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Call reset handlers upon BL3-1 entry.

Browse Source 
This patch adds support to call the reset_handler() function in BL3-1 in the
cold and warm boot paths when another Boot ROM reset_handler() has already run.

This means the BL1 and BL3-1 versions of the CPU and platform specific reset
handlers may execute different code to each other. This enables a developer to
perform additional actions or undo actions already performed during the first
call of the reset handlers e.g. apply additional errata workarounds.

Typically, the reset handler will be first called from the BL1 Boot ROM. Any
additional functionality can be added to the reset handler when it is called
from BL3-1 resident in RW memory. The constant FIRST_RESET_HANDLER_CALL is used
to identify whether this is the first version of the reset handler code to be
executed or an overridden version of the code.

The Cortex-A57 errata workarounds are applied only if they have not already been
applied.

Fixes ARM-software/tf-issue#275

Change-Id: Id295f106e4fda23d6736debdade2ac7f2a9a9053
This commit is contained in:
Yatharth Kochar 2014-11-20 18:09:41 +00:00 committed by Achin Gupta
parent 9d21255797
commit 79a97b2ef7
10 changed files with 141 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
bl31/aarch64/bl31_entrypoint.S
View File

@ -61,15 +61,21 @@ func bl31_entrypoint
bic x0, x0, #SCTLR_EE_BIT
msr sctlr_el3, x0
isb
#endif
/* -----------------------------------------------------
* Perform any processor specific actions upon reset
* e.g. cache, tlb invalidations etc. Override the
* Boot ROM(BL0) programming sequence
* -----------------------------------------------------
/* ---------------------------------------------
* When RESET_TO_BL31 is true, perform any
* processor specific actions upon reset e.g.
* cache, tlb invalidations, errata workarounds
* etc.
* When RESET_TO_BL31 is false, perform any
* processor specific actions which undo or are
* in addition to the actions performed by the
* reset handler in the Boot ROM (BL1).
* ---------------------------------------------
*/
bl reset_handler
#endif
/* ---------------------------------------------
* Enable the instruction cache, stack pointer
* and data access alignment checks

