Mike Kelly, le sam. 26 sept. 2026 23:28:45 +0100, a ecrit:
> multiboot2 now boots so removed the protective panic when it is used.
As mentioned before, it looks nicer to me to just have panics in the
unimplemented places, rather than in a place that needs to be updated
exactly at the proper time in the patch series. With panics in
unimplemented places, the kernel will naturally panic when it reaches
whatever was not implemented yet.
Samuel
> ---
> i386/i386at/model_dep.c | 181 +++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 177 insertions(+), 4 deletions(-)
>
> diff --git a/i386/i386at/model_dep.c b/i386/i386at/model_dep.c
> index b28a3b5f..36773ae3 100644
> --- a/i386/i386at/model_dep.c
> +++ b/i386/i386at/model_dep.c
> @@ -490,11 +490,186 @@ finalise_mb1_boot_info(void)
> }
> }
>
> +static const char* const mb2_alloc_mem_failed =
> + "Cannot allocate memory for multiboot2 conversion\n";
> +
> +/* Rebuild multiboot1 'boot_info' from the multiboot2 data structure. */
> static void
> finalise_mb2_boot_info(const struct multiboot2_raw_info *mb2_info)
> {
> - /* Not implemented yet. */
> - (void)mb2_info;
> + const uint32_t tags_len =
> + (mb2_info->total_size - offsetof(struct multiboot2_raw_info, content));
> + uint32_t mod_count = 0;
> + uint32_t offset = 0;
> +
> + boot_info.flags = 0;
> +
> + while (offset < tags_len)
> + {
> + const struct multiboot2_tag *tag =
> + (const struct multiboot2_tag *)&mb2_info->content[offset];
> +
> + if (tag->type == MULTIBOOT2_TAG_TYPE_MODULE)
> + mod_count++;
> +
> + offset += MULTIBOOT2_NEXT_TAG_OFFSET(tag->size);
> + }
> +
> + if (mod_count)
> + {
> + size_t mod_sz = (mod_count * sizeof(struct multiboot_raw_module));
> + vm_offset_t addr;
> +
> + if (! init_alloc_aligned(round_page(mod_sz), &addr))
> + panic(mb2_alloc_mem_failed);
> +
> + boot_info.mods_addr = addr;
> + boot_info.flags |= MULTIBOOT_MODS;
> + }
> +
> + /* Initialise to zero in all cases and increment below as each
> + module is added. */
> + boot_info.mods_count = 0;
> +
> + offset = 0;
> +
> + while (offset < tags_len)
> + {
> + const struct multiboot2_tag *tag =
> + (const struct multiboot2_tag *)&mb2_info->content[offset];
> +
> + switch (tag->type)
> + {
> + case MULTIBOOT2_TAG_TYPE_MMAP:
> + {
> + const struct multiboot2_tag_mmap *mmap_tag =
> + (const struct multiboot2_tag_mmap *)tag;
> +
> + const uint8_t *mb2_entries = (const uint8_t *)mmap_tag->entries;
> + const uint8_t *mb2_entries_end =
> + mb2_entries + tag->size - offsetof(struct multiboot2_tag_mmap,
> entries);
> + size_t buf_sz = ((mb2_entries_end - mb2_entries)
> + / mmap_tag->entry_size
> + * sizeof(struct multiboot_raw_mmap_entry));
> + vm_offset_t addr;
> +
> + if (! init_alloc_aligned(round_page(buf_sz), &addr))
> + panic(mb2_alloc_mem_failed);
> +
> + struct multiboot_raw_mmap_entry* mb1_entry =
> + (struct multiboot_raw_mmap_entry *)phystokv(addr);
> +
> + while (mb2_entries < mb2_entries_end)
> + {
> + const multiboot2_memory_map_t *mb2_entry =
> + (const multiboot2_memory_map_t *)mb2_entries;
> +
> + mb1_entry->size = (sizeof(*mb1_entry) -
> sizeof(mb1_entry->size));
> + mb1_entry->base_addr = mb2_entry->addr;
> + mb1_entry->length = mb2_entry->len;
> + mb1_entry->type = mb2_entry->type;
> +
> + mb2_entries += mmap_tag->entry_size;
> + mb1_entry++;
> + }
> +
