Hi Alex
On 9/2/21 7:34 PM, Alex G. wrote:
Hi Patrick,
On 9/1/21 10:10 AM, Alex G. wrote:
Hi Patrick,
On 8/31/21 12:24 PM, Patrick DELAUNAY wrote:
Hi,
On 8/26/21 11:42 PM, Alexandru Gagniuc wrote:
OP-TEE does not take a devicetree for its own use. However, it does
pass the devicetree to the normal world OS. In most cases that will
be some other devicetree-bearing platform, such as linux.
As in other cases where there's an OPTEE payload (e.g. BOOTM_OPTEE),
it is required to copy the optee nodes to he target's FDT. Do this as
part of spl_board_prepare_for_optee().
Signed-off-by: Alexandru Gagniuc <[email protected]>
---
arch/arm/mach-stm32mp/spl.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/arch/arm/mach-stm32mp/spl.c b/arch/arm/mach-stm32mp/spl.c
index d9fdc5926c..94fbb45cf9 100644
--- a/arch/arm/mach-stm32mp/spl.c
+++ b/arch/arm/mach-stm32mp/spl.c
@@ -19,6 +19,7 @@
#include <asm/arch/sys_proto.h>
#include <mach/tzc.h>
#include <linux/libfdt.h>
+#include <tee/optee.h>
u32 spl_boot_device(void)
{
@@ -182,6 +183,7 @@ void stm32_init_tzc_for_optee(void)
void spl_board_prepare_for_optee(void *fdt)
{
stm32_fdt_setup_mac_addr(fdt);
+ optee_copy_fdt_nodes(fdt);
stm32_init_tzc_for_optee();
}
NAK the OP-TEE nodes are ADDED by the OP-TEE firmware in the
unsecure device tree (when CFG_DT is activated)
before to jump to the kernel (that remove the need to have DT
allignement with U-Boot SPL device tree)
=> SPL should not copy the OP-TEE nodes in next stage DT
reference in optee_os = core/arch/arm/kernel/boot.c:
add_optee_dt_node()
add_optee_dt_node() <= update_external_dt() <= paged_init_primary()
It is the expected configuration for OP-TEE on STM32MP15 platform.
I agree that if a component modifies the platform, it should be
responsible for updating the devicetree. Two issues though
1. Consistency
The STM32IMAGE boot path expects u-boot to add the optee nodes, while
the FIP path expects OP-TEE to add the nodes. Which one do we stick to?
STM32MP platform expects U-Boot to copy the OP-TEE nodes because it is a
generic U-Boot behavior when OP-TEE is supported
FIP path expects OP-TEE to add their nodes because it is a generic
OP-TEE behavior
then the added nodes are copied by U-Boot in kernel DT
It is generic, flexible (OP-TEE configuration update wihout change in
kernel DT or in U-Boot)
but not time optimized...
for STM32IMAGE image support, I have a issue (restriction) = the U-Boot
DT can't updated by
OP-TEE (U-Boot DT is embedded in u-boot.stm32 not available by OP-TEE)
=> I force presence of OP-TEE node in U-Boot DT for STM32IMAGE support
to allow copy to kernel DT.
But it is less generic (dependency between U-Boot device tree and OP-TEE):
it is one reason we switch to FIP support
in you use case: SPL -> OP-TEE -> kernel
I think the kernel device tree can be updated by OP-TEE (to be generic) or
the kernel DT have already the correct OP-TEE nodes to reduce the DT
update time penalty,
as you are sure of the OP-TEE support / configuration for you board.
drawback: the kernel device tree need to be aligned with the OP-TEE
configuration.
2. Memory access
I don't understand is how OP-TEE would get past the TZC.
If we look at optee_os => plat-0stm32mp1/plat_tzc400:
"Early boot stage is in charge of configuring memory regions"
The following memory has been set up by SPL (or TF-A for that matter):
Nonsec: c0000000->ddffffff
Sec: de000000->dfdfffff
SHMEM: dfe00000->dfffffff
The external DTB will be in the nonsec region, which OP-TEE allegedly
can't access. So how would this get patched?
