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qemu: Support ARM_LINUX_KERNEL_AS_BL33 to pass FDT address. 

This lets the Linux kernel or any other image which expects an FDT in x0 be
loaded directly as BL33 without a separate bootloader on QEMU.

Signed-off-by: Andrew Walbran <qwandor@google.com>
Change-Id: Ia8eb4710a3d97cdd877af3b8aae36a2de7cfc654
This commit is contained in:
Andrew Walbran 2020-01-15 14:11:31 +00:00
parent d81e38f66e
commit 74464d5b51
4 changed files with 38 additions and 3 deletions
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4
docs/plat/qemu.rst
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@ -10,6 +10,10 @@ loop to be released by normal world via PSCI.
BL2 edits the Flattened Device Tree, FDT, generated by QEMU at run-time to
add a node describing PSCI and also enable methods for the CPUs.
If ``ARM_LINUX_KERNEL_AS_BL33`` is set to 1 then this FDT will be passed to BL33
via register x0, as expected by a Linux kernel. This allows a Linux kernel image
to be booted directly as BL33 rather than using a bootloader.
An ARM64 defconfig v4.5 Linux kernel is known to boot, FDT doesn't need to be
provided as it's generated by QEMU.

21
plat/qemu/common/qemu_bl2_setup.c
View File

@ -51,7 +51,7 @@ static void security_setup(void)
static void update_dt(void)
{
int ret;
void *fdt = (void *)(uintptr_t)PLAT_QEMU_DT_BASE;
void *fdt = (void *)(uintptr_t)ARM_PRELOADED_DTB_BASE;
ret = fdt_open_into(fdt, fdt, PLAT_QEMU_DT_MAX_SIZE);
if (ret < 0) {
@ -172,12 +172,12 @@ static int qemu_bl2_handle_post_image_load(unsigned int image_id)
* OP-TEE expect to receive DTB address in x2.
* This will be copied into x2 by dispatcher.
*/
bl_mem_params->ep_info.args.arg3 = PLAT_QEMU_DT_BASE;
bl_mem_params->ep_info.args.arg3 = ARM_PRELOADED_DTB_BASE;
#else /* case AARCH32_SP_OPTEE */
bl_mem_params->ep_info.args.arg0 =
bl_mem_params->ep_info.args.arg1;
bl_mem_params->ep_info.args.arg1 = 0;
bl_mem_params->ep_info.args.arg2 = PLAT_QEMU_DT_BASE;
bl_mem_params->ep_info.args.arg2 = ARM_PRELOADED_DTB_BASE;
bl_mem_params->ep_info.args.arg3 = 0;
#endif
#endif
@ -192,8 +192,23 @@ static int qemu_bl2_handle_post_image_load(unsigned int image_id)
pager_mem_params->ep_info.lr_svc = bl_mem_params->ep_info.pc;
#endif
#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.
*/
bl_mem_params->ep_info.args.arg0 =
(u_register_t)ARM_PRELOADED_DTB_BASE;
bl_mem_params->ep_info.args.arg1 = 0U;
bl_mem_params->ep_info.args.arg2 = 0U;
bl_mem_params->ep_info.args.arg3 = 0U;
#else
/* BL33 expects to receive the primary CPU MPID (through r0) */
bl_mem_params->ep_info.args.arg0 = 0xffff & read_mpidr();
#endif
bl_mem_params->ep_info.spsr = qemu_get_spsr_for_bl33_entry();
break;
default:

8
plat/qemu/qemu/platform.mk
View File

@ -186,5 +186,13 @@ endif
# Process flags
$(eval $(call add_define,BL32_RAM_LOCATION_ID))
# 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))
ARM_PRELOADED_DTB_BASE := PLAT_QEMU_DT_BASE
$(eval $(call add_define,ARM_PRELOADED_DTB_BASE))
# Do not enable SVE
ENABLE_SVE_FOR_NS := 0

8
plat/qemu/qemu_sbsa/platform.mk
View File

@ -97,5 +97,13 @@ PRELOADED_BL33_BASE ?= 0x10000000
BL32_RAM_LOCATION_ID = SEC_SRAM_ID
$(eval $(call add_define,BL32_RAM_LOCATION_ID))
# 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))
ARM_PRELOADED_DTB_BASE := PLAT_QEMU_DT_BASE
$(eval $(call add_define,ARM_PRELOADED_DTB_BASE))
# Do not enable SVE
ENABLE_SVE_FOR_NS := 0