> + boot_info.mmap_addr = addr;
> + boot_info.mmap_length = buf_sz;
> + boot_info.flags |= MULTIBOOT_MEM_MAP;
> + }
> + break;
> +
> + case MULTIBOOT2_TAG_TYPE_BASIC_MEMINFO:
> + {
> + const struct multiboot2_tag_basic_meminfo *bi_tag =
> + (const struct multiboot2_tag_basic_meminfo *)tag;
> +
> + boot_info.mem_lower = bi_tag->mem_lower;
> + boot_info.mem_upper = bi_tag->mem_upper;
> + boot_info.flags |= MULTIBOOT_MEMORY;
> + }
> + break;
> +
> + case MULTIBOOT2_TAG_TYPE_CMDLINE:
> + {
> + const struct multiboot2_tag_string *cl_tag =
> + (const struct multiboot2_tag_string *)tag;
> +
> + const size_t cl_sz = (cl_tag->size - sizeof(struct multiboot2_tag));
> + vm_offset_t addr;
> +
> + if (! init_alloc_aligned(round_page(cl_sz), &addr))
> + panic(mb2_alloc_mem_failed);
> +
> + memcpy((void*)phystokv(addr), cl_tag->string, cl_sz);
> + boot_info.cmdline = addr;
> + boot_info.flags |= MULTIBOOT_CMDLINE;
> + }
> + break;
> +
> + case MULTIBOOT2_TAG_TYPE_ELF_SECTIONS:
> + {
> + const struct multiboot2_tag_elf_sections *elf_tag =
> + (const struct multiboot2_tag_elf_sections *)tag;
> +
> + const size_t sections_sz =
> + (elf_tag->size
> + - offsetof(struct multiboot2_tag_elf_sections, sections));
> + vm_offset_t addr;
> +
> + if (! init_alloc_aligned(round_page(sections_sz), &addr))
> + panic(mb2_alloc_mem_failed);
> +
> + memcpy((void*)phystokv(addr), elf_tag->sections, sections_sz);
> + boot_info.shdr_num = elf_tag->num;
> + boot_info.shdr_size = elf_tag->entsize;
> + boot_info.shdr_addr = addr;
> + boot_info.shdr_strndx = elf_tag->shndx;
> + boot_info.flags |= MULTIBOOT_ELF_SHDR;
> + }
> + break;
> +
> + case MULTIBOOT2_TAG_TYPE_MODULE:
> + {
> + const struct multiboot2_tag_module *mod_tag =
> + (const struct multiboot2_tag_module *)tag;
> +
> + struct multiboot_raw_module * module =
> + (struct multiboot_raw_module *)phystokv(boot_info.mods_addr) +
> + boot_info.mods_count;
> +
> + vm_offset_t addr;
> + vm_size_t mod_sz = (mod_tag->mod_end - mod_tag->mod_start);
> + if (! init_alloc_aligned(round_page(mod_sz), &addr))
> + panic(mb2_alloc_mem_failed);
> + memcpy((void*) phystokv(addr), (void*)
> phystokv(mod_tag->mod_start), mod_sz);
> + module->mod_start = addr;
> + module->mod_end = (addr + mod_sz);
> +
> + size_t cl_sz = (mod_tag->size - offsetof(struct
> multiboot2_tag_module, cmdline));
> +
> + if (! init_alloc_aligned(round_page(cl_sz), &addr))
> + panic(mb2_alloc_mem_failed);
> +
> + memcpy((void*)phystokv(addr), &mod_tag->cmdline, cl_sz);
> + module->string = addr;
> +
> + boot_info.flags |= MULTIBOOT_MODS;
> + boot_info.mods_count++;
> + }
> + break;
> +
> + default:
> + break;
> + }
> +
> + offset += MULTIBOOT2_NEXT_TAG_OFFSET(tag->size);
> + }
> +
> + if (boot_info.flags & MULTIBOOT_CMDLINE)
> + kernel_cmdline = (char*)phystokv(boot_info.cmdline);
> +
> + mbinfo_register_boot_data(&boot_info);
> }
>
> #endif /* MACH_HYP */
> @@ -644,8 +819,6 @@ void c_boot_entry(vm_offset_t bi)
> memory bootstrapping which means that we cannot
> immediately use 'boot_info'. */
> mb2_info = (const struct multiboot2_raw_info *)phystokv(bi);
> -
> - panic("Multiboot2 not implemented yet");
> }
> else if (magic != MULTIBOOT_LOADER_MAGIC)
> {
> --
> 2.47.3
>
>
--
Samuel
j'etais en train de nettoyer ma souris et le coup est parti...
-+- s sur #ens-mim - et en plus c vrai... -+-
