Messages in this thread | | | From | Arnd Bergmann <> | Subject | Re: [PATCH v1 1/4] net: ti: netcp: restore get/set_pad_info() functionality | Date | Fri, 19 Feb 2016 15:41:26 +0100 |
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On Thursday 18 February 2016 14:46:14 Murali Karicheri wrote: > From: Arnd Bergmann <arnd@arndb.de> > > The commit 899077791403 ("netcp: try to reduce type confusion in > descriptors") introduces a regression in Kernel 4.5-rc1 and it breaks > get/set_pad_info() functionality. > > The TI NETCP driver uses pad0 and pad1 fields of knav_dma_desc to > store DMA/MEM buffer pointer and buffer size respectively. And in both > cases for Keystone 2 the pointer type size is 32 bit regardless of > LAPE enabled or not, because CONFIG_ARCH_DMA_ADDR_T_64BIT originally > is not expected to be defined. > > !LAPE LPAE > sizeof(void*) 32bit 32bit > sizeof(dma_addr_t) 32bit 32bit > sizeof(phys_addr_t) 32bit 64bit
As this was never relevant or true, I don't think it needs to be mentioned here, it just confuses things. Please just assume that dma_addr_t can be 64-bit wide, but will only contain 32-bit numbers on keystone.
> Unfortunately, above commit changed buffer's pointers save/restore > code (get/set_pad_info()) and added intermediate conversation to u64 > which works incorrectly on 32bit Keystone 2 and causes TI NETCP driver > crash in RX/TX path due to "Unable to handle kernel NULL pointer" > exception. This issue was reported and discussed in [1].
Have you been able to figure out why it actually broke? I'd still like to know.
> Hence, fix it by partially reverting above commit and restoring > get/set_pad_info() functionality as it was before. > > [1] https://www.mail-archive.com/netdev@vger.kernel.org/msg95361.html > Cc: Wingman Kwok <w-kwok2@ti.com> > Cc: Mugunthan V N <mugunthanvnm@ti.com> > CC: David Laight <David.Laight@ACULAB.COM> > Reported-by: Franklin S Cooper Jr <fcooper@ti.com> > Signed-off-by: Arnd Bergmann <arnd@arndb.de> > Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com> > Signed-off-by: Murali Karicheri <m-karicheri2@ti.com>
I don't think I sent this patch with a 'Signed-off-by', did I? (I could be misremembering that).
Arnd
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