2005-04-17 06:20:36 +08:00
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/*
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* Copyright (C) Paul Mackerras 1997.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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2011-04-13 04:38:55 +08:00
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* NOTE: this code runs in 32 bit mode, is position-independent,
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* and is packaged as ELF32.
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2005-04-17 06:20:36 +08:00
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*/
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2005-08-08 11:24:38 +08:00
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#include "ppc_asm.h"
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2005-04-17 06:20:36 +08:00
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.text
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2011-04-13 04:38:55 +08:00
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/* A procedure descriptor used when booting this as a COFF file.
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* When making COFF, this comes first in the link and we're
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* linked at 0x500000.
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*/
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2007-06-07 20:21:31 +08:00
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.globl _zimage_start_opd
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2006-01-14 12:04:06 +08:00
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_zimage_start_opd:
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2011-04-13 04:38:55 +08:00
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.long 0x500000, 0, 0, 0
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p_start: .long _start
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p_etext: .long _etext
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p_bss_start: .long __bss_start
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p_end: .long _end
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.weak _platform_stack_top
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p_pstack: .long _platform_stack_top
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2006-01-14 12:04:06 +08:00
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[POWERPC] zImage: Cleanup and improve zImage entry point
This patch re-organises the way the zImage wrapper code is entered, to
allow more flexibility on platforms with unusual entry conditions.
After this patch, a platform .o file has two options:
1) It can define a _zimage_start, in which case the platform code gets
control from the very beginning of execution. In this case the
platform code is responsible for relocating the zImage if necessary,
clearing the BSS, performing any platform specific initialization, and
finally calling start() to load and enter the kernel.
2) It can define platform_init(). In this case the generic crt0.S
handles initial entry, and calls platform_init() before calling
start(). The signature of platform_init() is changed, however, to
take up to 5 parameters (in r3..r7) as they come from the platform's
initial loader, instead of a fixed set of parameters based on OF's
usage.
When using the generic crt0.S, the platform .o can optionally
supply a custom stack to use, using the BSS_STACK() macro. If this
is not supplied, the crt0.S will assume that the loader has
supplied a usable stack.
In either case, the platform code communicates information to the
generic code (specifically, a PROM pointer for OF systems, and/or an
initrd image address supplied by the bootloader) via a global
structure "loader_info".
In addition the wrapper script is rearranged to ensure that the
platform .o is always linked first. This means that platforms where
the zImage entry point is at a fixed address or offset, rather than
being encoded in the binary header can be supported using option (1).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-05 11:24:52 +08:00
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.weak _zimage_start
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2005-10-29 08:46:49 +08:00
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.globl _zimage_start
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_zimage_start:
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2007-03-21 23:02:53 +08:00
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.globl _zimage_start_lib
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_zimage_start_lib:
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2006-01-14 12:04:06 +08:00
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/* Work out the offset between the address we were linked at
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and the address where we're running. */
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2011-04-13 04:38:55 +08:00
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bl .+4
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p_base: mflr r10 /* r10 now points to runtime addr of p_base */
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/* grab the link address of the dynamic section in r11 */
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addis r11,r10,(_GLOBAL_OFFSET_TABLE_-p_base)@ha
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lwz r11,(_GLOBAL_OFFSET_TABLE_-p_base)@l(r11)
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cmpwi r11,0
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beq 3f /* if not linked -pie */
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/* get the runtime address of the dynamic section in r12 */
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.weak __dynamic_start
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addis r12,r10,(__dynamic_start-p_base)@ha
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addi r12,r12,(__dynamic_start-p_base)@l
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subf r11,r11,r12 /* runtime - linktime offset */
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/* The dynamic section contains a series of tagged entries.
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* We need the RELA and RELACOUNT entries. */
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RELA = 7
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RELACOUNT = 0x6ffffff9
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li r9,0
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li r0,0
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9: lwz r8,0(r12) /* get tag */
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cmpwi r8,0
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beq 10f /* end of list */
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cmpwi r8,RELA
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bne 11f
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lwz r9,4(r12) /* get RELA pointer in r9 */
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b 12f
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11: addis r8,r8,(-RELACOUNT)@ha
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cmpwi r8,RELACOUNT@l
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bne 12f
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lwz r0,4(r12) /* get RELACOUNT value in r0 */
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12: addi r12,r12,8
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b 9b
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2005-10-29 08:46:48 +08:00
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2011-04-13 04:38:55 +08:00
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/* The relocation section contains a list of relocations.
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* We now do the R_PPC_RELATIVE ones, which point to words
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* which need to be initialized with addend + offset.
