RE: [RFC PATCH V2 net-next 1/5] ethtool: Allow network drivers to dump arbitrary EEPROM data

From: Don Bollinger <hidden>
Date: 2021-03-05 00:57:52

On Thu, Mar 04, 2021 at 10:57AM-0800, Moshe Shemesh wrote:

quoted hunk ↗ jump to hunk

From: Vladyslav Tarasiuk <redacted>

Define get_module_eeprom_data_by_page() ethtool callback and
implement netlink infrastructure.

get_module_eeprom_data_by_page() allows network drivers to dump a
part of module's EEPROM specified by page and bank numbers along with
offset and length. It is effectively a netlink replacement for
get_module_info() and get_module_eeprom() pair, which is needed due to
emergence of complex non-linear EEPROM layouts.

Signed-off-by: Vladyslav Tarasiuk <redacted>
---
 include/linux/ethtool.h              |   7 +-
 include/uapi/linux/ethtool.h         |  26 +++++
 include/uapi/linux/ethtool_netlink.h |  19 ++++
 net/ethtool/Makefile                 |   2 +-
 net/ethtool/eeprom.c                 | 157 +++++++++++++++++++++++++++
 net/ethtool/netlink.c                |  10 ++
 net/ethtool/netlink.h                |   2 +
 7 files changed, 221 insertions(+), 2 deletions(-)  create mode 100644
net/ethtool/eeprom.c

diff --git a/include/linux/ethtool.h b/include/linux/ethtool.h index

ec4cd3921c67..2f65aae5f492 100644

--- a/include/linux/ethtool.h
+++ b/include/linux/ethtool.h

@@ -81,6 +81,7 @@ enum {
 #define ETH_RSS_HASH_NO_CHANGE	0

 struct net_device;
+struct netlink_ext_ack;

 /* Some generic methods drivers may use in their ethtool_ops */
 u32 ethtool_op_get_link(struct net_device *dev); @@ -410,6 +411,8 @@

struct ethtool_pause_stats {
  * @get_ethtool_phy_stats: Return extended statistics about the PHY
device.
  *	This is only useful if the device maintains PHY statistics and
  *	cannot use the standard PHY library helpers.
+ * @get_module_eeprom_data_by_page: Get a region of plug-in module
EEPROM data
+ *	from specified page. Returns a negative error code or zero.
  *
  * All operations are optional (i.e. the function pointer may be set
  * to %NULL) and callers must take this into account.  Callers must @@

-515,6

+518,9 @@ struct ethtool_ops {
 				   const struct ethtool_tunable *, void *);
 	int	(*set_phy_tunable)(struct net_device *,
 				   const struct ethtool_tunable *, const

void

quoted hunk ↗ jump to hunk

*);
+	int	(*get_module_eeprom_data_by_page)(struct net_device
*dev,
+						  const struct
ethtool_eeprom_data *page,
+						  struct netlink_ext_ack
*extack);
 };

 int ethtool_check_ops(const struct ethtool_ops *ops); @@ -538,7 +544,6

@@ int ethtool_virtdev_set_link_ksettings(struct net_device *dev,
 				       const struct ethtool_link_ksettings

*cmd,

quoted hunk ↗ jump to hunk

 				       u32 *dev_speed, u8 *dev_duplex);

-struct netlink_ext_ack;
 struct phy_device;
 struct phy_tdr_config;

diff --git a/include/uapi/linux/ethtool.h b/include/uapi/linux/ethtool.h

index

quoted hunk ↗ jump to hunk

cde753bb2093..2459571fc1d1 100644

--- a/include/uapi/linux/ethtool.h
+++ b/include/uapi/linux/ethtool.h

@@ -340,6 +340,28 @@ struct ethtool_eeprom {
 	__u8	data[0];
 };

+/**
+ * struct ethtool_eeprom_data - EEPROM dump from specified page
+ * @offset: Offset within the specified EEPROM page to begin read, in

bytes.

Note here that bytes at offset 0-127 are the same for every page of the
module, only bytes at offset 128 and higher are actually paged.

+ * @length: Number of bytes to read.
+ * @page: Page number to read from.
+ * @bank: Page bank number to read from, if applicable by EEPROM spec.
+ * @i2c_address: I2C address of a page. Value less than 0x7f expected.
Most
+ *	EEPROMs use 0x50 or 0x51.

