:: commit 916994f07223472903d2597453c7be96f1419775
multiboot: Backport b92d48e to multiboot1
diff --git a/common/protos/multiboot.h b/common/protos/multiboot.h
new file mode 100644
index 00000000..d1aaeff6
--- /dev/null
+++ b/common/protos/multiboot.h
@@ -0,0 +1,13 @@
+#ifndef __PROTOS__MULTIBOOT_H__
+#define __PROTOS__MULTIBOOT_H__
+
+#include <stdint.h>
+
+struct mb_reloc_stub {
+ char jmp[4];
+ uint32_t magic;
+ uint32_t entry_point;
+ uint32_t mb_info_target;
+};
+
+#endif
diff --git a/common/protos/multiboot1.32.c b/common/protos/multiboot1.32.c
index e4b77d19..b67eb3b0 100644
--- a/common/protos/multiboot1.32.c
+++ b/common/protos/multiboot1.32.c
@@ -6,8 +6,14 @@
#if bios == 1
# include <sys/idt.h>
#endif
-
-noreturn void multiboot1_spinup_32(uint32_t entry_point, uint32_t multiboot1_info) {
+#include <protos/multiboot.h>
+
+noreturn void multiboot1_spinup_32(uint32_t entry_point,
+ uint32_t multiboot1_info, uint32_t mb_info_target,
+ uint32_t mb_info_size,
+ uint32_t elf_ranges, uint32_t elf_ranges_count,
+ uint32_t slide,
+ struct mb_reloc_stub *reloc_stub) {
#if bios == 1
struct idtr idtr;
@@ -22,22 +28,16 @@ noreturn void multiboot1_spinup_32(uint32_t entry_point, uint32_t multiboot1_inf
);
#endif
- asm volatile (
- "cld\n\t"
-
- "push %2\n\t"
+ reloc_stub->magic = 0x2badb002;
+ reloc_stub->entry_point = entry_point;
+ reloc_stub->mb_info_target = mb_info_target;
- "xor %%ecx, %%ecx\n\t"
- "xor %%edx, %%edx\n\t"
- "xor %%esi, %%esi\n\t"
- "xor %%edi, %%edi\n\t"
- "xor %%ebp, %%ebp\n\t"
-
- "ret\n\t"
+ asm volatile (
+ "jmp *%%ebx"
:
- : "a" (0x2badb002),
- "b" (multiboot1_info),
- "r" (entry_point)
+ : "b"(reloc_stub), "S"(multiboot1_info),
+ "c"(mb_info_size), "a"(elf_ranges), "d"(elf_ranges_count),
+ "D"(slide)
: "memory"
);
diff --git a/common/protos/multiboot1.c b/common/protos/multiboot1.c
index e562a203..9aacae80 100644
--- a/common/protos/multiboot1.c
+++ b/common/protos/multiboot1.c
@@ -19,10 +19,18 @@
#include <mm/pmm.h>
#include <drivers/vga_textmode.h>
+extern symbol multiboot_reloc_stub, multiboot_reloc_stub_end;
+
noreturn void multiboot1_spinup_32(uint32_t entry_point, uint32_t multiboot1_info);
static uint32_t kernel_top;
+static bool mb1_overlap_check(uint64_t base1, uint64_t top1,
+ uint64_t base2, uint64_t top2) {
+ return ((base1 >= base2 && base1 < top2)
+ || (top1 > base2 && top1 <= top2));
+}
+
static void *mb1_alloc(size_t size) {
void *ret = (void *)(uintptr_t)ALIGN_UP(kernel_top, 4096);
@@ -70,8 +78,6 @@ bool multiboot1_load(char *config, char *cmdline) {
print("multiboot1: Loading kernel `%s`...\n", kernel_path);
- struct multiboot1_info *multiboot1_info = conv_mem_alloc(sizeof(struct multiboot1_info));
-
if (header.magic + header.flags + header.checksum)
panic(true, "multiboot1: Header checksum is invalid");
@@ -79,6 +85,9 @@ bool multiboot1_load(char *config, char *cmdline) {
struct elf_section_hdr_info *section_hdr_info = NULL;
+ struct elf_range *elf_ranges;
+ uint64_t elf_ranges_count, slide;
+
if (header.flags & (1 << 16)) {
if (header.load_addr > header.header_addr)
panic(true, "multiboot1: Illegal load address");
@@ -125,15 +134,21 @@ bool multiboot1_load(char *config, char *cmdline) {
switch (bits) {
case 32:
- if (elf32_load(kernel, &entry_point, &kernel_top, MEMMAP_KERNEL_AND_MODULES))
+ if (elf32_load(kernel, &entry_point, &kernel_top, MEMMAP_BOOTLOADER_RECLAIMABLE))
panic(true, "multiboot1: ELF32 load failure");
break;
case 64: {
uint64_t e, t;
- if (elf64_load(kernel, &e, &t, NULL, MEMMAP_KERNEL_AND_MODULES, false, true, NULL, NULL, false, NULL, NULL, NULL, NULL))
+ if (elf64_load(kernel, &e, &t, &slide, MEMMAP_BOOTLOADER_RECLAIMABLE, false, true, &elf_ranges, &elf_ranges_count, false, NULL, NULL, NULL, NULL))
panic(true, "multiboot1: ELF64 load failure");
- entry_point = e;
- kernel_top = t;
+ entry_point = e - slide;
+
+ t -= slide;
+ if (t < 0x100000) {
+ kernel_top = 0x100000;
+ } else {
+ kernel_top = t;
+ }
break;
}
@@ -142,6 +157,43 @@ bool multiboot1_load(char *config, char *cmdline) {
}
}
+ // GRUB allocates boot info at 0x10000, *except* if the kernel happens
+ // to overlap this region, then it gets moved to right after the
+ // kernel, or whichever PHDR happens to sit at 0x10000.
