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linux/arch/powerpc/boot/crt0.S

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Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 15:20:36 -07:00
/*
* Copyright (C) Paul Mackerras 1997.
*
* This program 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
* 2 of the License, or (at your option) any later version.
*
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
* NOTE: this code runs in 32 bit mode, is position-independent,
* and is packaged as ELF32.
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 15:20:36 -07:00
*/
[PATCH] ppc64: make arch/ppc64/boot standalone Make the bootheader for ppc64 independent from kernel and libc headers. * add -nostdinc -isystem $gccincludes to not include libc headers * declare all functions in header files, also the stuff from string.S * declare some functions static * use stddef.h to get size_t (hopefully ok) * remove ppc32-types.h, only elf.h used the __NN types With further modifications by Paul Mackerras and Stephen Rothwell. Signed-off-by: Olaf Hering <olh@suse.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-08-07 20:24:38 -07:00
#include "ppc_asm.h"
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 15:20:36 -07:00
.text
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
/* A procedure descriptor used when booting this as a COFF file.
* When making COFF, this comes first in the link and we're
* linked at 0x500000.
*/
[POWERPC] Fix building of COFF zImages The COFF zImage (for booting oldworld powermacs) wasn't being built correctly because the procedure descriptor in crt0.S for the zImage entry point wasn't declared as .globl, and therefore wasn't getting pulled in from wrapper.a by the linker. This adds the necessary .globl statement. Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-06-07 05:21:31 -07:00
.globl _zimage_start_opd
powerpc: Make COFF zImages for old 32-bit powermacs This adds code to build zImage.coff and/or zImage.initrd.coff when CONFIG_PPC32 and CONFIG_PPC_PMAC are defined. It also restructures the OF client code and adds some workarounds for OF quirks on the older machines. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-13 21:04:06 -07:00
_zimage_start_opd:
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
.long 0x500000, 0, 0, 0
p_start: .long _start
p_etext: .long _etext
p_bss_start: .long __bss_start
p_end: .long _end
.weak _platform_stack_top
p_pstack: .long _platform_stack_top
powerpc: Make COFF zImages for old 32-bit powermacs This adds code to build zImage.coff and/or zImage.initrd.coff when CONFIG_PPC32 and CONFIG_PPC_PMAC are defined. It also restructures the OF client code and adds some workarounds for OF quirks on the older machines. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-13 21:04:06 -07:00
[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>
2007-03-04 20:24:52 -07:00
.weak _zimage_start
[PATCH] ppc64 boot: proof that reloc works To prove that the relocation works, move the crt0.o away from the beginning. Move linker options from command line into linker script. rename entry point because '_start' is referenced in printf output. Signed-off-by: Olaf Hering <olh@suse.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-28 17:46:49 -07:00
.globl _zimage_start
_zimage_start:
[POWERPC] bootwrapper: Allow platforms to call library zImage_start Some platforms might need to run some code before the zImage start, but could otherwise use the bss clear and relocation code. Export the start address strongly as zImage_start_lib. Signed-off-by: Milton Miller <miltonm@bga.com> Acked-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Paul Mackerras <paulus@samba.org>
2007-03-21 08:02:53 -07:00
.globl _zimage_start_lib
_zimage_start_lib:
powerpc: Make COFF zImages for old 32-bit powermacs This adds code to build zImage.coff and/or zImage.initrd.coff when CONFIG_PPC32 and CONFIG_PPC_PMAC are defined. It also restructures the OF client code and adds some workarounds for OF quirks on the older machines. Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-01-13 21:04:06 -07:00
/* Work out the offset between the address we were linked at
and the address where we're running. */
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
bl .+4
p_base: mflr r10 /* r10 now points to runtime addr of p_base */
/* grab the link address of the dynamic section in r11 */
addis r11,r10,(_GLOBAL_OFFSET_TABLE_-p_base)@ha
lwz r11,(_GLOBAL_OFFSET_TABLE_-p_base)@l(r11)
cmpwi r11,0
beq 3f /* if not linked -pie */
/* get the runtime address of the dynamic section in r12 */
.weak __dynamic_start
addis r12,r10,(__dynamic_start-p_base)@ha
addi r12,r12,(__dynamic_start-p_base)@l
subf r11,r11,r12 /* runtime - linktime offset */
/* The dynamic section contains a series of tagged entries.
* We need the RELA and RELACOUNT entries. */
RELA = 7
RELACOUNT = 0x6ffffff9
li r9,0
li r0,0
9: lwz r8,0(r12) /* get tag */
cmpwi r8,0
beq 10f /* end of list */
cmpwi r8,RELA
bne 11f
lwz r9,4(r12) /* get RELA pointer in r9 */
b 12f
11: addis r8,r8,(-RELACOUNT)@ha
cmpwi r8,RELACOUNT@l
bne 12f
lwz r0,4(r12) /* get RELACOUNT value in r0 */
12: addi r12,r12,8
b 9b
[PATCH] ppc64 boot: make the zImage relocateable Make the zImage relocateable. So yaboot could just load and run any ELF binary, without worrying about its load address. Signed-off-by: Olaf Hering <olh@suse.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-28 17:46:48 -07:00
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
/* The relocation section contains a list of relocations.