The standards are all very clear, the only legal values are 0x50 and 0x51.
It isn't 'expected', it is required.  I suggest that 0xA0 and 0xA2 also be
silently accepted, and translated to 0x50 and 0x51 respectively.  Some
of the specs use A0/A2 instead of 0x50/0x51.  They actually mean the
same thing.

quoted hunk ↗ jump to hunk

+ * @data: Pointer to buffer with EEPROM data of @length size.
+ *
+ * This can be used to manage pages during EEPROM dump in ethtool and
+pass
+ * required information to the driver.
+ */
+struct ethtool_eeprom_data {
+	__u32	offset;
+	__u32	length;
+	__u32	page;
+	__u32	bank;
+	__u32	i2c_address;
+	__u8	*data;
+};
+
 /**
  * struct ethtool_eee - Energy Efficient Ethernet information
  * @cmd: ETHTOOL_{G,S}EEE

@@ -1865,6 +1887,10 @@ static inline int ethtool_validate_duplex(__u8

duplex)
 #define ETH_MODULE_SFF_8636_MAX_LEN     640
 #define ETH_MODULE_SFF_8436_MAX_LEN     640

+#define ETH_MODULE_EEPROM_MAX_LEN	640

Please don't add this MAX_LEN constant.  Even better, remove
the two above it as well.

The proper value for all 3 of these MAX_LEN items is the
architectural limit imposed by the 8 bit page register plus the constant
lower page (hence 257*128 bytes).  The 8436 and 8636
specs do not actually limit these devices to 640 bytes (3 pages). 

There is no MAX_LEN listed for SFF_8472.  If there is one, it should
actually be 259 * 128 bytes (to account for 256 more bytes on the
unpaged 0x50 i2c address). 

 Nor is there one for CMIS.  The maximum
architected length for CMIS is (257*128) + (127 * 16 * 128).  That's
the QSFP max length plus 127 more banks of 16 pages.

+#define ETH_MODULE_EEPROM_PAGE_LEN	256
+#define ETH_MODULE_MAX_I2C_ADDRESS	0x7f

Actually there are only two legal values for the i2c address (0x50, 0x51).
Rather than defining a MAX address, consider defining the legal values,
or...  is it used at all?  Leave it out?

+
 /* Reset flags */
 /* The reset() operation must clear the flags for the components which
  * were actually reset.  On successful return, the flags indicate the

diff --git

quoted hunk ↗ jump to hunk

a/include/uapi/linux/ethtool_netlink.h
b/include/uapi/linux/ethtool_netlink.h
index a286635ac9b8..60dd848d0b54 100644

--- a/include/uapi/linux/ethtool_netlink.h
+++ b/include/uapi/linux/ethtool_netlink.h

@@ -42,6 +42,7 @@ enum {
 	ETHTOOL_MSG_CABLE_TEST_ACT,
 	ETHTOOL_MSG_CABLE_TEST_TDR_ACT,
 	ETHTOOL_MSG_TUNNEL_INFO_GET,
+	ETHTOOL_MSG_EEPROM_DATA_GET,

 	/* add new constants above here */
 	__ETHTOOL_MSG_USER_CNT,

@@ -80,6 +81,7 @@ enum {
 	ETHTOOL_MSG_CABLE_TEST_NTF,
 	ETHTOOL_MSG_CABLE_TEST_TDR_NTF,
 	ETHTOOL_MSG_TUNNEL_INFO_GET_REPLY,
+	ETHTOOL_MSG_EEPROM_DATA_GET_REPLY,

 	/* add new constants above here */
 	__ETHTOOL_MSG_KERNEL_CNT,

@@ -629,6 +631,23 @@ enum {
 	ETHTOOL_A_TUNNEL_INFO_MAX =

(__ETHTOOL_A_TUNNEL_INFO_CNT - 1)  };

+/* MODULE EEPROM DATA */
+
+enum {
+	ETHTOOL_A_EEPROM_DATA_UNSPEC,
+	ETHTOOL_A_EEPROM_DATA_HEADER,
+
+	ETHTOOL_A_EEPROM_DATA_OFFSET,
+	ETHTOOL_A_EEPROM_DATA_LENGTH,
+	ETHTOOL_A_EEPROM_DATA_PAGE,
+	ETHTOOL_A_EEPROM_DATA_BANK,
+	ETHTOOL_A_EEPROM_DATA_I2C_ADDRESS,
+	ETHTOOL_A_EEPROM_DATA,
+
+	__ETHTOOL_A_EEPROM_DATA_CNT,
+	ETHTOOL_A_EEPROM_DATA_MAX =
(__ETHTOOL_A_EEPROM_DATA_CNT - 1) };
+
 /* generic netlink info */
 #define ETHTOOL_GENL_NAME "ethtool"
 #define ETHTOOL_GENL_VERSION 1

