* Patched longjmp to be context-switch safe
longjmp modifies the windowbase and windowstart
registers, which isn't safe if a context switch
occurs during the modification. After a context
switch, windowstart and windowbase will be
different, leading to a wrongly set windowstart
bit due to longjmp writing it based on the
windowbase before the context switch. This
corrupts the registers at the next window
overflow reaching that wrongly set bit.
The solution is to disable interrupts during
this code. It is only 6 instructions long,
the impact shouldn't be significant.
The fix is implemented as a wrapper which
replaces the original first instructions of
longjmp which are buggy. Then, it jumps back
to execute the rest of the original longjmp
function.
Added a comparably reliable test to the
test apps.
The previous location was the return from the first ets_printf call
that prints ROM sign-on message. Since the main function was patched
in ECO3, the new address no longer works — there is no instruction at
0x40007901 in ECO3 ROM. This could be solved by setting two
breakpoints (one would work for ECO <=2, the other for ECO3), but we
would need to remove the unused breakpoint later.
Fix this by setting the breakpoint at ets_printf. This means that when
debugging a loadable ELF the ROM sign-on message will no longer be
shown, but this doesn't seem to be an issue.
InstrFetchProhibited usually occurs because of a jump to an invalid
pointer. In this case, PC in the exception frame is the address of
the jump destination. 'esp_ptr_executable' check in print_backtrace
function recognizes the first frame as invalid, and the backtrace is
interrupted. This prevents the user from finding the location where
the invalid pointer is dereferenced.
Bypass the 'esp_ptr_executable' check if the exception cause is
InstrFetchProhibited. Update the test case to no longer ignore this
issue.
