summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/kernel/iommu.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/kernel/iommu.c')
-rw-r--r--arch/powerpc/kernel/iommu.c294
1 files changed, 235 insertions, 59 deletions
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c
index 359f078..8226c6c 100644
--- a/arch/powerpc/kernel/iommu.c
+++ b/arch/powerpc/kernel/iommu.c
@@ -33,6 +33,9 @@
#include <linux/bitmap.h>
#include <linux/iommu-helper.h>
#include <linux/crash_dump.h>
+#include <linux/hash.h>
+#include <linux/fault-inject.h>
+#include <linux/pci.h>
#include <asm/io.h>
#include <asm/prom.h>
#include <asm/iommu.h>
@@ -40,6 +43,7 @@
#include <asm/machdep.h>
#include <asm/kdump.h>
#include <asm/fadump.h>
+#include <asm/vio.h>
#define DBG(...)
@@ -58,6 +62,114 @@ static int __init setup_iommu(char *str)
__setup("iommu=", setup_iommu);
+static DEFINE_PER_CPU(unsigned int, iommu_pool_hash);
+
+/*
+ * We precalculate the hash to avoid doing it on every allocation.
+ *
+ * The hash is important to spread CPUs across all the pools. For example,
+ * on a POWER7 with 4 way SMT we want interrupts on the primary threads and
+ * with 4 pools all primary threads would map to the same pool.
+ */
+static int __init setup_iommu_pool_hash(void)
+{
+ unsigned int i;
+
+ for_each_possible_cpu(i)
+ per_cpu(iommu_pool_hash, i) = hash_32(i, IOMMU_POOL_HASHBITS);
+
+ return 0;
+}
+subsys_initcall(setup_iommu_pool_hash);
+
+#ifdef CONFIG_FAIL_IOMMU
+
+static DECLARE_FAULT_ATTR(fail_iommu);
+
+static int __init setup_fail_iommu(char *str)
+{
+ return setup_fault_attr(&fail_iommu, str);
+}
+__setup("fail_iommu=", setup_fail_iommu);
+
+static bool should_fail_iommu(struct device *dev)
+{
+ return dev->archdata.fail_iommu && should_fail(&fail_iommu, 1);
+}
+
+static int __init fail_iommu_debugfs(void)
+{
+ struct dentry *dir = fault_create_debugfs_attr("fail_iommu",
+ NULL, &fail_iommu);
+
+ return IS_ERR(dir) ? PTR_ERR(dir) : 0;
+}
+late_initcall(fail_iommu_debugfs);
+
+static ssize_t fail_iommu_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%d\n", dev->archdata.fail_iommu);
+}
+
+static ssize_t fail_iommu_store(struct device *dev,
+ struct device_attribute *attr, const char *buf,
+ size_t count)
+{
+ int i;
+
+ if (count > 0 && sscanf(buf, "%d", &i) > 0)
+ dev->archdata.fail_iommu = (i == 0) ? 0 : 1;
+
+ return count;
+}
+
+static DEVICE_ATTR(fail_iommu, S_IRUGO|S_IWUSR, fail_iommu_show,
+ fail_iommu_store);
+
+static int fail_iommu_bus_notify(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct device *dev = data;
+
+ if (action == BUS_NOTIFY_ADD_DEVICE) {
+ if (device_create_file(dev, &dev_attr_fail_iommu))
+ pr_warn("Unable to create IOMMU fault injection sysfs "
+ "entries\n");
+ } else if (action == BUS_NOTIFY_DEL_DEVICE) {
+ device_remove_file(dev, &dev_attr_fail_iommu);
+ }
+
+ return 0;
+}
+
+static struct notifier_block fail_iommu_bus_notifier = {
+ .notifier_call = fail_iommu_bus_notify
+};
+
+static int __init fail_iommu_setup(void)
+{
+#ifdef CONFIG_PCI
+ bus_register_notifier(&pci_bus_type, &fail_iommu_bus_notifier);
+#endif
+#ifdef CONFIG_IBMVIO
+ bus_register_notifier(&vio_bus_type, &fail_iommu_bus_notifier);
+#endif
+
+ return 0;
+}
+/*
+ * Must execute after PCI and VIO subsystem have initialised but before
+ * devices are probed.
