Anomaly 05000312 - Errors When SSYNC, CSYNC, or Loads to LT, LB and LC Registers Are Interrupted:
DESCRIPTION:
When instruction cache is enabled, erroneous behavior may occur when any of the following instructions are interrupted:
. CSYNC
• SSYNC
• LCx =
• LTx = (only when LCx is non-zero)
• LBx = (only when LCx is non-zero)
When this problem occurs, a variety of incorrect things could happen, including an illegal instruction exception. Additional errors could
show up as an exception, a hardware error, or an instruction that is valid but different than the one that was expected.
WORKAROUND:
Place a cli before all SSYNC, CSYNC, "LCx =", "LTx =", and "LBx =" instructions to disable interrupts, and place an sti after each of these
instructions to re-enable interrupts. When these instructions are executed in code that is already non-interruptible, the problem will not
occur.
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
/*
* CPUs often take a performance hit when accessing unaligned memory
* locations. The actual performance hit varies, it can be small if the
* hardware handles it or large if we have to take an exception and fix
* it
* in software.
*
* Since an ethernet header is 14 bytes network drivers often end up
* with
* the IP header at an unaligned offset. The IP header can be aligned by
* shifting the start of the packet by 2 bytes. Drivers should do this
* with:
*
* skb_reserve(NET_IP_ALIGN);
*
* The downside to this alignment of the IP header is that the DMA is
* now
* unaligned. On some architectures the cost of an unaligned DMA is high
* and this cost outweighs the gains made by aligning the IP header.
*
* Since this trade off varies between architectures, we allow
* NET_IP_ALIGN
* to be overridden.
*/
This new function insl_16 allows to read form 32-bit IO and writes to
16-bit aligned memory. This is useful in above described scenario -
In particular with the AXIS AX88180 Gigabit Ethernet MAC.
Once the device is in 32-bit mode, reads from the RX FIFO always
decrements 4bytes.
While on the other side the destination address in SDRAM is always
16-bit aligned.
If we use skb_reserve(0) the receive buffer is 32-bit aligned but later
we hit a unaligned exception in the IP code.
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
The only user is the a.out support.
It was therefore removed prior to the blackfin merge from all
architectures not supporting a.out.
Currently, Blackfin doesn't suppport a.out.
Signed-off-by: Adrian Bunk <bunk@kernel.org>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
VDSP has double fault on core a/b inverted for BF561 -- bit 11 is core a while bit 12 is core b
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
since we have this always turned on now and dont want it off (and hasnt been an option in a while)
Signed-off-by: Mike Frysinger <michael.frysinger@analog.com>
Signed-off-by: Bryan Wu <bryan.wu@analog.com>
Change the page member of the scatterlist structure to be an unsigned
long, and encode more stuff in the lower bits:
- Bits 0 and 1 zero: this is a normal sg entry. Next sg entry is located
at sg + 1.
- Bit 0 set: this is a chain entry, the next real entry is at ->page_link
with the two low bits masked off.
- Bit 1 set: this is the final entry in the sg entry. sg_next() will return
NULL when passed such an entry.
It's thus important that sg table users use the proper accessors to get
and set the page member.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
