Hi,
For reference, the following questions refer to a Linux 3.10 aarch64 kernel
(ARMv8, ARMv8-A) compiled with Linaro 5.3-2016.02 (5.3-2016.02 arm64
CROSS_COMPILE and 5.3-2016.02 armhf CROSS32CC cross compiled from x86_64). This
Linux kernel compile requires the full 64-bit tool chain plus the 32-bit gcc.
There is a Linux kernel file "arch/arm64/kernel/deprecated.c". Within that file
is a block of code which is apparently designed to detect some sort of older
obsolete 32-bit code. Specifically, the warning message is "Using deprecated
CP15 barrier instruction". I wouldn't think that this kernel, when compiled
with such a recent compiler, would ever introduce CP15 barrier code (from what
I see barrier code was deprecated in ARMv7 and used to deal with obsolete ARMv6
code). Is there any chance the 32-bit 5.3 gcc would still generate CP15 barrier
code?
Although this kernel and "most" modules are built with Linaro 5.3 I'd like to
be able to narrow the cause down to existing binary modules not compiled with
the 5.3 Linaro. If I can guarantee 5.3 32-bit gcc does not produce the CP15
barrier instruction then I'll know it is in pre-built binary modules. Can
anyone tell me if C code compiled from Linaro version 5.3 32-bit gcc code would
ever contain CP15 instructions?
Thanks!
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