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Enable preloaded BL33 alternative boot flow 

Enable alternative boot flow where BL2 does not load BL33 from
non-volatile storage, and BL31 hands execution over to a preloaded
BL33.

The flag used to enable this bootflow is BL33_BASE, which must hold
the entrypoint address of the BL33 image. The User Guide has been
updated with an example of how to use this option with a bootwrapped
kernel.

Change-Id: I48087421a7b0636ac40dca7d457d745129da474f
This commit is contained in:
Antonio Nino Diaz 2016-02-15 14:53:10 +00:00
parent 85320724af
commit cf2c8a33e0
4 changed files with 141 additions and 30 deletions
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52
Makefile
View File

@ -300,6 +300,29 @@ endif
include lib/cpus/cpu-ops.mk
################################################################################
# Check incompatible options
################################################################################
ifdef EL3_PAYLOAD_BASE
ifdef BL33_BASE
$(warning "BL33_BASE and EL3_PAYLOAD_BASE are incompatible \
build options. EL3_PAYLOAD_BASE has priority.")
endif
endif
ifeq (${NEED_BL33},yes)
ifdef EL3_PAYLOAD_BASE
$(warning "BL33 image is not needed when option \
BL33_PAYLOAD_BASE is used and won't be added to the FIP file.")
endif
ifdef BL33_BASE
$(warning "BL33 image is not needed when option BL33_BASE is \
used and won't be added to the FIP file.")
endif
endif
################################################################################
# Process platform overrideable behaviour
################################################################################
@ -313,12 +336,19 @@ endif
# supplied for the FIP and Certificate generation tools. This flag can be
# overridden by the platform.
ifdef BL2_SOURCES
ifndef EL3_PAYLOAD_BASE
NEED_BL33 ?= yes
else
# The BL33 image is not needed when booting an EL3 payload.
NEED_BL33 := no
endif
ifdef EL3_PAYLOAD_BASE
# If booting an EL3 payload there is no need for a BL33 image
# in the FIP file.
NEED_BL33 := no
else
ifdef BL33_BASE
# If booting a BL33 preloaded image there is no need of
# another one in the FIP file.
NEED_BL33 := no
else
NEED_BL33 ?= yes
endif
endif
endif
# Process TBB related flags
@ -398,11 +428,17 @@ $(eval $(call add_define,PSCI_EXTENDED_STATE_ID))
$(eval $(call add_define,ERROR_DEPRECATED))
$(eval $(call add_define,ENABLE_PLAT_COMPAT))
$(eval $(call add_define,SPIN_ON_BL1_EXIT))
$(eval $(call add_define,PL011_GENERIC_UART))
# Define the EL3_PAYLOAD_BASE flag only if it is provided.
ifdef EL3_PAYLOAD_BASE
$(eval $(call add_define,EL3_PAYLOAD_BASE))
$(eval $(call add_define,EL3_PAYLOAD_BASE))
else
# Define the BL33_BASE flag only if it is provided and EL3_PAYLOAD_BASE
# is not defined, as it has priority.
ifdef BL33_BASE
$(eval $(call add_define,BL33_BASE))
endif
endif
$(eval $(call add_define,PL011_GENERIC_UART))
################################################################################

16
bl2/bl2_main.c
View File

@ -169,6 +169,7 @@ static int load_bl32(bl31_params_t *bl2_to_bl31_params)
return e;
}
#ifndef BL33_BASE
/*******************************************************************************
* Load the BL33 image.
* The bl2_to_bl31_params param will be updated with the relevant BL33
@ -199,6 +200,8 @@ static int load_bl33(bl31_params_t *bl2_to_bl31_params)
return e;
}
#endif /* BL33_BASE */
#endif /* EL3_PAYLOAD_BASE */
/*******************************************************************************
@ -253,7 +256,7 @@ void bl2_main(void)
* bl31_params_t structure makes sense in the context of EL3 payloads.
* This will be refined in the future.
*/
VERBOSE("BL2: Populating the entrypoint info for the EL3 payload\n");
INFO("BL2: Populating the entrypoint info for the EL3 payload\n");
bl31_ep_info->pc = EL3_PAYLOAD_BASE;
bl31_ep_info->args.arg0 = (unsigned long) bl2_to_bl31_params;
bl2_plat_set_bl31_ep_info(NULL, bl31_ep_info);
@ -274,11 +277,22 @@ void bl2_main(void)
}
}
#ifdef BL33_BASE
/*
* In this case, don't load the BL33 image as it's already loaded in
* memory. Update BL33 entrypoint information.
*/
INFO("BL2: Populating the entrypoint info for the preloaded BL33\n");
bl2_to_bl31_params->bl33_ep_info->pc = BL33_BASE;
bl2_plat_set_bl33_ep_info(NULL, bl2_to_bl31_params->bl33_ep_info);
#else
e = load_bl33(bl2_to_bl31_params);
if (e) {
ERROR("Failed to load BL33 (%i)\n", e);
plat_error_handler(e);
}
#endif /* BL33_BASE */
#endif /* EL3_PAYLOAD_BASE */
/* Flush the params to be passed to memory */

