Sometimes, especially in a production system we may not want to use a "smart bootloader" like u-boot to load kernel, ramdisk and device tree from a filesystem on eMMC, but rather load the kernel from a NAND partition and just run it as soon as we can, and in this case it is convenient to have device tree compiled into the kernel binary. Since this case is not limited to MMU-less systems, let's support it for these which have MMU enabled too.
While at it, provide __dtb_start as a parameter to setup_vm() in BUILTIN_DTB case, so we don't have to duplicate BUILTIN_DTB specific processing in MMU-enabled and MMU-disabled versions of setup_vm(). Signed-off-by: Vitaly Wool <vitaly.w...@konsulko.com> --- Changes from v2: * folded "RISC-V: simplify BUILTIN_DTB processing" patch [http://lists.infradead.org/pipermail/linux-riscv/2021-January/004153.html] Changes from v1: * no direct initial_boot_params assignment * skips the temporary mapping for DT if BUILTIN_DTB=y arch/riscv/Kconfig | 1 - arch/riscv/kernel/head.S | 4 ++++ arch/riscv/mm/init.c | 19 +++++++++++++------ 3 files changed, 17 insertions(+), 7 deletions(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 2ef05ef921b5..444a1ed1e847 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -445,7 +445,6 @@ endmenu config BUILTIN_DTB def_bool n - depends on RISCV_M_MODE depends on OF menu "Power management options" diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index 16e9941900c4..f5a9bad86e58 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -260,7 +260,11 @@ clear_bss_done: /* Initialize page tables and relocate to virtual addresses */ la sp, init_thread_union + THREAD_SIZE +#ifdef CONFIG_BUILTIN_DTB + la a0, __dtb_start +#else mv a0, s1 +#endif /* CONFIG_BUILTIN_DTB */ call setup_vm #ifdef CONFIG_MMU la a0, early_pg_dir diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 30b61f2c6b87..45faad7c4291 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -192,10 +192,13 @@ void __init setup_bootmem(void) #endif /* CONFIG_BLK_DEV_INITRD */ /* - * Avoid using early_init_fdt_reserve_self() since __pa() does + * If DTB is built in, no need to reserve its memblock. + * Otherwise, do reserve it but avoid using + * early_init_fdt_reserve_self() since __pa() does * not work for DTB pointers that are fixmap addresses */ - memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); + if (!IS_ENABLED(CONFIG_BUILTIN_DTB)) + memblock_reserve(dtb_early_pa, fdt_totalsize(dtb_early_va)); early_init_fdt_scan_reserved_mem(); dma_contiguous_reserve(dma32_phys_limit); @@ -499,6 +502,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) /* Setup early PMD for DTB */ create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA, (uintptr_t)early_dtb_pmd, PGDIR_SIZE, PAGE_TABLE); +#ifndef CONFIG_BUILTIN_DTB /* Create two consecutive PMD mappings for FDT early scan */ pa = dtb_pa & ~(PMD_SIZE - 1); create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA, @@ -506,7 +510,11 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) create_pmd_mapping(early_dtb_pmd, DTB_EARLY_BASE_VA + PMD_SIZE, pa + PMD_SIZE, PMD_SIZE, PAGE_KERNEL); dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PMD_SIZE - 1)); +#else /* CONFIG_BUILTIN_DTB */ + dtb_early_va = __va(dtb_pa); +#endif /* CONFIG_BUILTIN_DTB */ #else +#ifndef CONFIG_BUILTIN_DTB /* Create two consecutive PGD mappings for FDT early scan */ pa = dtb_pa & ~(PGDIR_SIZE - 1); create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA, @@ -514,6 +522,9 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) create_pgd_mapping(early_pg_dir, DTB_EARLY_BASE_VA + PGDIR_SIZE, pa + PGDIR_SIZE, PGDIR_SIZE, PAGE_KERNEL); dtb_early_va = (void *)DTB_EARLY_BASE_VA + (dtb_pa & (PGDIR_SIZE - 1)); +#else /* CONFIG_BUILTIN_DTB */ + dtb_early_va = __va(dtb_pa); +#endif /* CONFIG_BUILTIN_DTB */ #endif dtb_early_pa = dtb_pa; @@ -604,11 +615,7 @@ static void __init setup_vm_final(void) #else asmlinkage void __init setup_vm(uintptr_t dtb_pa) { -#ifdef CONFIG_BUILTIN_DTB - dtb_early_va = (void *) __dtb_start; -#else dtb_early_va = (void *)dtb_pa; -#endif dtb_early_pa = dtb_pa; } -- 2.20.1
