*
*/
+ .arch i386
+ .section ".prefix.lib", "awx", @progbits
+ .section ".data16", "aw", @progbits
+
/**
* High memory temporary load address
*
* We use the start of an even megabyte so that we don't have to worry
* about the current state of the A20 line.
*
- * We use 4MB rather than 2MB because there is at least one commercial
- * PXE ROM ("Broadcom UNDI, PXE-2.1 (build 082) v2.0.4") which stores
- * data required by the UNDI ROM loader (yes, the ROM loader; that's
- * the component which should be impossible to damage short of
- * screwing with the MMU) around the 2MB mark. Sadly, this is not a
- * joke.
- *
+ * We use 4MB rather than 2MB because some PXE stack / PMM BIOS
+ * combinations are known to place data required by other UNDI ROMs
+ * loader around the 2MB mark.
*/
-#define HIGHMEM_LOADPOINT ( 4 << 20 )
+ .globl HIGHMEM_LOADPOINT
+ .equ HIGHMEM_LOADPOINT, ( 4 << 20 )
/* Image compression enabled */
#define COMPRESS 1
#define CR0_PE 1
- .arch i386
- .section ".prefix.lib", "awx", @progbits
- .section ".data16", "aw", @progbits
-
/****************************************************************************
* pm_call (real-mode near call)
*
* Returns:
* %ds:esi : next source address (will be a multiple of 16)
* Corrupts:
- * %edi, %ecx, %edx
+ * %ecx, %edx
****************************************************************************
*/
.section ".prefix.lib"
.code16
install_block:
+ /* Preserve registers */
+ pushl %edi
+
#if COMPRESS
/* Decompress source to destination */
call decompress16
addl $0xf, %esi
andl $~0xf, %esi
+ /* Restore registers and return */
+ popl %edi
ret
.size install_block, . - install_block
*/
.section ".prefix.lib"
.code16
+ .globl alloc_basemem
alloc_basemem:
/* FBMS => %ax as segment address */
movw $0x40, %ax
* Returns:
* %esi : next source physical address (will be a multiple of 16)
* Corrupts:
- * %edi, %ecx, %edx
+ * %ecx, %edx
****************************************************************************
*/
.section ".prefix.lib"
.code16
install_basemem:
/* Preserve registers */
+ pushl %edi
pushw %ds
/* Preserve original %esi */
/* Restore registers */
popw %ds
+ popl %edi
ret
.size install_basemem, . - install_basemem
* Returns:
* %esi : next source physical address (will be a multiple of 16)
* Corrupts:
- * %edi, %ecx, %edx
+ * %ecx, %edx
****************************************************************************
*/
/****************************************************************************
* install (real-mode near call)
- * install_prealloc (real-mode near call)
*
* Install all text and data segments.
*
* Parameters:
- * %ax : .text16 segment address (install_prealloc only)
- * %bx : .data16 segment address (install_prealloc only)
+ * none
* Returns:
- * %ax : .text16 segment address
- * %bx : .data16 segment address
- * %edi : .text physical address (if applicable)
+ * %ax : .text16 segment address
+ * %bx : .data16 segment address
* Corrupts:
* none
****************************************************************************
.code16
.globl install
install:
+ /* Preserve registers */
+ pushl %esi
+ pushl %edi
/* Allocate space for .text16 and .data16 */
call alloc_basemem
+ /* Image source = %cs:0000 */
+ xorl %esi, %esi
+ /* Image destination = HIGHMEM_LOADPOINT */
+ movl $HIGHMEM_LOADPOINT, %edi
+ /* Install text and data segments */
+ call install_prealloc
+ /* Restore registers and return */
+ popl %edi
+ popl %esi
+ ret
.size install, . - install
+
+/****************************************************************************
+ * install_prealloc (real-mode near call)
+ *
+ * Install all text and data segments.
+ *
+ * Parameters:
+ * %ax : .text16 segment address
+ * %bx : .data16 segment address
+ * %esi : Image source physical address (or zero for %cs:0000)
+ * %edi : Decompression temporary area physical address
+ * Corrupts:
+ * none
+ ****************************************************************************
+ */
+ .section ".prefix.lib"
+ .code16
.globl install_prealloc
install_prealloc:
/* Save registers */
+ pushal
pushw %ds
pushw %es
- pushl %esi
- pushl %ecx
- pushl %edx
/* Sanity: clear the direction flag asap */
cld
/* Calculate physical address of payload (i.e. first source) */
- xorl %esi, %esi
+ testl %esi, %esi
+ jnz 1f
movw %cs, %si
shll $4, %esi
- addl $_payload_offset, %esi
+1: addl $_payload_offset, %esi
/* Install .text16 */
movw %ax, %es
* prior to reading the E820 memory map and relocating
* properly.
