[PATCH v2] dma-mapping: fix dma_addressing_limited if dma_range_map can't cover all system RAM
From: Jia He
Date: Mon Oct 09 2023 - 22:09:02 EST
There is an unusual case that the range map covers right up to the top of
system RAM, but leaves a hole somewhere lower down. Then it prevents the
nvme device dma mapping in the checking path of phys_to_dma() and causes
the hangs at boot.
E.g. On an Armv8 Ampere server, the dsdt ACPI table is:
Method (_DMA, 0, Serialized) // _DMA: Direct Memory Access
{
Name (RBUF, ResourceTemplate ()
{
QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
0x0000000000000000, // Granularity
0x0000000000000000, // Range Minimum
0x00000000FFFFFFFF, // Range Maximum
0x0000000000000000, // Translation Offset
0x0000000100000000, // Length
,, , AddressRangeMemory, TypeStatic)
QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
0x0000000000000000, // Granularity
0x0000006010200000, // Range Minimum
0x000000602FFFFFFF, // Range Maximum
0x0000000000000000, // Translation Offset
0x000000001FE00000, // Length
,, , AddressRangeMemory, TypeStatic)
QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
0x0000000000000000, // Granularity
0x00000060F0000000, // Range Minimum
0x00000060FFFFFFFF, // Range Maximum
0x0000000000000000, // Translation Offset
0x0000000010000000, // Length
,, , AddressRangeMemory, TypeStatic)
QWordMemory (ResourceConsumer, PosDecode, MinFixed,
MaxFixed, Cacheable, ReadWrite,
0x0000000000000000, // Granularity
0x0000007000000000, // Range Minimum
0x000003FFFFFFFFFF, // Range Maximum
0x0000000000000000, // Translation Offset
0x0000039000000000, // Length
,, , AddressRangeMemory, TypeStatic)
})
But the System RAM ranges are:
cat /proc/iomem |grep -i ram
90000000-91ffffff : System RAM
92900000-fffbffff : System RAM
880000000-fffffffff : System RAM
8800000000-bff5990fff : System RAM
bff59d0000-bff5a4ffff : System RAM
bff8000000-bfffffffff : System RAM
So some RAM ranges are out of dma_range_map.
Fixes it by checking whether each of the system RAM resources can be
properly encompassed within the dma_range_map.
Signed-off-by: Jia He <justin.he@xxxxxxx>
---
v2:
- refine the subject and commit msg (By Robin Murphy)
- refactor the checking loop in check_ram_in_range_map() in the pages
unit to avoid wrap to 0 on 32bits platforms (Robin)
include/linux/dma-mapping.h | 12 +++++++++--
kernel/dma/mapping.c | 42 +++++++++++++++++++++++++++++++++++++
2 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/include/linux/dma-mapping.h b/include/linux/dma-mapping.h
index f0ccca16a0ac..b8abbb2619a2 100644
--- a/include/linux/dma-mapping.h
+++ b/include/linux/dma-mapping.h
@@ -144,6 +144,7 @@ bool dma_pci_p2pdma_supported(struct device *dev);
int dma_set_mask(struct device *dev, u64 mask);
int dma_set_coherent_mask(struct device *dev, u64 mask);
u64 dma_get_required_mask(struct device *dev);
+bool all_ram_in_dma_range_map(struct device *dev);
size_t dma_max_mapping_size(struct device *dev);
size_t dma_opt_mapping_size(struct device *dev);
bool dma_need_sync(struct device *dev, dma_addr_t dma_addr);
@@ -264,6 +265,10 @@ static inline u64 dma_get_required_mask(struct device *dev)
{
return 0;
}
+static inline bool all_ram_in_dma_range_map(struct device *dev)
+{
+ return 1;
+}
static inline size_t dma_max_mapping_size(struct device *dev)
{
return 0;
@@ -475,8 +480,11 @@ static inline int dma_coerce_mask_and_coherent(struct device *dev, u64 mask)
*/
static inline bool dma_addressing_limited(struct device *dev)
{
- return min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
- dma_get_required_mask(dev);
+ if (min_not_zero(dma_get_mask(dev), dev->bus_dma_limit) <
+ dma_get_required_mask(dev))
+ return true;
+
+ return !all_ram_in_dma_range_map(dev);
}
static inline unsigned int dma_get_max_seg_size(struct device *dev)
diff --git a/kernel/dma/mapping.c b/kernel/dma/mapping.c
index e323ca48f7f2..5f454949a428 100644
--- a/kernel/dma/mapping.c
+++ b/kernel/dma/mapping.c
@@ -7,6 +7,7 @@
*/
#include <linux/memblock.h> /* for max_pfn */
#include <linux/acpi.h>
+#include <linux/dma-direct.h> /* for bus_dma_region */
#include <linux/dma-map-ops.h>
#include <linux/export.h>
#include <linux/gfp.h>
@@ -819,6 +820,47 @@ size_t dma_opt_mapping_size(struct device *dev)
}
EXPORT_SYMBOL_GPL(dma_opt_mapping_size);
+/*
+ * To check whether all ram resource ranges are mapped in dma range map
+ * Returns 0 when continuous check is needed
+ * Returns 1 if there is some ram range can't be mapped to dma_range_map
+ */
+static int check_ram_in_range_map(unsigned long start_pfn,
+ unsigned long nr_pages, void *data)
+{
+ unsigned long end_pfn = start_pfn + nr_pages;
+ struct device *dev = (struct device *)data;
+ struct bus_dma_region *region = NULL;
+ const struct bus_dma_region *m;
+
+ while (start_pfn < end_pfn) {
+ for (m = dev->dma_range_map; PFN_DOWN(m->size); m++) {
+ unsigned long cpu_start_pfn = PFN_DOWN(m->cpu_start);
+
+ if (start_pfn >= cpu_start_pfn
+ && start_pfn - cpu_start_pfn < PFN_DOWN(m->size)) {
+ region = (struct bus_dma_region *)m;
+ break;
+ }
+ }
+ if (!region)
+ return 1;
+
+ start_pfn = PFN_DOWN(region->cpu_start) + PFN_DOWN(region->size);
+ }
+
+ return 0;
+}
+
+bool all_ram_in_dma_range_map(struct device *dev)
+{
+ if (!dev->dma_range_map)
+ return 1;
+
+ return !walk_system_ram_range(0, ULONG_MAX, dev, check_ram_in_range_map);
+}
+EXPORT_SYMBOL_GPL(all_ram_in_dma_range_map);
+
bool dma_need_sync(struct device *dev, dma_addr_t dma_addr)
{
const struct dma_map_ops *ops = get_dma_ops(dev);
--
2.25.1