linux/arch/arm/kernel/vmlinux.lds.S
Linus Walleij a9ff696160 ARM: mm: Make virt_to_pfn() a static inline
Making virt_to_pfn() a static inline taking a strongly typed
(const void *) makes the contract of a passing a pointer of that
type to the function explicit and exposes any misuse of the
macro virt_to_pfn() acting polymorphic and accepting many types
such as (void *), (unitptr_t) or (unsigned long) as arguments
without warnings.

Doing this is a bit intrusive: virt_to_pfn() requires
PHYS_PFN_OFFSET and PAGE_SHIFT to be defined, and this is defined in
<asm/page.h>, so this must be included *before* <asm/memory.h>.

The use of macros were obscuring the unclear inclusion order here,
as the macros would eventually be resolved, but a static inline
like this cannot be compiled with unresolved macros.

The naive solution to include <asm/page.h> at the top of
<asm/memory.h> does not work, because <asm/memory.h> sometimes
includes <asm/page.h> at the end of itself, which would create a
confusing inclusion loop. So instead, take the approach to always
unconditionally include <asm/page.h> at the end of <asm/memory.h>

arch/arm uses <asm/memory.h> explicitly in a lot of places,
however it turns out that if we just unconditionally include
<asm/memory.h> into <asm/page.h> and switch all inclusions of
<asm/memory.h> to <asm/page.h> instead, we enforce the right
order and <asm/memory.h> will always have access to the
definitions.

Put an inclusion guard in place making it impossible to include
<asm/memory.h> explicitly.

Link: https://lore.kernel.org/linux-mm/20220701160004.2ffff4e5ab59a55499f4c736@linux-foundation.org/
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2023-05-29 11:27:08 +02:00

181 lines
3.4 KiB
ArmAsm

/* SPDX-License-Identifier: GPL-2.0 */
/* ld script to make ARM Linux kernel
* taken from the i386 version by Russell King
* Written by Martin Mares <mj@atrey.karlin.mff.cuni.cz>
*/
#ifdef CONFIG_XIP_KERNEL
#include "vmlinux-xip.lds.S"
#else
#include <linux/pgtable.h>
#include <asm/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/page.h>
#include <asm/mpu.h>
OUTPUT_ARCH(arm)
ENTRY(stext)
#ifndef __ARMEB__
jiffies = jiffies_64;
#else
jiffies = jiffies_64 + 4;
#endif
SECTIONS
{
/*
* XXX: The linker does not define how output sections are
* assigned to input sections when there are multiple statements
* matching the same input section name. There is no documented
* order of matching.
*
* unwind exit sections must be discarded before the rest of the
* unwind sections get included.
*/
/DISCARD/ : {
ARM_DISCARD
#ifndef CONFIG_SMP_ON_UP
*(.alt.smp.init)
#endif
#ifndef CONFIG_ARM_UNWIND
*(.ARM.exidx) *(.ARM.exidx.*)
*(.ARM.extab) *(.ARM.extab.*)
#endif
}
. = KERNEL_OFFSET + TEXT_OFFSET;
.head.text : {
_text = .;
HEAD_TEXT
}
#ifdef CONFIG_STRICT_KERNEL_RWX
. = ALIGN(1<<SECTION_SHIFT);
#endif
#ifdef CONFIG_ARM_MPU
. = ALIGN(PMSAv8_MINALIGN);
#endif
.text : { /* Real text segment */
_stext = .; /* Text and read-only data */
ARM_TEXT
}
#ifdef CONFIG_DEBUG_ALIGN_RODATA
. = ALIGN(1<<SECTION_SHIFT);
#endif
_etext = .; /* End of text section */
RO_DATA(PAGE_SIZE)
. = ALIGN(4);
__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
__start___ex_table = .;
ARM_MMU_KEEP(*(__ex_table))
__stop___ex_table = .;
}
#ifdef CONFIG_ARM_UNWIND
ARM_UNWIND_SECTIONS
#endif
#ifdef CONFIG_STRICT_KERNEL_RWX
. = ALIGN(1<<SECTION_SHIFT);
#else
. = ALIGN(PAGE_SIZE);
#endif
__init_begin = .;
ARM_VECTORS
INIT_TEXT_SECTION(8)
.exit.text : {
ARM_EXIT_KEEP(EXIT_TEXT)
}
.init.proc.info : {
ARM_CPU_DISCARD(PROC_INFO)
}
.init.arch.info : {
__arch_info_begin = .;
*(.arch.info.init)
__arch_info_end = .;
}
.init.tagtable : {
__tagtable_begin = .;
*(.taglist.init)
__tagtable_end = .;
}
#ifdef CONFIG_SMP_ON_UP
.init.smpalt : {
__smpalt_begin = .;
*(.alt.smp.init)
__smpalt_end = .;
}
#endif
.init.pv_table : {
__pv_table_begin = .;
*(.pv_table)
__pv_table_end = .;
}
INIT_DATA_SECTION(16)
.exit.data : {
ARM_EXIT_KEEP(EXIT_DATA)
}
#ifdef CONFIG_SMP
PERCPU_SECTION(L1_CACHE_BYTES)
#endif
#ifdef CONFIG_HAVE_TCM
ARM_TCM
#endif
#ifdef CONFIG_STRICT_KERNEL_RWX
. = ALIGN(1<<SECTION_SHIFT);
#else
. = ALIGN(THREAD_ALIGN);
#endif
__init_end = .;
_sdata = .;
RW_DATA(L1_CACHE_BYTES, PAGE_SIZE, THREAD_ALIGN)
_edata = .;
BSS_SECTION(0, 0, 0)
#ifdef CONFIG_ARM_MPU
. = ALIGN(PMSAv8_MINALIGN);
#endif
_end = .;
STABS_DEBUG
DWARF_DEBUG
ARM_DETAILS
ARM_ASSERTS
}
#ifdef CONFIG_STRICT_KERNEL_RWX
/*
* Without CONFIG_DEBUG_ALIGN_RODATA, __start_rodata_section_aligned will
* be the first section-aligned location after __start_rodata. Otherwise,
* it will be equal to __start_rodata.
*/
__start_rodata_section_aligned = ALIGN(__start_rodata, 1 << SECTION_SHIFT);
#endif
/*
* These must never be empty
* If you have to comment these two assert statements out, your
* binutils is too old (for other reasons as well)
*/
ASSERT((__proc_info_end - __proc_info_begin), "missing CPU support")
#ifndef CONFIG_COMPILE_TEST
ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined")
#endif
#endif /* CONFIG_XIP_KERNEL */