Date: Fri, 3 Feb 2023 15:50:49 GMT From: Warner Losh <imp@FreeBSD.org> To: src-committers@FreeBSD.org, dev-commits-src-all@FreeBSD.org, dev-commits-src-main@FreeBSD.org Subject: git: dfcca210755e - main - kboot: aarch64 trampoline implementation Message-ID: <202302031550.313FonY2024021@gitrepo.freebsd.org>
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The branch main has been updated by imp: URL: https://cgit.FreeBSD.org/src/commit/?id=dfcca210755e2c3448ed6094de0331f02ff5176d commit dfcca210755e2c3448ed6094de0331f02ff5176d Author: Warner Losh <imp@FreeBSD.org> AuthorDate: 2023-02-03 15:40:04 +0000 Commit: Warner Losh <imp@FreeBSD.org> CommitDate: 2023-02-03 15:41:40 +0000 kboot: aarch64 trampoline implementation Update exec.c (copyied from efi/loader/arch/arm64/exec.c) to allow execution of aarch64 kernels. This includes a new trampoline code that handles copying the UEFI memory map, if available from the Linux FDT provided PA. This is a complete implementation now, able to boot from the LinuxBoot environment on an aarch64 server that only offers LinuxBoot (though a workaround for the gicv3 inability to re-init is not yet in FreeBSD). Many 'fit and finish' issues will be addressed in subsequent commits. Sponsored by: Netflix Reviewed by: tsoome, kevans, andrew Differential Revision: https://reviews.freebsd.org/D38258 --- stand/kboot/arch/aarch64/exec.c | 166 ++++++++++++++++++++++++++++++++------- stand/kboot/arch/aarch64/tramp.S | 88 ++++++++++++++------- 2 files changed, 199 insertions(+), 55 deletions(-) diff --git a/stand/kboot/arch/aarch64/exec.c b/stand/kboot/arch/aarch64/exec.c index 56a206c0f09f..b0cb2fcbb531 100644 --- a/stand/kboot/arch/aarch64/exec.c +++ b/stand/kboot/arch/aarch64/exec.c @@ -34,16 +34,17 @@ __FBSDID("$FreeBSD$"); #include <sys/linker.h> #include <machine/elf.h> -#include <bootstrap.h> - #ifdef EFI #include <efi.h> #include <efilib.h> - #include "loader_efi.h" - +#else +#include "host_syscall.h" #endif +#include <machine/metadata.h> +#include "bootstrap.h" +#include "kboot.h" #include "bootstrap.h" #include "platform/acfreebsd.h" @@ -54,6 +55,10 @@ __FBSDID("$FreeBSD$"); #include "cache.h" +#ifndef EFI +#define LOADER_PAGE_SIZE PAGE_SIZE +#endif + #ifdef EFI static EFI_GUID acpi_guid = ACPI_TABLE_GUID; static EFI_GUID acpi20_guid = ACPI_20_TABLE_GUID; @@ -62,13 +67,14 @@ static EFI_GUID acpi20_guid = ACPI_20_TABLE_GUID; static int elf64_exec(struct preloaded_file *amp); static int elf64_obj_exec(struct preloaded_file *amp); -/* Stub out temporarily */ -static int -bi_load(char *args, vm_offset_t *modulep, vm_offset_t *kernendp, - bool exit_bs) -{ - return EINVAL; -} +bool do_mem_map = false; + +extern uint32_t efi_map_size; +extern vm_paddr_t efi_map_phys_src; /* From DTB */ +extern vm_paddr_t efi_map_phys_dst; /* From our memory map metadata module */ + +int bi_load(char *args, vm_offset_t *modulep, vm_offset_t *kernendp, + bool exit_bs); static struct file_format arm64_elf = { elf64_loadfile, @@ -80,21 +86,47 @@ struct file_format *file_formats[] = { NULL }; +#ifndef EFI +extern uintptr_t tramp; +extern uint32_t tramp_size; +extern uint32_t tramp_data_offset; + +struct trampoline_data { + uint64_t entry; // 0 (PA where kernel loaded) + uint64_t