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authorDave Airlie <airlied@redhat.com>2015-04-20 11:32:26 +1000
committerDave Airlie <airlied@redhat.com>2015-04-20 13:05:20 +1000
commit2c33ce009ca2389dbf0535d0672214d09738e35e (patch)
tree6186a6458c3c160385d794a23eaf07c786a9e61b /arch/x86/kernel/process.c
parentcec32a47010647e8b0603726ebb75b990a4057a4 (diff)
parent09d51602cf84a1264946711dd4ea0dddbac599a1 (diff)
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Merge Linus master into drm-next
The merge is clean, but the arm build fails afterwards, due to API changes in the regulator tree. I've included the patch into the merge to fix the build. Signed-off-by: Dave Airlie <airlied@redhat.com>
Diffstat (limited to 'arch/x86/kernel/process.c')
-rw-r--r--arch/x86/kernel/process.c106
1 files changed, 89 insertions, 17 deletions
diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c
index 046e2d620bbe..8213da62b1b7 100644
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -9,7 +9,7 @@
#include <linux/sched.h>
#include <linux/module.h>
#include <linux/pm.h>
-#include <linux/clockchips.h>
+#include <linux/tick.h>
#include <linux/random.h>
#include <linux/user-return-notifier.h>
#include <linux/dmi.h>
@@ -24,6 +24,7 @@
#include <asm/syscalls.h>
#include <asm/idle.h>
#include <asm/uaccess.h>
+#include <asm/mwait.h>
#include <asm/i387.h>
#include <asm/fpu-internal.h>
#include <asm/debugreg.h>
@@ -37,7 +38,26 @@
* section. Since TSS's are completely CPU-local, we want them
* on exact cacheline boundaries, to eliminate cacheline ping-pong.
*/
-__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, init_tss) = INIT_TSS;
+__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = {
+ .x86_tss = {
+ .sp0 = TOP_OF_INIT_STACK,
+#ifdef CONFIG_X86_32
+ .ss0 = __KERNEL_DS,
+ .ss1 = __KERNEL_CS,
+ .io_bitmap_base = INVALID_IO_BITMAP_OFFSET,
+#endif
+ },
+#ifdef CONFIG_X86_32
+ /*
+ * Note that the .io_bitmap member must be extra-big. This is because
+ * the CPU will access an additional byte beyond the end of the IO
+ * permission bitmap. The extra byte must be all 1 bits, and must
+ * be within the limit.
+ */
+ .io_bitmap = { [0 ... IO_BITMAP_LONGS] = ~0 },
+#endif
+};
+EXPORT_PER_CPU_SYMBOL_GPL(cpu_tss);
#ifdef CONFIG_X86_64
static DEFINE_PER_CPU(unsigned char, is_idle);
@@ -69,8 +89,8 @@ int arch_dup_task_struct(struct task_struct *dst, struct task_struct *src)
dst->thread.fpu_counter = 0;
dst->thread.fpu.has_fpu = 0;
- dst->thread.fpu.last_cpu = ~0;
dst->thread.fpu.state = NULL;
+ task_disable_lazy_fpu_restore(dst);
if (tsk_used_math(src)) {
int err = fpu_alloc(&dst->thread.fpu);
if (err)
@@ -109,7 +129,7 @@ void exit_thread(void)
unsigned long *bp = t->io_bitmap_ptr;
if (bp) {
- struct tss_struct *tss = &per_cpu(init_tss, get_cpu());
+ struct tss_struct *tss = &per_cpu(cpu_tss, get_cpu());
t->io_bitmap_ptr = NULL;
clear_thread_flag(TIF_IO_BITMAP);
@@ -131,13 +151,18 @@ void flush_thread(void)
flush_ptrace_hw_breakpoint(tsk);
memset(tsk->thread.tls_array, 0, sizeof(tsk->thread.tls_array));
- drop_init_fpu(tsk);
- /*
- * Free the FPU state for non xsave platforms. They get reallocated
- * lazily at the first use.
- */
- if (!use_eager_fpu())
+
+ if (!use_eager_fpu()) {
+ /* FPU state will be reallocated lazily at the first use. */
+ drop_fpu(tsk);
free_thread_xstate(tsk);
+ } else if (!used_math()) {
+ /* kthread execs. TODO: cleanup this horror. */
+ if (WARN_ON(init_fpu(tsk)))
+ force_sig(SIGKILL, tsk);
+ user_fpu_begin();
+ restore_init_xstate();
+ }
}
static void hard_disable_TSC(void)
@@ -377,14 +402,11 @@ static void amd_e400_idle(void)
if (!cpumask_test_cpu(cpu, amd_e400_c1e_mask)) {
cpumask_set_cpu(cpu, amd_e400_c1e_mask);
- /*
- * Force broadcast so ACPI can not interfere.
- */
- clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
- &cpu);
+ /* Force broadcast so ACPI can not interfere. */
+ tick_broadcast_force();
pr_info("Switch to broadcast mode on CPU%d\n", cpu);
}
- clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
+ tick_broadcast_enter();
default_idle();
@@ -393,12 +415,59 @@ static void amd_e400_idle(void)
* called with interrupts disabled.
*/
local_irq_disable();
- clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
+ tick_broadcast_exit();
local_irq_enable();
} else
default_idle();
}
+/*
+ * Intel Core2 and older machines prefer MWAIT over HALT for C1.
+ * We can't rely on cpuidle installing MWAIT, because it will not load
+ * on systems that support only C1 -- so the boot default must be MWAIT.
+ *
+ * Some AMD machines are the opposite, they depend on using HALT.
+ *
+ * So for default C1, which is used during boot until cpuidle loads,
+ * use MWAIT-C1 on Intel HW that has it, else use HALT.
+ */
+static int prefer_mwait_c1_over_halt(const struct cpuinfo_x86 *c)
+{
+ if (c->x86_vendor != X86_VENDOR_INTEL)
+ return 0;
+
+ if (!cpu_has(c, X86_FEATURE_MWAIT))
+ return 0;
+
+ return 1;
+}
+
+/*
+ * MONITOR/MWAIT with no hints, used for default default C1 state.
+ * This invokes MWAIT with interrutps enabled and no flags,
+ * which is backwards compatible with the original MWAIT implementation.
+ */
+
+static void mwait_idle(void)
+{
+ if (!current_set_polling_and_test()) {
+ if (this_cpu_has(X86_BUG_CLFLUSH_MONITOR)) {
+ smp_mb(); /* quirk */
+ clflush((void *)&current_thread_info()->flags);
+ smp_mb(); /* quirk */
+ }
+
+ __monitor((void *)&current_thread_info()->flags, 0, 0);
+ if (!need_resched())
+ __sti_mwait(0, 0);
+ else
+ local_irq_enable();
+ } else {
+ local_irq_enable();
+ }
+ __current_clr_polling();
+}
+
void select_idle_routine(const struct cpuinfo_x86 *c)
{
#ifdef CONFIG_SMP
@@ -412,6 +481,9 @@ void select_idle_routine(const struct cpuinfo_x86 *c)
/* 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;
+ } else if (prefer_mwait_c1_over_halt(c)) {
+ pr_info("using mwait in idle threads\n");
+ x86_idle = mwait_idle;
} else
x86_idle = default_idle;
}