68
docs/firmware-design.md
View File

@ -9,12 +9,13 @@ Contents :
4. [Power State Coordination Interface](#4--power-state-coordination-interface)
5. [Secure-EL1 Payloads and Dispatchers](#5--secure-el1-payloads-and-dispatchers)
6. [Crash Reporting in BL3-1](#6--crash-reporting-in-bl3-1)
7. [CPU specific operations framework](#7--cpu-specific-operations-framework)
8. [Memory layout of BL images](#8-memory-layout-of-bl-images)
9. [Firmware Image Package (FIP)](#9--firmware-image-package-fip)
10. [Use of coherent memory in Trusted Firmware](#10--use-of-coherent-memory-in-trusted-firmware)
11. [Code Structure](#11--code-structure)
12. [References](#12--references)
7. [Guidelines for Reset Handlers](#7--guidelines-for-reset-handlers)
8. [CPU specific operations framework](#8--cpu-specific-operations-framework)
9. [Memory layout of BL images](#9-memory-layout-of-bl-images)
10. [Firmware Image Package (FIP)](#10--firmware-image-package-fip)
11. [Use of coherent memory in Trusted Firmware](#11--use-of-coherent-memory-in-trusted-firmware)
12. [Code Structure](#12--code-structure)
13. [References](#13--references)
1. Introduction
@ -960,8 +961,48 @@ The sample crash output is shown below.
fpexc32_el2 :0x0000000004000700
sp_el0 :0x0000000004010780
7. Guidelines for Reset Handlers
---------------------------------
7. CPU specific operations framework
Trusted Firmware implements a framework that allows CPU and platform ports to
perform actions immediately after a CPU is released from reset in both the cold
and warm boot paths. This is done by calling the `reset_handler()` function in
both the BL1 and BL3-1 images. It in turn calls the platform and CPU specific
reset handling functions.
Details for implementing a CPU specific reset handler can be found in
Section 8. Details for implementing a platform specific reset handler can be
found in the [Porting Guide](see the `plat_reset_handler()` function).
When adding functionality to a reset handler, the following points should be
kept in mind.
1. The first reset handler in the system exists either in a ROM image
(e.g. BL1), or BL3-1 if `RESET_TO_BL31` is true. This may be detected at
compile time using the constant `FIRST_RESET_HANDLER_CALL`.
2. When considering ROM images, it's important to consider non TF-based ROMs
and ROMs based on previous versions of the TF code.
3. If the functionality should be applied to a ROM and there is no possibility
of a ROM being used that does not apply the functionality (or equivalent),
then the functionality should be applied within a `#if
FIRST_RESET_HANDLER_CALL` block.
4. If the functionality should execute in BL3-1 in order to override or
supplement a ROM version of the functionality, then the functionality
should be applied in the `#else` part of a `#if FIRST_RESET_HANDLER_CALL`
block.
5. If the functionality should be applied to a ROM but there is a possibility
of ROMs being used that do not apply the functionality, then the
functionality should be applied outside of a `FIRST_RESET_HANDLER_CALL`
block, so that BL3-1 has an opportunity to apply the functionality instead.
In this case, additional code may be needed to cope with different ROMs
that do or do not apply the functionality.
8. CPU specific operations framework
-----------------------------
Certain aspects of the ARMv8 architecture are implementation defined,
@ -1026,6 +1067,9 @@ in midr are used to find the matching `cpu_ops` entry. The `reset_func()` in
the returned `cpu_ops` is then invoked which executes the required reset
handling for that CPU and also any errata workarounds enabled by the platform.
Refer to Section "Guidelines for Reset Handlers" for general guidelines
regarding placement of code in a reset handler.
### CPU specific power down sequence
During the BL3-1 initialization sequence, the pointer to the matching `cpu_ops`
@ -1056,7 +1100,7 @@ be reported and a pointer to the ASCII list of register names in a format
expected by the crash reporting framework.
8. Memory layout of BL images
9. Memory layout of BL images
-----------------------------
Each bootloader image can be divided in 2 parts:
@ -1378,7 +1422,7 @@ Loading the BL3-2 image in DRAM doesn't change the memory layout of the other
images in Trusted SRAM.
9. Firmware Image Package (FIP)
10. Firmware Image Package (FIP)
---------------------------------
Using a Firmware Image Package (FIP) allows for packing bootloader images (and
@ -1456,7 +1500,7 @@ Currently the FVP's policy only allows loading of a known set of images. The
platform policy can be modified to allow additional images.
10. Use of coherent memory in Trusted Firmware
11. Use of coherent memory in Trusted Firmware
----------------------------------------------
There might be loss of coherency when physical memory with mismatched
@ -1657,7 +1701,7 @@ reserve memory in `cpu_data` by defining the macro `PLAT_PCPU_DATA_SIZE` (see
the [Porting Guide]). Refer to the reference platform code for examples.
11. Code Structure
12. Code Structure
-------------------
Trusted Firmware code is logically divided between the three boot loader
@ -1702,7 +1746,7 @@ FDTs provide a description of the hardware platform and are used by the Linux
kernel at boot time. These can be found in the `fdts` directory.
12. References
13. References
---------------
1. Trusted Board Boot Requirements CLIENT PDD (ARM DEN 0006B-5). Available

5
docs/porting-guide.md
View File

@ -483,7 +483,9 @@ specific errata workarounds could also be implemented here. The api should
preserve the value in x10 register as it is used by the caller to store the
return address.
The default implementation doesn't do anything.
The default implementation doesn't do anything. If a platform needs to override
the default implementation, refer to the [Firmware Design Guide] for general
guidelines regarding placement of code in a reset handler.
### Function : plat_disable_acp()
@ -1476,6 +1478,7 @@ _Copyright (c) 2013-2014, ARM Limited and Contributors. All rights reserved._
[IMF Design Guide]: interrupt-framework-design.md
[User Guide]: user-guide.md
[FreeBSD]: http://www.freebsd.org
[Firmware Design Guide]: firmware-design.md
[plat/common/aarch64/platform_mp_stack.S]: ../plat/common/aarch64/platform_mp_stack.S
[plat/common/aarch64/platform_up_stack.S]: ../plat/common/aarch64/platform_up_stack.S