diff --git a/net/ethtool/Makefile b/net/ethtool/Makefile index

7a849ff22dad..d604346bc074 100644

--- a/net/ethtool/Makefile
+++ b/net/ethtool/Makefile

@@ -7,4 +7,4 @@ obj-$(CONFIG_ETHTOOL_NETLINK)	+= ethtool_nl.o
 ethtool_nl-y	:= netlink.o bitset.o strset.o linkinfo.o linkmodes.o \
 		   linkstate.o debug.o wol.o features.o privflags.o rings.o

 		   channels.o coalesce.o pause.o eee.o tsinfo.o cabletest.o

quoted hunk ↗ jump to hunk

-		   tunnels.o
+		   tunnels.o eeprom.o

diff --git a/net/ethtool/eeprom.c b/net/ethtool/eeprom.c new file mode

100644 index 000000000000..2618a55b9a40

--- /dev/null
+++ b/net/ethtool/eeprom.c

@@ -0,0 +1,157 @@
+// SPDX-License-Identifier: GPL-2.0-only
+
+#include <linux/ethtool.h>
+#include "netlink.h"
+#include "common.h"
+
+struct eeprom_data_req_info {
+	struct ethnl_req_info	base;
+	u32			offset;
+	u32			length;
+	u32			page;
+	u32			bank;
+	u32			i2c_address;
+};
+
+struct eeprom_data_reply_data {
+	struct ethnl_reply_data base;
+	u32			length;
+	u32			i2c_address;
+	u8			*data;
+};
+
+#define EEPROM_DATA_REQINFO(__req_base) \
+	container_of(__req_base, struct eeprom_data_req_info, base)
+
+#define EEPROM_DATA_REPDATA(__reply_base) \
+	container_of(__reply_base, struct eeprom_data_reply_data, base)
+
+static int eeprom_data_prepare_data(const struct ethnl_req_info

*req_base,
+				    struct ethnl_reply_data *reply_base,
+				    struct genl_info *info)
+{
+	struct eeprom_data_reply_data *reply =
EEPROM_DATA_REPDATA(reply_base);
+	struct eeprom_data_req_info *request =
EEPROM_DATA_REQINFO(req_base);
+	struct ethtool_eeprom_data page_data = {0};
+	struct net_device *dev = reply_base->dev;
+	int err;
+
+	if (!dev->ethtool_ops->get_module_eeprom_data_by_page)
+		return -EOPNOTSUPP;
+
+	page_data.offset = request->offset;
+	page_data.length = request->length;
+	page_data.i2c_address = request->i2c_address;
+	page_data.page = request->page;
+	page_data.bank = request->bank;
+	page_data.data = kmalloc(page_data.length, GFP_KERNEL);
+	if (!page_data.data)
+		return -ENOMEM;
+	err = ethnl_ops_begin(dev);
+	if (err)
+		goto err_free;
+
+	err = dev->ethtool_ops->get_module_eeprom_data_by_page(dev,
&page_data,
+

info->extack);

+	if (err)
+		goto err_ops;
+
+	reply->length = page_data.length;
+	reply->i2c_address = page_data.i2c_address;
+	reply->data = page_data.data;
+
+	ethnl_ops_complete(dev);

The two error paths below kfree(page_data.data).  Does someone else
free this memory when there is no error?

+	return 0;
+
+err_ops:
+	ethnl_ops_complete(dev);
+err_free:
+	kfree(page_data.data);
+	return err;
+}
+
+static int eeprom_data_parse_request(struct ethnl_req_info *req_info,
struct nlattr **tb,
+				     struct netlink_ext_ack *extack) {
+	struct eeprom_data_req_info *request =
EEPROM_DATA_REQINFO(req_info);
+
+	if (!tb[ETHTOOL_A_EEPROM_DATA_OFFSET] ||
+	    !tb[ETHTOOL_A_EEPROM_DATA_LENGTH] ||
+	    !tb[ETHTOOL_A_EEPROM_DATA_I2C_ADDRESS])
+		return -EINVAL;
+
+	request->i2c_address =
nla_get_u32(tb[ETHTOOL_A_EEPROM_DATA_I2C_ADDRESS]);
+	if (request->i2c_address > ETH_MODULE_MAX_I2C_ADDRESS)
+		return -EINVAL;

I would be much more restrictive, with one flexibility...

