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author | 2023-03-11 15:40:01 +0100 | |
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committer | 2023-03-21 12:27:08 -0700 | |
commit | fbaa38214cd9e150764ccaa82e04ecf42cc1140c (patch) | |
tree | 740bead46ae1b468da5ec7629794f658fa685f85 /drivers/cxl | |
parent | Linux 6.3-rc3 (diff) | |
download | linux-fbaa38214cd9e150764ccaa82e04ecf42cc1140c.tar.gz linux-fbaa38214cd9e150764ccaa82e04ecf42cc1140c.tar.bz2 linux-fbaa38214cd9e150764ccaa82e04ecf42cc1140c.zip |
cxl/pci: Fix CDAT retrieval on big endian
The CDAT exposed in sysfs differs between little endian and big endian
arches: On big endian, every 4 bytes are byte-swapped.
PCI Configuration Space is little endian (PCI r3.0 sec 6.1). Accessors
such as pci_read_config_dword() implicitly swap bytes on big endian.
That way, the macros in include/uapi/linux/pci_regs.h work regardless of
the arch's endianness. For an example of implicit byte-swapping, see
ppc4xx_pciex_read_config(), which calls in_le32(), which uses lwbrx
(Load Word Byte-Reverse Indexed).
DOE Read/Write Data Mailbox Registers are unlike other registers in
Configuration Space in that they contain or receive a 4 byte portion of
an opaque byte stream (a "Data Object" per PCIe r6.0 sec 7.9.24.5f).
They need to be copied to or from the request/response buffer verbatim.
So amend pci_doe_send_req() and pci_doe_recv_resp() to undo the implicit
byte-swapping.
The CXL_DOE_TABLE_ACCESS_* and PCI_DOE_DATA_OBJECT_DISC_* macros assume
implicit byte-swapping. Byte-swap requests after constructing them with
those macros and byte-swap responses before parsing them.
Change the request and response type to __le32 to avoid sparse warnings.
Per a request from Jonathan, replace sizeof(u32) with sizeof(__le32) for
consistency.
Fixes: c97006046c79 ("cxl/port: Read CDAT table")
Tested-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Cc: stable@vger.kernel.org # v6.0+
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Link: https://lore.kernel.org/r/3051114102f41d19df3debbee123129118fc5e6d.1678543498.git.lukas@wunner.de
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Diffstat (limited to 'drivers/cxl')
-rw-r--r-- | drivers/cxl/core/pci.c | 26 |
1 files changed, 13 insertions, 13 deletions
diff --git a/drivers/cxl/core/pci.c b/drivers/cxl/core/pci.c index 7328a2552411..49a99a84b6aa 100644 --- a/drivers/cxl/core/pci.c +++ b/drivers/cxl/core/pci.c @@ -462,7 +462,7 @@ static struct pci_doe_mb *find_cdat_doe(struct device *uport) return NULL; } -#define CDAT_DOE_REQ(entry_handle) \ +#define CDAT_DOE_REQ(entry_handle) cpu_to_le32 \ (FIELD_PREP(CXL_DOE_TABLE_ACCESS_REQ_CODE, \ CXL_DOE_TABLE_ACCESS_REQ_CODE_READ) | \ FIELD_PREP(CXL_DOE_TABLE_ACCESS_TABLE_TYPE, \ @@ -475,8 +475,8 @@ static void cxl_doe_task_complete(struct pci_doe_task *task) } struct cdat_doe_task { - u32 request_pl; - u32 response_pl[32]; + __le32 request_pl; + __le32 response_pl[32]; struct completion c; struct pci_doe_task task; }; @@ -510,10 +510,10 @@ static int cxl_cdat_get_length(struct device *dev, return rc; } wait_for_completion(&t.c); - if (t.task.rv < sizeof(u32)) + if (t.task.rv < sizeof(__le32)) return -EIO; - *length = t.response_pl[1]; + *length = le32_to_cpu(t.response_pl[1]); dev_dbg(dev, "CDAT length %zu\n", *length); return 0; @@ -524,13 +524,13 @@ static int cxl_cdat_read_table(struct device *dev, struct cxl_cdat *cdat) { size_t length = cdat->length; - u32 *data = cdat->table; + __le32 *data = cdat->table; int entry_handle = 0; do { DECLARE_CDAT_DOE_TASK(CDAT_DOE_REQ(entry_handle), t); size_t entry_dw; - u32 *entry; + __le32 *entry; int rc; rc = pci_doe_submit_task(cdat_doe, &t.task); @@ -540,21 +540,21 @@ static int cxl_cdat_read_table(struct device *dev, } wait_for_completion(&t.c); /* 1 DW header + 1 DW data min */ - if (t.task.rv < (2 * sizeof(u32))) + if (t.task.rv < (2 * sizeof(__le32))) return -EIO; /* Get the CXL table access header entry handle */ entry_handle = FIELD_GET(CXL_DOE_TABLE_ACCESS_ENTRY_HANDLE, - t.response_pl[0]); + le32_to_cpu(t.response_pl[0])); entry = t.response_pl + 1; - entry_dw = t.task.rv / sizeof(u32); + entry_dw = t.task.rv / sizeof(__le32); /* Skip Header */ entry_dw -= 1; - entry_dw = min(length / sizeof(u32), entry_dw); + entry_dw = min(length / sizeof(__le32), entry_dw); /* Prevent length < 1 DW from causing a buffer overflow */ if (entry_dw) { - memcpy(data, entry, entry_dw * sizeof(u32)); - length -= entry_dw * sizeof(u32); + memcpy(data, entry, entry_dw * sizeof(__le32)); + length -= entry_dw * sizeof(__le32); data += entry_dw; } } while (entry_handle != CXL_DOE_TABLE_ACCESS_LAST_ENTRY); |