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/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _ASM_POWERPC_HEAD_64_H
#define _ASM_POWERPC_HEAD_64_H
#include <asm/cache.h>
#ifdef __ASSEMBLY__
/*
* We can't do CPP stringification and concatination directly into the section
* name for some reason, so these macros can do it for us.
*/
.macro define_ftsec name
.section ".head.text.\name\()","ax",@progbits
.endm
.macro define_data_ftsec name
.section ".head.data.\name\()","a",@progbits
.endm
.macro use_ftsec name
.section ".head.text.\name\()"
.endm
/*
* Fixed (location) sections are used by opening fixed sections and emitting
* fixed section entries into them before closing them. Multiple fixed sections
* can be open at any time.
*
* Each fixed section created in a .S file must have corresponding linkage
* directives including location, added to arch/powerpc/kernel/vmlinux.lds.S
*
* For each fixed section, code is generated into it in the order which it
* appears in the source. Fixed section entries can be placed at a fixed
* location within the section using _LOCATION postifx variants. These must
* be ordered according to their relative placements within the section.
*
* OPEN_FIXED_SECTION(section_name, start_address, end_address)
* FIXED_SECTION_ENTRY_BEGIN(section_name, label1)
*
* USE_FIXED_SECTION(section_name)
* label3:
* li r10,128
* mv r11,r10
* FIXED_SECTION_ENTRY_BEGIN_LOCATION(section_name, label2, start_address, size)
* FIXED_SECTION_ENTRY_END_LOCATION(section_name, label2, start_address, size)
* CLOSE_FIXED_SECTION(section_name)
*
* ZERO_FIXED_SECTION can be used to emit zeroed data.
*
* Troubleshooting:
* - If the build dies with "Error: attempt to move .org backwards" at
* CLOSE_FIXED_SECTION() or elsewhere, there may be something
* unexpected being added there. Remove the '. = x_len' line, rebuild, and
* check what is pushing the section down.
* - If the build dies in linking, check arch/powerpc/tools/head_check.sh
* comments.
* - If the kernel crashes or hangs in very early boot, it could be linker
* stubs at the start of the main text.
*/
#define OPEN_FIXED_SECTION(sname, start, end) \
sname##_start = (start); \
sname##_end = (end); \
sname##_len = (end) - (start); \
define_ftsec sname; \
. = 0x0; \
start_##sname:
/*
* .linker_stub_catch section is used to catch linker stubs from being
* inserted in our .text section, above the start_text label (which breaks
* the ABS_ADDR calculation). See kernel/vmlinux.lds.S and tools/head_check.sh
* for more details. We would prefer to just keep a cacheline (0x80), but
* 0x100 seems to be how the linker aligns branch stub groups.
*/
#ifdef CONFIG_LD_HEAD_STUB_CATCH
#define OPEN_TEXT_SECTION(start) \
.section ".linker_stub_catch","ax",@progbits; \
linker_stub_catch: \
. = 0x4; \
text_start = (start) + 0x100; \
.section ".text","ax",@progbits; \
.balign 0x100; \
start_text:
#else
#define OPEN_TEXT_SECTION(start) \
text_start = (start); \
.section ".text","ax",@progbits; \
. = 0x0; \
start_text:
#endif
#define ZERO_FIXED_SECTION(sname, start, end) \
sname##_start = (start); \
sname##_end = (end); \
sname##_len = (end) - (start); \
define_data_ftsec sname; \
. = 0x0; \
. = sname##_len;
#define USE_FIXED_SECTION(sname) \
fs_label = start_##sname; \
fs_start = sname##_start; \
use_ftsec sname;
#define USE_TEXT_SECTION() \
fs_label = start_text; \
fs_start = text_start; \
.text
#define CLOSE_FIXED_SECTION(sname) \
USE_FIXED_SECTION(sname); \
. = sname##_len; \
end_##sname:
#define __FIXED_SECTION_ENTRY_BEGIN(sname, name, __align) \
USE_FIXED_SECTION(sname); \
.balign __align; \
.global name; \
name:
#define FIXED_SECTION_ENTRY_BEGIN(sname, name) \
__FIXED_SECTION_ENTRY_BEGIN(sname, name, IFETCH_ALIGN_BYTES)
#define FIXED_SECTION_ENTRY_BEGIN_LOCATION(sname, name, start, size) \
USE_FIXED_SECTION(sname); \
name##_start = (start); \
.if ((start) % (size) != 0); \
.error "Fixed section exception vector misalignment"; \
.endif; \
.if ((size) != 0x20) && ((size) != 0x80) && ((size) != 0x100); \
.error "Fixed section exception vector bad size"; \
.endif; \
.if (start) < sname##_start; \
.error "Fixed section underflow"; \
.abort; \
.endif; \
. = (start) - sname##_start; \
.global name; \
name:
#define FIXED_SECTION_ENTRY_END_LOCATION(sname, name, start, size) \
.if (start) + (size) > sname##_end; \
.error "Fixed section overflow"; \
.abort; \
.endif; \
.if (. - name > (start) + (size) - name##_start); \
.error "Fixed entry overflow"; \
.abort; \
.endif; \
. = ((start) + (size) - sname##_start); \
/*
* These macros are used to change symbols in other fixed sections to be
* absolute or related to our current fixed section.
*
* - DEFINE_FIXED_SYMBOL / FIXED_SYMBOL_ABS_ADDR is used to find the
* absolute address of a symbol within a fixed section, from any section.
*
* - ABS_ADDR is used to find the absolute address of any symbol, from within
* a fixed section.
*/
#define DEFINE_FIXED_SYMBOL(label) \
label##_absolute = (label - fs_label + fs_start)
#define FIXED_SYMBOL_ABS_ADDR(label) \
(label##_absolute)
#define ABS_ADDR(label) (label - fs_label + fs_start)
#endif /* __ASSEMBLY__ */
#endif /* _ASM_POWERPC_HEAD_64_H */
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