30
docs/porting-guide.md
View File

@ -230,11 +230,6 @@ platform port to define additional platform porting constants in
Defines the maximum address in secure RAM that the BL31 image can occupy.
* **#define : NS_IMAGE_OFFSET**
Defines the base address in non-secure DRAM where BL2 loads the BL33 binary
image. Must be aligned on a page-size boundary.
For every image, the platform must define individual identifiers that will be
used by BL1 or BL2 to load the corresponding image into memory from non-volatile
storage. For the sake of performance, integer numbers will be used as
@ -1012,10 +1007,10 @@ using the `platform_is_primary_cpu()` function. BL1 passed control to BL2 at
structure in memory provided by the platform with information about how
BL31 should pass control to the BL32 image.
5. Loading the normal world BL33 binary image into non-secure DRAM from
platform storage and arranging for BL31 to pass control to this image. This
address is determined using the `plat_get_ns_image_entrypoint()` function
described below.
5. (Optional) Loading the normal world BL33 binary image (if not loaded by
other means) into non-secure DRAM from platform storage and arranging for
BL31 to pass control to this image. This address is determined using the
`plat_get_ns_image_entrypoint()` function described below.
6. BL2 populates an `entry_point_info` structure in memory provided by the
platform with information about how BL31 should pass control to the
@ -1183,6 +1178,10 @@ This function is called after loading BL33 image and it can be used to
overwrite the entry point set by loader and also set the security state
and SPSR which represents the entry point system state for BL33.
In the preloaded BL33 alternative boot flow, this function is called after
populating its entry point address. It is passed a null pointer as its first
argument in this case.
### Function : bl2_plat_get_bl32_meminfo() [mandatory]
@ -1204,6 +1203,9 @@ BL33 image. The meminfo provided by this is used by load_image() to
validate whether the BL33 image can be loaded with in the given
memory from the given base.
This function isn't needed if either `BL33_BASE` or `EL3_PAYLOAD_BASE` build
options are used.
### Function : bl2_plat_flush_bl31_params() [mandatory]
Argument : void
@ -1226,6 +1228,9 @@ entrypoint of that image, which BL31 uses to jump to it.
BL2 is responsible for loading the normal world BL33 image (e.g. UEFI).
This function isn't needed if either `BL33_BASE` or `EL3_PAYLOAD_BASE` build
options are used.
3.3 FWU Boot Loader Stage 2 (BL2U)
----------------------------------
@ -1899,9 +1904,10 @@ build system.
* **NEED_BL33**
By default, this flag is defined `yes` by the build system and `BL33`
build option should be supplied as a build option. The platform has the option
of excluding the BL33 image in the `fip` image by defining this flag to
`no`.
build option should be supplied as a build option. The platform has the
option of excluding the BL33 image in the `fip` image by defining this flag
to `no`. If any of the options `EL3_PAYLOAD_BASE` or `BL33_BASE` are used,
this flag will be set to `no` automatically.
5. C Library
-------------

