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cxl/pci: Fix CDAT retrieval on big endian

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commit fbaa38214c upstream.

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: c97006046c ("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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Lukas Wunner 2023-03-11 15:40:01 +01:00 committed by Greg Kroah-Hartman
parent f540da0fd2
commit 027882381a
3 changed files with 33 additions and 26 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

26
drivers/cxl/core/pci.c
View file

@ -480,7 +480,7 @@ static struct pci_doe_mb *find_cdat_doe(struct device *uport)
return NULL; 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, \ (FIELD_PREP(CXL_DOE_TABLE_ACCESS_REQ_CODE, \
CXL_DOE_TABLE_ACCESS_REQ_CODE_READ) | \ CXL_DOE_TABLE_ACCESS_REQ_CODE_READ) | \
FIELD_PREP(CXL_DOE_TABLE_ACCESS_TABLE_TYPE, \ FIELD_PREP(CXL_DOE_TABLE_ACCESS_TABLE_TYPE, \
@ -493,8 +493,8 @@ static void cxl_doe_task_complete(struct pci_doe_task *task)
} }
struct cdat_doe_task { struct cdat_doe_task {
u32 request_pl; __le32 request_pl;
u32 response_pl[32]; __le32 response_pl[32];
struct completion c; struct completion c;
struct pci_doe_task task; struct pci_doe_task task;
}; };
@ -528,10 +528,10 @@ static int cxl_cdat_get_length(struct device *dev,
return rc; return rc;
} }
wait_for_completion(&t.c); wait_for_completion(&t.c);
if (t.task.rv < sizeof(u32)) if (t.task.rv < sizeof(__le32))
return -EIO; return -EIO;
*length = t.response_pl[1]; *length = le32_to_cpu(t.response_pl[1]);
dev_dbg(dev, "CDAT length %zu\n", *length); dev_dbg(dev, "CDAT length %zu\n", *length);
return 0; return 0;
@ -542,13 +542,13 @@ static int cxl_cdat_read_table(struct device *dev,
struct cxl_cdat *cdat) struct cxl_cdat *cdat)
{ {
size_t length = cdat->length; size_t length = cdat->length;
u32 *data = cdat->table; __le32 *data = cdat->table;
int entry_handle = 0; int entry_handle = 0;
do { do {
DECLARE_CDAT_DOE_TASK(CDAT_DOE_REQ(entry_handle), t); DECLARE_CDAT_DOE_TASK(CDAT_DOE_REQ(entry_handle), t);
size_t entry_dw; size_t entry_dw;
u32 *entry; __le32 *entry;
int rc; int rc;
rc = pci_doe_submit_task(cdat_doe, &t.task); rc = pci_doe_submit_task(cdat_doe, &t.task);
@ -558,21 +558,21 @@ static int cxl_cdat_read_table(struct device *dev,
} }
wait_for_completion(&t.c); wait_for_completion(&t.c);
/* 1 DW header + 1 DW data min */ /* 1 DW header + 1 DW data min */
if (t.task.rv < (2 * sizeof(u32))) if (t.task.rv < (2 * sizeof(__le32)))
return -EIO; return -EIO;
/* Get the CXL table access header entry handle */ /* Get the CXL table access header entry handle */
entry_handle = FIELD_GET(CXL_DOE_TABLE_ACCESS_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 = t.response_pl + 1;
entry_dw = t.task.rv / sizeof(u32); entry_dw = t.task.rv / sizeof(__le32);
/* Skip Header */ /* Skip Header */
entry_dw -= 1; 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 */ /* Prevent length < 1 DW from causing a buffer overflow */
if (entry_dw) { if (entry_dw) {
memcpy(data, entry, entry_dw * sizeof(u32)); memcpy(data, entry, entry_dw * sizeof(__le32));
length -= entry_dw * sizeof(u32); length -= entry_dw * sizeof(__le32);
data += entry_dw; data += entry_dw;
} }
} while (entry_handle != CXL_DOE_TABLE_ACCESS_LAST_ENTRY); } while (entry_handle != CXL_DOE_TABLE_ACCESS_LAST_ENTRY);