*/
- movl $HIGHMEM_LOADPOINT, %edi
movl $_textdata_progbits_size, %ecx
movl $_textdata_size, %edx
pushl %edi
#endif
/* Restore registers */
- popl %edx
- popl %ecx
- popl %esi
popw %es
popw %ds
+ popal
ret
.size install_prealloc, . - install_prealloc
* table so using a noticeable amount of stack space is a no-no.
*/
+#define PNP_SIGNATURE ( '$' + ( 'P' << 8 ) + ( 'n' << 16 ) + ( 'P' << 24 ) )
+#define PMM_SIGNATURE ( '$' + ( 'P' << 8 ) + ( 'M' << 16 ) + ( 'M' << 24 ) )
+#define STACK_MAGIC ( 'L' + ( 'R' << 8 ) + ( 'E' << 16 ) + ( 'T' << 24 ) )
+
.text
.code16
.arch i386
romheader:
.word 0xAA55 /* BIOS extension signature */
romheader_size: .byte _load_size_sect /* Size in 512-byte blocks */
- jmp init_vector /* Initialisation vector */
+ jmp init /* Initialisation vector */
+checksum:
+ .byte 0
.org 0x16
.word undiheader
.org 0x18
.byte 0x54 /* Device indicator */
.word 0x0000 /* Boot connection vector */
.word 0x0000 /* Disconnect vector */
- .word exec_vector /* Boot execution vector */
+ .word bev_entry /* Boot execution vector */
.word 0x0000 /* Reserved */
.word 0x0000 /* Static resource information vector*/
.equ pnpheader_len, . - pnpheader
.equ undiheader_len, . - undiheader
.size undiheader, . - undiheader
-/* Initialisation vector
+/* Initialisation (called once during POST)
*
* Determine whether or not this is a PnP system via a signature
* check. If it is PnP, return to the PnP BIOS indicating that we are
* a boot-capable device; the BIOS will call our boot execution vector
* if it wants to boot us. If it is not PnP, hook INT 19.
*/
-init_vector:
- pushw %si
- cmpw $'$'+'P'*256, %es:0(%di)
- jne notpnp
- cmpw $'n'+'P'*256, %es:2(%di)
- jne notpnp
-ispnp:
- movw $ispnp_message, %si
- jmp 99f
-notpnp:
+init:
+ /* Preserve registers, clear direction flag, set %ds=%cs */
+ pushaw
pushw %ds
- pushw $0
- popw %ds
+ pushw %es
+ cld
pushw %cs
- pushw $exec_vector
- popl ( 0x19 * 4 )
popw %ds
- movw $notpnp_message, %si
+ /* Print message as early as possible */
+ movw $init_message, %si
+ call print_message
+ /* Check for PnP BIOS */
+ cmpl $PNP_SIGNATURE, %es:0(%di)
+ je ispnp
+notpnp: /* Not PnP: hook INT19 */
+ xorw %ax, %ax
+ movw %ax, %es
+ pushw %cs
+ pushw $int19_entry
+ popl %es:( 0x19 * 4 )
+ jmp 99f
+ispnp: /* Is PnP: print PnP message */
+ movw $init_message_pnp, %si
+ call print_message
+ /* Check for PMM */
+ movw $( 0xe000 - 1 ), %di
+pmm_scan:
+ incw %di
+ jz 99f
+ movw %di, %es
+ cmpl $PMM_SIGNATURE, %es:0
+ jne pmm_scan
+ xorw %bx, %bx
+ xorw %si, %si
+ movzbw %es:5, %cx
+1: es lodsb
+ addb %al, %bl
+ loop 1b
+ jnz pmm_scan
+ /* PMM found: print PMM message */
+ movw $init_message_pmm, %si
+ call print_message
+ /* Try to allocate 2MB block via PMM */
+ pushw $0x0006 /* Aligned, extended memory */
+ pushl $0xffffffff /* No handle */
+ pushl $( 0x00200000 / 16 ) /* 2MB in paragraphs */
+ pushw $0x0000 /* pmmAllocate */
+ lcall %es:*(7)
+ addw $12, %sp
+ testw %dx, %dx /* %ax==0 even on success, since align=2MB */
+ jnz gotpmm
+ movw $init_message_pmm_failed, %si
+ call print_message
+ jmp 99f
+gotpmm: /* PMM allocation succeeded: copy ROM to PMM block */
+ pushal /* PMM presence implies 1kB stack */
+ movw %ax, %es /* %ax=0 already - see above */
+ pushw %dx
+ pushw %ax
+ popl %edi
+ movl %edi, image_source
+ xorl %esi, %esi
+ movzbl romheader_size, %ecx
+ shll $9, %ecx
+ addr32 rep movsb /* PMM presence implies flat real mode */
+ movl %edi, decompress_to
+ /* Shrink ROM and update checksum */
+ xorw %bx, %bx
+ xorw %si, %si
+ movb $_prefix_size_sect, romheader_size
+ shlw $9, %cx
+1: lodsb
+ addb %al, %bl
+ loop 1b
+ subb %bl, checksum
+ popal
99:
+ /* Print CRLF to terminate messages */
+ movw $init_message_crlf, %si
call print_message
+ /* Restore registers */
+ popw %es
+ popw %ds
+ popaw
+ /* Indicate boot capability to PnP BIOS, if present */
movw $0x20, %ax
- popw %si
lret
- .size init_vector, . - init_vector
-
-ispnp_message:
- .asciz "gPXE detected PnP BIOS\r\n"
- .size ispnp_message, . - ispnp_message
-notpnp_message:
- .asciz "gPXE detected non-PnP BIOS\r\n"
- .size notpnp_message, . - notpnp_message
-
-/* Boot execution vector
- *pciheader_size
- * Called by the PnP BIOS when it wants to boot us, or via the hooked
- * INT 19 if we detected a non-PnP BIOS.