modulep; // 8 module metadata + uint64_t memmap_src; // 16 Linux-provided memory map PA + uint64_t memmap_dst; // 24 Module data copy PA + uint64_t memmap_len; // 32 Length to copy +}; +#endif + +extern vm_offset_t kboot_get_phys_load_segment(void); + static int elf64_exec(struct preloaded_file *fp) { vm_offset_t modulep, kernendp; - vm_offset_t clean_addr; - size_t clean_size; - struct file_metadata *md; - Elf_Ehdr *ehdr; +#ifdef EFI + vm_offset_t clean_addr; + size_t clean_size; void (*entry)(vm_offset_t); - int err; +#else + vm_offset_t trampolinebase; + vm_offset_t staging; + void *trampcode; + uint64_t *trampoline; + struct trampoline_data *trampoline_data; + int nseg; + void *kseg; +#endif + struct file_metadata *md; + Elf_Ehdr *ehdr; + int error; #ifdef EFI ACPI_TABLE_RSDP *rsdp; char buf[24]; int revision; -#endif + /* * Report the RSDP to the kernel. The old code used the 'hints' method * to communite this to the kernel. However, while convenient, the @@ -103,7 +135,6 @@ elf64_exec(struct preloaded_file *fp) * that start with acpi. The old 'hints' can be removed before we branch * for FreeBSD 15. */ -#ifdef EFI rsdp = efi_get_table(&acpi20_guid); if (rsdp == NULL) { rsdp = efi_get_table(&acpi_guid); @@ -137,6 +168,46 @@ elf64_exec(struct preloaded_file *fp) } } #else + vm_offset_t rsdp; + rsdp = acpi_rsdp(); + if (rsdp != 0) { + char buf[24]; + + printf("Found ACPI 2.0 at %#016lx\n", rsdp); + sprintf(buf, "0x%016llx", (unsigned long long)rsdp); + setenv("hint.acpi.0.rsdp", buf, 1); /* For 13.1R bootability */ + setenv("acpi.rsdp", buf, 1); + /* Nobody uses the rest of that stuff */ + } + + + // XXX Question: why not just use malloc? + trampcode = host_getmem(LOADER_PAGE_SIZE); + if (trampcode == NULL) { + printf("Unable to allocate trampoline\n"); + return (ENOMEM); + } + bzero((void *)trampcode, LOADER_PAGE_SIZE); + bcopy((void *)&tramp, (void *)trampcode, tramp_size); + trampoline = (void *)trampcode; + + /* + * Figure out where to put it. + * + * Linux does not allow us to kexec_load into any part of memory. Ask + * arch_loadaddr to resolve the first available chunk of physical memory + * where loading is possible (load_addr). + * + * The kernel is loaded at the 'base' address in continguous physical + * memory. We use the 2MB in front of the kernel as a place to put our + * trampoline, but that's really overkill since we only need ~100 bytes. + * The arm64 kernel's entry requirements are only 'load the kernel at a + * 2MB alignment' and it figures out the rest, creates the right page + * tables, etc. + */ + staging = kboot_get_phys_load_segment(); + printf("Load address at %#jx\n", (uintmax_t)staging); + printf("Relocation offset is %#jx\n", (uintmax_t)elf64_relocation_offset); #endif if ((md = file_findmetadata(fp, MODINFOMD_ELFHDR)) == NULL) @@ -147,33 +218,72 @@ elf64_exec(struct preloaded_file *fp) entry = efi_translate(ehdr->e_entry); efi_time_fini(); -#else - entry = (void *)ehdr->e_entry; #endif - err = bi_load(fp->f_args, &modulep, &kernendp, true); - if (err != 0) { + error = bi_load(fp->f_args, &modulep, &kernendp, true); + if (error != 0) { #ifdef EFI efi_time_init(); #endif - return (err); + return (error); } dev_cleanup(); - /* Clean D-cache under kernel area and