+ */
+arch_initcall(fail_iommu_setup);
+#else
+static inline bool should_fail_iommu(struct device *dev)
+{
+ return false;
+}
+#endif
+
static unsigned long iommu_range_alloc(struct device *dev,
struct iommu_table *tbl,
unsigned long npages,
@@ -71,6 +183,9 @@ static unsigned long iommu_range_alloc(struct device *dev,
int pass = 0;
unsigned long align_mask;
unsigned long boundary_size;
+ unsigned long flags;
+ unsigned int pool_nr;
+ struct iommu_pool *pool;
align_mask = 0xffffffffffffffffl >> (64 - align_order);
@@ -83,36 +198,52 @@ static unsigned long iommu_range_alloc(struct device *dev,
return DMA_ERROR_CODE;
}
- if (handle && *handle)
- start = *handle;
+ if (should_fail_iommu(dev))
+ return DMA_ERROR_CODE;
+
+ /*
+ * We don't need to disable preemption here because any CPU can
+ * safely use any IOMMU pool.
+ */
+ pool_nr = __raw_get_cpu_var(iommu_pool_hash) & (tbl->nr_pools - 1);
+
+ if (largealloc)
+ pool = &(tbl->large_pool);
else
- start = largealloc ? tbl->it_largehint : tbl->it_hint;
+ pool = &(tbl->pools[pool_nr]);
- /* Use only half of the table for small allocs (15 pages or less) */
- limit = largealloc ? tbl->it_size : tbl->it_halfpoint;
+ spin_lock_irqsave(&(pool->lock), flags);
- if (largealloc && start < tbl->it_halfpoint)
- start = tbl->it_halfpoint;
+again:
+ if ((pass == 0) && handle && *handle &&
+ (*handle >= pool->start) && (*handle < pool->end))
+ start = *handle;
+ else
+ start = pool->hint;
+
+ limit = pool->end;
/* The case below can happen if we have a small segment appended
* to a large, or when the previous alloc was at the very end of
* the available space. If so, go back to the initial start.
*/
if (start >= limit)
- start = largealloc ? tbl->it_largehint : tbl->it_hint;
-
- again:
+ start = pool->start;
if (limit + tbl->it_offset > mask) {
limit = mask - tbl->it_offset + 1;
/* If we're constrained on address range, first try
* at the masked hint to avoid O(n) search complexity,
- * but on second pass, start at 0.
+ * but on second pass, start at 0 in pool 0.
*/
- if ((start & mask) >= limit || pass > 0)
- start = 0;
- else
+ if ((start & mask) >= limit || pass > 0) {
+ spin_unlock(&(pool->lock));
+ pool = &(tbl->pools[0]);
+ spin_lock(&(pool->lock));
+ start = pool->start;
+ } else {
start &= mask;
+ }
}
if (dev)
@@ -126,16 +257,25 @@ static unsigned long iommu_range_alloc(struct device *dev,
tbl->it_offset, boundary_size >> IOMMU_PAGE_SHIFT,
align_mask);
if (n == -1) {
- if (likely(pass < 2)) {
- /* First failure, just rescan the half of the table.
- * Second failure, rescan the other half of the table.