73
docs/user-guide.md
View File

@ -10,10 +10,11 @@ Contents :
5. [Building the Trusted Firmware](#5--building-the-trusted-firmware)
6. [Building the rest of the software stack](#6--building-the-rest-of-the-software-stack)
7. [EL3 payloads alternative boot flow](#7--el3-payloads-alternative-boot-flow)
8. [Preparing the images to run on FVP](#8--preparing-the-images-to-run-on-fvp)
9. [Running the software on FVP](#9--running-the-software-on-fvp)
10. [Running the software on Juno](#10--running-the-software-on-juno)
11. [Changes required for booting Linux on FVP in GICv3 mode](#11--changes-required-for-booting-linux-on-fvp-in-gicv3-mode)
8. [Preloaded BL33 alternative boot flow](#8--preloaded-bl33-alternative-boot-flow)
9. [Preparing the images to run on FVP](#9--preparing-the-images-to-run-on-fvp)
10. [Running the software on FVP](#10--running-the-software-on-fvp)
11. [Running the software on Juno](#11--running-the-software-on-juno)
12. [Changes required for booting Linux on FVP in GICv3 mode](#12--changes-required-for-booting-linux-on-fvp-in-gicv3-mode)
1. Introduction
@ -407,6 +408,12 @@ performed.
payload. Please refer to the "Booting an EL3 payload" section for more
details.
* `BL33_BASE`: This option enables booting a preloaded BL33 image instead of
the normal boot flow. When defined, it must specify the entry point address
for the preloaded BL33 image. This option is incompatible with
`EL3_PAYLOAD_BASE`. If both are defined, `EL3_PAYLOAD_BASE` has priority
over `BL33_BASE`.
* `PL011_GENERIC_UART`: Boolean option to indicate the PL011 driver that
the underlying hardware is not a full PL011 UART but a minimally compliant
generic UART, which is a subset of the PL011. The driver will not access
@ -938,7 +945,55 @@ Alternatively, the same DS-5 command mentioned in the FVP section above can
be used to load the EL3 payload's ELF file over JTAG on Juno.
8. Preparing the images to run on FVP
8. Preloaded BL33 alternative boot flow
----------------------------------------
Some platforms have the ability to preload BL33 into memory instead of relying
on Trusted Firmware to load it. This may simplify packaging of the normal world
code and improve performance in a development environment. When secure world
cold boot is complete, Trusted Firmware simply jumps to a BL33 base address
provided at build time.
For this option to be used, the `BL33_BASE` build option has to be used when
compiling the Trusted Firmware. For example, the following command will create
a FIP without a BL33 and prepare to jump to a BL33 image loaded at address
0x80000000:
CROSS_COMPILE=<path-to>/bin/aarch64-linux-gnu- \
make BL33_BASE=0x80000000 PLAT=fvp all fip
#### Boot of a preloaded bootwrapped kernel image on Base FVP
The following example uses the AArch64 boot wrapper. This simplifies normal
world booting while also making use of TF features. It can be obtained from its
repository with:
git clone git://git.kernel.org/pub/scm/linux/kernel/git/mark/boot-wrapper-aarch64.git
After compiling it, an ELF file is generated. It can be loaded with the
following command:
<path-to>/FVP_Base_AEMv8A-AEMv8A \
-C bp.secureflashloader.fname=bl1.bin \
-C bp.flashloader0.fname=fip.bin \
-a cluster0.cpu0=<bootwrapped-kernel.elf> \
--start cluster0.cpu0=0x0
The `-a cluster0.cpu0=<bootwrapped-kernel.elf>` option loads the ELF file. It
also sets the PC register to the ELF entry point address, which is not the
desired behaviour, so the `--start cluster0.cpu0=0x0` option forces the PC back
to 0x0 (the BL1 entry point address) on CPU #0. The `BL33_BASE` define used when
compiling the FIP must match the ELF entry point.
#### Boot of a preloaded bootwrapped kernel image on Juno
The procedure to obtain and compile the boot wrapper is very similar to the case
of the FVP. Once compiled, the `SPIN_ON_BL1_EXIT=1` loading method explained
above in the EL3 payload boot flow section may be used to load the ELF file over
JTAG on Juno.
9. Preparing the images to run on FVP
--------------------------------------
Note: This section can be ignored when booting an EL3 payload, as no Flattened
@ -991,8 +1046,8 @@ Copy the kernel image file `linux/arch/arm64/boot/Image` to the directory from
which the FVP is launched. Alternatively a symbolic link may be used.
9. Running the software on FVP
-------------------------------
10. Running the software on FVP
--------------------------------
This version of the ARM Trusted Firmware has been tested on the following ARM
FVPs (64-bit versions only).
@ -1290,7 +1345,7 @@ The `bp.variant` parameter corresponds to the build variant field of the
detect the legacy VE memory map while configuring the GIC.
10. Running the software on Juno
11. Running the software on Juno
---------------------------------
This version of the ARM Trusted Firmware has been tested on Juno r0 and Juno r1.
@ -1372,7 +1427,7 @@ The Juno board should suspend to RAM and then wakeup after 10 seconds due to
wakeup interrupt from RTC.
11. Changes required for booting Linux on FVP in GICv3 mode
12. Changes required for booting Linux on FVP in GICv3 mode
------------------------------------------------------------
In case the TF FVP port is built with the build option