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>
diff --git a/bl31/aarch64/runtime_exceptions.S b/bl31/aarch64/runtime_exceptions.S
index 220d1cc..6909d08 100644
--- a/bl31/aarch64/runtime_exceptions.S
+++ b/bl31/aarch64/runtime_exceptions.S
@@ -73,7 +73,7 @@
b.eq smc_handler64
/* Other kinds of synchronous exceptions are not handled */
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
.endm
@@ -176,7 +176,7 @@
*/
vector_entry sync_exception_sp_el0
/* We don't expect any synchronous exceptions from EL3 */
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
check_vector_size sync_exception_sp_el0
vector_entry irq_sp_el0
@@ -184,17 +184,17 @@
* EL3 code is non-reentrant. Any asynchronous exception is a serious
* error. Loop infinitely.
*/
- bl report_unhandled_interrupt
+ no_ret report_unhandled_interrupt
check_vector_size irq_sp_el0
vector_entry fiq_sp_el0
- bl report_unhandled_interrupt
+ no_ret report_unhandled_interrupt
check_vector_size fiq_sp_el0
vector_entry serror_sp_el0
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
check_vector_size serror_sp_el0
/* ---------------------------------------------------------------------
@@ -208,19 +208,19 @@
* synchronous exception. There is a high probability that SP_EL3 is
* corrupted.
*/
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
check_vector_size sync_exception_sp_elx
vector_entry irq_sp_elx
- bl report_unhandled_interrupt
+ no_ret report_unhandled_interrupt
check_vector_size irq_sp_elx
vector_entry fiq_sp_elx
- bl report_unhandled_interrupt
+ no_ret report_unhandled_interrupt
check_vector_size fiq_sp_elx
vector_entry serror_sp_elx
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
check_vector_size serror_sp_elx
/* ---------------------------------------------------------------------
@@ -250,7 +250,7 @@
* SError exceptions from lower ELs are not currently supported.
* Report their occurrence.
*/
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
check_vector_size serror_aarch64
/* ---------------------------------------------------------------------
@@ -280,7 +280,7 @@
* SError exceptions from lower ELs are not currently supported.
* Report their occurrence.
*/
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
check_vector_size serror_aarch32
@@ -415,5 +415,5 @@
rt_svc_fw_critical_error:
/* Switch to SP_ELx */
msr spsel, #1
- bl report_unhandled_exception
+ no_ret report_unhandled_exception
endfunc smc_handler