mirror of
https://github.com/xcat2/xNBA.git
synced 2024-12-14 23:31:39 +00:00
Use full protected mode for access to high memory within prefix, to
work around limitations in real-mode virtualisation support on Intel VT-capable chips.
This commit is contained in:
Michael Brown
parent
a7eee64506
commit
dec325fe43
@ -47,17 +47,181 @@
|
||||
.section ".data16", "aw", @progbits
|
||||
|
||||
/****************************************************************************
|
||||
* install_block (real-mode near call)
|
||||
* pm_call (real-mode near call)
|
||||
*
|
||||
* Call routine in 16-bit protected mode for access to extended memory
|
||||
*
|
||||
* Parameters:
|
||||
* %ax : address of routine to call in 16-bit protected mode
|
||||
* Returns:
|
||||
* none
|
||||
* Corrupts:
|
||||
* %ax
|
||||
*
|
||||
* The specified routine is called in 16-bit protected mode, with:
|
||||
*
|
||||
* %cs : 16-bit code segment with base matching real-mode %cs
|
||||
* %ss : 16-bit data segment with base matching real-mode %ss
|
||||
* %ds,%es,%fs,%gs : 32-bit data segment with zero base and 4GB limit
|
||||
*
|
||||
****************************************************************************
|
||||
*/
|
||||
|
||||
#ifndef KEEP_IT_REAL
|
||||
|
||||
/* GDT for protected-mode calls */
|
||||
.section ".data16"
|
||||
.align 16
|
||||
gdt:
|
||||
gdt_limit: .word gdt_length - 1
|
||||
gdt_base: .long 0
|
||||
.word 0 /* padding */
|
||||
pm_cs: /* 16-bit protected-mode code segment */
|
||||
.equ PM_CS, pm_cs - gdt
|
||||
.word 0xffff, 0
|
||||
.byte 0, 0x9b, 0x00, 0
|
||||
pm_ss: /* 16-bit protected-mode stack segment */
|
||||
.equ PM_SS, pm_ss - gdt
|
||||
.word 0xffff, 0
|
||||
.byte 0, 0x93, 0x00, 0
|
||||
pm_ds: /* 32-bit protected-mode flat data segment */
|
||||
.equ PM_DS, pm_ds - gdt
|
||||
.word 0xffff, 0
|
||||
.byte 0, 0x93, 0xcf, 0
|
||||
gdt_end:
|
||||
.equ gdt_length, . - gdt
|
||||
.size gdt, . - gdt
|
||||
|
||||
.section ".data16"
|
||||
.align 16
|
||||
pm_saved_gdt:
|
||||
.long 0, 0
|
||||
.size pm_saved_gdt, . - pm_saved_gdt
|
||||
|
||||
.section ".prefix.lib"
|
||||
.code16
|
||||
pm_call:
|
||||
/* Preserve registers, flags, GDT, and RM return point */
|
||||
pushfl
|
||||
sgdt pm_saved_gdt
|
||||
pushw %gs
|
||||
pushw %fs
|
||||
pushw %es
|
||||
pushw %ds
|
||||
pushw %ss
|
||||
pushw %cs
|
||||
pushw $99f
|
||||
|
||||
/* Set up GDT bases */
|
||||
pushl %eax
|
||||
pushw %bx
|
||||
xorl %eax, %eax
|
||||
movw %ds, %ax
|
||||
shll $4, %eax
|
||||
addl $gdt, %eax
|
||||
movl %eax, gdt_base
|
||||
movw %cs, %ax
|
||||
movw $pm_cs, %bx
|
||||
call set_seg_base
|
||||
movw %ss, %ax
|
||||
movw $pm_ss, %bx
|
||||
call set_seg_base
|
||||
popw %bx
|
||||
popl %eax
|
||||
|
||||
/* Switch CPU to protected mode and load up segment registers */
|
||||
pushl %eax
|
||||
cli
|
||||
lgdt gdt
|
||||
movl %cr0, %eax
|
||||
orb $CR0_PE, %al
|
||||
movl %eax, %cr0
|
||||
ljmp $PM_CS, $1f
|
||||
1: movw $PM_SS, %ax
|
||||
movw %ax, %ss
|
||||
movw $PM_DS, %ax
|
||||
movw %ax, %ds
|
||||
movw %ax, %es
|
||||
movw %ax, %fs
|
||||
movw %ax, %gs
|
||||
popl %eax
|
||||
|
||||
/* Call PM routine */
|
||||
call *%ax
|
||||
|
||||
/* Set real-mode segment limits on %ds, %es, %fs and %gs */
|
||||
movw %ss, %ax
|
||||
movw %ax, %ds
|
||||
movw %ax, %es
|
||||
movw %ax, %fs
|
||||
movw %ax, %gs
|
||||
|
||||
/* Return CPU to real mode */
|
||||
