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linux-next/arch/arm/kernel/vmlinux-xip.lds.S
Russell King c608906165 ARM: probes: avoid adding kprobes to sensitive kernel-entry/exit code
Avoid adding kprobes to any of the kernel entry/exit or startup
assembly code, or code in the identity-mapped region.  This code does
not conform to the standard C conventions, which means that the
expectations of the kprobes code is not forfilled.

Placing kprobes at some of these locations results in the kernel trying
to return to userspace addresses while retaining the CPU in kernel mode.

Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Russell King <rmk+kernel@armlinux.org.uk>
2017-12-17 22:14:21 +00:00

341 lines
8.0 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>
*/
/* No __ro_after_init data in the .rodata section - which will always be ro */
#define RO_AFTER_INIT_DATA
#include <linux/sizes.h>
#include <asm-generic/vmlinux.lds.h>
#include <asm/cache.h>
#include <asm/thread_info.h>
#include <asm/memory.h>
#include <asm/page.h>
#define PROC_INFO \
. = ALIGN(4); \
VMLINUX_SYMBOL(__proc_info_begin) = .; \
*(.proc.info.init) \
VMLINUX_SYMBOL(__proc_info_end) = .;
#define IDMAP_TEXT \
ALIGN_FUNCTION(); \
VMLINUX_SYMBOL(__idmap_text_start) = .; \
*(.idmap.text) \
VMLINUX_SYMBOL(__idmap_text_end) = .; \
. = ALIGN(PAGE_SIZE); \
VMLINUX_SYMBOL(__hyp_idmap_text_start) = .; \
*(.hyp.idmap.text) \
VMLINUX_SYMBOL(__hyp_idmap_text_end) = .;
#ifdef CONFIG_HOTPLUG_CPU
#define ARM_CPU_DISCARD(x)
#define ARM_CPU_KEEP(x) x
#else
#define ARM_CPU_DISCARD(x) x
#define ARM_CPU_KEEP(x)
#endif
#if (defined(CONFIG_SMP_ON_UP) && !defined(CONFIG_DEBUG_SPINLOCK)) || \
defined(CONFIG_GENERIC_BUG)
#define ARM_EXIT_KEEP(x) x
#define ARM_EXIT_DISCARD(x)
#else
#define ARM_EXIT_KEEP(x)
#define ARM_EXIT_DISCARD(x) x
#endif
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.exidx.exit.text)
*(.ARM.extab.exit.text)
ARM_CPU_DISCARD(*(.ARM.exidx.cpuexit.text))
ARM_CPU_DISCARD(*(.ARM.extab.cpuexit.text))
ARM_EXIT_DISCARD(EXIT_TEXT)
ARM_EXIT_DISCARD(EXIT_DATA)
EXIT_CALL
#ifndef CONFIG_MMU
*(.text.fixup)
*(__ex_table)
#endif
*(.alt.smp.init)
*(.discard)
*(.discard.*)
}
. = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
_xiprom = .; /* XIP ROM area to be mapped */
.head.text : {
_text = .;
HEAD_TEXT
}
.text : { /* Real text segment */
_stext = .; /* Text and read-only data */
IDMAP_TEXT
__entry_text_start = .;
*(.entry.text)
__entry_text_end = .;
IRQENTRY_TEXT
TEXT_TEXT
SCHED_TEXT
CPUIDLE_TEXT
LOCK_TEXT
KPROBES_TEXT
*(.gnu.warning)
*(.glue_7)
*(.glue_7t)
. = ALIGN(4);
*(.got) /* Global offset table */
ARM_CPU_KEEP(PROC_INFO)
}
RO_DATA(PAGE_SIZE)
. = ALIGN(4);
__ex_table : AT(ADDR(__ex_table) - LOAD_OFFSET) {
__start___ex_table = .;
#ifdef CONFIG_MMU
*(__ex_table)
#endif
__stop___ex_table = .;
}
#ifdef CONFIG_ARM_UNWIND
/*
* Stack unwinding tables
*/
. = ALIGN(8);
.ARM.unwind_idx : {
__start_unwind_idx = .;
*(.ARM.exidx*)
__stop_unwind_idx = .;
}
.ARM.unwind_tab : {
__start_unwind_tab = .;
*(.ARM.extab*)
__stop_unwind_tab = .;
}
#endif
NOTES
_etext = .; /* End of text and rodata section */
/*
* The vectors and stubs are relocatable code, and the
* only thing that matters is their relative offsets
*/
__vectors_start = .;
.vectors 0xffff0000 : AT(__vectors_start) {
*(.vectors)
}
. = __vectors_start + SIZEOF(.vectors);
__vectors_end = .;
__stubs_start = .;
.stubs ADDR(.vectors) + 0x1000 : AT(__stubs_start) {
*(.stubs)
}
. = __stubs_start + SIZEOF(.stubs);
__stubs_end = .;
PROVIDE(vector_fiq_offset = vector_fiq - ADDR(.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 = .;
}
.init.rodata : {
INIT_SETUP(16)
INIT_CALLS
CON_INITCALL
SECURITY_INITCALL
INIT_RAM_FS
}
#ifdef CONFIG_ARM_MPU
. = ALIGN(SZ_128K);
#endif
_exiprom = .; /* End of XIP ROM area */
