arm32: libutils, libutee, ta: add .note.GNU-stack section to .S files

When building for arm32 with GNU binutils 2.39, the linker outputs
warnings when linking Trusted Applications:

arm-unknown-lin

arm32: libutils, libutee, ta: add .note.GNU-stack section to .S files

When building for arm32 with GNU binutils 2.39, the linker outputs
warnings when linking Trusted Applications:

arm-unknown-linux-uclibcgnueabihf-ld.bfd: warning: utee_syscalls_a32.o: missing .note.GNU-stack section implies executable stack
arm-unknown-linux-uclibcgnueabihf-ld.bfd: NOTE: This behaviour is deprecated and will be removed in a future version of the linker

We could silence the warning by adding the '--no-warn-execstack' option
to the TA link flags, like we did in the parent commit for the TEE core
and ldelf. Indeed, ldelf always allocates a non-executable piece of
memory for the TA to use as a stack.

However it seems preferable to comply with the common ELF practices in
this case. A better fix is therefore to add the missing .note.GNU-stack
sections in the assembler files.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>

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arm32: fold UNWIND(.fnstart/.fnend) into the FUNC macros

This change applies to arm32 assembler sources.

Instead of using UNWIND(.fnstart) after FUNC or LOCAL_FUNC and
UNWIND(.fnend) before END_FUN

arm32: fold UNWIND(.fnstart/.fnend) into the FUNC macros

This change applies to arm32 assembler sources.

Instead of using UNWIND(.fnstart) after FUNC or LOCAL_FUNC and
UNWIND(.fnend) before END_FUNC, let's fold these statements into the
FUNC macros.

The .fnstart/.fnend directives mark the start and end of a function
with an unwind table entry (.ARM.exidx) and therefore a function
without them has no entry and cannot be unwound. This means that a
stack dump (on abort or panic) would stop when reaching such a
function.

As a result of this patch, a small number of functions now have an
entry in the unwind table when they had none before (the functions
which were using FUNC or LOCAL_FUNC but had no .fnstart/.fnend). It was
almost always a bug and this pacth only increases the size of the
.ARM.exidx section by a few bytes (tested on QEMU).

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

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arm32: move the UNWIND() macro to <asm.S>

All the users of the UNWIND() macro include <asm.S> already, which is
therefore a good place to define this macro. Let's move it from
<kernel/unwind.h> to <

arm32: move the UNWIND() macro to <asm.S>

All the users of the UNWIND() macro include <asm.S> already, which is
therefore a good place to define this macro. Let's move it from
<kernel/unwind.h> to <asm.S>, remove a couple of duplicates in
assembler files, and drop the useless includes.

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>
Reviewed-by: Etienne Carriere <etienne.carriere@linaro.org>

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symbolize.py: infer PC from (E)LR

When translating a call stack address to source file and line number,
subtract 2 to try and reflect the PC at the time the call was made or
the exception occurred.

symbolize.py: infer PC from (E)LR

When translating a call stack address to source file and line number,
subtract 2 to try and reflect the PC at the time the call was made or
the exception occurred. This makes the calls easier to follow and
corresponds to what the GDB backtrace command (bt) does. For data or
prefetch aborts it is even more important because now we report exactly
the line that caused the abort instead of showing the next one, which
could be misleading.

As a result of this fix, the extra "nop" instruction in __ta_entry() is
not needed anymore so remove it.

Signed-off-by: Jerome Forissier <jerome@forissier.org>
Reviewed-by: Jens Wiklander <jens.wiklander@linaro.org>

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arm32: make __ta_entry() an assembler wrapper

Clang errors out when asm(".cantunwind") is used in a C function:

user_ta_header.c:44:6: error: .fnstart must precede .cantunwind directive

arm32: make __ta_entry() an assembler wrapper

Clang errors out when asm(".cantunwind") is used in a C function:

user_ta_header.c:44:6: error: .fnstart must precede .cantunwind directive
asm(".cantunwind");
^
Fix this by turning __ta_entry() into an assembler wrapper.

Signed-off-by: Jerome Forissier <jerome.forissier@linaro.org>
Acked-by: Jens Wiklander <jens.wiklander@linaro.org>

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