movl %cr0, %eax
|
||||
andb $0!CR0_PE, %al
|
||||
movl %eax, %cr0
|
||||
|
||||
/* Restore registers and flags */
|
||||
lret
|
||||
99: popw %ss
|
||||
popw %ds
|
||||
popw %es
|
||||
popw %fs
|
||||
popw %gs
|
||||
lgdt pm_saved_gdt
|
||||
popfl
|
||||
|
||||
ret
|
||||
.size pm_call, . - pm_call
|
||||
|
||||
set_seg_base:
|
||||
rolw $4, %ax
|
||||
movw %ax, 2(%bx)
|
||||
andw $0xfff0, 2(%bx)
|
||||
movb %al, 4(%bx)
|
||||
andb $0x0f, 4(%bx)
|
||||
ret
|
||||
.size set_seg_base, . - set_seg_base
|
||||
|
||||
#endif /* KEEP_IT_REAL */
|
||||
|
||||
/****************************************************************************
|
||||
* copy_bytes (real-mode or 16-bit protected-mode near call)
|
||||
*
|
||||
* Copy bytes
|
||||
*
|
||||
* Parameters:
|
||||
* %ds:esi : source address
|
||||
* %es:edi : destination address
|
||||
* %ecx : length
|
||||
* Returns:
|
||||
* %ds:esi : next source address
|
||||
* %ds:esi : next destination address
|
||||
* Corrupts:
|
||||
* None
|
||||
****************************************************************************
|
||||
*/
|
||||
.section ".prefix.lib"
|
||||
.code16
|
||||
copy_bytes:
|
||||
pushl %ecx
|
||||
rep addr32 movsb
|
||||
popl %ecx
|
||||
ret
|
||||
.size copy_bytes, . - copy_bytes
|
||||
|
||||
/****************************************************************************
|
||||
* install_block (real-mode or 16-bit protected-mode near call)
|
||||
*
|
||||
* Install block to specified address
|
||||
*
|
||||
* Parameters:
|
||||
* %esi : start offset within loaded image (must be a multiple of 16)
|
||||
* %ds:esi : source address (must be a multiple of 16)
|
||||
* %es:edi : destination address
|
||||
* %ecx : length of (decompressed) data
|
||||
* %edx : total length of block (including any uninitialised data portion)
|
||||
* Returns:
|
||||
* %esi : end offset within image (rounded up to next multiple of 16)
|
||||
* %ds:esi : next source address (will be a multiple of 16)
|
||||
* Corrupts:
|
||||
* %edi, %ecx, %edx
|
||||
****************************************************************************
|
||||
@ -65,46 +229,26 @@
|
||||
.section ".prefix.lib"
|
||||
.code16
|
||||
install_block:
|
||||
/* Preserve registers */
|
||||
pushw %ds
|
||||
pushl %eax
|
||||
pushl %ebx
|
||||
movl %esi, %ebx
|
||||
|
||||
/* Starting segment => %ds */
|
||||
movw %cs, %ax
|
||||
shrl $4, %esi
|
||||
addw %si, %ax
|
||||
movw %ax, %ds
|
||||
xorl %esi, %esi
|
||||
|
||||
/* Calculate start and length of uninitialised data portion */
|
||||
addr32 leal (%edi,%ecx), %eax
|
||||
subl %ecx, %edx
|
||||
|
||||
/* Do the copy */
|
||||
cld
|
||||
#if COMPRESS
|
||||
/* Decompress source to destination */
|
||||
call decompress16
|
||||
#else
|
||||
rep addr32 movsb
|
||||
/* Copy source to destination */
|
||||
call copy_bytes
|
||||
#endif
|
||||
|
||||
/* Zero remaining space */
|
||||
movl %eax, %edi
|
||||
movl %edx, %ecx
|
||||
xorb %al, %al
|
||||
/* Zero .bss portion */
|
||||
negl %ecx
|
||||
addl %edx, %ecx
|
||||
pushw %ax
|
||||
xorw %ax, %ax
|
||||
rep addr32 stosb
|
||||
popw %ax
|
||||
|
||||
/* Adjust %esi */
|
||||
addl %ebx, %esi
|
||||
/* Round up %esi to start of next source block */
|
||||
addl $0xf, %esi
|
||||
andl $~0xf, %esi
|
||||
|
||||
/* Restore registers */
|
||||
popl %ebx
|
||||
popl %eax
|
||||
popw %ds
|
||||
ret
|
||||
.size install_block, . - install_block
|