/*
* From this point, stuff is considered writable and will be copied to RAM
*/
__data_loc = ALIGN(4); /* location in file */
. = PAGE_OFFSET + TEXT_OFFSET; /* location in memory */
#undef LOAD_OFFSET
#define LOAD_OFFSET (PAGE_OFFSET + TEXT_OFFSET - __data_loc)
. = ALIGN(THREAD_SIZE);
_sdata = .;
RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
.data.ro_after_init : AT(ADDR(.data.ro_after_init) - LOAD_OFFSET) {
*(.data..ro_after_init)
}
_edata = .;
. = ALIGN(PAGE_SIZE);
__init_begin = .;
.init.data : AT(ADDR(.init.data) - LOAD_OFFSET) {
INIT_DATA
}
.exit.data : AT(ADDR(.exit.data) - LOAD_OFFSET) {
ARM_EXIT_KEEP(EXIT_DATA)
}
#ifdef CONFIG_SMP
PERCPU_SECTION(L1_CACHE_BYTES)
#endif
/*
* End of copied data. We need a dummy section to get its LMA.
* Also located before final ALIGN() as trailing padding is not stored
* in the resulting binary file and useless to copy.
*/
.data.endmark : AT(ADDR(.data.endmark) - LOAD_OFFSET) { }
_edata_loc = LOADADDR(.data.endmark);
. = ALIGN(PAGE_SIZE);
__init_end = .;
#ifdef CONFIG_HAVE_TCM
/*
* We align everything to a page boundary so we can
* free it after init has commenced and TCM contents have
* been copied to its destination.
*/
.tcm_start : {
. = ALIGN(PAGE_SIZE);
__tcm_start = .;
__itcm_start = .;
}
/*
* Link these to the ITCM RAM
* Put VMA to the TCM address and LMA to the common RAM
* and we'll upload the contents from RAM to TCM and free
* the used RAM after that.
*/
.text_itcm ITCM_OFFSET : AT(__itcm_start)
{
__sitcm_text = .;
*(.tcm.text)
*(.tcm.rodata)
. = ALIGN(4);
__eitcm_text = .;
}
/*
* Reset the dot pointer, this is needed to create the
* relative __dtcm_start below (to be used as extern in code).
*/
. = ADDR(.tcm_start) + SIZEOF(.tcm_start) + SIZEOF(.text_itcm);
.dtcm_start : {
__dtcm_start = .;
}
/* TODO: add remainder of ITCM as well, that can be used for data! */
.data_dtcm DTCM_OFFSET : AT(__dtcm_start)
{
. = ALIGN(4);
__sdtcm_data = .;
*(.tcm.data)
. = ALIGN(4);
__edtcm_data = .;
}
/* Reset the dot pointer or the linker gets confused */
. = ADDR(.dtcm_start) + SIZEOF(.data_dtcm);
/* End marker for freeing TCM copy in linked object */
.tcm_end : AT(ADDR(.dtcm_start) + SIZEOF(.data_dtcm)){
. = ALIGN(PAGE_SIZE);
__tcm_end = .;
}
#endif
BSS_SECTION(0, 0, 8)
_end = .;
STABS_DEBUG
}
/*
* 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")
ASSERT((__arch_info_end - __arch_info_begin), "no machine record defined")
/*
* The HYP init code can't be more than a page long,
* and should not cross a page boundary.
* The above comment applies as well.
*/
ASSERT(__hyp_idmap_text_end - (__hyp_idmap_text_start & PAGE_MASK) <= PAGE_SIZE,
"HYP init code too big or misaligned")
#ifdef CONFIG_XIP_DEFLATED_DATA
/*
* The .bss is used as a stack area for __inflate_kernel_data() whose stack
* frame is 9568 bytes. Make sure it has extra room left.
*/
ASSERT((_end - __bss_start) >= 12288, ".bss too small for CONFIG_XIP_DEFLATED_DATA")
#endif
#ifdef CONFIG_ARM_MPU
/*
* Due to PMSAv7 restriction on base address and size we have to
* enforce minimal alignment restrictions. It was seen that weaker
* alignment restriction on _xiprom will likely force XIP address
* space spawns multiple MPU regions thus it is likely we run in
* situation when we are reprogramming MPU region we run on with
* something which doesn't cover reprogramming code itself, so as soon
* as we update MPU settings we'd immediately try to execute straight
* from background region which is XN.
* It seem that alignment in 1M should suit most users.
* _exiprom is aligned as 1/8 of 1M so can be covered by subregion
* disable
*/
ASSERT(!(_xiprom & (SZ_1M - 1)), "XIP start address may cause MPU programming issues")
ASSERT(!(_exiprom & (SZ_128K - 1)), "XIP end address may cause MPU programming issues")
#endif