+ // Allocate it wherever, then move it to where GRUB puts it
+ // afterwards.
+ size_t mb1_info_size = sizeof(struct multiboot1_info);
+ struct multiboot1_info *multiboot1_info = ext_mem_alloc(mb1_info_size);
+ uint64_t mb1_info_final_loc = 0x10000;
+retry_mb1_info_reloc:
+ for (size_t i = 0; i < elf_ranges_count; i++) {
+ uint64_t mb1_info_top = mb1_info_final_loc + mb1_info_size;
+
+ uint64_t base = elf_ranges[i].base - slide;
+ uint64_t length = elf_ranges[i].length - slide;
+ uint64_t top = base + length;
+
+ // Do they overlap?
+ if (mb1_overlap_check(base, top, mb1_info_final_loc, mb1_info_top)) {
+ mb1_info_final_loc = top;
+ goto retry_mb1_info_reloc;
+ }
+
+ // Make sure it is memory that actually exists.
+ if (!memmap_alloc_range(mb1_info_final_loc, mb1_info_size, MEMMAP_BOOTLOADER_RECLAIMABLE,
+ MEMMAP_USABLE, false, true, false)) {
+ if (!memmap_alloc_range(mb1_info_final_loc, mb1_info_size, MEMMAP_BOOTLOADER_RECLAIMABLE,
+ MEMMAP_BOOTLOADER_RECLAIMABLE, false, true, false)) {
+ mb1_info_final_loc += 0x1000;
+ goto retry_mb1_info_reloc;
+ }
+ }
+ }
+
+ if (mb1_info_final_loc + mb1_info_size > kernel_top) {
+ kernel_top = mb1_info_final_loc + mb1_info_size;
+ }
+
if (section_hdr_info != NULL) {
multiboot1_info->elf_sect.num = section_hdr_info->num;
multiboot1_info->elf_sect.size = section_hdr_info->section_entry_size;
@@ -169,7 +221,6 @@ bool multiboot1_load(char *config, char *cmdline) {
multiboot1_info->flags |= (1 << 5);
}
-
uint32_t n_modules;
for (n_modules = 0; ; n_modules++) {
@@ -298,6 +349,11 @@ nofb:;
#endif
}
+ // Load relocation stub where it won't get overwritten
+ size_t reloc_stub_size = (size_t)multiboot_reloc_stub_end - (size_t)multiboot_reloc_stub;
+ void *reloc_stub = mb1_alloc(reloc_stub_size);
+ memcpy(reloc_stub, multiboot_reloc_stub, reloc_stub_size);
+
#if uefi == 1
efi_exit_boot_services();
#endif
@@ -331,6 +387,11 @@ nofb:;
irq_flush_type = IRQ_PIC_ONLY_FLUSH;
- common_spinup(multiboot1_spinup_32, 2,
- entry_point, (uint32_t)(uintptr_t)multiboot1_info);
+ common_spinup(multiboot1_spinup_32, 8,
+ entry_point,
+ (uint32_t)(uintptr_t)multiboot1_info, (uint32_t)mb1_info_final_loc,
+ (uint32_t)mb1_info_size,
+ (uint32_t)(uintptr_t)elf_ranges, (uint32_t)elf_ranges_count,
+ (uint32_t)slide,
+ (uint32_t)(uintptr_t)reloc_stub);
}
diff --git a/common/protos/multiboot2.32.c b/common/protos/multiboot2.32.c
index e4c79ff6..c73ee8b4 100644
--- a/common/protos/multiboot2.32.c
+++ b/common/protos/multiboot2.32.c
@@ -6,20 +6,14 @@
#if bios == 1
# include <sys/idt.h>
#endif
-
-struct reloc_stub {
- char jmp[4];
- uint32_t magic;
- uint32_t entry_point;
- uint32_t mb_info_target;
-};
+#include <protos/multiboot.h>
noreturn void multiboot2_spinup_32(uint32_t entry_point,
uint32_t multiboot2_info, uint32_t mb_info_target,
uint32_t mb_info_size,
uint32_t elf_ranges, uint32_t elf_ranges_count,
uint32_t slide,
- struct reloc_stub *reloc_stub) {
+ struct mb_reloc_stub *reloc_stub) {
#if bios == 1
struct idtr idtr;
