linux/arch/arm/kernel/vmlinux.lds.S
Simon Glass 87e040b645 ARM: 7017/1: Use generic BUG() handler
ARM uses its own BUG() handler which makes its output slightly different
from other archtectures.

One of the problems is that the ARM implementation doesn't report the function
with the BUG() in it, but always reports the PC being in __bug(). The generic
implementation doesn't have this problem.

Currently we get something like:

kernel BUG at fs/proc/breakme.c:35!
Unable to handle kernel NULL pointer dereference at virtual address 00000000
...
PC is at __bug+0x20/0x2c

With this patch it displays:

kernel BUG at fs/proc/breakme.c:35!
Internal error: Oops - undefined instruction: 0 [#1] PREEMPT SMP
...
PC is at write_breakme+0xd0/0x1b4

This implementation uses an undefined instruction to implement BUG, and sets up
a bug table containing the relevant information. Many versions of gcc do not
support %c properly for ARM (inserting a # when they shouldn't) so we work
around this using distasteful macro magic.

v1: Initial version to replace existing ARM BUG() implementation with something
more similar to other architectures.

v2: Add Thumb support, remove backtrace whitespace output changes. Change to
use macros instead of requiring the asm %d flag to work (thanks to
Dave Martin <dave.martin@linaro.org>)

v3: Remove old BUG() implementation in favor of this one.
Remove the Backtrace: message (will submit this separately).
Use ARM_EXIT_KEEP() so that some architectures can dump exit text at link time
thanks to Stephen Boyd <sboyd@codeaurora.org> (although since we always
define GENERIC_BUG this might be academic.)
Rebase to linux-2.6.git master.

v4: Allow BUGS in modules (these were not reported correctly in v3)
(thanks to Stephen Boyd <sboyd@codeaurora.org> for suggesting that.)
Remove __bug() as this is no longer needed.

v5: Add %progbits as the section flags.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Tested-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2011-10-17 09:13:41 +01:00

295 lines
5.5 KiB
ArmAsm

/* 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>
*/
#include <asm-generic/vmlinux.lds.h>
#include <asm/thread_info.h>
#include <asm/memory.h>
#include <asm/page.h>
#define PROC_INFO \
VMLINUX_SYMBOL(__proc_info_begin) = .; \
*(.proc.info.init) \
VMLINUX_SYMBOL(__proc_info_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
#else
#define ARM_EXIT_KEEP(x)
#endif
OUTPUT_ARCH(arm)
ENTRY(stext)
#ifndef __ARMEB__
jiffies = jiffies_64;
#else
jiffies = jiffies_64 + 4;
#endif
SECTIONS
{
/*
* 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))
#ifndef CONFIG_HOTPLUG
*(.ARM.exidx.devexit.text)
*(.ARM.extab.devexit.text)
#endif
#ifndef CONFIG_MMU
*(.fixup)
*(__ex_table)
#endif
#ifndef CONFIG_SMP_ON_UP
*(.alt.smp.init)
#endif
}
#ifdef CONFIG_XIP_KERNEL
. = XIP_VIRT_ADDR(CONFIG_XIP_PHYS_ADDR);
#else
. = PAGE_OFFSET + TEXT_OFFSET;
#endif
.head.text : {
_text = .;
HEAD_TEXT
}
.text : { /* Real text segment */
_stext = .; /* Text and read-only data */
__exception_text_start = .;
*(.exception.text)
__exception_text_end = .;
IRQENTRY_TEXT
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
#ifdef CONFIG_MMU
*(.fixup)
#endif
*(.gnu.warning)
*(.glue_7)
*(.glue_7t)
. = ALIGN(4);
*(.got) /* Global offset table */
ARM_CPU_KEEP(PROC_INFO)
}
RO_DATA(PAGE_SIZE)
#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
_etext = .; /* End of text and rodata section */
#ifndef CONFIG_XIP_KERNEL
. = ALIGN(PAGE_SIZE);
__init_begin = .;
#endif
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 : {
#ifndef CONFIG_XIP_KERNEL
INIT_DATA
#endif
INIT_SETUP(16)
INIT_CALLS
CON_INITCALL
SECURITY_INITCALL
INIT_RAM_FS
}
#ifndef CONFIG_XIP_KERNEL
.exit.data : {
ARM_EXIT_KEEP(EXIT_DATA)
}
#endif
PERCPU_SECTION(32)
#ifdef CONFIG_XIP_KERNEL
__data_loc = ALIGN(4); /* location in binary */
. = PAGE_OFFSET + TEXT_OFFSET;
#else
__init_end = .;
. = ALIGN(THREAD_SIZE);
__data_loc = .;
#endif
.data : AT(__data_loc) {
_data = .; /* address in memory */
_sdata = .;
/*
* first, the init task union, aligned
* to an 8192 byte boundary.
*/
INIT_TASK_DATA(THREAD_SIZE)
#ifdef CONFIG_XIP_KERNEL
. = ALIGN(PAGE_SIZE);
__init_begin = .;
INIT_DATA
ARM_EXIT_KEEP(EXIT_DATA)
. = ALIGN(PAGE_SIZE);
__init_end = .;
#endif
NOSAVE_DATA
CACHELINE_ALIGNED_DATA(32)
READ_MOSTLY_DATA(32)
/*
* The exception fixup table (might need resorting at runtime)
*/
. = ALIGN(32);
__start___ex_table = .;
#ifdef CONFIG_MMU
*(__ex_table)
#endif
__stop___ex_table = .;
/*
* and the usual data section
*/
DATA_DATA
CONSTRUCTORS
_edata = .;
}
_edata_loc = __data_loc + SIZEOF(.data);
#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
NOTES
BSS_SECTION(0, 0, 0)
_end = .;
STABS_DEBUG
.comment 0 : { *(.comment) }
/* Default discards */
DISCARDS
}
/*
* 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")