From 022eb43419f896a3647f769cdc3b5e13a8fb8ee7 Mon Sep 17 00:00:00 2001
From: Andrew Morton <akpm@osdl.org>
Date: Wed, 30 Jan 2008 13:30:47 +0100
Subject: x86: kmap_atomic() debugging
[ mingo@elte.hu: cleanups and made dependent on CONFIG_DEBUG_HIGHMEM.
this caught a handful of bugs already, so lets apply it. If it gets
things wrong we'll disable it. ]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/mm/highmem_32.c | 47 ++++++++++++++++++++++++++++++++++++++++++++++-
1 file changed, 46 insertions(+), 1 deletion(-)
(limited to 'arch')
diff --git a/arch/x86/mm/highmem_32.c b/arch/x86/mm/highmem_32.c
index 1c3bf95f7356..3d936f232704 100644
--- a/arch/x86/mm/highmem_32.c
+++ b/arch/x86/mm/highmem_32.c
@@ -18,6 +18,49 @@ void kunmap(struct page *page)
kunmap_high(page);
}
+static void debug_kmap_atomic_prot(enum km_type type)
+{
+#ifdef CONFIG_DEBUG_HIGHMEM
+ static unsigned warn_count = 10;
+
+ if (unlikely(warn_count == 0))
+ return;
+
+ if (unlikely(in_interrupt())) {
+ if (in_irq()) {
+ if (type != KM_IRQ0 && type != KM_IRQ1 &&
+ type != KM_BIO_SRC_IRQ && type != KM_BIO_DST_IRQ &&
+ type != KM_BOUNCE_READ) {
+ WARN_ON(1);
+ warn_count--;
+ }
+ } else if (!irqs_disabled()) { /* softirq */
+ if (type != KM_IRQ0 && type != KM_IRQ1 &&
+ type != KM_SOFTIRQ0 && type != KM_SOFTIRQ1 &&
+ type != KM_SKB_SUNRPC_DATA &&
+ type != KM_SKB_DATA_SOFTIRQ &&
+ type != KM_BOUNCE_READ) {
+ WARN_ON(1);
+ warn_count--;
+ }
+ }
+ }
+
+ if (type == KM_IRQ0 || type == KM_IRQ1 || type == KM_BOUNCE_READ ||
+ type == KM_BIO_SRC_IRQ || type == KM_BIO_DST_IRQ) {
+ if (!irqs_disabled()) {
+ WARN_ON(1);
+ warn_count--;
+ }
+ } else if (type == KM_SOFTIRQ0 || type == KM_SOFTIRQ1) {
+ if (irq_count() == 0 && !irqs_disabled()) {
+ WARN_ON(1);
+ warn_count--;
+ }
+ }
+#endif
+}
+
/*
* kmap_atomic/kunmap_atomic is significantly faster than kmap/kunmap because
* no global lock is needed and because the kmap code must perform a global TLB
@@ -30,8 +73,10 @@ void *kmap_atomic_prot(struct page *page, enum km_type type, pgprot_t prot)
{
enum fixed_addresses idx;
unsigned long vaddr;
-
/* even !CONFIG_PREEMPT needs this, for in_atomic in do_page_fault */
+
+ debug_kmap_atomic_prot(type);
+
pagefault_disable();
if (!PageHighMem(page))
--
cgit v1.2.2