* We now do the R_PPC_RELATIVE ones, which point to words
* which need to be initialized with addend + offset.
* The R_PPC_RELATIVE ones come first and there are RELACOUNT
* of them. */
10: /* skip relocation if we don't have both */
cmpwi r0,0
[PATCH] ppc boot: replace string labels with numbers Replacing the string labels with numbers saves 117 bytes in the final zImage. These local labels are not discared. Signed-off-by: Olaf Hering <olh@suse.de> arch/powerpc/boot/crt0.S | 23 +++++++++++------------ 1 files changed, 11 insertions(+), 12 deletions(-) Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-17 14:09:02 -07:00
beq 3f
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
cmpwi r9,0
beq 3f
add r9,r9,r11 /* Relocate RELA pointer */
mtctr r0
2: lbz r0,4+3(r9) /* ELF32_R_INFO(reloc->r_info) */
cmpwi r0,22 /* R_PPC_RELATIVE */
bne 3f
lwz r12,0(r9) /* reloc->r_offset */
lwz r0,8(r9) /* reloc->r_addend */
add r0,r0,r11
stwx r0,r11,r12
addi r9,r9,12
[PATCH] ppc boot: replace string labels with numbers Replacing the string labels with numbers saves 117 bytes in the final zImage. These local labels are not discared. Signed-off-by: Olaf Hering <olh@suse.de> arch/powerpc/boot/crt0.S | 23 +++++++++++------------ 1 files changed, 11 insertions(+), 12 deletions(-) Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-17 14:09:02 -07:00
bdnz 2b
[PATCH] ppc64 boot: make the zImage relocateable Make the zImage relocateable. So yaboot could just load and run any ELF binary, without worrying about its load address. Signed-off-by: Olaf Hering <olh@suse.de> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Anton Blanchard <anton@samba.org> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-10-28 17:46:48 -07:00
[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>
2007-03-04 20:24:52 -07:00
/* Do a cache flush for our text, in case the loader didn't */
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
3: lwz r9,p_start-p_base(r10) /* note: these are relocated now */
lwz r8,p_etext-p_base(r10)
[PATCH] ppc boot: replace string labels with numbers Replacing the string labels with numbers saves 117 bytes in the final zImage. These local labels are not discared. Signed-off-by: Olaf Hering <olh@suse.de> arch/powerpc/boot/crt0.S | 23 +++++++++++------------ 1 files changed, 11 insertions(+), 12 deletions(-) Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-17 14:09:02 -07:00
4: dcbf r0,r9
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 15:20:36 -07:00
icbi r0,r9
addi r9,r9,0x20
[PATCH] powerpc: correct cacheflush loop in zImage Correct the loop for cacheflush. No idea where I copied the code from, but the original does not work correct. Maybe the flush is not needed. Signed-off-by: Olaf Hering <olh@suse.de> Signed-off-by: Paul Mackerras <paulus@samba.org>
2006-03-04 05:15:40 -07:00
cmplw cr0,r9,r8
[PATCH] ppc boot: replace string labels with numbers Replacing the string labels with numbers saves 117 bytes in the final zImage. These local labels are not discared. Signed-off-by: Olaf Hering <olh@suse.de> arch/powerpc/boot/crt0.S | 23 +++++++++++------------ 1 files changed, 11 insertions(+), 12 deletions(-) Signed-off-by: Paul Mackerras <paulus@samba.org>
2005-11-17 14:09:02 -07:00
blt 4b
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 15:20:36 -07:00
sync
isync
[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>
2007-03-04 20:24:52 -07:00
/* Clear the BSS */
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
lwz r9,p_bss_start-p_base(r10)
lwz r8,p_end-p_base(r10)
li r0,0
5: stw r0,0(r9)
[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>
2007-03-04 20:24:52 -07:00
addi r9,r9,4
cmplw cr0,r9,r8
blt 5b
Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip!
2005-04-16 15:20:36 -07:00
[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>
2007-03-04 20:24:52 -07:00
/* Possibly set up a custom stack */
powerpc/boot: Allow building the zImage wrapper as a relocatable ET_DYN This patch adds code, linker script and makefile support to allow building the zImage wrapper around the kernel as a position independent executable. This results in an ET_DYN instead of an ET_EXEC ELF output file, which can be loaded at any location by the firmware and will process its own relocations to work correctly at the loaded address. This is of interest particularly since the standard ePAPR image format must be an ET_DYN (although this patch alone is not sufficient to produce a fully ePAPR compliant boot image). Note for now we don't enable building with -pie for anything. Signed-off-by: Paul Mackerras <paulus@samba.org> Signed-off-by: David Gibson <david@gibson.dropbear.id.au> Signed-off-by: Michael Ellerman <michael@ellerman.id.au> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
2011-04-12 13:38:55 -07:00
lwz r8,p_pstack-p_base(r10)
[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>
2007-03-04 20:24:52 -07:00
cmpwi r8,0
beq 6f
lwz r1,0(r8)
li r0,0
stwu r0,-16(r1) /* establish a stack frame */
6:
/* Call platform_init() */
bl platform_init
/* Call start */
b start
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