ARM: 8800/1: use choice for kernel unwinders
While in theory multiple unwinders could be compiled in, it does not make sense in practise. Use a choice to make the unwinder selection mutually exclusive and mandatory. Already before this commit it has not been possible to deselect FRAME_POINTER. Remove the obsolete comment. Furthermore, to produce a meaningful backtrace with FRAME_POINTER enabled the kernel needs a specific function prologue: mov ip, sp stmfd sp!, {fp, ip, lr, pc} sub fp, ip, #4 To get to the required prologue gcc uses apcs and no-sched-prolog. This compiler options are not available on clang, and clang is not able to generate the required prologue. Make the FRAME_POINTER config symbol depending on !clang. Suggested-by:Arnd Bergmann <arnd@arndb.de> Signed-off-by:
Stefan Agner <stefan@agner.ch> Reviewed-by:
Arnd Bergmann <arnd@arndb.de> Signed-off-by:
Russell King <rmk+kernel@armlinux.org.uk>
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3f539501