summaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>2010-08-26 13:57:58 -0400
committerH. Peter Anvin <hpa@linux.intel.com>2010-08-26 15:13:19 -0700
commit5bef80a4b826b9cee1c6aec7ecc371ec395260cc (patch)
treeda37af1b6760d443e1c8a301bb0af17b16ebcd9b
parent480125ba49ba62be93beea37770f266846e077ab (diff)
x86, iommu: Add proper dependency sort routine (and sanity check).
We are using a very simple sort routine which sorts the .iommu_table array in the order of dependencies. Specifically each structure of iommu_table_entry has a field 'depend' which contains the function pointer to the IOMMU that MUST be run before us. We sort the array of structures so that the struct iommu_table_entry with no 'depend' field are first, and then the subsequent ones are the ones for which the 'depend' function has been already invoked (in other words, precede us). Using the kernel's version 'sort', which is a mergeheap is feasible, but would require making the comparison operator scan recursivly the array to satisfy the "heapify" process: setting the levels properly. The end result would much more complex than it should be an it is just much simpler to utilize this simple sort routine. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> LKML-Reference: <1282845485-8991-4-git-send-email-konrad.wilk@oracle.com> CC: H. Peter Anvin <hpa@zytor.com> CC: Fujita Tomonori <fujita.tomonori@lab.ntt.co.jp> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
-rw-r--r--arch/x86/include/asm/iommu_table.h6
-rw-r--r--arch/x86/kernel/Makefile1
-rw-r--r--arch/x86/kernel/pci-iommu_table.c89
3 files changed, 96 insertions, 0 deletions
diff --git a/arch/x86/include/asm/iommu_table.h b/arch/x86/include/asm/iommu_table.h
index 435176f96a56..2124e3ef6f98 100644
--- a/arch/x86/include/asm/iommu_table.h
+++ b/arch/x86/include/asm/iommu_table.h
@@ -92,4 +92,10 @@ struct iommu_table_entry {
#define IOMMU_INIT(_detect, _depend, _init, _late_init) \
__IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
+void sort_iommu_table(struct iommu_table_entry *start,
+ struct iommu_table_entry *finish);
+
+void check_iommu_entries(struct iommu_table_entry *start,
+ struct iommu_table_entry *finish);
+
#endif /* _ASM_X86_IOMMU_TABLE_H */
diff --git a/arch/x86/kernel/Makefile b/arch/x86/kernel/Makefile
index 0925676266bd..6817546595ef 100644
--- a/arch/x86/kernel/Makefile
+++ b/arch/x86/kernel/Makefile
@@ -42,6 +42,7 @@ obj-y += bootflag.o e820.o
obj-y += pci-dma.o quirks.o i8237.o topology.o kdebugfs.o
obj-y += alternative.o i8253.o pci-nommu.o hw_breakpoint.o
obj-y += tsc.o io_delay.o rtc.o
+obj-y += pci-iommu_table.o
obj-$(CONFIG_X86_TRAMPOLINE) += trampoline.o
obj-y += process.o
diff --git a/arch/x86/kernel/pci-iommu_table.c b/arch/x86/kernel/pci-iommu_table.c
new file mode 100644
index 000000000000..55d745ec1181
--- /dev/null
+++ b/arch/x86/kernel/pci-iommu_table.c
@@ -0,0 +1,89 @@
+#include <linux/dma-mapping.h>
+#include <asm/iommu_table.h>
+#include <linux/string.h>
+#include <linux/kallsyms.h>
+
+
+#define DEBUG 1
+
+static struct iommu_table_entry * __init
+find_dependents_of(struct iommu_table_entry *start,
+ struct iommu_table_entry *finish,
+ struct iommu_table_entry *q)
+{
+ struct iommu_table_entry *p;
+
+ if (!q)
+ return NULL;
+
+ for (p = start; p < finish; p++)
+ if (p->detect == q->depend)
+ return p;
+
+ return NULL;
+}
+
+
+void __init sort_iommu_table(struct iommu_table_entry *start,
+ struct iommu_table_entry *finish) {
+
+ struct iommu_table_entry *p, *q, tmp;
+
+ for (p = start; p < finish; p++) {
+again:
+ q = find_dependents_of(start, finish, p);
+ /* We are bit sneaky here. We use the memory address to figure
+ * out if the node we depend on is past our point, if so, swap.
+ */
+ if (q > p) {
+ tmp = *p;
+ memmove(p, q, sizeof(*p));
+ *q = tmp;
+ goto again;
+ }
+ }
+
+}
+
+#ifdef DEBUG
+void __init check_iommu_entries(struct iommu_table_entry *start,
+ struct iommu_table_entry *finish)
+{
+ struct iommu_table_entry *p, *q, *x;
+ char sym_p[KSYM_SYMBOL_LEN];
+ char sym_q[KSYM_SYMBOL_LEN];
+
+ /* Simple cyclic dependency checker. */
+ for (p = start; p < finish; p++) {
+ q = find_dependents_of(start, finish, p);
+ x = find_dependents_of(start, finish, q);
+ if (p == x) {
+ sprint_symbol(sym_p, (unsigned long)p->detect);
+ sprint_symbol(sym_q, (unsigned long)q->detect);
+
+ printk(KERN_ERR "CYCLIC DEPENDENCY FOUND! %s depends" \
+ " on %s and vice-versa. BREAKING IT.\n",
+ sym_p, sym_q);
+ /* Heavy handed way..*/
+ x->depend = 0;
+ }
+ }
+
+ for (p = start; p < finish; p++) {
+ q = find_dependents_of(p, finish, p);
+ if (q && q > p) {
+ sprint_symbol(sym_p, (unsigned long)p->detect);
+ sprint_symbol(sym_q, (unsigned long)q->detect);
+
+ printk(KERN_ERR "EXECUTION ORDER INVALID! %s "\
+ "should be called before %s!\n",
+ sym_p, sym_q);
+ }
+ }
+}
+#else
+inline void check_iommu_entries(struct iommu_table_entry *start,
+ struct iommu_table_entry *finish)
+{
+}
+#endif