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| author | Jeenu Viswambharan <jeenu.viswambharan@arm.com> | 2016-11-30 15:21:11 +0000 |
|---|---|---|
| committer | Jeenu Viswambharan <jeenu.viswambharan@arm.com> | 2016-12-05 14:55:35 +0000 |
| commit | a806dad58c4cf752238d7bbffbc9a1ce17f63cea (patch) | |
| tree | 9981b72bc40a9169972103ca315549d8a35bb052 /common/aarch64/debug.S | |
| parent | c59428b1502f37c9b2f551613da1b491c4226d10 (diff) | |
| download | platform_external_arm-trusted-firmware-a806dad58c4cf752238d7bbffbc9a1ce17f63cea.tar.gz platform_external_arm-trusted-firmware-a806dad58c4cf752238d7bbffbc9a1ce17f63cea.tar.bz2 platform_external_arm-trusted-firmware-a806dad58c4cf752238d7bbffbc9a1ce17f63cea.zip | |
Define and use no_ret macro where no return is expected
There are many instances in ARM Trusted Firmware where control is
transferred to functions from which return isn't expected. Such jumps
are made using 'bl' instruction to provide the callee with the location
from which it was jumped to. Additionally, debuggers infer the caller by
examining where 'lr' register points to. If a 'bl' of the nature
described above falls at the end of an assembly function, 'lr' will be
left pointing to a location outside of the function range. This misleads
the debugger back trace.
This patch defines a 'no_ret' macro to be used when jumping to functions
from which return isn't expected. The macro ensures to use 'bl'
instruction for the jump, and also, for debug builds, places a 'nop'
instruction immediately thereafter (unless instructed otherwise) so as
to leave 'lr' pointing within the function range.
Change-Id: Ib34c69fc09197cfd57bc06e147cc8252910e01b0
Co-authored-by: Douglas Raillard <douglas.raillard@arm.com>
Signed-off-by: Jeenu Viswambharan <jeenu.viswambharan@arm.com>
Diffstat (limited to 'common/aarch64/debug.S')
| -rw-r--r-- | common/aarch64/debug.S | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/common/aarch64/debug.S b/common/aarch64/debug.S index d3538792d..9dd53ca96 100644 --- a/common/aarch64/debug.S +++ b/common/aarch64/debug.S @@ -191,5 +191,5 @@ _panic_handler: /* Pass to plat_panic_handler the address from where el3_panic was * called, not the address of the call from el3_panic. */ mov x30,x6 - b plat_panic_handler + no_ret plat_panic_handler endfunc do_panic |