        if (request->i2c_address == 0xA0) request->i2c_address = 0x50;
        if (request->i2c_address == 0xA2) request->i2c_address = 0x51;
        if (request->i2c_address < 0x50) || (request->i2c_address > 0x51)
                return -EINVAL;

+
+	request->offset =
nla_get_u32(tb[ETHTOOL_A_EEPROM_DATA_OFFSET]);
+	request->length =
nla_get_u32(tb[ETHTOOL_A_EEPROM_DATA_LENGTH]);
+	if (request->length > ETH_MODULE_EEPROM_MAX_LEN)
+		return -EINVAL;

This is really problematic as there are MANY different max values, within
the specs, for the various EEPROMs being generically supported here.
I would leave it to the drivers to handle out-of-range requests.  If you
really want to check, you need to know which spec the module supports,
whether it supports pages, and whether it supports banks.  I have not
found a register that actually reports the number of supported pages
that an eeprom supports.  The specs should have included that :-(.

+	if (tb[ETHTOOL_A_EEPROM_DATA_PAGE] &&
+	    request->offset + request->length >
ETH_MODULE_EEPROM_PAGE_LEN)
+		return -EINVAL;

Why does this stanza depend on DATA_PAGE?  In this new data 
structure, no requests can cross the 256 byte page boundary.

I suggest, rather then -EINVAL, you should reduce the length to reach
the end of the page:

        if (request->offset + request->length) > ETH_MODULE_EEPROM_PAGE_LEN)
                request->length = ETH_MODULE_EEPROM_PAGE_LEN - 
                                                      request->offset.

Note that this matches the choice you made to truncate rather than
error out in fallback_set_parms().

+
+	if (tb[ETHTOOL_A_EEPROM_DATA_PAGE])
+		request->page =
nla_get_u32(tb[ETHTOOL_A_EEPROM_DATA_PAGE]);
+	if (tb[ETHTOOL_A_EEPROM_DATA_BANK])
+		request->bank =
nla_get_u32(tb[ETHTOOL_A_EEPROM_DATA_BANK]);

Other checks:

Page and bank have to be between 0 and 255 (inclusive), they
go into an 8 bit register in the eeprom.

Offset and length can't be negative.

+
+	return 0;
+}
+
+static int eeprom_data_reply_size(const struct ethnl_req_info *req_base,
+				  const struct ethnl_reply_data *reply_base)

+	const struct eeprom_data_req_info *request =
+EEPROM_DATA_REQINFO(req_base);
+
+	return nla_total_size(sizeof(u32)) + /* _EEPROM_DATA_LENGTH */
+	       nla_total_size(sizeof(u32)) + /* _EEPROM_DATA_I2C_ADDRESS
*/
+	       nla_total_size(sizeof(u8) * request->length); /* _EEPROM_DATA
+*/ }
+
+static int eeprom_data_fill_reply(struct sk_buff *skb,
+				  const struct ethnl_req_info *req_base,
+				  const struct ethnl_reply_data *reply_base)

quoted hunk ↗ jump to hunk

+	struct eeprom_data_reply_data *reply =
+EEPROM_DATA_REPDATA(reply_base);
+
+	if (nla_put_u32(skb, ETHTOOL_A_EEPROM_DATA_LENGTH, reply-

quoted

length) ||

+	    nla_put_u32(skb, ETHTOOL_A_EEPROM_DATA_I2C_ADDRESS,
reply->i2c_address) ||
+	    nla_put(skb, ETHTOOL_A_EEPROM_DATA, reply->length, reply-

quoted

data))

+		return -EMSGSIZE;
+
+	return 0;
+}
+
+static void eeprom_data_cleanup_data(struct ethnl_reply_data
+*reply_base) {
+	struct eeprom_data_reply_data *reply =
+EEPROM_DATA_REPDATA(reply_base);
+
+	kfree(reply->data);
+}
+
+const struct ethnl_request_ops ethnl_eeprom_data_request_ops = {
+	.request_cmd		= ETHTOOL_MSG_EEPROM_DATA_GET,
+	.reply_cmd		=
ETHTOOL_MSG_EEPROM_DATA_GET_REPLY,
+	.hdr_attr		= ETHTOOL_A_EEPROM_DATA_HEADER,
+	.req_info_size		= sizeof(struct eeprom_data_req_info),
+	.reply_data_size	= sizeof(struct eeprom_data_reply_data),
+
+	.parse_request		= eeprom_data_parse_request,
+	.prepare_data		= eeprom_data_prepare_data,
+	.reply_size		= eeprom_data_reply_size,
+	.fill_reply		= eeprom_data_fill_reply,
+	.cleanup_data		= eeprom_data_cleanup_data,
+};
+
+const struct nla_policy ethnl_eeprom_data_get_policy[] = {
+	[ETHTOOL_A_EEPROM_DATA_HEADER]		=
NLA_POLICY_NESTED(ethnl_header_policy),
+	[ETHTOOL_A_EEPROM_DATA_OFFSET]		= { .type =
NLA_U32 },
+	[ETHTOOL_A_EEPROM_DATA_LENGTH]		= { .type =
NLA_U32 },
+	[ETHTOOL_A_EEPROM_DATA_PAGE]		= { .type = NLA_U32 },
+	[ETHTOOL_A_EEPROM_DATA_BANK]		= { .type = NLA_U32 },
+	[ETHTOOL_A_EEPROM_DATA_I2C_ADDRESS]	= { .type = NLA_U32 },
+	[ETHTOOL_A_EEPROM_DATA]			= { .type =
NLA_BINARY },
+};
+

