Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
x86: oprofile: don't set counter width from cpuid on Core2
x86: fix init_memory_mapping() to handle small ranges
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 7049815..68d6494 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -233,12 +233,13 @@
unsigned int cachetype = read_cpuid_cachetype();
unsigned int arch = cpu_architecture();
- if (arch >= CPU_ARCH_ARMv7) {
- cacheid = CACHEID_VIPT_NONALIASING;
- if ((cachetype & (3 << 14)) == 1 << 14)
- cacheid |= CACHEID_ASID_TAGGED;
- } else if (arch >= CPU_ARCH_ARMv6) {
- if (cachetype & (1 << 23))
+ if (arch >= CPU_ARCH_ARMv6) {
+ if ((cachetype & (7 << 29)) == 4 << 29) {
+ /* ARMv7 register format */
+ cacheid = CACHEID_VIPT_NONALIASING;
+ if ((cachetype & (3 << 14)) == 1 << 14)
+ cacheid |= CACHEID_ASID_TAGGED;
+ } else if (cachetype & (1 << 23))
cacheid = CACHEID_VIPT_ALIASING;
else
cacheid = CACHEID_VIPT_NONALIASING;
diff --git a/arch/arm/mach-at91/pm.c b/arch/arm/mach-at91/pm.c
index 9bb4f04..7ac812d 100644
--- a/arch/arm/mach-at91/pm.c
+++ b/arch/arm/mach-at91/pm.c
@@ -332,7 +332,6 @@
at91_sys_read(AT91_AIC_IPR) & at91_sys_read(AT91_AIC_IMR));
error:
- sdram_selfrefresh_disable();
target_state = PM_SUSPEND_ON;
at91_irq_resume();
at91_gpio_resume();
diff --git a/arch/arm/mm/abort-ev6.S b/arch/arm/mm/abort-ev6.S
index 8a7f65b..94077fb 100644
--- a/arch/arm/mm/abort-ev6.S
+++ b/arch/arm/mm/abort-ev6.S
@@ -23,7 +23,8 @@
#ifdef CONFIG_CPU_32v6K
clrex
#else
- strex r0, r1, [sp] @ Clear the exclusive monitor
+ sub r1, sp, #4 @ Get unused stack location
+ strex r0, r1, [r1] @ Clear the exclusive monitor
#endif
mrc p15, 0, r1, c5, c0, 0 @ get FSR
mrc p15, 0, r0, c6, c0, 0 @ get FAR
diff --git a/arch/arm/plat-s3c64xx/irq-eint.c b/arch/arm/plat-s3c64xx/irq-eint.c
index 1f7cc00..ebb305c 100644
--- a/arch/arm/plat-s3c64xx/irq-eint.c
+++ b/arch/arm/plat-s3c64xx/irq-eint.c
@@ -55,7 +55,7 @@
u32 mask;
mask = __raw_readl(S3C64XX_EINT0MASK);
- mask |= eint_irq_to_bit(irq);
+ mask &= ~eint_irq_to_bit(irq);
__raw_writel(mask, S3C64XX_EINT0MASK);
}
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 93d8203..9f20503 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -32,11 +32,14 @@
struct list_head list;
struct kmmio_fault_page *release_next;
unsigned long page; /* location of the fault page */
+ bool old_presence; /* page presence prior to arming */
+ bool armed;
/*
* Number of times this page has been registered as a part
* of a probe. If zero, page is disarmed and this may be freed.
- * Used only by writers (RCU).
+ * Used only by writers (RCU) and post_kmmio_handler().
+ * Protected by kmmio_lock, when linked into kmmio_page_table.