||||
|
||||
@ -159,9 +303,9 @@ alloc_basemem:
|
||||
* Parameters:
|
||||
* %ax : .text16 segment address
|
||||
* %bx : .data16 segment address
|
||||
* %esi : start offset within loaded image (must be a multiple of 16)
|
||||
* %esi : source physical address (must be a multiple of 16)
|
||||
* Returns:
|
||||
* %esi : end offset within image (rounded up to next multiple of 16)
|
||||
* %esi : next source physical address (will be a multiple of 16)
|
||||
* Corrupts:
|
||||
* none
|
||||
****************************************************************************
|
||||
@ -170,43 +314,57 @@ alloc_basemem:
|
||||
.code16
|
||||
install_basemem:
|
||||
/* Preserve registers */
|
||||
pushw %ds
|
||||
pushw %es
|
||||
pushl %edi
|
||||
pushl %ecx
|
||||
pushl %edx
|
||||
|
||||
/* Install .text16 */
|
||||
pushl %esi
|
||||
shrl $4, %esi
|
||||
movw %si, %ds
|
||||
xorw %si, %si
|
||||
movw %ax, %es
|
||||
xorl %edi, %edi
|
||||
movl $_text16_size, %ecx
|
||||
movl %ecx, %edx
|
||||
call install_block
|
||||
popl %ecx
|
||||
addl %ecx, %esi
|
||||
|
||||
/* Install .data16 */
|
||||
pushl %esi
|
||||
shrl $4, %esi
|
||||
movw %si, %ds
|
||||
xorw %si, %si
|
||||
movw %bx, %es
|
||||
xorl %edi, %edi
|
||||
xorl %edi, %edi
|
||||
movl $_data16_progbits_size, %ecx
|
||||
movl $_data16_size, %edx
|
||||
call install_block
|
||||
popl %ecx
|
||||
addl %ecx, %esi
|
||||
|
||||
/* Restore registers */
|
||||
popl %edx
|
||||
popl %ecx
|
||||
popl %edi
|
||||
popw %es
|
||||
popw %ds
|
||||
ret
|
||||
.size install_basemem, . - install_basemem
|
||||
|
||||
/****************************************************************************
|
||||
* install_highmem (flat real-mode near call)
|
||||
* install_highmem (real-mode near call)
|
||||
*
|
||||
* Install .text and .data into high memory
|
||||
*
|
||||
* Parameters:
|
||||
* %esi : start offset within loaded image (must be a multiple of 16)
|
||||
* %es:edi : address in high memory
|
||||
* %esi : source physical address (must be a multiple of 16)
|
||||
* %edi : destination physical address
|
||||
* Returns:
|
||||
* %esi : end offset within image (rounded up to next multiple of 16)
|
||||
* %esi : next source physical address (will be a multiple of 16)
|
||||
* Corrupts:
|
||||
* none
|
||||
****************************************************************************
|
||||
@ -218,115 +376,27 @@ install_basemem:
|
||||
.code16
|
||||
install_highmem:
|
||||
/* Preserve registers */
|
||||
pushw %ax
|
||||
pushl %edi
|
||||
pushl %ecx
|
||||
pushl %edx
|
||||
|
||||
|
||||
/* Install .text and .data to specified address */
|
||||
movl $_textdata_progbits_size, %ecx
|
||||
movl $_textdata_size, %edx
|
||||
call install_block
|
||||
movw $install_block, %ax
|
||||
call pm_call
|
||||
|
||||
/* Restore registers and interrupt status */
|
||||
/* Restore registers */
|
||||
popl %edx
|
||||
popl %ecx
|
||||
popl %edi
|
||||
popw %ax
|
||||
ret
|
||||
.size install_highmem, . - install_highmem
|
||||
|
||||
#endif /* KEEP_IT_REAL */
|
||||
|
||||
/****************************************************************************
|
||||
* GDT for flat real mode
|
||||
*
|
||||
* We only ever use this GDT to set segment limits; the bases are
|
||||
* unused. Also, we only change data segments, so we don't need to
|
||||
* worry about the code or stack segments. This makes everything much
|
||||
* simpler.
