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-rw-r--r--arch/x86/kernel/kprobes.c3
-rw-r--r--arch/x86/kernel/tsc.c110
-rw-r--r--arch/x86/mm/kmmio.c15
-rw-r--r--arch/x86/mm/pageattr.c11
4 files changed, 87 insertions, 52 deletions
diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index e948b28a5a9..4558dd3918c 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -193,6 +193,9 @@ static int __kprobes can_boost(kprobe_opcode_t *opcodes)
kprobe_opcode_t opcode;
kprobe_opcode_t *orig_opcodes = opcodes;
+ if (search_exception_tables(opcodes))
+ return 0; /* Page fault may occur on this address. */
+
retry:
if (opcodes - orig_opcodes > MAX_INSN_SIZE - 1)
return 0;
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 599e5816863..d5cebb52d45 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -273,30 +273,43 @@ static unsigned long pit_calibrate_tsc(u32 latch, unsigned long ms, int loopmin)
* use the TSC value at the transitions to calculate a pretty
* good value for the TSC frequencty.
*/
-static inline int pit_expect_msb(unsigned char val)
+static inline int pit_expect_msb(unsigned char val, u64 *tscp, unsigned long *deltap)
{
- int count = 0;
+ int count;
+ u64 tsc = 0;
for (count = 0; count < 50000; count++) {
/* Ignore LSB */
inb(0x42);
if (inb(0x42) != val)
break;
+ tsc = get_cycles();
}
- return count > 50;
+ *deltap = get_cycles() - tsc;
+ *tscp = tsc;
+
+ /*
+ * We require _some_ success, but the quality control
+ * will be based on the error terms on the TSC values.
+ */
+ return count > 5;
}
/*
- * How many MSB values do we want to see? We aim for a
- * 15ms calibration, which assuming a 2us counter read
- * error should give us roughly 150 ppm precision for
- * the calibration.
+ * How many MSB values do we want to see? We aim for
+ * a maximum error rate of 500ppm (in practice the
+ * real error is much smaller), but refuse to spend
+ * more than 25ms on it.
*/
-#define QUICK_PIT_MS 15
-#define QUICK_PIT_ITERATIONS (QUICK_PIT_MS * PIT_TICK_RATE / 1000 / 256)
+#define MAX_QUICK_PIT_MS 25
+#define MAX_QUICK_PIT_ITERATIONS (MAX_QUICK_PIT_MS * PIT_TICK_RATE / 1000 / 256)
static unsigned long quick_pit_calibrate(void)
{
+ int i;
+ u64 tsc, delta;
+ unsigned long d1, d2;
+
/* Set the Gate high, disable speaker */
outb((inb(0x61) & ~0x02) | 0x01, 0x61);
@@ -315,45 +328,52 @@ static unsigned long quick_pit_calibrate(void)
outb(0xff, 0x42);
outb(0xff, 0x42);
- if (pit_expect_msb(0xff)) {
- int i;
- u64 t1, t2, delta;
- unsigned char expect = 0xfe;
-
- t1 = get_cycles();
- for (i = 0; i < QUICK_PIT_ITERATIONS; i++, expect--) {
- if (!pit_expect_msb(expect))
- goto failed;
+ /*
+ * The PIT starts counting at the next edge, so we
+ * need to delay for a microsecond. The easiest way
+ * to do that is to just read back the 16-bit counter
+ * once from the PIT.
+ */
+ inb(0x42);
+ inb(0x42);
+
+ if (pit_expect_msb(0xff, &tsc, &d1)) {
+ for (i = 1; i <= MAX_QUICK_PIT_ITERATIONS; i++) {
+ if (!pit_expect_msb(0xff-i, &delta, &d2))
+ break;
+
+ /*
+ * Iterate until the error is less than 500 ppm
+ */
+ delta -= tsc;
+ if (d1+d2 < delta >> 11)
+ goto success;
}
- t2 = get_cycles();
-
- /*
- * Make sure we can rely on the second TSC timestamp:
- */
- if (!pit_expect_msb(expect))
- goto failed;
-
- /*
- * Ok, if we get here, then we've seen the
- * MSB of the PIT decrement QUICK_PIT_ITERATIONS
- * times, and each MSB had many hits, so we never
- * had any sudden jumps.
