Provide a macro ASM_EXCEPTIONTABLE_ENTRY() to create exception table
entries and convert all open-coded places to use that macro.
This patch is a first step toward creating a exception table which only
holds 32bit pointers even on a 64bit kernel. That way in my own kernel
I was able to reduce the in-kernel exception table from 44kB to 22kB.
Signed-off-by: Helge Deller <deller@gmx.de>
The get_stack_use_cr30 and get_stack_use_r30 macros allocate a stack
frame for external interrupts and interruptions requiring a stack frame.
They are currently not reentrant in that they save register context
before the stack is set or adjusted.
I have observed a number of system crashes where there was clear
evidence of stack corruption during interrupt processing, and as a
result register corruption. Some interruptions can still occur during
interruption processing, however external interrupts are disabled and
data TLB misses don't occur for absolute accesses. So, it's not entirely
clear what triggers this issue. Also, if an interruption occurs when
Q=0, it is generally not possible to recover as the shadowed registers
are not copied.
The attached patch reworks the get_stack_use_cr30 and get_stack_use_r30
macros to allocate stack before doing register saves. The new code is a
couple of instructions shorter than the old implementation. Thus, it's
an improvement even if it doesn't fully resolve the stack corruption
issue. Based on limited testing, it improves SMP system stability.
Signed-off-by: John David Anglin <dave.anglin@bell.net>
Signed-off-by: Helge Deller <deller@gmx.de>
Add braces around the macro arguments, else for example
"shl %r1, 5-3, %r2" would not expand to what you would assume.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Kyle McMartin <kyle@mcmartin.ca>
