDED_INFO         0x01
-#define MWAIT_EDX_C1                    0xf0
-
-int mwait_usable(const struct cpuinfo_x86 *c)
-{
-        u32 eax, ebx, ecx, edx;
-
-        /* Use mwait if idle=mwait boot option is given */
-        if (boot_option_idle_override == IDLE_FORCE_MWAIT)
-                return 1;
-
-        /*
-         * Any idle= boot option other than idle=mwait means that we must not
-         * use mwait. Eg: idle=halt or idle=poll or idle=nomwait
-         */
-        if (boot_option_idle_override != IDLE_NO_OVERRIDE)
-                return 0;
-
-        if (c->cpuid_level < MWAIT_INFO)
-                return 0;
-
-        cpuid(MWAIT_INFO, &eax, &ebx, &ecx, &edx);
-        /* Check, whether EDX has extended info about MWAIT */
-        if (!(ecx & MWAIT_ECX_EXTENDED_INFO))
-                return 1;
-
-        /*
-         * edx enumeratios MONITOR/MWAIT extensions. Check, whether
-         * C1  supports MWAIT
-         */
-        return (edx & MWAIT_EDX_C1);
-}
-
 bool amd_e400_c1e_detected;
 EXPORT_SYMBOL(amd_e400_c1e_detected);
 
@@ -567,13 +499,7 @@ void __cpuinit select_idle_routine(const struct cpuinfo_x86 *c)
         if (x86_idle)
                 return;
 
-        if (cpu_has(c, X86_FEATURE_MWAIT) && mwait_usable(c)) {
-                /*
-                 * One CPU supports mwait => All CPUs supports mwait
-                 */
-                pr_info("using mwait in idle threads\n");
-                x86_idle = mwait_idle;
-        } else if (cpu_has_amd_erratum(amd_erratum_400)) {
+        if (cpu_has_amd_erratum(amd_erratum_400)) {
                 /* E400: APIC timer interrupt does not wake up CPU from C1e */
                 pr_info("using AMD E400 aware idle routine\n");
                 x86_idle = amd_e400_idle;
@@ -597,9 +523,6 @@ static int __init idle_setup(char *str)
                 pr_info("using polling idle threads\n");
                 x86_idle = poll_idle;
                 boot_option_idle_override = IDLE_POLL;
-        } else if (!strcmp(str, "mwait")) {
-                boot_option_idle_override = IDLE_FORCE_MWAIT;
-                WARN_ONCE(1, "\"idle=mwait\" will be removed in 2012\n");
         } else if (!strcmp(str, "halt")) {
                 /*
                  * When the boot option of idle=halt is added, halt is
diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c
index ed0fe385289d..a6ceaedc396a 100644
--- a/arch/x86/kernel/smpboot.c
+++ b/arch/x86/kernel/smpboot.c
@@ -1369,7 +1369,7 @@ static inline void mwait_play_dead(void)
         void *mwait_ptr;
         struct cpuinfo_x86 *c = __this_cpu_ptr(&cpu_info);
 
-        if (!(this_cpu_has(X86_FEATURE_MWAIT) && mwait_usable(c)))
+        if (!this_cpu_has(X86_FEATURE_MWAIT))
                 return;
         if (!this_cpu_has(X86_FEATURE_CLFLSH))
                 return;
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 8971a26d21ab..94eac5c85cdc 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -556,12 +556,9 @@ void __init xen_arch_setup(void)
                COMMAND_LINE_SIZE : MAX_GUEST_CMDLINE);
 
         /* Set up idle, making sure it calls safe_halt() pvop */
-#ifdef CONFIG_X86_32
-        boot_cpu_data.hlt_works_ok = 1;
-#endif
         disable_cpuidle();
         disable_cpufreq();
-        WARN_ON(set_pm_idle_to_default());
+        WARN_ON(xen_set_default_idle());
         fiddle_vdso();
 #ifdef CONFIG_NUMA
         numa_off = 1;
diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 8b433cb08a33..fc95308e9a11 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -71,7 +71,6 @@ static struct acpi_processor_cx *acpi_cstate[CPUIDLE_STATE_MAX];
 static int disabled_by_idle_boot_param(void)
 {
         return boot_option_idle_override == IDLE_POLL ||
-                boot_option_idle_override == IDLE_FORCE_MWAIT ||
                 boot_option_idle_override == IDLE_HALT;
 }