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a806dad58c
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>
180 lines
6 KiB
ArmAsm
180 lines
6 KiB
ArmAsm
/*
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* Copyright (c) 2016, ARM Limited and Contributors. All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* Redistributions of source code must retain the above copyright notice, this
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* list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright notice,
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* this list of conditions and the following disclaimer in the documentation
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* and/or other materials provided with the distribution.
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*
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* Neither the name of ARM nor the names of its contributors may be used
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* to endorse or promote products derived from this software without specific
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* prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <asm_macros.S>
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#include <platform_def.h>
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#include <psci.h>
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.globl psci_do_pwrdown_cache_maintenance
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.globl psci_do_pwrup_cache_maintenance
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.globl psci_power_down_wfi
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/* -----------------------------------------------------------------------
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* void psci_do_pwrdown_cache_maintenance(unsigned int power level);
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*
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* This function performs cache maintenance for the specified power
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* level. The levels of cache affected are determined by the power
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* level which is passed as the argument i.e. level 0 results
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* in a flush of the L1 cache. Both the L1 and L2 caches are flushed
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* for a higher power level.
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*
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* Additionally, this function also ensures that stack memory is correctly
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* flushed out to avoid coherency issues due to a change in its memory
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* attributes after the data cache is disabled.
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* -----------------------------------------------------------------------
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*/
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func psci_do_pwrdown_cache_maintenance
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push {r4, lr}
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/* ----------------------------------------------
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* Turn OFF cache and do stack maintenance
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* prior to cpu operations . This sequence is
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* different from AArch64 because in AArch32 the
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* assembler routines for cpu operations utilize
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* the stack whereas in AArch64 it doesn't.
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* ----------------------------------------------
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*/
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mov r4, r0
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bl do_stack_maintenance
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/* ---------------------------------------------
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* Determine how many levels of cache will be
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* subject to cache maintenance. Power level
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* 0 implies that only the cpu is being powered
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* down. Only the L1 data cache needs to be
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* flushed to the PoU in this case. For a higher
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* power level we are assuming that a flush
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* of L1 data and L2 unified cache is enough.
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* This information should be provided by the
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* platform.
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* ---------------------------------------------
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*/
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cmp r4, #PSCI_CPU_PWR_LVL
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pop {r4,lr}
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beq prepare_core_pwr_dwn
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b prepare_cluster_pwr_dwn
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endfunc psci_do_pwrdown_cache_maintenance
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/* -----------------------------------------------------------------------
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* void psci_do_pwrup_cache_maintenance(void);
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*
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* This function performs cache maintenance after this cpu is powered up.
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* Currently, this involves managing the used stack memory before turning
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* on the data cache.
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* -----------------------------------------------------------------------
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*/
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func psci_do_pwrup_cache_maintenance
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push {lr}
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/* ---------------------------------------------
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* Ensure any inflight stack writes have made it
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* to main memory.
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* ---------------------------------------------
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*/
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dmb st
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/* ---------------------------------------------
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* Calculate and store the size of the used
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* stack memory in r1. Calculate and store the
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* stack base address in r0.
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* ---------------------------------------------
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*/
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bl plat_get_my_stack
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mov r1, sp
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sub r1, r0, r1
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mov r0, sp
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bl inv_dcache_range
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/* ---------------------------------------------
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* Enable the data cache.
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* ---------------------------------------------
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*/
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ldcopr r0, SCTLR
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orr r0, r0, #SCTLR_C_BIT
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stcopr r0, SCTLR
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isb
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pop {pc}
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endfunc psci_do_pwrup_cache_maintenance
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/* ---------------------------------------------
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* void do_stack_maintenance(void)
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* Do stack maintenance by flushing the used
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* stack to the main memory and invalidating the
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* remainder.
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* ---------------------------------------------
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*/
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func do_stack_maintenance
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push {r4, lr}
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bl plat_get_my_stack
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/* Turn off the D-cache */
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ldcopr r1, SCTLR
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bic r1, #SCTLR_C_BIT
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stcopr r1, SCTLR
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isb
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/* ---------------------------------------------
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* Calculate and store the size of the used
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* stack memory in r1.
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* ---------------------------------------------
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*/
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mov r4, r0
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mov r1, sp
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sub r1, r0, r1
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mov r0, sp
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bl flush_dcache_range
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/* ---------------------------------------------
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* Calculate and store the size of the unused
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* stack memory in r1. Calculate and store the
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* stack base address in r0.
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* ---------------------------------------------
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*/
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sub r0, r4, #PLATFORM_STACK_SIZE
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sub r1, sp, r0
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bl inv_dcache_range
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pop {r4, pc}
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endfunc do_stack_maintenance
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/* -----------------------------------------------------------------------
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* This function is called to indicate to the power controller that it
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* is safe to power down this cpu. It should not exit the wfi and will
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* be released from reset upon power up.
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* -----------------------------------------------------------------------
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*/
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func psci_power_down_wfi
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dsb sy // ensure write buffer empty
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wfi
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no_ret plat_panic_handler
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endfunc psci_power_down_wfi
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