diff --git a/conf/i386.rmk b/conf/i386.rmk
index 72ea6d465..2efd9895a 100644
--- a/conf/i386.rmk
+++ b/conf/i386.rmk
@@ -17,7 +17,7 @@ vga_text_mod_LDFLAGS = $(COMMON_LDFLAGS)
pkglib_MODULES += relocator.mod
relocator_mod_SOURCES = lib/relocator.c lib/i386/relocator32.S \
- lib/i386/relocator64.S \
+ lib/i386/relocator64.S lib/i386/relocator16.S \
lib/i386/relocator_asm.S lib/i386/relocator.c
relocator_mod_CFLAGS = $(COMMON_CFLAGS)
relocator_mod_ASFLAGS = $(COMMON_ASFLAGS)
diff --git a/include/grub/i386/relocator.h b/include/grub/i386/relocator.h
index ac49dd29e..f32413a1b 100644
--- a/include/grub/i386/relocator.h
+++ b/include/grub/i386/relocator.h
@@ -34,6 +34,18 @@ struct grub_relocator32_state
grub_uint32_t esi;
};
+struct grub_relocator16_state
+{
+ grub_uint16_t cs;
+ grub_uint16_t ds;
+ grub_uint16_t es;
+ grub_uint16_t fs;
+ grub_uint16_t gs;
+ grub_uint16_t ss;
+ grub_uint16_t sp;
+ grub_uint16_t ip;
+};
+
struct grub_relocator64_state
{
grub_uint64_t rsp;
@@ -46,6 +58,9 @@ struct grub_relocator64_state
grub_addr_t cr3;
};
+grub_err_t grub_relocator16_boot (struct grub_relocator *rel,
+ struct grub_relocator16_state state);
+
grub_err_t grub_relocator32_boot (struct grub_relocator *rel,
struct grub_relocator32_state state);
diff --git a/lib/i386/relocator.c b/lib/i386/relocator.c
index 6e1e13b04..5757bb6df 100644
--- a/lib/i386/relocator.c
+++ b/lib/i386/relocator.c
@@ -39,6 +39,17 @@ extern void *grub_relocator_forward_dest;
extern void *grub_relocator_forward_src;
extern grub_size_t grub_relocator_forward_chunk_size;
+extern grub_uint8_t grub_relocator16_start;
+extern grub_uint8_t grub_relocator16_end;
+extern grub_uint16_t grub_relocator16_cs;
+extern grub_uint16_t grub_relocator16_ip;
+extern grub_uint16_t grub_relocator16_ds;
+extern grub_uint16_t grub_relocator16_es;
+extern grub_uint16_t grub_relocator16_fs;
+extern grub_uint16_t grub_relocator16_gs;
+extern grub_uint16_t grub_relocator16_ss;
+extern grub_uint16_t grub_relocator16_sp;
+
extern grub_uint8_t grub_relocator32_start;
extern grub_uint8_t grub_relocator32_end;
extern grub_uint32_t grub_relocator32_eax;
@@ -155,6 +166,46 @@ grub_relocator32_boot (struct grub_relocator *rel,
return GRUB_ERR_NONE;
}
+grub_err_t
+grub_relocator16_boot (struct grub_relocator *rel,
+ struct grub_relocator16_state state)
+{
+ grub_addr_t target;
+ void *src;
+ grub_err_t err;
+ grub_addr_t relst;
+
+ err = grub_relocator_alloc_chunk_align (rel, &src, &target, 0,
+ 0xa0000 - RELOCATOR_SIZEOF (16),
+ RELOCATOR_SIZEOF (16), 16,
+ GRUB_RELOCATOR_PREFERENCE_NONE);
+ if (err)
+ return err;
+
+ grub_relocator16_cs = state.cs;
+ grub_relocator16_ip = state.ip;
+
+ grub_relocator16_ds = state.ds;
+ grub_relocator16_es = state.es;
+ grub_relocator16_fs = state.fs;
+ grub_relocator16_gs = state.gs;
+
+ grub_relocator16_ss = state.ss;
+ grub_relocator16_sp = state.sp;
+
+ grub_memmove (src, &grub_relocator16_start, RELOCATOR_SIZEOF (16));
+
+ err = grub_relocator_prepare_relocs (rel, target, &relst);
+ if (err)
+ return err;
+
+ asm volatile ("cli");
+ ((void (*) (void)) relst) ();
+
+ /* Not reached. */
+ return GRUB_ERR_NONE;
+}
+
grub_err_t
grub_relocator64_boot (struct grub_relocator *rel,
struct grub_relocator64_state state,
diff --git a/lib/i386/relocator16.S b/lib/i386/relocator16.S
new file mode 100644
index 000000000..d35adecd8
--- /dev/null
+++ b/lib/i386/relocator16.S
@@ -0,0 +1,225 @@
+/*
+ * GRUB -- GRand Unified Bootloader
+ * Copyright (C) 2009,2010 Free Software Foundation, Inc.
