Commit b726c169 authored by Antonio Nino Diaz's avatar Antonio Nino Diaz
Browse files

plat/arm: Introduce ARM_LINUX_KERNEL_AS_BL33 build option



Normally, BL33 needs to contain a boot loader like U-Boot or UEFI that
eventually gives control to the OS. However, in some cases, this boot
sequence may be too slow. For example, when doing tests in a
cycle-accurate emulator, the user may only be interested in the
interaction between the Trusted Firmware and the OS, not in the boot
process itself.

The new option ARM_LINUX_KERNEL_AS_BL33 allows BL33 to contain the Linux
kernel image by changing the value of registers x0-x3 to the values
expected by the kernel. This option requires the device tree blob (DTB)
to be present in memory. Its address must be specified in the newly
introduced ARM_PRELOADED_DTB_BASE build option. For now, it only supports
AArch64 kernels.

This option is only available when RESET_TO_BL31=1. For this reason
the BL33 binary must be preloaded in memory and PRELOADED_BL33_BASE must
be used.

For example, if the kernel is loaded at 0x80080000 and the DTB is loaded
at address 0x82000000, the firmware could be built like this:

    CROSS_COMPILE=aarch64-linux-gnu-  \
    make PLAT=fvp DEBUG=1             \
    RESET_TO_BL31=1                   \
    ARM_LINUX_KERNEL_AS_BL33=1        \
    PRELOADED_BL33_BASE=0x80080000    \
    ARM_PRELOADED_DTB_BASE=0x82000000 \
    all fip