*/
int count;
};
@@ -105,57 +108,85 @@
return NULL;
}
-static void set_page_present(unsigned long addr, bool present,
- unsigned int *pglevel)
+static void set_pmd_presence(pmd_t *pmd, bool present, bool *old)
{
- pteval_t pteval;
- pmdval_t pmdval;
+ pmdval_t v = pmd_val(*pmd);
+ *old = !!(v & _PAGE_PRESENT);
+ v &= ~_PAGE_PRESENT;
+ if (present)
+ v |= _PAGE_PRESENT;
+ set_pmd(pmd, __pmd(v));
+}
+
+static void set_pte_presence(pte_t *pte, bool present, bool *old)
+{
+ pteval_t v = pte_val(*pte);
+ *old = !!(v & _PAGE_PRESENT);
+ v &= ~_PAGE_PRESENT;
+ if (present)
+ v |= _PAGE_PRESENT;
+ set_pte_atomic(pte, __pte(v));
+}
+
+static int set_page_presence(unsigned long addr, bool present, bool *old)
+{
unsigned int level;
- pmd_t *pmd;
pte_t *pte = lookup_address(addr, &level);
if (!pte) {
pr_err("kmmio: no pte for page 0x%08lx\n", addr);
- return;
+ return -1;
}
- if (pglevel)
- *pglevel = level;
-
switch (level) {
case PG_LEVEL_2M:
- pmd = (pmd_t *)pte;
- pmdval = pmd_val(*pmd) & ~_PAGE_PRESENT;
- if (present)
- pmdval |= _PAGE_PRESENT;
- set_pmd(pmd, __pmd(pmdval));
+ set_pmd_presence((pmd_t *)pte, present, old);
break;
-
case PG_LEVEL_4K:
- pteval = pte_val(*pte) & ~_PAGE_PRESENT;
- if (present)
- pteval |= _PAGE_PRESENT;
- set_pte_atomic(pte, __pte(pteval));
+ set_pte_presence(pte, present, old);
break;
-
default:
pr_err("kmmio: unexpected page level 0x%x.\n", level);
- return;
+ return -1;
}
__flush_tlb_one(addr);
+ return 0;
}
-/** Mark the given page as not present. Access to it will trigger a fault. */
-static void arm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
+/*
+ * Mark the given page as not present. Access to it will trigger a fault.
+ *
+ * Struct kmmio_fault_page is protected by RCU and kmmio_lock, but the
+ * protection is ignored here. RCU read lock is assumed held, so the struct
+ * will not disappear unexpectedly. Furthermore, the caller must guarantee,
+ * that double arming the same virtual address (page) cannot occur.
+ *
+ * Double disarming on the other hand is allowed, and may occur when a fault
+ * and mmiotrace shutdown happen simultaneously.
+ */
+static int arm_kmmio_fault_page(struct kmmio_fault_page *f)
{
- set_page_present(page & PAGE_MASK, false, pglevel);
+ int ret;
+ WARN_ONCE(f->armed, KERN_ERR "kmmio page already armed.\n");
+ if (f->armed) {
+ pr_warning("kmmio double-arm: page 0x%08lx, ref %d, old %d\n",
+ f->page, f->count, f->old_presence);
+ }
+ ret = set_page_presence(f->page, false, &f->old_presence);
+ WARN_ONCE(ret < 0, KERN_ERR "kmmio arming 0x%08lx failed.\n", f->page);
+ f->armed = true;
+ return ret;
}
-/** Mark the given page as present. */
-static void disarm_kmmio_fault_page(unsigned long page, unsigned int *pglevel)
+/** Restore the given page to saved presence state. */
+static void disarm_kmmio_fault_page(struct kmmio_fault_page *f)
{
- set_page_present(page & PAGE_MASK, true, pglevel);
+ bool tmp;
+ int ret = set_page_presence(f->page, f->old_presence, &tmp);
+ WARN_ONCE(ret < 0,
+ KERN_ERR "kmmio disarming 0x%08lx failed.\n", f->page);
+ f->armed = false;
}
/*
@@ -202,28 +233,32 @@
ctx = &get_cpu_var(kmmio_ctx);
if (ctx->active) {
- disarm_kmmio_fault_page(faultpage->page, NULL);
if (addr == ctx->addr) {
/*
- * On SMP we sometimes get recursive probe hits on the
- * same address. Context is already saved, fall out.