12
include/common/bl_common.h
View File

@ -90,6 +90,18 @@
(_p)->h.attr = (uint32_t)(_attr) ; \
} while (0)
/*******************************************************************************
* Constant that indicates if this is the first version of the reset handler
* contained in an image. This will be the case when the image is BL1 or when
* its BL3-1 and RESET_TO_BL31 is true. This constant enables a subsequent
* version of the reset handler to perform actions that override the ones
* performed in the first version of the code. This will be required when the
* first version exists in an un-modifiable image e.g. a BootROM image.
******************************************************************************/
#if IMAGE_BL1 || (IMAGE_BL31 && RESET_TO_BL31)
#define FIRST_RESET_HANDLER_CALL
#endif
#ifndef __ASSEMBLY__
#include <cdefs.h> /* For __dead2 */
#include <cassert.h>

4
include/lib/cpus/aarch64/cpu_macros.S
View File

@ -40,7 +40,7 @@
CPU_MIDR: /* cpu_ops midr */
.space 8
/* Reset fn is needed in BL at reset vector */
#if IMAGE_BL1 || (IMAGE_BL31 && RESET_TO_BL31)
#if IMAGE_BL1 || IMAGE_BL31
CPU_RESET_FUNC: /* cpu_ops reset_func */
.space 8
#endif
@ -65,7 +65,7 @@ CPU_OPS_SIZE = .
.section cpu_ops, "a"; .align 3
.type cpu_ops_\_name, %object
.quad \_midr
#if IMAGE_BL1 || (IMAGE_BL31 && RESET_TO_BL31)
#if IMAGE_BL1 || IMAGE_BL31
.if \_noresetfunc
.quad 0
.else

7
lib/cpus/aarch64/cortex_a53.S
View File

@ -29,6 +29,7 @@
*/
#include <arch.h>
#include <asm_macros.S>
#include <bl_common.h>
#include <cortex_a53.h>
#include <cpu_macros.S>
#include <plat_macros.S>
@ -58,13 +59,17 @@ func cortex_a53_disable_smp
func cortex_a53_reset_func
/* ---------------------------------------------
* As a bare minimum enable the SMP bit.
* As a bare minimum enable the SMP bit if it is
* not already set.
* ---------------------------------------------
*/
mrs x0, CPUECTLR_EL1
tst x0, #CPUECTLR_SMP_BIT
b.ne skip_smp_setup
orr x0, x0, #CPUECTLR_SMP_BIT
msr CPUECTLR_EL1, x0
isb
skip_smp_setup:
ret
func cortex_a53_core_pwr_dwn