Change-Id: If9dc847c65ae2d0c27b51f0fd44fc06b28497db9
Signed-off-by: default avatarAntonio Nino Diaz <antonio.ninodiaz@arm.com>
parent 885ca54a
...@@ -678,6 +678,15 @@ Arm development platform specific build options ...@@ -678,6 +678,15 @@ Arm development platform specific build options
Trusted Watchdog may be disabled at build time for testing or development Trusted Watchdog may be disabled at build time for testing or development
purposes. purposes.
- ``ARM_LINUX_KERNEL_AS_BL33``: The Linux kernel expects registers x0-x3 to
have specific values at boot. This boolean option allows the Trusted Firmware
to have a Linux kernel image as BL33 by preparing the registers to these
values before jumping to BL33. This option defaults to 0 (disabled). For now,
it only supports AArch64 kernels. ``RESET_TO_BL31`` must be 1 when using it.
If this option is set to 1, ``ARM_PRELOADED_DTB_BASE`` must be set to the
location of a device tree blob (DTB) already loaded in memory. The Linux
Image address must be specified using the ``PRELOADED_BL33_BASE`` option.
- ``ARM_RECOM_STATE_ID_ENC``: The PSCI1.0 specification recommends an encoding - ``ARM_RECOM_STATE_ID_ENC``: The PSCI1.0 specification recommends an encoding
for the construction of composite state-ID in the power-state parameter. for the construction of composite state-ID in the power-state parameter.
The existing PSCI clients currently do not support this encoding of The existing PSCI clients currently do not support this encoding of
......
...@@ -80,7 +80,7 @@ void arm_bl31_early_platform_setup(bl31_params_t *from_bl2, uintptr_t soc_fw_con ...@@ -80,7 +80,7 @@ void arm_bl31_early_platform_setup(bl31_params_t *from_bl2, uintptr_t soc_fw_con
assert(from_bl2 == NULL); assert(from_bl2 == NULL);
assert(plat_params_from_bl2 == NULL); assert(plat_params_from_bl2 == NULL);
#ifdef BL32_BASE # ifdef BL32_BASE
/* Populate entry point information for BL32 */ /* Populate entry point information for BL32 */
SET_PARAM_HEAD(&bl32_image_ep_info, SET_PARAM_HEAD(&bl32_image_ep_info,
PARAM_EP, PARAM_EP,
...@@ -89,7 +89,7 @@ void arm_bl31_early_platform_setup(bl31_params_t *from_bl2, uintptr_t soc_fw_con ...@@ -89,7 +89,7 @@ void arm_bl31_early_platform_setup(bl31_params_t *from_bl2, uintptr_t soc_fw_con
SET_SECURITY_STATE(bl32_image_ep_info.h.attr, SECURE); SET_SECURITY_STATE(bl32_image_ep_info.h.attr, SECURE);
bl32_image_ep_info.pc = BL32_BASE; bl32_image_ep_info.pc = BL32_BASE;
bl32_image_ep_info.spsr = arm_get_spsr_for_bl32_entry(); bl32_image_ep_info.spsr = arm_get_spsr_for_bl32_entry();
#endif /* BL32_BASE */ # endif /* BL32_BASE */
/* Populate entry point information for BL33 */ /* Populate entry point information for BL33 */
SET_PARAM_HEAD(&bl33_image_ep_info, SET_PARAM_HEAD(&bl33_image_ep_info,
...@@ -105,6 +105,19 @@ void arm_bl31_early_platform_setup(bl31_params_t *from_bl2, uintptr_t soc_fw_con ...@@ -105,6 +105,19 @@ void arm_bl31_early_platform_setup(bl31_params_t *from_bl2, uintptr_t soc_fw_con
bl33_image_ep_info.spsr = arm_get_spsr_for_bl33_entry(); bl33_image_ep_info.spsr = arm_get_spsr_for_bl33_entry();
SET_SECURITY_STATE(bl33_image_ep_info.h.attr, NON_SECURE); SET_SECURITY_STATE(bl33_image_ep_info.h.attr, NON_SECURE);
# if ARM_LINUX_KERNEL_AS_BL33
/*
* According to the file ``Documentation/arm64/booting.txt`` of the
* Linux kernel tree, Linux expects the physical address of the device
* tree blob (DTB) in x0, while x1-x3 are reserved for future use and
* must be 0.
*/
bl33_image_ep_info.args.arg0 = (u_register_t)ARM_PRELOADED_DTB_BASE;
bl33_image_ep_info.args.arg1 = 0U;
bl33_image_ep_info.args.arg2 = 0U;
bl33_image_ep_info.args.arg3 = 0U;
# endif
#else /* RESET_TO_BL31 */ #else /* RESET_TO_BL31 */
/* /*
......
...@@ -80,6 +80,27 @@ ARM_XLAT_TABLES_LIB_V1 := 0 ...@@ -80,6 +80,27 @@ ARM_XLAT_TABLES_LIB_V1 := 0
$(eval $(call assert_boolean,ARM_XLAT_TABLES_LIB_V1)) $(eval $(call assert_boolean,ARM_XLAT_TABLES_LIB_V1))
$(eval $(call add_define,ARM_XLAT_TABLES_LIB_V1)) $(eval $(call add_define,ARM_XLAT_TABLES_LIB_V1))
# Don't have the Linux kernel as a BL33 image by default
ARM_LINUX_KERNEL_AS_BL33 := 0
$(eval $(call assert_boolean,ARM_LINUX_KERNEL_AS_BL33))
$(eval $(call add_define,ARM_LINUX_KERNEL_AS_BL33))
ifeq (${ARM_LINUX_KERNEL_AS_BL33},1)
ifneq (${ARCH},aarch64)
$(error "ARM_LINUX_KERNEL_AS_BL33 is only available in AArch64.")
endif
ifneq (${RESET_TO_BL31},1)
$(error "ARM_LINUX_KERNEL_AS_BL33 is only available if RESET_TO_BL31=1.")
endif
ifndef PRELOADED_BL33_BASE
$(error "PRELOADED_BL33_BASE must be set if ARM_LINUX_KERNEL_AS_BL33 is used.")
endif
ifndef ARM_PRELOADED_DTB_BASE
$(error "ARM_PRELOADED_DTB_BASE must be set if ARM_LINUX_KERNEL_AS_BL33 is used.")
endif
$(eval $(call add_define,ARM_PRELOADED_DTB_BASE))
endif
# Use an implementation of SHA-256 with a smaller memory footprint but reduced # Use an implementation of SHA-256 with a smaller memory footprint but reduced
# speed. # speed.
$(eval $(call add_define,MBEDTLS_SHA256_SMALLER)) $(eval $(call add_define,MBEDTLS_SHA256_SMALLER))
......
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