173 lines
5.4 KiB
C
173 lines
5.4 KiB
C
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/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _ASM_POWERPC_HEAD_64_H
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#define _ASM_POWERPC_HEAD_64_H
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#include <asm/cache.h>
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#ifdef __ASSEMBLY__
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/*
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* We can't do CPP stringification and concatination directly into the section
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* name for some reason, so these macros can do it for us.
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*/
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.macro define_ftsec name
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.section ".head.text.\name\()","ax",@progbits
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.endm
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.macro define_data_ftsec name
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.section ".head.data.\name\()","a",@progbits
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.endm
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.macro use_ftsec name
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.section ".head.text.\name\()","ax",@progbits
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.endm
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/*
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* Fixed (location) sections are used by opening fixed sections and emitting
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* fixed section entries into them before closing them. Multiple fixed sections
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* can be open at any time.
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*
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* Each fixed section created in a .S file must have corresponding linkage
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* directives including location, added to arch/powerpc/kernel/vmlinux.lds.S
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*
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* For each fixed section, code is generated into it in the order which it
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* appears in the source. Fixed section entries can be placed at a fixed
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* location within the section using _LOCATION postifx variants. These must
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* be ordered according to their relative placements within the section.
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*
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* OPEN_FIXED_SECTION(section_name, start_address, end_address)
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* FIXED_SECTION_ENTRY_BEGIN(section_name, label1)
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*
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* USE_FIXED_SECTION(section_name)
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* label3:
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* li r10,128
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* mv r11,r10
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* FIXED_SECTION_ENTRY_BEGIN_LOCATION(section_name, label2, start_address, size)
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* FIXED_SECTION_ENTRY_END_LOCATION(section_name, label2, start_address, size)
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* CLOSE_FIXED_SECTION(section_name)
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*
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* ZERO_FIXED_SECTION can be used to emit zeroed data.
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*
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* Troubleshooting:
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* - If the build dies with "Error: attempt to move .org backwards" at
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* CLOSE_FIXED_SECTION() or elsewhere, there may be something
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* unexpected being added there. Remove the '. = x_len' line, rebuild, and
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* check what is pushing the section down.
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* - If the build dies in linking, check arch/powerpc/tools/head_check.sh
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* comments.
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* - If the kernel crashes or hangs in very early boot, it could be linker
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* stubs at the start of the main text.
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*/
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#define OPEN_FIXED_SECTION(sname, start, end) \
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sname##_start = (start); \
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sname##_end = (end); \
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sname##_len = (end) - (start); \
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define_ftsec sname; \
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. = 0x0; \
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start_##sname:
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/*
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* .linker_stub_catch section is used to catch linker stubs from being
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* inserted in our .text section, above the start_text label (which breaks
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* the ABS_ADDR calculation). See kernel/vmlinux.lds.S and tools/head_check.sh
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* for more details. We would prefer to just keep a cacheline (0x80), but
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* 0x100 seems to be how the linker aligns branch stub groups.
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*/
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#ifdef CONFIG_LD_HEAD_STUB_CATCH
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#define OPEN_TEXT_SECTION(start) \
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.section ".linker_stub_catch","ax",@progbits; \
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linker_stub_catch: \
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. = 0x4; \
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text_start = (start) + 0x100; \
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.section ".text","ax",@progbits; \
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.balign 0x100; \
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start_text:
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#else
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#define OPEN_TEXT_SECTION(start) \
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text_start = (start); \
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.section ".text","ax",@progbits; \
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. = 0x0; \
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start_text:
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#endif
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#define ZERO_FIXED_SECTION(sname, start, end) \
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sname##_start = (start); \
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sname##_end = (end); \
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sname##_len = (end) - (start); \
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define_data_ftsec sname; \
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. = 0x0; \
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. = sname##_len;
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#define USE_FIXED_SECTION(sname) \
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use_ftsec sname;
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#define USE_TEXT_SECTION() \
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.text
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#define CLOSE_FIXED_SECTION(sname) \
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USE_FIXED_SECTION(sname); \
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. = sname##_len; \
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end_##sname:
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#define __FIXED_SECTION_ENTRY_BEGIN(sname, name, __align) \
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USE_FIXED_SECTION(sname); \
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.balign __align; \
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.global name; \
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name:
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#define FIXED_SECTION_ENTRY_BEGIN(sname, name) \
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__FIXED_SECTION_ENTRY_BEGIN(sname, name, IFETCH_ALIGN_BYTES)
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#define FIXED_SECTION_ENTRY_BEGIN_LOCATION(sname, name, start, size) \
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USE_FIXED_SECTION(sname); \
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name##_start = (start); \
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.if ((start) % (size) != 0); \
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.error "Fixed section exception vector misalignment"; \
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.endif; \
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.if ((size) != 0x20) && ((size) != 0x80) && ((size) != 0x100) && ((size) != 0x1000); \
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.error "Fixed section exception vector bad size"; \
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.endif; \
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.if (start) < sname##_start; \
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.error "Fixed section underflow"; \
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.abort; \
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.endif; \
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. = (start) - sname##_start; \
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.global name; \
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name:
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#define FIXED_SECTION_ENTRY_END_LOCATION(sname, name, start, size) \
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.if (start) + (size) > sname##_end; \
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.error "Fixed section overflow"; \
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.abort; \
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.endif; \
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.if (. - name > (start) + (size) - name##_start); \
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.error "Fixed entry overflow"; \
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.abort; \
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.endif; \
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. = ((start) + (size) - sname##_start); \
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/*
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* These macros are used to change symbols in other fixed sections to be
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* absolute or related to our current fixed section.
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*
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* - DEFINE_FIXED_SYMBOL / FIXED_SYMBOL_ABS_ADDR is used to find the
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* absolute address of a symbol within a fixed section, from any section.
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*
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* - ABS_ADDR is used to find the absolute address of any symbol, from within
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* a fixed section.
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*/
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// define label as being _in_ sname
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#define DEFINE_FIXED_SYMBOL(label, sname) \
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label##_absolute = (label - start_ ## sname + sname ## _start)
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#define FIXED_SYMBOL_ABS_ADDR(label) \
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(label##_absolute)
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// find label from _within_ sname
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#define ABS_ADDR(label, sname) (label - start_ ## sname + sname ## _start)
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_POWERPC_HEAD_64_H */
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