qed: Don't collect too many protection override GRC elements

qed: Don't collect too many protection override GRC elements

[ Upstream commit 56c0a2a9ddc2f5b5078c5fb0f81ab76bbc3d4c37 ]

In the protection override dump path, the firmware can return far too
many GRC elements, resulting in attempting to write past the end of the
previously-kmalloc'ed dump buffer.

This will result in a kernel panic with reason:

 BUG: unable to handle kernel paging request at ADDRESS

where "ADDRESS" is just past the end of the protection override dump
buffer. The start address of the buffer is:
 p_hwfn->cdev->dbg_features[DBG_FEATURE_PROTECTION_OVERRIDE].dump_buf
and the size of the buffer is buf_size in the same data structure.

The panic can be arrived at from either the qede Ethernet driver path:

    [exception RIP: qed_grc_dump_addr_range+0x108]
 qed_protection_override_dump at ffffffffc02662ed [qed]
 qed_dbg_protection_override_dump at ffffffffc0267792 [qed]
 qed_dbg_feature at ffffffffc026aa8f [qed]
 qed_dbg_all_data at ffffffffc026b211 [qed]
 qed_fw_fatal_reporter_dump at ffffffffc027298a [qed]
 devlink_health_do_dump at ffffffff82497f61
 devlink_health_report at ffffffff8249cf29
 qed_report_fatal_error at ffffffffc0272baf [qed]
 qede_sp_task at ffffffffc045ed32 [qede]
 process_one_work at ffffffff81d19783

or the qedf storage driver path:

    [exception RIP: qed_grc_dump_addr_range+0x108]
 qed_protection_override_dump at ffffffffc068b2ed [qed]
 qed_dbg_protection_override_dump at ffffffffc068c792 [qed]
 qed_dbg_feature at ffffffffc068fa8f [qed]
 qed_dbg_all_data at ffffffffc0690211 [qed]
 qed_fw_fatal_reporter_dump at ffffffffc069798a [qed]
 devlink_health_do_dump at ffffffff8aa95e51
 devlink_health_report at ffffffff8aa9ae19
 qed_report_fatal_error at ffffffffc0697baf [qed]
 qed_hw_err_notify at ffffffffc06d32d7 [qed]
 qed_spq_post at ffffffffc06b1011 [qed]
 qed_fcoe_destroy_conn at ffffffffc06b2e91 [qed]
 qedf_cleanup_fcport at ffffffffc05e7597 [qedf]
 qedf_rport_event_handler at ffffffffc05e7bf7 [qedf]
 fc_rport_work at ffffffffc02da715 [libfc]
 process_one_work at ffffffff8a319663

Resolve this by clamping the firmware's return value to the maximum
number of legal elements the firmware should return.

Fixes: d52c89f120de8 ("qed*: Utilize FW 8.37.2.0")
Signed-off-by: Jamie Bainbridge <jamie.bainbridge@gmail.com>
Link: https://patch.msgid.link/f8e1182934aa274c18d0682a12dbaf347595469c.1757485536.git.jamie.bainbridge@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>