Let's set aside the above for a bit. I tried the following OP-TEE
configs:
"CFG_DT=y CFG_DTB_MAX_SIZE=0x80000"
Crashes with 'unhandled pageable abort' somewhere in
core/arch/arm/plat-stm32mp1/ . I don't have much more time to spend
debugging this.
"CFG_DT=y CFG_DTB_MAX_SIZE=0x80000 PLATFORM_FLAVOR=157C_DK2"
This adds about 800 ms to the boot time. (power on to kernel printing
the first line). I have an allowance of 1 second to get to the kernel.
I cannot just add 800ms to the boot time and hope nobody notices.
However, calling optee_copy_fdt_nodes() adds no measureable amount of
time.
Unless OP-TEE can modify the devicetree without increasing boot time,
I will not go down this path. This is an engineering decision driven
by the product requirements.
That being said, I request that you reconsider your NAK based on this
new data.
in my previous answer I think on generic support and you have specific
boot time requirement.
but after cross-check with TF-A boot in FIP mode,
in TF-A set the correct firewall configuration at the end of BL2 (it is
not done in OP-TEE as I expect)
based on configuration description found in FIP.
To be coherent with you configuration (SPL->OP-TEE->kernel),
this firewall configuration should be done by SPL before to start OP-TEE.
And to avoid to lost time in device tree parsing the DT modification or
copy of node should be avoid:
the OP-TEE reserved should be already present in your kernel device tree
=> no more need to copied them
I dig again with OPTEE features support in SPL and to avoid dependancy
issue I pushed a serie:
"lib: optee: remove the duplicate CONFIG_OPTEE"
http://patchwork.ozlabs.org/project/uboot/list/?series=260701&state=*
=> in your use case and for reduce the boot time
- activate CONFIG_SPL_OPTEE_IMAGE : load OP-TEE image by SPL
- manage OPTEE / firewall configuration with your defconfig
(=> no more need of OP-TEE nodes in SPL DT / reduced SPL size and
parsing time)
by using the existing configurations in lib/optee/Kconfig instead DT
information:
=> CONFIG_OPTEE_LOAD_ADDR
=> CONFIG_OPTEE_TZDRAM_SIZE
=> CONFIG_OPTEE_TZDRAM_BASE
PS: need to add a configuration for OPTEE SHMEM_SIZE ?
- manually add OP-TEE nodes / reserved memory in the kernel (and U-Boot)
device tree and OP-TEE config CFG_DT is not activated
(update_external_dt not used)
=> OP-TEE don't modify the devicetre (as nodes are already present in NS DT)
=> in spl_board_prepare_for_optee, avoid to update device tree to lost time
in all the case : optee_copy_fdt_nodes in not done by SPL but by U-Boot
started
by OP-TEE (for dynamic support) or not done (no static configuration)
The only reason to copy the OP-TEE node for FIP support or for your use
case is
to copy the nodes dynamically added by OP-TEE.
SPL / TFA -> OP-TEE -> U-Boot -> Kernel
(1) (2) (3)
OP-TEE only the U-Boot DT (non secure DT) in boot parameter
(1) => OP-TEE add the node in U-Boot DT
(2) => U-Boot load the kernel DT / copied the OP-TEE in kernel DT
(3) => kernel use the DT with correct OP-TEE node
The OP-TEE node copy is not necessary if the kernel start with the U-Boot DT
this sequence allow to have dynamic support of OP-TEE configuration.
But for product with fixed configuration it is not required.
I hope it is more clear.
one question:
why spl_fixup_fdt isn't called (for generic fixup = arch_fixup_fdt) for
OP-TEE boot
before to call spl_board_prepare_for_optee ?
Alex
Patrick