24
lib/cpus/aarch64/cortex_a57.S
View File

@ -30,6 +30,7 @@
#include <arch.h>
#include <asm_macros.S>
#include <assert_macros.S>
#include <bl_common.h>
#include <cortex_a57.h>
#include <cpu_macros.S>
#include <plat_macros.S>
@ -99,9 +100,17 @@ func errata_a57_806969_wa
ret
#endif
apply_806969:
/*
* Test if errata has already been applied in an earlier
* invocation of the reset handler and does not need to
* be applied again.
*/
mrs x1, CPUACTLR_EL1
tst x1, #CPUACTLR_NO_ALLOC_WBWA
b.ne skip_806969
orr x1, x1, #CPUACTLR_NO_ALLOC_WBWA
msr CPUACTLR_EL1, x1
skip_806969:
ret
@ -123,9 +132,17 @@ func errata_a57_813420_wa
ret
#endif
apply_813420:
/*
* Test if errata has already been applied in an earlier
* invocation of the reset handler and does not need to
* be applied again.
*/
mrs x1, CPUACTLR_EL1
tst x1, #CPUACTLR_DCC_AS_DCCI
b.ne skip_813420
orr x1, x1, #CPUACTLR_DCC_AS_DCCI
msr CPUACTLR_EL1, x1
skip_813420:
ret
/* -------------------------------------------------
@ -154,13 +171,18 @@ func cortex_a57_reset_func
mov x0, x20
bl errata_a57_813420_wa
#endif
/* ---------------------------------------------
* As a bare minimum enable the SMP bit.
* As a bare minimum enable the SMP bit if it is
* not already set.
* ---------------------------------------------
*/
mrs x0, CPUECTLR_EL1
tst x0, #CPUECTLR_SMP_BIT
b.ne skip_smp_setup
orr x0, x0, #CPUECTLR_SMP_BIT
msr CPUECTLR_EL1, x0
skip_smp_setup:
isb
ret x19

4
lib/cpus/aarch64/cpu_helpers.S
View File

@ -37,7 +37,7 @@
#endif
/* Reset fn is needed in BL at reset vector */
#if IMAGE_BL1 || (IMAGE_BL31 && RESET_TO_BL31)
#if IMAGE_BL1 || IMAGE_BL31
/*
* The reset handler common to all platforms. After a matching
* cpu_ops structure entry is found, the correponding reset_handler
@ -64,7 +64,7 @@ func reset_handler
1:
ret
#endif /* IMAGE_BL1 || (IMAGE_BL31 && RESET_TO_BL31) */
#endif /* IMAGE_BL1 || IMAGE_BL31 */
#if IMAGE_BL31 /* The power down core and cluster is needed only in BL31 */
/*

17
plat/juno/aarch64/plat_helpers.S
View File

@ -115,12 +115,20 @@ func platform_mem_init
/* -----------------------------------------------------
* void plat_reset_handler(void);
*
* Before adding code in this function, refer to the
* guidelines in docs/firmware-design.md to determine
* whether the code should reside within the
* FIRST_RESET_HANDLER_CALL block or not.
*
* Implement workaround for defect id 831273 by enabling
* an event stream every 65536 cycles and set the L2 RAM
* latencies for Cortex-A57.
* latencies for Cortex-A57. This code is included only
* when FIRST_RESET_HANDLER_CALL is defined since it
* should be executed only during BL1.
* -----------------------------------------------------
*/
func plat_reset_handler
#ifdef FIRST_RESET_HANDLER_CALL
/* Read the MIDR_EL1 */
mrs x0, midr_el1
ubfx x1, x0, MIDR_PN_SHIFT, #12
@ -135,11 +143,12 @@ func plat_reset_handler
1:
/* ---------------------------------------------
* Enable the event stream every 65536 cycles
* ---------------------------------------------
*/
* Enable the event stream every 65536 cycles
* ---------------------------------------------
*/
mov x0, #(0xf << EVNTI_SHIFT)
orr x0, x0, #EVNTEN_BIT
msr CNTKCTL_EL1, x0
isb
#endif /* FIRST_RESET_HANDLER_CALL */
ret

13
services/std_svc/psci/psci_entry.S
View File

@ -53,10 +53,19 @@ psci_aff_suspend_finish_entry:
psci_aff_common_finish_entry:
#if !RESET_TO_BL31
/* ---------------------------------------------
* Perform any processor specific actions which
* undo or are in addition to the actions
* performed by the reset handler in the BootROM
* (BL1) e.g. cache, tlb invalidations, errata
* workarounds etc.
* ---------------------------------------------
*/
bl reset_handler
/* ---------------------------------------------
* Enable the instruction cache, stack pointer
* and data access alignment checks. Also, set
* the EL3 exception endianess to little-endian.
* and data access alignment checks.
* It can be assumed that BL3-1 entrypoint code
* will do this when RESET_TO_BL31 is set. The
* same assumption cannot be made when another