+ * A second fault on the same page means some other
+ * condition needs handling by do_page_fault(), the
+ * page really not being present is the most common.
*/
- pr_debug("kmmio: duplicate probe hit on CPU %d, for "
- "address 0x%08lx.\n",
- smp_processor_id(), addr);
- ret = 1;
- goto no_kmmio_ctx;
- }
- /*
- * Prevent overwriting already in-flight context.
- * This should not happen, let's hope disarming at least
- * prevents a panic.
- */
- pr_emerg("kmmio: recursive probe hit on CPU %d, "
+ pr_debug("kmmio: secondary hit for 0x%08lx CPU %d.\n",
+ addr, smp_processor_id());
+
+ if (!faultpage->old_presence)
+ pr_info("kmmio: unexpected secondary hit for "
+ "address 0x%08lx on CPU %d.\n", addr,
+ smp_processor_id());
+ } else {
+ /*
+ * Prevent overwriting already in-flight context.
+ * This should not happen, let's hope disarming at
+ * least prevents a panic.
+ */
+ pr_emerg("kmmio: recursive probe hit on CPU %d, "
"for address 0x%08lx. Ignoring.\n",
smp_processor_id(), addr);
- pr_emerg("kmmio: previous hit was at 0x%08lx.\n",
- ctx->addr);
+ pr_emerg("kmmio: previous hit was at 0x%08lx.\n",
+ ctx->addr);
+ disarm_kmmio_fault_page(faultpage);
+ }
goto no_kmmio_ctx;
}
ctx->active++;
@@ -244,7 +279,7 @@
regs->flags &= ~X86_EFLAGS_IF;
/* Now we set present bit in PTE and single step. */
- disarm_kmmio_fault_page(ctx->fpage->page, NULL);
+ disarm_kmmio_fault_page(ctx->fpage);
/*
* If another cpu accesses the same page while we are stepping,
@@ -275,7 +310,7 @@
struct kmmio_context *ctx = &get_cpu_var(kmmio_ctx);
if (!ctx->active) {
- pr_debug("kmmio: spurious debug trap on CPU %d.\n",
+ pr_warning("kmmio: spurious debug trap on CPU %d.\n",
smp_processor_id());
goto out;
}
@@ -283,7 +318,11 @@
if (ctx->probe && ctx->probe->post_handler)
ctx->probe->post_handler(ctx->probe, condition, regs);
- arm_kmmio_fault_page(ctx->fpage->page, NULL);
+ /* Prevent racing against release_kmmio_fault_page(). */
+ spin_lock(&kmmio_lock);
+ if (ctx->fpage->count)
+ arm_kmmio_fault_page(ctx->fpage);
+ spin_unlock(&kmmio_lock);
regs->flags &= ~X86_EFLAGS_TF;
regs->flags |= ctx->saved_flags;
@@ -315,20 +354,24 @@
f = get_kmmio_fault_page(page);
if (f) {
if (!f->count)
- arm_kmmio_fault_page(f->page, NULL);
+ arm_kmmio_fault_page(f);
f->count++;
return 0;
}
- f = kmalloc(sizeof(*f), GFP_ATOMIC);
+ f = kzalloc(sizeof(*f), GFP_ATOMIC);
if (!f)
return -1;
f->count = 1;
f->page = page;
- list_add_rcu(&f->list, kmmio_page_list(f->page));
- arm_kmmio_fault_page(f->page, NULL);
+ if (arm_kmmio_fault_page(f)) {
+ kfree(f);
+ return -1;
+ }
+
+ list_add_rcu(&f->list, kmmio_page_list(f->page));
return 0;
}
@@ -347,7 +390,7 @@
f->count--;
BUG_ON(f->count < 0);
if (!f->count) {
