From: Pavel Skripkin <paskripkin@gmail.com>
To: Michael Straube <straube.linux@gmail.com>,
Larry Finger <Larry.Finger@lwfinger.net>
Cc: Phillip Potter <phil@philpotter.co.uk>,
Greg KH <gregkh@linuxfoundation.org>,
"open list:STAGING SUBSYSTEM" <linux-staging@lists.linux.dev>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: staging: r8188eu: struct rt_firmware_header issues
Date: Wed, 13 Apr 2022 23:58:51 +0300 [thread overview]
Message-ID: <f819690c-b53e-4693-5de1-cc4cfa1db0da@gmail.com> (raw)
In-Reply-To: <94a72ecc-3acd-758b-15a4-a7d56bf03fbe@gmail.com>
Hi Michael,
On 4/13/22 19:27, Michael Straube wrote:
> Hi all,
>
> I think the rt_firmware_hdr structure in rtw_fw.c has some issues.
>
>
> struct rt_firmware_hdr {
> /* 8-byte alinment required */
> /* LONG WORD 0 ---- */
> __le16 Signature; /* 92C0: test chip; 92C,
> * 88C0: test chip; 88C1: MP A-cut;
> * 92C1: MP A-cut */
> u8 Category; /* AP/NIC and USB/PCI */
> u8 Function; /* Reserved for different FW function
> * indcation, for further use when
> * driver needs to download different
> * FW for different conditions */
> __le16 Version; /* FW Version */
> u8 Subversion; /* FW Subversion, default 0x00 */
> u16 Rsvd1;
>
> /* LONG WORD 1 ---- */
> u8 Month; /* Release time Month field */
> u8 Date; /* Release time Date field */
> u8 Hour; /* Release time Hour field */
> u8 Minute; /* Release time Minute field */
> __le16 RamCodeSize; /* The size of RAM code */
> u8 Foundry;
> u8 Rsvd2;
>
> /* LONG WORD 2 ---- */
> __le32 SvnIdx; /* The SVN entry index */
> u32 Rsvd3;
>
> /* LONG WORD 3 ---- */
> u32 Rsvd4;
> u32 Rsvd5;
> };
>
>
> Then we have in rtl8188e_firmware_download():
>
>
> fwhdr = (struct rt_firmware_hdr *)dvobj->firmware.data;
>
> <snip>
>
> if (IS_FW_HEADER_EXIST(fwhdr)) {
> /* Shift 32 bytes for FW header */
> fw_data = fw_data + 32;
> fw_size = fw_size - 32;
> }
>
> We add/sub 32 bytes but the size of struct rt_firmware_hdr is actually
> 33 bytes. I noticed this when I wanted to replace:
>
Looks like size of that structure is 36
└──$ pahole -C rt_firmware_hdr r8188eu.ko
struct rt_firmware_hdr {
__le16 Signature; /* 0 2 */
u8 Category; /* 2 1 */
u8 Function; /* 3 1 */
__le16 Version; /* 4 2 */
u8 Subversion; /* 6 1 */
/* XXX 1 byte hole, try to pack */
u16 Rsvd1; /* 8 2 */
u8 Month; /* 10 1 */
u8 Date; /* 11 1 */
u8 Hour; /* 12 1 */
u8 Minute; /* 13 1 */
__le16 RamCodeSize; /* 14 2 */
u8 Foundry; /* 16 1 */
u8 Rsvd2; /* 17 1 */
/* XXX 2 bytes hole, try to pack */
__le32 SvnIdx; /* 20 4 */
u32 Rsvd3; /* 24 4 */
u32 Rsvd4; /* 28 4 */
u32 Rsvd5; /* 32 4 */
/* size: 36, cachelines: 1, members: 17 */
/* sum members: 33, holes: 2, sum holes: 3 */
/* last cacheline: 36 bytes */
};
And these comments like 'LONG WORD 1' looks misleading, maybe worth
removing.
> fw_data = fw_data + 32;
> fw_size = fw_size - 32;
>
> with:
> fw_data = fw_data + sizeof(struct rt_firmware_hdr);
> fw_size = fw_size - sizeof(struct rt_firmware_hdr);;
>
> To me it looks add/sub 32 is correct here but the struct is
> wrong. I don't know if the firmware for this driver is so much different
> from firmware for the drivers in drivers/net/wireless/realtek/rtlwifi.
> They use a struct of size 32.
>
I am not sure about 32... Why non-packed structures are passed via
wires? Maybe `__packed` is missing? Is realtek fw open-source?
Just thoughts.
> Also, souldn't the u16 and u32 variables in the struct be __le16 and
> __le32 ?
>
> I wonder if we can just use the rtlwifi_firmware_header structure from
> drivers/net/wireless/realtek/rtlwifi/wifi.h ?
>
We _should_ use it, since its size is indeed 32 bytes.
└──$ pahole -s vmlinux | rg rtlwifi_firmware_header
rtlwifi_firmware_header 32 0
Looks like you have found a real bug
With regards,
Pavel Skripkin
next prev parent reply other threads:[~2022-04-13 20:59 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-04-13 16:27 staging: r8188eu: struct rt_firmware_header issues Michael Straube
2022-04-13 19:42 ` Michael Straube
2022-04-13 21:12 ` Larry Finger
2022-04-14 8:41 ` David Laight
2022-04-14 10:08 ` Michael Straube
2022-04-14 10:14 ` David Laight
2022-04-14 15:46 ` Larry Finger
2022-04-13 20:58 ` Pavel Skripkin [this message]
2022-04-13 21:26 ` Michael Straube
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