- */
- start = (largealloc ^ pass) ? tbl->it_halfpoint : 0;
- limit = pass ? tbl->it_size : limit;
+ if (likely(pass == 0)) {
+ /* First try the pool from the start */
+ pool->hint = pool->start;
pass++;
goto again;
+
+ } else if (pass <= tbl->nr_pools) {
+ /* Now try scanning all the other pools */
+ spin_unlock(&(pool->lock));
+ pool_nr = (pool_nr + 1) & (tbl->nr_pools - 1);
+ pool = &tbl->pools[pool_nr];
+ spin_lock(&(pool->lock));
+ pool->hint = pool->start;
+ pass++;
+ goto again;
+
} else {
- /* Third failure, give up */
+ /* Give up */
+ spin_unlock_irqrestore(&(pool->lock), flags);
return DMA_ERROR_CODE;
}
}
@@ -145,10 +285,10 @@ static unsigned long iommu_range_alloc(struct device *dev,
/* Bump the hint to a new block for small allocs. */
if (largealloc) {
/* Don't bump to new block to avoid fragmentation */
- tbl->it_largehint = end;
+ pool->hint = end;
} else {
/* Overflow will be taken care of at the next allocation */
- tbl->it_hint = (end + tbl->it_blocksize - 1) &
+ pool->hint = (end + tbl->it_blocksize - 1) &
~(tbl->it_blocksize - 1);
}
@@ -156,6 +296,8 @@ static unsigned long iommu_range_alloc(struct device *dev,
if (handle)
*handle = end;
+ spin_unlock_irqrestore(&(pool->lock), flags);
+
return n;
}
@@ -165,18 +307,14 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
unsigned long mask, unsigned int align_order,
struct dma_attrs *attrs)
{
- unsigned long entry, flags;
+ unsigned long entry;
dma_addr_t ret = DMA_ERROR_CODE;
int build_fail;
- spin_lock_irqsave(&(tbl->it_lock), flags);
-
entry = iommu_range_alloc(dev, tbl, npages, NULL, mask, align_order);
- if (unlikely(entry == DMA_ERROR_CODE)) {
- spin_unlock_irqrestore(&(tbl->it_lock), flags);
+ if (unlikely(entry == DMA_ERROR_CODE))
return DMA_ERROR_CODE;
- }
entry += tbl->it_offset; /* Offset into real TCE table */
ret = entry << IOMMU_PAGE_SHIFT; /* Set the return dma address */
@@ -193,8 +331,6 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
*/
if (unlikely(build_fail)) {
__iommu_free(tbl, ret, npages);
-
- spin_unlock_irqrestore(&(tbl->it_lock), flags);
return DMA_ERROR_CODE;
}
@@ -202,16 +338,14 @@ static dma_addr_t iommu_alloc(struct device *dev, struct iommu_table *tbl,
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
- spin_unlock_irqrestore(&(tbl->it_lock), flags);
-
/* Make sure updates are seen by hardware */
mb();
return ret;
}
-static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
- unsigned int npages)
+static bool iommu_free_check(struct iommu_table *tbl, dma_addr_t dma_addr,
+ unsigned int npages)
{
unsigned long entry, free_entry;
@@ -231,20 +365,57 @@ static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
printk(KERN_INFO "\tindex = 0x%llx\n", (u64)tbl->it_index);
WARN_ON(1);
}
- return;
+
+ return false;
+ }
+
+ return true;
+}
+
+static struct iommu_pool *get_pool(struct iommu_table *tbl,
+ unsigned long entry)
+{
+ struct iommu_pool *p;
+ unsigned long largepool_start = tbl->large_pool.start;
+
+ /* The large pool is the last pool at the top of the table */
+ if (entry >= largepool_start) {
+ p = &tbl->large_pool;
+ } else {
+ unsigned int pool_nr = entry / tbl->poolsize;
+
+ BUG_ON(pool_nr > tbl->nr_pools);
+ p = &tbl->pools[pool_nr];
}
+ return p;
+}
+
+static void __iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
+ unsigned int npages)
+{
+ unsigned long entry, free_entry;
+ unsigned long flags;
+ struct iommu_pool *pool;
+
+ entry = dma_addr >> IOMMU_PAGE_SHIFT;
+ free_entry = entry - tbl->it_offset;
+
