arm-trusted-firmware/plat/xilinx/zynqmp/aarch64/zynqmp_helpers.S
Jeenu Viswambharan a806dad58c 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>
2016-12-05 14:55:35 +00:00

73 lines
2.7 KiB
ArmAsm

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#include <asm_macros.S>
#include <gicv2.h>
#include <platform_def.h>
.globl plat_secondary_cold_boot_setup
.globl plat_is_my_cpu_primary
/* -----------------------------------------------------
* void plat_secondary_cold_boot_setup (void);
*
* This function performs any platform specific actions
* needed for a secondary cpu after a cold reset e.g
* mark the cpu's presence, mechanism to place it in a
* holding pen etc.
* TODO: Should we read the PSYS register to make sure
* that the request has gone through.
* -----------------------------------------------------
*/
func plat_secondary_cold_boot_setup
mrs x0, mpidr_el1
/* Deactivate the gic cpu interface */
ldr x1, =BASE_GICC_BASE
mov w0, #(IRQ_BYP_DIS_GRP1 | FIQ_BYP_DIS_GRP1)
orr w0, w0, #(IRQ_BYP_DIS_GRP0 | FIQ_BYP_DIS_GRP0)
str w0, [x1, #GICC_CTLR]
/*
* There is no sane reason to come out of this wfi. This
* cpu will be powered on and reset by the cpu_on pm api
*/
dsb sy
1:
no_ret plat_panic_handler
endfunc plat_secondary_cold_boot_setup
func plat_is_my_cpu_primary
mov x9, x30
bl plat_my_core_pos
cmp x0, #ZYNQMP_PRIMARY_CPU
cset x0, eq
ret x9
endfunc plat_is_my_cpu_primary