From 66f1e68093979816a23412a3fad066f5bcbc0360 Mon Sep 17 00:00:00 2001 From: Frederik Haxel Date: Tue, 12 Dec 2023 14:01:12 +0100 Subject: [PATCH 1/3] riscv: Make XIP bootable again Currently, the XIP kernel seems to fail to boot due to missing XIP_FIXUP and a wrong page_offset value. A superfluous XIP_FIXUP has also been removed. Signed-off-by: Frederik Haxel Link: https://lore.kernel.org/r/20231212130116.848530-2-haxel@fzi.de Signed-off-by: Palmer Dabbelt --- arch/riscv/kernel/head.S | 1 + arch/riscv/mm/init.c | 8 ++++++-- 2 files changed, 7 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index b77397432403d..a2e2f0dd3899a 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -89,6 +89,7 @@ relocate_enable_mmu: /* Compute satp for kernel page tables, but don't load it yet */ srl a2, a0, PAGE_SHIFT la a1, satp_mode + XIP_FIXUP_OFFSET a1 REG_L a1, 0(a1) or a2, a2, a1 diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c index 2e011cbddf3af..a65937336cdc8 100644 --- a/arch/riscv/mm/init.c +++ b/arch/riscv/mm/init.c @@ -174,6 +174,9 @@ void __init mem_init(void) /* Limit the memory size via mem. */ static phys_addr_t memory_limit; +#ifdef CONFIG_XIP_KERNEL +#define memory_limit (*(phys_addr_t *)XIP_FIXUP(&memory_limit)) +#endif /* CONFIG_XIP_KERNEL */ static int __init early_mem(char *p) { @@ -952,7 +955,7 @@ static void __init create_fdt_early_page_table(uintptr_t fix_fdt_va, * setup_vm_final installs the linear mapping. For 32-bit kernel, as the * kernel is mapped in the linear mapping, that makes no difference. */ - dtb_early_va = kernel_mapping_pa_to_va(XIP_FIXUP(dtb_pa)); + dtb_early_va = kernel_mapping_pa_to_va(dtb_pa); #endif dtb_early_pa = dtb_pa; @@ -1055,9 +1058,9 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) #endif kernel_map.virt_addr = KERNEL_LINK_ADDR + kernel_map.virt_offset; - kernel_map.page_offset = _AC(CONFIG_PAGE_OFFSET, UL); #ifdef CONFIG_XIP_KERNEL + kernel_map.page_offset = PAGE_OFFSET_L3; kernel_map.xiprom = (uintptr_t)CONFIG_XIP_PHYS_ADDR; kernel_map.xiprom_sz = (uintptr_t)(&_exiprom) - (uintptr_t)(&_xiprom); @@ -1067,6 +1070,7 @@ asmlinkage void __init setup_vm(uintptr_t dtb_pa) kernel_map.va_kernel_xip_pa_offset = kernel_map.virt_addr - kernel_map.xiprom; #else + kernel_map.page_offset = _AC(CONFIG_PAGE_OFFSET, UL); kernel_map.phys_addr = (uintptr_t)(&_start); kernel_map.size = (uintptr_t)(&_end) - kernel_map.phys_addr; #endif From 5daa3726410288075ba73c336bb2e80d6b06aa4d Mon Sep 17 00:00:00 2001 From: Frederik Haxel Date: Tue, 12 Dec 2023 14:01:13 +0100 Subject: [PATCH 2/3] riscv: Fixed wrong register in XIP_FIXUP_FLASH_OFFSET macro During the refactoring, a bug was introduced in the rarly used XIP_FIXUP_FLASH_OFFSET macro. Fixes: bee7fbc38579 ("RISC-V CPU Idle Support") Fixes: e7681beba992 ("RISC-V: Split out the XIP fixups into their own file") Signed-off-by: Frederik Haxel Link: https://lore.kernel.org/r/20231212130116.848530-3-haxel@fzi.de Signed-off-by: Palmer Dabbelt --- arch/riscv/include/asm/xip_fixup.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/riscv/include/asm/xip_fixup.h b/arch/riscv/include/asm/xip_fixup.h index d4ffc3c37649f..b65bf6306f69c 100644 --- a/arch/riscv/include/asm/xip_fixup.h +++ b/arch/riscv/include/asm/xip_fixup.h @@ -13,7 +13,7 @@ add \reg, \reg, t0 .endm .macro XIP_FIXUP_FLASH_OFFSET reg - la t1, __data_loc + la t0, __data_loc REG_L t1, _xip_phys_offset sub \reg, \reg, t1 add \reg, \reg, t0 From 6c4a2f6329f0925161a80d2fd90aa8438c1ca82f Mon Sep 17 00:00:00 2001 From: Frederik Haxel Date: Tue, 12 Dec 2023 14:01:14 +0100 Subject: [PATCH 3/3] riscv: Allow disabling of BUILTIN_DTB for XIP This enables, among other things, testing with the QEMU virt machine. To build an XIP kernel for the QEMU virt machine, configure the the kernel as desired and apply the following configuration ``` CONFIG_NONPORTABLE=y CONFIG_XIP_KERNEL=y CONFIG_XIP_PHYS_ADDR=0x20000000 CONFIG_PHYS_RAM_BASE=0x80200000 CONFIG_BUILTIN_DTB=n ``` Since the QEMU virt flash memory expects a 32 MB file, the built image must be padded. For example, with `truncate -s 32M arch/riscv/boot/xipImage` The kernel can be started using the following command in QEMU (v8+) ``` qemu-system-riscv64 -M virt,pflash0=pflash0 \ -blockdev node-name=pflash0,driver=file,read-only=on,\ filename=arch/riscv/boot/xipImage ``` Signed-off-by: Frederik Haxel Link: https://lore.kernel.org/r/20231212130116.848530-4-haxel@fzi.de Signed-off-by: Palmer Dabbelt --- arch/riscv/Kconfig | 6 +++--- arch/riscv/kernel/head.S | 4 +++- 2 files changed, 6 insertions(+), 4 deletions(-) diff --git a/arch/riscv/Kconfig b/arch/riscv/Kconfig index 95a2a06acc6a6..72bc31b6eeb95 100644 --- a/arch/riscv/Kconfig +++ b/arch/riscv/Kconfig @@ -904,13 +904,13 @@ config RISCV_ISA_FALLBACK on the replacement properties, "riscv,isa-base" and "riscv,isa-extensions". -endmenu # "Boot options" - config BUILTIN_DTB - bool + bool "Built-in device tree" depends on OF && NONPORTABLE default y if XIP_KERNEL +endmenu # "Boot options" + config PORTABLE bool default !NONPORTABLE diff --git a/arch/riscv/kernel/head.S b/arch/riscv/kernel/head.S index a2e2f0dd3899a..a8939558702cb 100644 --- a/arch/riscv/kernel/head.S +++ b/arch/riscv/kernel/head.S @@ -266,10 +266,12 @@ SYM_CODE_START(_start_kernel) la sp, _end + THREAD_SIZE XIP_FIXUP_OFFSET sp mv s0, a0 + mv s1, a1 call __copy_data - /* Restore a0 copy */ + /* Restore a0 & a1 copy */ mv a0, s0 + mv a1, s1 #endif #ifndef CONFIG_XIP_KERNEL