diff --git a/net/ethtool/netlink.c b/net/ethtool/netlink.c index

50d3c8896f91..ff2528bee192 100644

--- a/net/ethtool/netlink.c
+++ b/net/ethtool/netlink.c

@@ -245,6 +245,7 @@

ethnl_default_requests[__ETHTOOL_MSG_USER_CNT] = {
 	[ETHTOOL_MSG_PAUSE_GET]		=
&ethnl_pause_request_ops,
 	[ETHTOOL_MSG_EEE_GET]		= &ethnl_eee_request_ops,
 	[ETHTOOL_MSG_TSINFO_GET]	= &ethnl_tsinfo_request_ops,
+	[ETHTOOL_MSG_EEPROM_DATA_GET]	=
&ethnl_eeprom_data_request_ops,
 };

 static struct ethnl_dump_ctx *ethnl_dump_context(struct netlink_callback
*cb) @@ -912,6 +913,15 @@ static const struct genl_ops ethtool_genl_ops[]
= {
 		.policy = ethnl_tunnel_info_get_policy,
 		.maxattr = ARRAY_SIZE(ethnl_tunnel_info_get_policy) - 1,
 	},
+	{
+		.cmd	= ETHTOOL_MSG_EEPROM_DATA_GET,
+		.doit	= ethnl_default_doit,
+		.start	= ethnl_default_start,
+		.dumpit	= ethnl_default_dumpit,
+		.done	= ethnl_default_done,
+		.policy = ethnl_eeprom_data_get_policy,
+		.maxattr = ARRAY_SIZE(ethnl_eeprom_data_get_policy) - 1,
+	},
 };

 static const struct genl_multicast_group ethtool_nl_mcgrps[] = { diff

--git

quoted hunk ↗ jump to hunk

a/net/ethtool/netlink.h b/net/ethtool/netlink.h index
6eabd58d81bf..60954c7b4dfe 100644

--- a/net/ethtool/netlink.h
+++ b/net/ethtool/netlink.h

@@ -344,6 +344,7 @@ extern const struct ethnl_request_ops

ethnl_coalesce_request_ops;  extern const struct ethnl_request_ops
ethnl_pause_request_ops;  extern const struct ethnl_request_ops
ethnl_eee_request_ops;  extern const struct ethnl_request_ops
ethnl_tsinfo_request_ops;
+extern const struct ethnl_request_ops ethnl_eeprom_data_request_ops;

 extern const struct nla_policy
ethnl_header_policy[ETHTOOL_A_HEADER_FLAGS + 1];  extern const struct
nla_policy ethnl_header_policy_stats[ETHTOOL_A_HEADER_FLAGS + 1]; @@
-375,6 +376,7 @@ extern const struct nla_policy
ethnl_tsinfo_get_policy[ETHTOOL_A_TSINFO_HEADER +  extern const struct
nla_policy ethnl_cable_test_act_policy[ETHTOOL_A_CABLE_TEST_HEADER +
1];  extern const struct nla_policy
ethnl_cable_test_tdr_act_policy[ETHTOOL_A_CABLE_TEST_TDR_CFG + 1];
extern const struct nla_policy
ethnl_tunnel_info_get_policy[ETHTOOL_A_TUNNEL_INFO_HEADER + 1];
+extern const struct nla_policy
+ethnl_eeprom_data_get_policy[ETHTOOL_A_EEPROM_DATA + 1];

 int ethnl_set_linkinfo(struct sk_buff *skb, struct genl_info *info);  int
ethnl_set_linkmodes(struct sk_buff *skb, struct genl_info *info);
--
2.18.2

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