|
||||
****************************************************************************
|
||||
*/
|
||||
|
||||
#ifndef KEEP_IT_REAL
|
||||
|
||||
.section ".prefix.lib"
|
||||
.align 16
|
||||
gdt:
|
||||
gdt_limit: .word gdt_length - 1
|
||||
gdt_base: .long 0
|
||||
.word 0 /* padding */
|
||||
|
||||
flat_ds: /* Flat real mode data segment */
|
||||
.equ FLAT_DS, flat_ds - gdt
|
||||
.word 0xffff, 0
|
||||
.byte 0, 0x93, 0xcf, 0
|
||||
|
||||
real_ds: /* Normal real mode data segment */
|
||||
.equ REAL_DS, real_ds - gdt
|
||||
.word 0xffff, 0
|
||||
.byte 0, 0x93, 0x00, 0
|
||||
|
||||
gdt_end:
|
||||
.equ gdt_length, gdt_end - gdt
|
||||
.size gdt, . - gdt
|
||||
|
||||
#endif /* KEEP_IT_REAL */
|
||||
|
||||
/****************************************************************************
|
||||
* set_real_mode_limits (real-mode near call)
|
||||
*
|
||||
* Sets limits on the data segments %ds and %es.
|
||||
*
|
||||
* Parameters:
|
||||
* %dx : segment type (FLAT_DS for 4GB or REAL_DS for 64kB)
|
||||
****************************************************************************
|
||||
*/
|
||||
|
||||
#ifndef KEEP_IT_REAL
|
||||
|
||||
.section ".prefix.lib"
|
||||
.code16
|
||||
set_real_mode_limits:
|
||||
/* Preserve real-mode segment values and temporary registers */
|
||||
pushw %es
|
||||
pushw %ds
|
||||
pushw %bp
|
||||
pushl %eax
|
||||
|
||||
/* Set GDT base and load GDT */
|
||||
xorl %eax, %eax
|
||||
movw %cs, %ax
|
||||
shll $4, %eax
|
||||
addl $gdt, %eax
|
||||
pushl %eax
|
||||
pushw %cs:gdt_limit
|
||||
movw %sp, %bp
|
||||
lgdt (%bp)
|
||||
addw $6, %sp
|
||||
|
||||
/* Switch to protected mode */
|
||||
movl %cr0, %eax
|
||||
orb $CR0_PE, %al
|
||||
movl %eax, %cr0
|
||||
|
||||
/* Set flat segment limits */
|
||||
movw %dx, %ds
|
||||
movw %dx, %es
|
||||
|
||||
/* Switch back to real mode */
|
||||
movl %cr0, %eax
|
||||
andb $0!CR0_PE, %al
|
||||
movl %eax, %cr0
|
||||
|
||||
/* Restore real-mode segment values and temporary registers */
|
||||
popl %eax
|
||||
popw %bp
|
||||
popw %ds
|
||||
popw %es
|
||||
ret
|
||||
.size set_real_mode_limits, . - set_real_mode_limits
|
||||
|
||||
#endif /* KEEP_IT_REAL */
|
||||
|
||||
/****************************************************************************
|
||||
* install (real-mode near call)
|
||||
* install_prealloc (real-mode near call)
|
||||
@ -354,72 +424,70 @@ install:
|
||||
.globl install_prealloc
|
||||
install_prealloc:
|
||||
/* Save registers */
|
||||
pushw %ds
|
||||
pushl %esi
|
||||
pushw %dx
|
||||
|
||||
/* Sanity: clear the direction flag asap */
|
||||
cld
|
||||
|
||||
/* Calculate physical address of payload (i.e. first source) */
|
||||