+ *
+ * GRUB is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * GRUB is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with GRUB. If not, see .
+ */
+
+#include
+#include
+
+#ifdef __x86_64__
+#define RAX %rax
+#define RSI %rdi
+#else
+#define RAX %eax
+#define RSI %esi
+#endif
+
+/* The code segment of the protected mode. */
+#define CODE_SEGMENT 0x08
+
+/* The data segment of the protected mode. */
+#define DATA_SEGMENT 0x10
+
+#define PSEUDO_REAL_CSEG 0x18
+
+#define PSEUDO_REAL_DSEG 0x20
+
+ .p2align 4 /* force 16-byte alignment */
+
+VARIABLE(grub_relocator16_start)
+LOCAL(base):
+ /* %rax contains now our new 'base'. */
+ mov RAX, RSI
+ add $(LOCAL(cont0) - LOCAL(base)), RAX
+ jmp *RAX
+LOCAL(cont0):
+ lea (LOCAL(cont1) - LOCAL(base)) (RSI, 1), RAX
+ movl %eax, (LOCAL(jump_vector) - LOCAL(base)) (RSI, 1)
+
+ lea (LOCAL(gdt) - LOCAL(base)) (RSI, 1), RAX
+ mov RAX, (LOCAL(gdt_addr) - LOCAL(base)) (RSI, 1)
+
+ movl %esi, %eax
+ movw %ax, (LOCAL (cs_base_bytes12) - LOCAL (base)) (RSI, 1)
+ shrl $16, %eax
+ movb %al, (LOCAL (cs_base_byte3) - LOCAL (base)) (RSI, 1)
+
+ /* Switch to compatibility mode. */
+
+ lgdt (LOCAL(gdtdesc) - LOCAL(base)) (RSI, 1)
+
+ /* Update %cs. */
+ ljmp *(LOCAL(jump_vector) - LOCAL(base)) (RSI, 1)
+
+LOCAL(cont1):
+ .code32
+
+ /* Disable paging. */
+ movl %cr0, %eax
+ andl $(~GRUB_MEMORY_CPU_CR0_PAGING_ON), %eax
+ movl %eax, %cr0
+
+ /* Disable amd64. */
+ movl $GRUB_MEMORY_CPU_AMD64_MSR, %ecx
+ rdmsr
+ andl $(~GRUB_MEMORY_CPU_AMD64_MSR_ON), %eax
+ wrmsr
+
+ /* Turn off PAE. */
+ movl %cr4, %eax
+ andl $GRUB_MEMORY_CPU_CR4_PAE_ON, %eax
+ movl %eax, %cr4
+
+ /* Update other registers. */
+ movl $PSEUDO_REAL_DSEG, %eax
+ movl %eax, %ds
+ movl %eax, %es
+ movl %eax, %fs
+ movl %eax, %gs
+ movl %eax, %ss
+
+ movl %esi, %eax
+ shrl $4, %eax
+ movw %ax, (LOCAL (segment) - LOCAL (base)) (RSI, 1)
+
+ /* jump to a 16 bit segment */
+ ljmp $PSEUDO_REAL_CSEG, $(LOCAL (cont2) - LOCAL(base))
+LOCAL(cont2):
+ .code16
+
+ /* clear the PE bit of CR0 */
+ movl %cr0, %eax
+ andl $(~GRUB_MEMORY_CPU_CR0_PE_ON), %eax
+ movl %eax, %cr0
+
+ /* flush prefetch queue, reload %cs */
+ /* ljmp */
+ .byte 0xea
+ .word LOCAL(cont3)-LOCAL(base)