25
drivers/pci/doe.c
View file

@ -128,7 +128,7 @@ static int pci_doe_send_req(struct pci_doe_mb *doe_mb,
return -EIO; return -EIO;
/* Length is 2 DW of header + length of payload in DW */ /* Length is 2 DW of header + length of payload in DW */
length = 2 + task->request_pl_sz / sizeof(u32); length = 2 + task->request_pl_sz / sizeof(__le32);
if (length > PCI_DOE_MAX_LENGTH) if (length > PCI_DOE_MAX_LENGTH)
return -EIO; return -EIO;
if (length == PCI_DOE_MAX_LENGTH) if (length == PCI_DOE_MAX_LENGTH)
@ -141,9 +141,9 @@ static int pci_doe_send_req(struct pci_doe_mb *doe_mb,
pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, pci_write_config_dword(pdev, offset + PCI_DOE_WRITE,
FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH, FIELD_PREP(PCI_DOE_DATA_OBJECT_HEADER_2_LENGTH,
length)); length));
for (i = 0; i < task->request_pl_sz / sizeof(u32); i++) for (i = 0; i < task->request_pl_sz / sizeof(__le32); i++)
pci_write_config_dword(pdev, offset + PCI_DOE_WRITE, pci_write_config_dword(pdev, offset + PCI_DOE_WRITE,
task->request_pl[i]); le32_to_cpu(task->request_pl[i]));
pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_GO); pci_doe_write_ctrl(doe_mb, PCI_DOE_CTRL_GO);
@ -195,11 +195,11 @@ static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *tas
/* First 2 dwords have already been read */ /* First 2 dwords have already been read */
length -= 2; length -= 2;
payload_length = min(length, task->response_pl_sz / sizeof(u32)); payload_length = min(length, task->response_pl_sz / sizeof(__le32));
/* Read the rest of the response payload */ /* Read the rest of the response payload */
for (i = 0; i < payload_length; i++) { for (i = 0; i < payload_length; i++) {
pci_read_config_dword(pdev, offset + PCI_DOE_READ, pci_read_config_dword(pdev, offset + PCI_DOE_READ, &val);
&task->response_pl[i]); task->response_pl[i] = cpu_to_le32(val);
/* Prior to the last ack, ensure Data Object Ready */ /* Prior to the last ack, ensure Data Object Ready */
if (i == (payload_length - 1) && !pci_doe_data_obj_ready(doe_mb)) if (i == (payload_length - 1) && !pci_doe_data_obj_ready(doe_mb))
return -EIO; return -EIO;
@ -217,7 +217,7 @@ static int pci_doe_recv_resp(struct pci_doe_mb *doe_mb, struct pci_doe_task *tas
if (FIELD_GET(PCI_DOE_STATUS_ERROR, val)) if (FIELD_GET(PCI_DOE_STATUS_ERROR, val))
return -EIO; return -EIO;
return min(length, task->response_pl_sz / sizeof(u32)) * sizeof(u32); return min(length, task->response_pl_sz / sizeof(__le32)) * sizeof(__le32);
} }
static void signal_task_complete(struct pci_doe_task *task, int rv) static void signal_task_complete(struct pci_doe_task *task, int rv)
@ -317,14 +317,16 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid,
{ {
u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX, u32 request_pl = FIELD_PREP(PCI_DOE_DATA_OBJECT_DISC_REQ_3_INDEX,
*index); *index);
__le32 request_pl_le = cpu_to_le32(request_pl);
__le32 response_pl_le;
u32 response_pl; u32 response_pl;
DECLARE_COMPLETION_ONSTACK(c); DECLARE_COMPLETION_ONSTACK(c);
struct pci_doe_task task = { struct pci_doe_task task = {
.prot.vid = PCI_VENDOR_ID_PCI_SIG, .prot.vid = PCI_VENDOR_ID_PCI_SIG,
.prot.type = PCI_DOE_PROTOCOL_DISCOVERY, .prot.type = PCI_DOE_PROTOCOL_DISCOVERY,
.request_pl = &request_pl, .request_pl = &request_pl_le,
.request_pl_sz = sizeof(request_pl), .request_pl_sz = sizeof(request_pl),
.response_pl = &response_pl, .response_pl = &response_pl_le,
.response_pl_sz = sizeof(response_pl), .response_pl_sz = sizeof(response_pl),
.complete = pci_doe_task_complete, .complete = pci_doe_task_complete,
.private = &c, .private = &c,
@ -340,6 +342,7 @@ static int pci_doe_discovery(struct pci_doe_mb *doe_mb, u8 *index, u16 *vid,
if (task.rv != sizeof(response_pl)) if (task.rv != sizeof(response_pl))
return -EIO; return -EIO;
response_pl = le32_to_cpu(response_pl_le);
*vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl); *vid = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_VID, response_pl);
*protocol = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL, *protocol = FIELD_GET(PCI_DOE_DATA_OBJECT_DISC_RSP_3_PROTOCOL,
response_pl); response_pl);
@ -533,8 +536,8 @@ int pci_doe_submit_task(struct pci_doe_mb *doe_mb, struct pci_doe_task *task)
* DOE requests must be a whole number of DW and the response needs to * DOE requests must be a whole number of DW and the response needs to
* be big enough for at least 1 DW * be big enough for at least 1 DW
*/ */
if (task->request_pl_sz % sizeof(u32) || if (task->request_pl_sz % sizeof(__le32) ||
task->response_pl_sz < sizeof(u32)) task->response_pl_sz < sizeof(__le32))
return -EINVAL; return -EINVAL;
if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags)) if (test_bit(PCI_DOE_FLAG_DEAD, &doe_mb->flags))

8
include/linux/pci-doe.h
View file

@ -34,6 +34,10 @@ struct pci_doe_mb;
* @work: Used internally by the mailbox * @work: Used internally by the mailbox
* @doe_mb: Used internally by the mailbox * @doe_mb: Used internally by the mailbox
* *
* Payloads are treated as opaque byte streams which are transmitted verbatim,
* without byte-swapping. If payloads contain little-endian register values,
* the caller is responsible for conversion with cpu_to_le32() / le32_to_cpu().
*
* The payload sizes and rv are specified in bytes with the following * The payload sizes and rv are specified in bytes with the following
* restrictions concerning the protocol. * restrictions concerning the protocol.
* *
@ -45,9 +49,9 @@ struct pci_doe_mb;
*/ */
struct pci_doe_task { struct pci_doe_task {
struct pci_doe_protocol prot; struct pci_doe_protocol prot;
u32 *request_pl; __le32 *request_pl;
size_t request_pl_sz; size_t request_pl_sz;
u32 *response_pl; __le32 *response_pl;
size_t response_pl_sz; size_t response_pl_sz;
int rv; int rv;
void (*complete)(struct pci_doe_task *task); void (*complete)(struct pci_doe_task *task);