- disarm_kmmio_fault_page(f->page, NULL);
+ disarm_kmmio_fault_page(f);
f->release_next = *release_list;
*release_list = f;
}
diff --git a/arch/x86/mm/testmmiotrace.c b/arch/x86/mm/testmmiotrace.c
index ab50a8d..427fd1b 100644
--- a/arch/x86/mm/testmmiotrace.c
+++ b/arch/x86/mm/testmmiotrace.c
@@ -1,5 +1,5 @@
/*
- * Written by Pekka Paalanen, 2008 <pq@iki.fi>
+ * Written by Pekka Paalanen, 2008-2009 <pq@iki.fi>
*/
#include <linux/module.h>
#include <linux/io.h>
@@ -9,35 +9,74 @@
static unsigned long mmio_address;
module_param(mmio_address, ulong, 0);
-MODULE_PARM_DESC(mmio_address, "Start address of the mapping of 16 kB.");
+MODULE_PARM_DESC(mmio_address, " Start address of the mapping of 16 kB "
+ "(or 8 MB if read_far is non-zero).");
+
+static unsigned long read_far = 0x400100;
+module_param(read_far, ulong, 0);
+MODULE_PARM_DESC(read_far, " Offset of a 32-bit read within 8 MB "
+ "(default: 0x400100).");
+
+static unsigned v16(unsigned i)
+{
+ return i * 12 + 7;
+}
+
+static unsigned v32(unsigned i)
+{
+ return i * 212371 + 13;
+}
static void do_write_test(void __iomem *p)
{
unsigned int i;
+ pr_info(MODULE_NAME ": write test.\n");
mmiotrace_printk("Write test.\n");
+
for (i = 0; i < 256; i++)
iowrite8(i, p + i);
+
for (i = 1024; i < (5 * 1024); i += 2)
- iowrite16(i * 12 + 7, p + i);
+ iowrite16(v16(i), p + i);
+
for (i = (5 * 1024); i < (16 * 1024); i += 4)
- iowrite32(i * 212371 + 13, p + i);
+ iowrite32(v32(i), p + i);
}
static void do_read_test(void __iomem *p)
{
unsigned int i;
+ unsigned errs[3] = { 0 };
+ pr_info(MODULE_NAME ": read test.\n");
mmiotrace_printk("Read test.\n");
+
for (i = 0; i < 256; i++)
- ioread8(p + i);
+ if (ioread8(p + i) != i)
+ ++errs[0];
+
for (i = 1024; i < (5 * 1024); i += 2)
- ioread16(p + i);
+ if (ioread16(p + i) != v16(i))
+ ++errs[1];
+
for (i = (5 * 1024); i < (16 * 1024); i += 4)
- ioread32(p + i);
+ if (ioread32(p + i) != v32(i))
+ ++errs[2];
+
+ mmiotrace_printk("Read errors: 8-bit %d, 16-bit %d, 32-bit %d.\n",
+ errs[0], errs[1], errs[2]);
}
-static void do_test(void)
+static void do_read_far_test(void __iomem *p)
{
- void __iomem *p = ioremap_nocache(mmio_address, 0x4000);
+ pr_info(MODULE_NAME ": read far test.\n");
+ mmiotrace_printk("Read far test.\n");
+
+ ioread32(p + read_far);
+}
+
+static void do_test(unsigned long size)
+{
+ void __iomem *p = ioremap_nocache(mmio_address, size);
if (!p) {
pr_err(MODULE_NAME ": could not ioremap, aborting.\n");
return;
@@ -45,11 +84,15 @@
mmiotrace_printk("ioremap returned %p.\n", p);
do_write_test(p);
do_read_test(p);
+ if (read_far && read_far < size - 4)
+ do_read_far_test(p);
iounmap(p);
}
static int __init init(void)
{
+ unsigned long size = (read_far) ? (8 << 20) : (16 << 10);
+