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* The R_PPC_RELATIVE ones come first and there are RELACOUNT
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* of them. */
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10: /* skip relocation if we don't have both */
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cmpwi r0,0
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2005-11-18 05:09:02 +08:00
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beq 3f
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2011-04-13 04:38:55 +08:00
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cmpwi r9,0
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beq 3f
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add r9,r9,r11 /* Relocate RELA pointer */
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mtctr r0
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2: lbz r0,4+3(r9) /* ELF32_R_INFO(reloc->r_info) */
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cmpwi r0,22 /* R_PPC_RELATIVE */
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bne 3f
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lwz r12,0(r9) /* reloc->r_offset */
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lwz r0,8(r9) /* reloc->r_addend */
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add r0,r0,r11
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stwx r0,r11,r12
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addi r9,r9,12
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2005-11-18 05:09:02 +08:00
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bdnz 2b
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2005-10-29 08:46:48 +08:00
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[POWERPC] zImage: Cleanup and improve zImage entry point
This patch re-organises the way the zImage wrapper code is entered, to
allow more flexibility on platforms with unusual entry conditions.
After this patch, a platform .o file has two options:
1) It can define a _zimage_start, in which case the platform code gets
control from the very beginning of execution. In this case the
platform code is responsible for relocating the zImage if necessary,
clearing the BSS, performing any platform specific initialization, and
finally calling start() to load and enter the kernel.
2) It can define platform_init(). In this case the generic crt0.S
handles initial entry, and calls platform_init() before calling
start(). The signature of platform_init() is changed, however, to
take up to 5 parameters (in r3..r7) as they come from the platform's
initial loader, instead of a fixed set of parameters based on OF's
usage.
When using the generic crt0.S, the platform .o can optionally
supply a custom stack to use, using the BSS_STACK() macro. If this
is not supplied, the crt0.S will assume that the loader has
supplied a usable stack.
In either case, the platform code communicates information to the
generic code (specifically, a PROM pointer for OF systems, and/or an
initrd image address supplied by the bootloader) via a global
structure "loader_info".
In addition the wrapper script is rearranged to ensure that the
platform .o is always linked first. This means that platforms where
the zImage entry point is at a fixed address or offset, rather than
being encoded in the binary header can be supported using option (1).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-05 11:24:52 +08:00
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/* Do a cache flush for our text, in case the loader didn't */
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2011-04-13 04:38:55 +08:00
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3: lwz r9,p_start-p_base(r10) /* note: these are relocated now */
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lwz r8,p_etext-p_base(r10)
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2005-11-18 05:09:02 +08:00
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4: dcbf r0,r9
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2005-04-17 06:20:36 +08:00
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icbi r0,r9
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addi r9,r9,0x20
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2006-03-04 20:15:40 +08:00
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cmplw cr0,r9,r8
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2005-11-18 05:09:02 +08:00
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blt 4b
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2005-04-17 06:20:36 +08:00
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sync
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isync
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[POWERPC] zImage: Cleanup and improve zImage entry point
This patch re-organises the way the zImage wrapper code is entered, to
allow more flexibility on platforms with unusual entry conditions.
After this patch, a platform .o file has two options:
1) It can define a _zimage_start, in which case the platform code gets
control from the very beginning of execution. In this case the
platform code is responsible for relocating the zImage if necessary,
clearing the BSS, performing any platform specific initialization, and
finally calling start() to load and enter the kernel.
2) It can define platform_init(). In this case the generic crt0.S
handles initial entry, and calls platform_init() before calling
start(). The signature of platform_init() is changed, however, to
take up to 5 parameters (in r3..r7) as they come from the platform's
initial loader, instead of a fixed set of parameters based on OF's
usage.
When using the generic crt0.S, the platform .o can optionally
supply a custom stack to use, using the BSS_STACK() macro. If this
is not supplied, the crt0.S will assume that the loader has
supplied a usable stack.
In either case, the platform code communicates information to the
generic code (specifically, a PROM pointer for OF systems, and/or an
initrd image address supplied by the bootloader) via a global
structure "loader_info".
In addition the wrapper script is rearranged to ensure that the
platform .o is always linked first. This means that platforms where
the zImage entry point is at a fixed address or offset, rather than
being encoded in the binary header can be supported using option (1).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-05 11:24:52 +08:00
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/* Clear the BSS */
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2011-04-13 04:38:55 +08:00
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lwz r9,p_bss_start-p_base(r10)
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lwz r8,p_end-p_base(r10)
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li r0,0
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5: stw r0,0(r9)
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[POWERPC] zImage: Cleanup and improve zImage entry point
This patch re-organises the way the zImage wrapper code is entered, to
allow more flexibility on platforms with unusual entry conditions.
