mirror of https://gitee.com/openkylin/linux.git
af6b8ee388
The construct "le16_to_cpu((__force __le16)(r >> 16))" has always bothered me when looking through the iwlwifi code, it shouldn't be necessary to __force anything, and before this code, "r" was obtained with an ioread32, which swaps each of the two u16 values in it properly when swapping the entire u32 value. I've had arguments about this code with people before, but always conceded they were right because removing it only made things not work at all on big endian platforms. However, analysing a failure of the OTP reading code, I now finally figured out what is going on, and why my intuition about that code being wrong was right all along. It turns out that the 'priv->eeprom' u8 array really wants to have the data in it in little endian. So the force code above and all really converts *to* little endian, not from it. Cf., for instance, the function iwl_eeprom_query16() -- it reads two u8 values and combines them into a u16, in a little-endian way. And considering it more, it makes sense to have the eeprom array as on the device, after all not all values really are 16-bit values, the MAC address for instance is not. Now, what this really means is that all the annotations are completely wrong. The eeprom reading code should fill the priv->eeprom array as a __le16 array, with __le16 values. This also means that iwl_read_otp_word() should really have a __le16 pointer as the data argument, since it should be filling that in a format suitable for priv->eeprom. Propagating these changes throughout, iwl_find_otp_image() is found to be, now obviously visible, defective -- it uses the data returned by iwl_read_otp_word() directly as if it was CPU endianness. Fixing that, which is this hunk of the patch: - next_link_addr = link_value * sizeof(u16); + next_link_addr = le16_to_cpu(link_value) * sizeof(u16); is the only real change of this patch. Everything else is just fixing the sparse annotations. Also, the bug only shows up on big endian platforms with a 1000 series card. 5000 and previous series do not use OTP, and 6000 series has shadow RAM support which means we don't ever use the defective code on any cards but 1000. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Cc: stable@kernel.org Signed-off-by: Reinette Chatre <reinette.chatre@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com> |
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| .. | ||
| ath | ||
| b43 | ||
| b43legacy | ||
| hostap | ||
| ipw2x00 | ||
| iwlwifi | ||
| iwmc3200wifi | ||
| libertas | ||
| libertas_tf | ||
| orinoco | ||
| p54 | ||
| prism54 | ||
| rt2x00 | ||
| rtl818x | ||
| wl12xx | ||
| zd1211rw | ||
| Kconfig | ||
| Makefile | ||
| adm8211.c | ||
| adm8211.h | ||
| airo.c | ||
| airo.h | ||
| airo_cs.c | ||
| at76c50x-usb.c | ||
| at76c50x-usb.h | ||
| atmel.c | ||
| atmel.h | ||
| atmel_cs.c | ||
| atmel_pci.c | ||
| mac80211_hwsim.c | ||
| mwl8k.c | ||
| ray_cs.c | ||
| ray_cs.h | ||
| rayctl.h | ||
| rndis_wlan.c | ||
| wl3501.h | ||
| wl3501_cs.c | ||
| zd1201.c | ||
| zd1201.h | ||