invalidate whole I-cache */ #ifdef EFI + /* Clean D-cache under kernel area and invalidate whole I-cache */ clean_addr = (vm_offset_t)efi_translate(fp->f_addr); clean_size = (vm_offset_t)efi_translate(kernendp) - clean_addr; -#else - clean_addr = (vm_offset_t)fp->f_addr; - clean_size = (vm_offset_t)kernendp - clean_addr; -#endif cpu_flush_dcache((void *)clean_addr, clean_size); cpu_inval_icache(); (*entry)(modulep); +#else + /* Linux will flush the caches, just pass this data into our trampoline and go */ + trampoline_data = (void *)trampoline + tramp_data_offset; + memset(trampoline_data, 0, sizeof(*trampoline_data)); + trampoline_data->entry = ehdr->e_entry - fp->f_addr + staging; + trampoline_data->modulep = modulep; + printf("Modulep = %jx\n", (uintmax_t)modulep); + if (efi_map_phys_src != 0) { + md = file_findmetadata(fp, MODINFOMD_EFI_MAP); + if (md == NULL || md->md_addr == 0) { + printf("Need to copy EFI MAP, but EFI MAP not found. %p\n", md); + } else { + printf("Metadata EFI map loaded at VA %lx\n", md->md_addr); + efi_map_phys_dst = md->md_addr + staging + + roundup2(sizeof(struct efi_map_header), 16) - fp->f_addr; + trampoline_data->memmap_src = efi_map_phys_src; + trampoline_data->memmap_dst = efi_map_phys_dst; + trampoline_data->memmap_len = efi_map_size - roundup2(sizeof(struct efi_map_header), 16); + printf("Copying UEFI Memory Map data from %#lx to %#lx %ld bytes\n", + efi_map_phys_src, + trampoline_data->memmap_dst, + trampoline_data->memmap_len); + } + } + /* + * Copy the trampoline to the ksegs. Since we're just bouncing off of + * this into the kernel, no need to preserve the pages. On arm64, the + * kernel sets up the initial page table, so we don't have to preserve + * the memory used for the trampoline past when it calls the kernel. + */ + printf("kernendp = %#llx\n", (long long)kernendp); + trampolinebase = staging + (kernendp - fp->f_addr); + printf("trampolinebase = %#llx\n", (long long)trampolinebase); + archsw.arch_copyin((void *)trampcode, kernendp, tramp_size); + printf("Trampoline bouncing to %#llx\n", (long long)trampoline_data->entry); + + if (archsw.arch_kexec_kseg_get == NULL) + panic("architecture did not provide kexec segment mapping"); + archsw.arch_kexec_kseg_get(&nseg, &kseg); + error = host_kexec_load(trampolinebase, nseg, kseg, HOST_KEXEC_ARCH_AARCH64); + if (error != 0) + panic("kexec_load returned error: %d", error); + host_reboot(HOST_REBOOT_MAGIC1, HOST_REBOOT_MAGIC2, HOST_REBOOT_CMD_KEXEC, 0); +#endif + panic("exec returned"); } diff --git a/stand/kboot/arch/aarch64/tramp.S b/stand/kboot/arch/aarch64/tramp.S index 1edb6823bdc9..9304ca325299 100644 --- a/stand/kboot/arch/aarch64/tramp.S +++ b/stand/kboot/arch/aarch64/tramp.S @@ -21,47 +21,81 @@ * struct trampoline_data { * uint64_t entry; // 0 (PA where kernel loaded) * uint64_t modulep; // 8 module metadata + * uint64_t memmap_src; // 16 Linux-provided memory map PA + * uint64_t memmap_dst; // 24 Module data copy PA + * uint64_t memmap_len; // 32 Length to copy * }; * - * The aarch64 _start routine assumes: + * FreeBSD's arm64 entry point is _start which assumes: * MMU on with an identity map, or off * D-Cache: off * I-Cache: on or off * We are loaded at a 2MiB aligned address * Module data (modulep) pointer in x0 * - * Unlike EFI, we don't support copying the staging area. We tell Linunx to land - * the kernel in its final location with the needed alignment, etc. + * The rest of the boot loader tells Linux to land the kernel in its final + * location with the needed alignment, etc. It does this, and then we take over. * - * This trampoline installs sets up the arguments the kernel expects, flushes - * the cache lines and jumps to the kernel _start address. We pass the modulep - * pointer in x0, as _start expects. + * The linux kernel will helpfully turn off the MMU, flush the caches, disables + * them, etc. It calls the tramp with two args: FDT blob addresss in x0 and the + * EL2 vectors in x1. Currently, we make use of neither of these parameters: we + * pass whatever dtb we think we need as part of the module data and we're a bit + * weak on hypervisor support at the moment. _start's requirements are all + * satisifed. + * + * This trampoline sets up the arguments the kernel expects and jumps to the + * kernel _start address. We pass the modulep pointer in x0, as _start + * expects. We assume that the various cache flushing, invalidation, etc that + * linux did during or after copying the data down is sufficient, though we may + * need to be mindful of cache flushing if we run in EL2 (TBD). + * + * Note, if TRAMP_MEMMAP_SRC is non-zero, then we have to copy the Linux + * provided UEFI memory map. It's easier to do that here. In kboot we couldn't + * access the physical memory, and it's a chicken and egg problem later in the + * kernel. */ + +#define TRAMP_ENTRY 0 +#define TRAMP_MODULEP 8 +#define TRAMP_MEMMAP_SRC 16 +#define TRAMP_MEMMAP_DST 24 +#define TRAMP_MEMMAP_LEN 32 +#define TRAMP_TOTAL 40 + .text - .globl aarch64_tramp -aarch64_tramp: - b 1f /* skip over our saved args */ - .p2align 3 -trampoline_data: -#define TRAMP_ENTRY 0 -#define TRAMP_MODULEP 8 -#define TRAMP_TOTAL 16 - .space TRAMP_TOTAL -#define TMPSTACKSIZE 48 /* 16 bytes for args +8 for pushq/popfq + 24 spare */ + .globl tramp +tramp: + adr x8, trampoline_data + ldr x10, [x8, #TRAMP_MEMMAP_SRC] + cmp x10, xzr + b.eq 9f + + /* + * Copy over the memory map into area we have reserved for it. Assume + * the copy is a multiple of 8, since we know table entries are made up + * of several 64-bit quantities. + */ + ldp x11, x12, [x8, #TRAMP_MEMMAP_DST] /* x12 = len */ 1: - adr x2, trampoline_data - ldr x1, [x2, #TRAMP_ENTRY] - ldr x0, [x2, #TRAMP_MODULEP] - br x1 + ldr x13, [x10], #8 + str x13, [x11], #8 + subs x12, x12, #8 + b.hi 1b +9: + ldp x9, x0, [x8, #TRAMP_ENTRY] /* x0 = modulep */ + br x9 .p2align 4 +trampoline_data: + .space TRAMP_TOTAL +#define TMPSTACKSIZE 48 /* 16 bytes for args +8 for pushq/popfq + 24 spare */ .space TMPSTACKSIZE -aarch64_tramp_end: /* padding doubles as stack */ +tramp_end: /* padding doubles as stack */ .data - .globl aarch64_tramp_size -aarch64_tramp_size: - .long aarch64_tramp_end-aarch64_tramp - .globl aarch64_tramp_data_offset -aarch64_tramp_data_offset: - .long trampoline_data-aarch64_tramp + .globl tramp_size +tramp_size: + .long tramp_end-tramp + .globl tramp_data_offset +tramp_data_offset: + .long trampoline_data-tramp
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