After this patch, a platform .o file has two options:
1) It can define a _zimage_start, in which case the platform code gets
control from the very beginning of execution. In this case the
platform code is responsible for relocating the zImage if necessary,
clearing the BSS, performing any platform specific initialization, and
finally calling start() to load and enter the kernel.
2) It can define platform_init(). In this case the generic crt0.S
handles initial entry, and calls platform_init() before calling
start(). The signature of platform_init() is changed, however, to
take up to 5 parameters (in r3..r7) as they come from the platform's
initial loader, instead of a fixed set of parameters based on OF's
usage.
When using the generic crt0.S, the platform .o can optionally
supply a custom stack to use, using the BSS_STACK() macro. If this
is not supplied, the crt0.S will assume that the loader has
supplied a usable stack.
In either case, the platform code communicates information to the
generic code (specifically, a PROM pointer for OF systems, and/or an
initrd image address supplied by the bootloader) via a global
structure "loader_info".
In addition the wrapper script is rearranged to ensure that the
platform .o is always linked first. This means that platforms where
the zImage entry point is at a fixed address or offset, rather than
being encoded in the binary header can be supported using option (1).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-05 11:24:52 +08:00
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addi r9,r9,4
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cmplw cr0,r9,r8
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blt 5b
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2005-04-17 06:20:36 +08:00
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[POWERPC] zImage: Cleanup and improve zImage entry point
This patch re-organises the way the zImage wrapper code is entered, to
allow more flexibility on platforms with unusual entry conditions.
After this patch, a platform .o file has two options:
1) It can define a _zimage_start, in which case the platform code gets
control from the very beginning of execution. In this case the
platform code is responsible for relocating the zImage if necessary,
clearing the BSS, performing any platform specific initialization, and
finally calling start() to load and enter the kernel.
2) It can define platform_init(). In this case the generic crt0.S
handles initial entry, and calls platform_init() before calling
start(). The signature of platform_init() is changed, however, to
take up to 5 parameters (in r3..r7) as they come from the platform's
initial loader, instead of a fixed set of parameters based on OF's
usage.
When using the generic crt0.S, the platform .o can optionally
supply a custom stack to use, using the BSS_STACK() macro. If this
is not supplied, the crt0.S will assume that the loader has
supplied a usable stack.
In either case, the platform code communicates information to the
generic code (specifically, a PROM pointer for OF systems, and/or an
initrd image address supplied by the bootloader) via a global
structure "loader_info".
In addition the wrapper script is rearranged to ensure that the
platform .o is always linked first. This means that platforms where
the zImage entry point is at a fixed address or offset, rather than
being encoded in the binary header can be supported using option (1).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-05 11:24:52 +08:00
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/* Possibly set up a custom stack */
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2011-04-13 04:38:55 +08:00
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lwz r8,p_pstack-p_base(r10)
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[POWERPC] zImage: Cleanup and improve zImage entry point
This patch re-organises the way the zImage wrapper code is entered, to
allow more flexibility on platforms with unusual entry conditions.
After this patch, a platform .o file has two options:
1) It can define a _zimage_start, in which case the platform code gets
control from the very beginning of execution. In this case the
platform code is responsible for relocating the zImage if necessary,
clearing the BSS, performing any platform specific initialization, and
finally calling start() to load and enter the kernel.
2) It can define platform_init(). In this case the generic crt0.S
handles initial entry, and calls platform_init() before calling
start(). The signature of platform_init() is changed, however, to
take up to 5 parameters (in r3..r7) as they come from the platform's
initial loader, instead of a fixed set of parameters based on OF's
usage.
When using the generic crt0.S, the platform .o can optionally
supply a custom stack to use, using the BSS_STACK() macro. If this
is not supplied, the crt0.S will assume that the loader has
supplied a usable stack.
In either case, the platform code communicates information to the
generic code (specifically, a PROM pointer for OF systems, and/or an
initrd image address supplied by the bootloader) via a global
structure "loader_info".
In addition the wrapper script is rearranged to ensure that the
platform .o is always linked first. This means that platforms where
the zImage entry point is at a fixed address or offset, rather than
being encoded in the binary header can be supported using option (1).
Signed-off-by: David Gibson <dwg@au1.ibm.com>
Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-05 11:24:52 +08:00
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cmpwi r8,0
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beq 6f
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lwz r1,0(r8)
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li r0,0
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stwu r0,-16(r1) /* establish a stack frame */
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6:
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/* Call platform_init() */
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bl platform_init
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/* Call start */
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b start
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