- */
-exec_vector:
- /* Obtain a reasonably-sized stack */
+ .size init, . - init
+
+init_message:
+ .asciz "gPXE (http://etherboot.org)"
+ .size init_message, . - init_message
+init_message_pnp:
+ .asciz " - PnP BIOS detected"
+ .size init_message_pnp, . - init_message_pnp
+init_message_pmm:
+ .asciz ", using PMM"
+ .size init_message_pmm, . - init_message_pmm
+init_message_pmm_failed:
+ .asciz " (failed)"
+ .size init_message_pmm_failed, . - init_message_pmm_failed
+init_message_crlf:
+ .asciz "\r\n"
+ .size init_message_crlf, . - init_message_crlf
+
+/* ROM image location
+ *
+ * May be either within option ROM space, or within PMM-allocated block.
+ */
+image_source:
+ .long 0
+ .size image_source, . - image_source
+/* Temporary decompression area
+ *
+ * May be either at HIGHMEM_LOADPOINT, or within PMM-allocated block.
+ */
+decompress_to:
+ .long HIGHMEM_LOADPOINT
+ .size decompress_to, . - decompress_to
+
+/* Boot Execution Vector entry point
+ *
+ * Called by the PnP BIOS when it wants to boot us.
+ */
+bev_entry:
+ pushw %cs
+ call exec
+ lret
+ .size bev_entry, . - bev_entry
+
+/* INT19 entry point
+ *
+ * Called via the hooked INT 19 if we detected a non-PnP BIOS.
+ */
+int19_entry:
+ pushw %cs
+ call exec
+ /* No real way to return from INT19 */
+ int $0x18
+ .size int19_entry, . - int19_entry
+
+/* Execute as a boot device
+ *
+ */
+exec: /* Set %ds = %cs */
+ pushw %cs
+ popw %ds
+
+ /* Print message as soon as possible */
+ movw $exec_message, %si
+ call print_message
+
+ /* Store magic word on BIOS stack and remember BIOS %ss:sp */
+ pushl $STACK_MAGIC
+ movw %ss, %dx
+ movw %sp, %bp
+
+ /* Obtain a reasonably-sized temporary stack */
xorw %ax, %ax
movw %ax, %ss
movw $0x7c00, %sp
-
- movw $exec_message, %si
- call print_message
- call install
+ /* Install gPXE */
+ movl image_source, %esi
+ movl decompress_to, %edi
+ call alloc_basemem
+ call install_prealloc
/* Set up real-mode stack */
movw %bx, %ss
pushw $1f
lret
.section ".text16", "awx", @progbits
-1:
+1: /* Call main() */
pushl $main
pushw %cs
call prot_call
- popl %eax /* discard */
+ /* No need to clean up stack; we are about to reload %ss:sp */
+
+ /* Restore BIOS stack */
+ movw %dx, %ss
+ movw %bp, %sp
- /* Boot next device */
+ /* Check magic word on BIOS stack */
+ popl %eax
+ cmpl $STACK_MAGIC, %eax
+ jne 1f
+ /* BIOS stack OK: return to caller */
+ lret
+1: /* BIOS stack corrupt: use INT 18 */
int $0x18
.previous
*/
undiloader:
/* Save registers */
+ pushl %esi
pushl %edi
pushw %es
pushw %bx
pushw %di
movw %es:12(%di), %bx
movw %es:14(%di), %ax
+ movl %cs:image_source, %esi
+ movl %cs:decompress_to, %edi
call install_prealloc
popw %di
/* Call UNDI loader C code */
popw %bx
popw %es
popl %edi
+ popl %esi
lret
.size undiloader, . - undiloader
pushw %bx
pushw %bp
movw $0x0007, %bx
-1: cs lodsb
+1: lodsb
testb %al, %al
je 2f
movb $0x0e, %ah /* write char, tty mode */
http://git.etherboot.org / gpxe.git / commitdiff