+LOCAL(segment):
+ .word 0
+
+LOCAL(cont3):
+ /* we are in real mode now
+ * set up the real mode segment registers : DS, SS, ES
+ */
+ /* movw imm16, %ax. */
+ .byte 0xb8
+VARIABLE(grub_relocator16_ds)
+ .word 0
+ movw %ax, %ds
+
+ /* movw imm16, %ax. */
+ .byte 0xb8
+VARIABLE(grub_relocator16_es)
+ .word 0
+ movw %ax, %es
+
+ /* movw imm16, %ax. */
+ .byte 0xb8
+VARIABLE(grub_relocator16_fs)
+ .word 0
+ movw %ax, %fs
+
+ /* movw imm16, %ax. */
+ .byte 0xb8
+VARIABLE(grub_relocator16_gs)
+ .word 0
+ movw %ax, %gs
+
+ /* movw imm16, %ax. */
+ .byte 0xb8
+VARIABLE(grub_relocator16_ss)
+ .word 0
+ movw %ax, %ss
+
+ /* movw imm16, %ax. */
+ .byte 0xb8
+VARIABLE(grub_relocator16_sp)
+ .word 0
+ movw %ax, %ss
+
+ /* Cleared direction flag is of no problem with any current
+ payload and makes this implementation easier. */
+ cld
+
+ /* ljmp */
+ .byte 0xea
+VARIABLE(grub_relocator16_ip)
+ .word 0
+VARIABLE(grub_relocator16_cs)
+ .word 0
+
+ .code32
+
+ /* GDT. Copied from loader/i386/linux.c. */
+ .p2align 4
+LOCAL(gdt):
+ .word 0, 0
+ .byte 0, 0, 0, 0
+
+ /* -- code segment --
+ * base = 0x00000000, limit = 0xFFFFF (4 KiB Granularity), present
+ * type = 32bit code execute/read, DPL = 0
+ */
+ .word 0xFFFF, 0
+ .byte 0, 0x9A, 0xCF, 0
+
+ /* -- data segment --
+ * base = 0x00000000, limit 0xFFFFF (4 KiB Granularity), present
+ * type = 32 bit data read/write, DPL = 0
+ */
+ .word 0xFFFF, 0
+ .byte 0, 0x92, 0xCF, 0
+
+ /* -- 16 bit real mode CS --
+ * base = 0x00000000, limit 0x0FFFF (1 B Granularity), present
+ * type = 16 bit code execute/read only/conforming, DPL = 0
+ */
+ .word 0xFFFF
+LOCAL(cs_base_bytes12):
+ .word 0
+LOCAL(cs_base_byte3):
+ .byte 0
+
+ .byte 0x9E, 0, 0
+
+ /* -- 16 bit real mode DS --
+ * base = 0x00000000, limit 0x0FFFF (1 B Granularity), present
+ * type = 16 bit data read/write, DPL = 0
+ */
+ .word 0xFFFF, 0
+ .byte 0, 0x92, 0, 0
+
+ .p2align 4
+LOCAL(gdtdesc):
+ .word 0x27
+LOCAL(gdt_addr):
+#ifdef __x86_64__
+ /* Filled by the code. */
+ .quad 0
+#else
+ /* Filled by the code. */
+ .long 0
+#endif
+
+ .p2align 4
+LOCAL(jump_vector):
+ /* Jump location. Is filled by the code */
+ .long 0
+ .long CODE_SEGMENT
+
+VARIABLE(grub_relocator16_end)