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From 23b388c973772e1e5fa418e211ebfb2d4c018dbf Mon Sep 17 00:00:00 2001
From: Ingo Molnar <mingo@elte.hu>
Date: Fri, 3 Jul 2009 08:30:02 -0500
Subject: [PATCH] x86: preempt-rt preparatory patches for x86 (32bit)
commit 2469057e21ee375fc84d93a6c109f17682fc8320 in tip.
[PG: drop _raw --> __raw remapping, we now have arch_spin instead.
See upstream 0199c4e68d1f02894bdefe4b5d9e9ee4aedd8d62 and
445c89514be242b1b0080056d50bdc1b72adeb5c ]
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
---
arch/x86/include/asm/tlbflush.h | 2 ++
arch/x86/kernel/apic/nmi.c | 2 ++
arch/x86/kernel/early_printk.c | 2 +-
arch/x86/kernel/head64.c | 6 +++++-
arch/x86/kernel/process_64.c | 4 +++-
arch/x86/kernel/signal.c | 7 +++++++
arch/x86/kernel/smp.c | 10 ++++++++++
7 files changed, 30 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/tlbflush.h b/arch/x86/include/asm/tlbflush.h
index 7f3eba0..2601600 100644
--- a/arch/x86/include/asm/tlbflush.h
+++ b/arch/x86/include/asm/tlbflush.h
@@ -17,7 +17,9 @@
static inline void __native_flush_tlb(void)
{
+ preempt_disable();
native_write_cr3(native_read_cr3());
+ preempt_enable();
}
static inline void __native_flush_tlb_global(void)
diff --git a/arch/x86/kernel/apic/nmi.c b/arch/x86/kernel/apic/nmi.c
index 1edaf15..4e41ae6 100644
--- a/arch/x86/kernel/apic/nmi.c
+++ b/arch/x86/kernel/apic/nmi.c
@@ -92,7 +92,9 @@ static inline unsigned int get_timer_irqs(int cpu)
*/
static __init void nmi_cpu_busy(void *data)
{
+#ifndef CONFIG_PREEMPT_RT
local_irq_enable_in_hardirq();
+#endif
/*
* Intentionally don't use cpu_relax here. This is
* to make sure that the performance counter really ticks,
diff --git a/arch/x86/kernel/early_printk.c b/arch/x86/kernel/early_printk.c
index b9c830c..3c5a9e0 100644
--- a/arch/x86/kernel/early_printk.c
+++ b/arch/x86/kernel/early_printk.c
@@ -166,7 +166,7 @@ static int __initdata early_console_initialized;
asmlinkage void early_printk(const char *fmt, ...)
{
- char buf[512];
+ static char buf[512];
int n;
va_list ap;
diff --git a/arch/x86/kernel/head64.c b/arch/x86/kernel/head64.c
index 7147143..cd0ef70 100644
--- a/arch/x86/kernel/head64.c
+++ b/arch/x86/kernel/head64.c
@@ -30,7 +30,11 @@ static void __init zap_identity_mappings(void)
{
pgd_t *pgd = pgd_offset_k(0UL);
pgd_clear(pgd);
- __flush_tlb_all();
+ /*
+ * preempt_disable/enable does not work this early in the
+ * bootup yet:
+ */
+ write_cr3(read_cr3());
}
/* Don't add a printk in there. printk relies on the PDA which is not initialized
diff --git a/arch/x86/kernel/process_64.c b/arch/x86/kernel/process_64.c
index bf82f58..3f90c51 100644
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -146,9 +146,11 @@ void cpu_idle(void)
}
tick_nohz_restart_sched_tick();
+ local_irq_disable();
__preempt_enable_no_resched();
- schedule();
+ __schedule();
preempt_disable();
+ local_irq_enable();
}
}
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index 4fd173c..fccd2c8 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -773,6 +773,13 @@ static void do_signal(struct pt_regs *regs)
int signr;
sigset_t *oldset;
+#ifdef CONFIG_PREEMPT_RT
+ /*
+ * Fully-preemptible kernel does not need interrupts disabled:
+ */
+ local_irq_enable();
+ preempt_check_resched();
+#endif
/*
* We want the common case to go fast, which is why we may in certain
* cases get here from kernel mode. Just return without doing anything
diff --git a/arch/x86/kernel/smp.c b/arch/x86/kernel/smp.c
index d801210..0b04e39 100644
--- a/arch/x86/kernel/smp.c
+++ b/arch/x86/kernel/smp.c
@@ -121,6 +121,16 @@ static void native_smp_send_reschedule(int cpu)
apic->send_IPI_mask(cpumask_of(cpu), RESCHEDULE_VECTOR);
}
+/*
+ * this function sends a 'reschedule' IPI to all other CPUs.
+ * This is used when RT tasks are starving and other CPUs
+ * might be able to run them:
+ */
+void smp_send_reschedule_allbutself(void)
+{
+ apic->send_IPI_allbutself(RESCHEDULE_VECTOR);
+}
+
void native_send_call_func_single_ipi(int cpu)
{
apic->send_IPI_mask(cpumask_of(cpu), CALL_FUNCTION_SINGLE_VECTOR);
--
1.7.0.4
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