if (mmio_address == 0) {
pr_err(MODULE_NAME ": you have to use the module argument "
"mmio_address.\n");
@@ -58,10 +101,11 @@
return -ENXIO;
}
- pr_warning(MODULE_NAME ": WARNING: mapping 16 kB @ 0x%08lx "
- "in PCI address space, and writing "
- "rubbish in there.\n", mmio_address);
- do_test();
+ pr_warning(MODULE_NAME ": WARNING: mapping %lu kB @ 0x%08lx in PCI "
+ "address space, and writing 16 kB of rubbish in there.\n",
+ size >> 10, mmio_address);
+ do_test(size);
+ pr_info(MODULE_NAME ": All done.\n");
return 0;
}
diff --git a/drivers/dma/iop-adma.c b/drivers/dma/iop-adma.c
index ea5440d..647374a 100644
--- a/drivers/dma/iop-adma.c
+++ b/drivers/dma/iop-adma.c
@@ -1401,7 +1401,7 @@
static struct platform_driver iop_adma_driver = {
.probe = iop_adma_probe,
- .remove = iop_adma_remove,
+ .remove = __devexit_p(iop_adma_remove),
.driver = {
.owner = THIS_MODULE,
.name = "iop-adma",
diff --git a/drivers/dma/mv_xor.c b/drivers/dma/mv_xor.c
index d35cbd1..5d5d5b3 100644
--- a/drivers/dma/mv_xor.c
+++ b/drivers/dma/mv_xor.c
@@ -1287,7 +1287,7 @@
static struct platform_driver mv_xor_driver = {
.probe = mv_xor_probe,
- .remove = mv_xor_remove,
+ .remove = __devexit_p(mv_xor_remove),
.driver = {
.owner = THIS_MODULE,
.name = MV_XOR_NAME,
diff --git a/drivers/i2c/busses/i2c-mv64xxx.c b/drivers/i2c/busses/i2c-mv64xxx.c
index eeda276f..7f186bb 100644
--- a/drivers/i2c/busses/i2c-mv64xxx.c
+++ b/drivers/i2c/busses/i2c-mv64xxx.c
@@ -482,7 +482,7 @@
return 0;
}
-static void __devexit
+static void
mv64xxx_i2c_unmap_regs(struct mv64xxx_i2c_data *drv_data)
{
if (drv_data->reg_base) {
@@ -577,7 +577,7 @@
static struct platform_driver mv64xxx_i2c_driver = {
.probe = mv64xxx_i2c_probe,
- .remove = mv64xxx_i2c_remove,
+ .remove = __devexit_p(mv64xxx_i2c_remove),
.driver = {
.owner = THIS_MODULE,
.name = MV64XXX_I2C_CTLR_NAME,
diff --git a/drivers/mtd/nand/orion_nand.c b/drivers/mtd/nand/orion_nand.c
index 917cf8d..c2dfd3e 100644
--- a/drivers/mtd/nand/orion_nand.c
+++ b/drivers/mtd/nand/orion_nand.c
@@ -149,7 +149,7 @@
static struct platform_driver orion_nand_driver = {
.probe = orion_nand_probe,
- .remove = orion_nand_remove,
+ .remove = __devexit_p(orion_nand_remove),
.driver = {
.name = "orion_nand",
.owner = THIS_MODULE,
diff --git a/drivers/net/arm/Makefile b/drivers/net/arm/Makefile
index c69c0cd..811a3cc 100644
--- a/drivers/net/arm/Makefile
+++ b/drivers/net/arm/Makefile
@@ -4,7 +4,7 @@
#
obj-$(CONFIG_ARM_AM79C961A) += am79c961a.o
-obj-$(CONFIG_ARM_ETHERH) += etherh.o ../8390.o
+obj-$(CONFIG_ARM_ETHERH) += etherh.o
obj-$(CONFIG_ARM_ETHER3) += ether3.o
obj-$(CONFIG_ARM_ETHER1) += ether1.o
obj-$(CONFIG_ARM_AT91_ETHER) += at91_ether.o
diff --git a/drivers/net/arm/etherh.c b/drivers/net/arm/etherh.c
