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Subject[PATCH v2] powerpc/iommu/ddw: Fix endianness
Date
rtas_call() accepts and returns values in CPU endianness.
The ddw_query_response and ddw_create_response structs members are
defined and treated as BE but as they are passed to rtas_call() as
(u32 *) and they get byteswapped automatically, the data is actually
CPU-endian. This fixes ddw_query_response and ddw_create_response
definitions and use.

of_read_number() is designed to work with device tree cells - it assumes
the input is big-endian and returns data in CPU-endian. However due
to the ddw_create_response struct fix, create.addr_hi/lo are already
CPU-endian so do not byteswap them.

ddw_avail is a pointer to the "ibm,ddw-applicable" property which contains
3 cells which are big-endian as it is a device tree. rtas_call() accepts
a RTAS token in CPU-endian. This converts RTAS tokens from big-endian to
CPU-endian. Since every token is used once till guest is rebooted, there is
no much sense in caching RTAS tokens in CPU-endian.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
Changes:
v2:
* updated commit log
* fixed definition of ddw_query_response and ddw_create_response
---
arch/powerpc/platforms/pseries/iommu.c | 38 ++++++++++++++++++----------------
1 file changed, 20 insertions(+), 18 deletions(-)

diff --git a/arch/powerpc/platforms/pseries/iommu.c b/arch/powerpc/platforms/pseries/iommu.c
index 4642d6a..f052cc8 100644
--- a/arch/powerpc/platforms/pseries/iommu.c
+++ b/arch/powerpc/platforms/pseries/iommu.c
@@ -329,16 +329,16 @@ struct direct_window {

/* Dynamic DMA Window support */
struct ddw_query_response {
- __be32 windows_available;
- __be32 largest_available_block;
- __be32 page_size;
- __be32 migration_capable;
+ u32 windows_available;
+ u32 largest_available_block;
+ u32 page_size;
+ u32 migration_capable;
};

struct ddw_create_response {
- __be32 liobn;
- __be32 addr_hi;
- __be32 addr_lo;
+ u32 liobn;
+ u32 addr_hi;
+ u32 addr_lo;
};

static LIST_HEAD(direct_window_list);
@@ -750,7 +750,7 @@ static void remove_ddw(struct device_node *np, bool remove_prop)
pr_debug("%s successfully cleared tces in window.\n",
np->full_name);

- ret = rtas_call(ddw_avail[2], 1, 1, NULL, liobn);
+ ret = rtas_call(be32_to_cpu(ddw_avail[2]), 1, 1, NULL, liobn);
if (ret)
pr_warning("%s: failed to remove direct window: rtas returned "
"%d to ibm,remove-pe-dma-window(%x) %llx\n",
@@ -841,7 +841,7 @@ static int query_ddw(struct pci_dev *dev, const u32 *ddw_avail,
cfg_addr = edev->pe_config_addr;
buid = edev->phb->buid;

- ret = rtas_call(ddw_avail[0], 3, 5, (u32 *)query,
+ ret = rtas_call(be32_to_cpu(ddw_avail[0]), 3, 5, (u32 *)query,
cfg_addr, BUID_HI(buid), BUID_LO(buid));
dev_info(&dev->dev, "ibm,query-pe-dma-windows(%x) %x %x %x"
" returned %d\n", ddw_avail[0], cfg_addr, BUID_HI(buid),
@@ -872,8 +872,9 @@ static int create_ddw(struct pci_dev *dev, const u32 *ddw_avail,

do {
/* extra outputs are LIOBN and dma-addr (hi, lo) */
- ret = rtas_call(ddw_avail[1], 5, 4, (u32 *)create, cfg_addr,
- BUID_HI(buid), BUID_LO(buid), page_shift, window_shift);
+ ret = rtas_call(be32_to_cpu(ddw_avail[1]), 5, 4, (u32 *)create,
+ cfg_addr, BUID_HI(buid), BUID_LO(buid),
+ page_shift, window_shift);
} while (rtas_busy_delay(ret));
dev_info(&dev->dev,
"ibm,create-pe-dma-window(%x) %x %x %x %x %x returned %d "
@@ -966,11 +967,11 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
dev_dbg(&dev->dev, "no free dynamic windows");
goto out_failed;
}
- if (be32_to_cpu(query.page_size) & 4) {
+ if (query.page_size & 4) {
page_shift = 24; /* 16MB */
- } else if (be32_to_cpu(query.page_size) & 2) {
+ } else if (query.page_size & 2) {
page_shift = 16; /* 64kB */
- } else if (be32_to_cpu(query.page_size) & 1) {
+ } else if (query.page_size & 1) {
page_shift = 12; /* 4kB */
} else {
dev_dbg(&dev->dev, "no supported direct page size in mask %x",
@@ -980,7 +981,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
/* verify the window * number of ptes will map the partition */
/* check largest block * page size > max memory hotplug addr */
max_addr = memory_hotplug_max();
- if (be32_to_cpu(query.largest_available_block) < (max_addr >> page_shift)) {
+ if (query.largest_available_block < (max_addr >> page_shift)) {
dev_dbg(&dev->dev, "can't map partiton max 0x%llx with %u "
"%llu-sized pages\n", max_addr, query.largest_available_block,
1ULL << page_shift);
@@ -1006,8 +1007,9 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
if (ret != 0)
goto out_free_prop;

- ddwprop->liobn = create.liobn;
- ddwprop->dma_base = cpu_to_be64(of_read_number(&create.addr_hi, 2));
+ ddwprop->liobn = cpu_to_be32(create.liobn);
+ ddwprop->dma_base = cpu_to_be64(((u64)create.addr_hi << 32) |
+ create.addr_lo);
ddwprop->tce_shift = cpu_to_be32(page_shift);
ddwprop->window_shift = cpu_to_be32(len);

@@ -1039,7 +1041,7 @@ static u64 enable_ddw(struct pci_dev *dev, struct device_node *pdn)
list_add(&window->list, &direct_window_list);
spin_unlock(&direct_window_list_lock);

- dma_addr = of_read_number(&create.addr_hi, 2);
+ dma_addr = be64_to_cpu(ddwprop->dma_base);
goto out_unlock;

out_free_window:
--
2.0.0


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