+ pool = get_pool(tbl, free_entry);
+
+ if (!iommu_free_check(tbl, dma_addr, npages))
+ return;
+
ppc_md.tce_free(tbl, entry, npages);
+
+ spin_lock_irqsave(&(pool->lock), flags);
bitmap_clear(tbl->it_map, free_entry, npages);
+ spin_unlock_irqrestore(&(pool->lock), flags);
}
static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
unsigned int npages)
{
- unsigned long flags;
-
- spin_lock_irqsave(&(tbl->it_lock), flags);
-
__iommu_free(tbl, dma_addr, npages);
/* Make sure TLB cache is flushed if the HW needs it. We do
@@ -253,8 +424,6 @@ static void iommu_free(struct iommu_table *tbl, dma_addr_t dma_addr,
*/
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
-
- spin_unlock_irqrestore(&(tbl->it_lock), flags);
}
int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
@@ -263,7 +432,6 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
struct dma_attrs *attrs)
{
dma_addr_t dma_next = 0, dma_addr;
- unsigned long flags;
struct scatterlist *s, *outs, *segstart;
int outcount, incount, i, build_fail = 0;
unsigned int align;
@@ -285,8 +453,6 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
DBG("sg mapping %d elements:\n", nelems);
- spin_lock_irqsave(&(tbl->it_lock), flags);
-
max_seg_size = dma_get_max_seg_size(dev);
for_each_sg(sglist, s, nelems, i) {
unsigned long vaddr, npages, entry, slen;
@@ -369,8 +535,6 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
- spin_unlock_irqrestore(&(tbl->it_lock), flags);
-
DBG("mapped %d elements:\n", outcount);
/* For the sake of iommu_unmap_sg, we clear out the length in the
@@ -402,7 +566,6 @@ int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
if (s == outs)
break;
}
- spin_unlock_irqrestore(&(tbl->it_lock), flags);
return 0;
}
@@ -412,15 +575,12 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
struct dma_attrs *attrs)
{
struct scatterlist *sg;
- unsigned long flags;
BUG_ON(direction == DMA_NONE);
if (!tbl)
return;
- spin_lock_irqsave(&(tbl->it_lock), flags);
-
sg = sglist;
while (nelems--) {
unsigned int npages;
@@ -440,8 +600,6 @@ void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
*/
if (ppc_md.tce_flush)
ppc_md.tce_flush(tbl);
-
- spin_unlock_irqrestore(&(tbl->it_lock), flags);
}
static void iommu_table_clear(struct iommu_table *tbl)
@@ -494,9 +652,8 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
unsigned long sz;
static int welcomed = 0;
struct page *page;
-
- /* Set aside 1/4 of the table for large allocations. */
- tbl->it_halfpoint = tbl->it_size * 3 / 4;
+ unsigned int i;
+ struct iommu_pool *p;
/* number of bytes needed for the bitmap */
sz = (tbl->it_size + 7) >> 3;
@@ -515,9 +672,28 @@ struct iommu_table *iommu_init_table(struct iommu_table *tbl, int nid)
if (tbl->it_offset == 0)
set_bit(0, tbl->it_map);
- tbl->it_hint = 0;
- tbl->it_largehint = tbl->it_halfpoint;
- spin_lock_init(&tbl->it_lock);
+ /* We only split the IOMMU table if we have 1GB or more of space */
+ if ((tbl->it_size << IOMMU_PAGE_SHIFT) >= (1UL * 1024 * 1024 * 1024))
+ tbl->nr_pools = IOMMU_NR_POOLS;
+ else
+ tbl->nr_pools = 1;
+
+ /* We reserve the top 1/4 of the table for large allocations */
+ tbl->poolsize = (tbl->it_size * 3 / 4) / tbl->nr_pools;
+
+ for (i = 0; i < tbl->nr_pools; i++) {
+ p = &tbl->pools[i];
+ spin_lock_init(&(p->lock));
+ p->start = tbl->poolsize * i;
+ p->hint = p->start;
+ p->end = p->start + tbl->poolsize;
+ }
+
+ p = &tbl->large_pool;
+ spin_lock_init(&(p->lock));
+ p->start = tbl->poolsize * i;
+ p->hint = p->start;
+ p->end = tbl->it_size;
iommu_table_clear(tbl);