index 54b52e5..f52f668c 100644
--- a/drivers/net/arm/etherh.c
+++ b/drivers/net/arm/etherh.c
@@ -641,15 +641,15 @@
.ndo_open = etherh_open,
.ndo_stop = etherh_close,
.ndo_set_config = etherh_set_config,
- .ndo_start_xmit = ei_start_xmit,
- .ndo_tx_timeout = ei_tx_timeout,
- .ndo_get_stats = ei_get_stats,
- .ndo_set_multicast_list = ei_set_multicast_list,
+ .ndo_start_xmit = __ei_start_xmit,
+ .ndo_tx_timeout = __ei_tx_timeout,
+ .ndo_get_stats = __ei_get_stats,
+ .ndo_set_multicast_list = __ei_set_multicast_list,
.ndo_validate_addr = eth_validate_addr,
.ndo_set_mac_address = eth_mac_addr,
.ndo_change_mtu = eth_change_mtu,
#ifdef CONFIG_NET_POLL_CONTROLLER
- .ndo_poll_controller = ei_poll,
+ .ndo_poll_controller = __ei_poll,
#endif
};
diff --git a/drivers/video/pxafb.c b/drivers/video/pxafb.c
index 48ff701..2552b9f 100644
--- a/drivers/video/pxafb.c
+++ b/drivers/video/pxafb.c
@@ -2230,7 +2230,7 @@
static struct platform_driver pxafb_driver = {
.probe = pxafb_probe,
- .remove = pxafb_remove,
+ .remove = __devexit_p(pxafb_remove),
.suspend = pxafb_suspend,
.resume = pxafb_resume,
.driver = {
diff --git a/include/linux/rcuclassic.h b/include/linux/rcuclassic.h
index f3f697d..80044a4 100644
--- a/include/linux/rcuclassic.h
+++ b/include/linux/rcuclassic.h
@@ -181,4 +181,10 @@
#define rcu_enter_nohz() do { } while (0)
#define rcu_exit_nohz() do { } while (0)
+/* A context switch is a grace period for rcuclassic. */
+static inline int rcu_blocking_is_gp(void)
+{
+ return num_online_cpus() == 1;
+}
+
#endif /* __LINUX_RCUCLASSIC_H */
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 921340a..528343e 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -52,6 +52,9 @@
void (*func)(struct rcu_head *head);
};
+/* Internal to kernel, but needed by rcupreempt.h. */
+extern int rcu_scheduler_active;
+
#if defined(CONFIG_CLASSIC_RCU)
#include <linux/rcuclassic.h>
#elif defined(CONFIG_TREE_RCU)
@@ -265,6 +268,7 @@
/* Internal to kernel */
extern void rcu_init(void);
+extern void rcu_scheduler_starting(void);
extern int rcu_needs_cpu(int cpu);
#endif /* __LINUX_RCUPDATE_H */
diff --git a/include/linux/rcupreempt.h b/include/linux/rcupreempt.h
index 3e05c09..74304b4 100644
--- a/include/linux/rcupreempt.h
+++ b/include/linux/rcupreempt.h
@@ -142,4 +142,19 @@
#define rcu_exit_nohz() do { } while (0)
#endif /* CONFIG_NO_HZ */
+/*
+ * A context switch is a grace period for rcupreempt synchronize_rcu()
+ * only during early boot, before the scheduler has been initialized.
+ * So, how the heck do we get a context switch? Well, if the caller
+ * invokes synchronize_rcu(), they are willing to accept a context
+ * switch, so we simply pretend that one happened.