- *
- * As a result, we can depend on there not being
- * any odd delays anywhere, and the TSC reads are
- * reliable.
- *
- * kHz = ticks / time-in-seconds / 1000;
- * kHz = (t2 - t1) / (QPI * 256 / PIT_TICK_RATE) / 1000
- * kHz = ((t2 - t1) * PIT_TICK_RATE) / (QPI * 256 * 1000)
- */
- delta = (t2 - t1)*PIT_TICK_RATE;
- do_div(delta, QUICK_PIT_ITERATIONS*256*1000);
- printk("Fast TSC calibration using PIT\n");
- return delta;
}
-failed:
+ printk("Fast TSC calibration failed\n");
return 0;
+
+success:
+ /*
+ * Ok, if we get here, then we've seen the
+ * MSB of the PIT decrement 'i' times, and the
+ * error has shrunk to less than 500 ppm.
+ *
+ * As a result, we can depend on there not being
+ * any odd delays anywhere, and the TSC reads are
+ * reliable (within the error). We also adjust the
+ * delta to the middle of the error bars, just
+ * because it looks nicer.
+ *
+ * kHz = ticks / time-in-seconds / 1000;
+ * kHz = (t2 - t1) / (I * 256 / PIT_TICK_RATE) / 1000
+ * kHz = ((t2 - t1) * PIT_TICK_RATE) / (I * 256 * 1000)
+ */
+ delta += (long)(d2 - d1)/2;
+ delta *= PIT_TICK_RATE;
+ do_div(delta, i*256*1000);
+ printk("Fast TSC calibration using PIT\n");
+ return delta;
}
/**
diff --git a/arch/x86/mm/kmmio.c b/arch/x86/mm/kmmio.c
index 9f205030d9a..6a518dd08a3 100644
--- a/arch/x86/mm/kmmio.c
+++ b/arch/x86/mm/kmmio.c
@@ -451,23 +451,24 @@ static void rcu_free_kmmio_fault_pages(struct rcu_head *head)
static void remove_kmmio_fault_pages(struct rcu_head *head)
{
- struct kmmio_delayed_release *dr = container_of(
- head,
- struct kmmio_delayed_release,
- rcu);
+ struct kmmio_delayed_release *dr =
+ container_of(head, struct kmmio_delayed_release, rcu);
struct kmmio_fault_page *p = dr->release_list;
struct kmmio_fault_page **prevp = &dr->release_list;
unsigned long flags;
+
spin_lock_irqsave(&kmmio_lock, flags);
while (p) {
- if (!p->count)
+ if (!p->count) {
list_del_rcu(&p->list);
- else
+ prevp = &p->release_next;
+ } else {
*prevp = p->release_next;
- prevp = &p->release_next;
+ }
p = p->release_next;
}
spin_unlock_irqrestore(&kmmio_lock, flags);
+
/* This is the real RCU destroy call. */
call_rcu(&dr->rcu, rcu_free_kmmio_fault_pages);
}
diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c
index 7be47d1a97e..7233bd7e357 100644
--- a/arch/x86/mm/pageattr.c
+++ b/arch/x86/mm/pageattr.c
@@ -515,6 +515,17 @@ static int split_large_page(pte_t *kpte, unsigned long address)
* primary protection behavior:
*/
__set_pmd_pte(kpte, address, mk_pte(base, __pgprot(_KERNPG_TABLE)));
+
+ /*
+ * Intel Atom errata AAH41 workaround.
+ *
+ * The real fix should be in hw or in a microcode update, but
+ * we also probabilistically try to reduce the window of having
+ * a large TLB mixed with 4K TLBs while instruction fetches are
+ * going on.
+ */
+ __flush_tlb_all();
+
base = NULL;
out_unlock:
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-21 16:04:56 +0000