xorl %esi, %esi
|
||||
movw %cs, %si
|
||||
shll $4, %esi
|
||||
addl $_payload_offset, %esi
|
||||
|
||||
/* Install .text16 and .data16 */
|
||||
movl $_payload_offset, %esi
|
||||
call install_basemem
|
||||
|
||||
#ifdef KEEP_IT_REAL
|
||||
/* Preserve %ds, call init_libkir, restore registers */
|
||||
pushw %ds
|
||||
/* Set up %ds for access to .data16 */
|
||||
movw %bx, %ds
|
||||
|
||||
#ifdef KEEP_IT_REAL
|
||||
/* Initialise libkir */
|
||||
movw %ax, (init_libkir_vector+2)
|
||||
lcall *init_libkir_vector
|
||||
popw %ds
|
||||
#else
|
||||
/* Preserve registers and interrupt status, and disable interrupts */
|
||||
pushfw
|
||||
pushw %ds
|
||||
pushw %es
|
||||
/* Save registers */
|
||||
pushl %edi
|
||||
pushl %ecx
|
||||
cli
|
||||
|
||||
/* Load up %ds and %es, and set up vectors for far calls to .text16 */
|
||||
movw %bx, %ds
|
||||
xorw %cx, %cx
|
||||
movw %cx, %es
|
||||
movw %ax, (init_librm_vector+2)
|
||||
movw %ax, (prot_call_vector+2)
|
||||
|
||||
/* Install .text and .data to temporary area in high memory,
|
||||
* prior to reading the E820 memory map and relocating
|
||||
* properly.
|
||||
*/
|
||||
movw $FLAT_DS, %dx
|
||||
call set_real_mode_limits
|
||||
movl $HIGHMEM_LOADPOINT, %edi
|
||||
call install_highmem
|
||||
|
||||
/* Set up initial protected-mode GDT, call relocate().
|
||||
/* Initialise librm at current location */
|
||||
movw %ax, (init_librm_vector+2)
|
||||
lcall *init_librm_vector
|
||||
|
||||
/* Call relocate() to determine target address for relocation.
|
||||
* relocate() will return with %esi, %edi and %ecx set up
|
||||
* ready for the copy to the new location.
|
||||
*/
|
||||
lcall *init_librm_vector
|
||||
movw %ax, (prot_call_vector+2)
|
||||
pushl $relocate
|
||||
lcall *prot_call_vector
|
||||
addw $4, %sp
|
||||
|
||||
/* Move code to new location, set up new protected-mode GDT */
|
||||
movw $FLAT_DS, %dx
|
||||
call set_real_mode_limits
|
||||
/* Copy code to new location */
|
||||
pushl %edi
|
||||
es rep addr32 movsb
|
||||
pushw %ax
|
||||
movw $copy_bytes, %ax
|
||||
call pm_call
|
||||
popw %ax
|
||||
popl %edi
|
||||
|
||||
/* Initialise librm at new location */
|
||||
lcall *init_librm_vector
|
||||
|
||||
/* Restore real-mode segment limits */
|
||||
movw $REAL_DS, %dx
|
||||
call set_real_mode_limits
|
||||
|
||||
/* Restore registers and interrupt status */
|
||||
/* Restore registers */
|
||||
popl %ecx
|
||||
popw %es
|
||||
popw %ds
|
||||
popfw
|
||||
popl %edi
|
||||
#endif
|
||||
popw %dx
|
||||
popl %esi
|
||||
popw %ds
|
||||
ret
|
||||
.size install_prealloc, . - install_prealloc
|
||||
|
||||
|
||||
Loading…
Reference in New Issue
Block a user