+ *
+ * After boot, there might be a blocked or preempted task in an RCU
+ * read-side critical section, so we cannot then take the fastpath.
+ */
+static inline int rcu_blocking_is_gp(void)
+{
+ return num_online_cpus() == 1 && !rcu_scheduler_active;
+}
+
#endif /* __LINUX_RCUPREEMPT_H */
diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h
index d4368b7..a722fb6 100644
--- a/include/linux/rcutree.h
+++ b/include/linux/rcutree.h
@@ -326,4 +326,10 @@
}
#endif /* CONFIG_NO_HZ */
+/* A context switch is a grace period for rcutree. */
+static inline int rcu_blocking_is_gp(void)
+{
+ return num_online_cpus() == 1;
+}
+
#endif /* __LINUX_RCUTREE_H */
diff --git a/init/main.c b/init/main.c
index 8442094..83697e1 100644
--- a/init/main.c
+++ b/init/main.c
@@ -97,7 +97,7 @@
extern void tc_init(void);
#endif
-enum system_states system_state;
+enum system_states system_state __read_mostly;
EXPORT_SYMBOL(system_state);
/*
@@ -463,6 +463,7 @@
* at least once to get things moving:
*/
init_idle_bootup_task(current);
+ rcu_scheduler_starting();
preempt_enable_no_resched();
schedule();
preempt_disable();
diff --git a/kernel/rcuclassic.c b/kernel/rcuclassic.c
index bd5a900..654c640 100644
--- a/kernel/rcuclassic.c
+++ b/kernel/rcuclassic.c
@@ -679,8 +679,8 @@
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
- (idle_cpu(cpu) && !in_softirq() &&
- hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
+ (idle_cpu(cpu) && rcu_scheduler_active &&
+ !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
/*
* Get here if this CPU took its interrupt from user
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index d92a76a..cae8a05 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -44,6 +44,7 @@
#include <linux/cpu.h>
#include <linux/mutex.h>
#include <linux/module.h>
+#include <linux/kernel_stat.h>
enum rcu_barrier {
RCU_BARRIER_STD,
@@ -55,6 +56,7 @@
static atomic_t rcu_barrier_cpu_count;
static DEFINE_MUTEX(rcu_barrier_mutex);
static struct completion rcu_barrier_completion;
+int rcu_scheduler_active __read_mostly;
/*
* Awaken the corresponding synchronize_rcu() instance now that a
@@ -80,6 +82,10 @@
void synchronize_rcu(void)
{
struct rcu_synchronize rcu;
+
+ if (rcu_blocking_is_gp())
+ return;
+
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu(&rcu.head, wakeme_after_rcu);
@@ -175,3 +181,9 @@
__rcu_init();
}
+void rcu_scheduler_starting(void)
+{
+ WARN_ON(num_online_cpus() != 1);
+ WARN_ON(nr_context_switches() > 0);
+ rcu_scheduler_active = 1;
+}
diff --git a/kernel/rcupreempt.c b/kernel/rcupreempt.c
index 33cfc50..5d59e85 100644
--- a/kernel/rcupreempt.c
+++ b/kernel/rcupreempt.c
@@ -1181,6 +1181,9 @@
{
struct rcu_synchronize rcu;
+ if (num_online_cpus() == 1)
+ return; /* blocking is gp if only one CPU! */
+
init_completion(&rcu.completion);
/* Will wake me after RCU finished. */
call_rcu_sched(&rcu.head, wakeme_after_rcu);
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index b2fd602..97ce315 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -948,8 +948,8 @@
void rcu_check_callbacks(int cpu, int user)
{
if (user ||
- (idle_cpu(cpu) && !in_softirq() &&
- hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
+ (idle_cpu(cpu) && rcu_scheduler_active &&
+ !in_softirq() && hardirq_count() <= (1 << HARDIRQ_SHIFT))) {
/*
* Get here if this CPU took its interrupt from user