linux/arch/parisc/kernel/vmlinux.lds.S
James Bottomley d7dd2ff11b [PARISC] only make executable areas executable
Currently parisc has the whole kernel marked as RWX, meaning any
kernel page at all is eligible to be executed.  This can cause a
theoretical problem on systems with combined I/D TLB because the act
of referencing a page causes a TLB insertion with an executable bit.
This TLB entry may be used by the CPU as the basis for speculating the
page into the I-Cache.  If this speculated page is subsequently used
for a user process, there is the possibility we will get a stale
I-cache line picked up as the binary executes.

As a point of good practise, only mark actual kernel text pages as
executable.  The same has to be done for init_text pages, but they're
converted to data pages (and the I-Cache flushed) when the init memory
is released.

Signed-off-by: James Bottomley <James.Bottomley@suse.de>
2011-04-15 12:55:18 -05:00

174 lines
3.7 KiB
ArmAsm

/* Kernel link layout for various "sections"
*
* Copyright (C) 1999-2003 Matthew Wilcox <willy at parisc-linux.org>
* Copyright (C) 2000-2003 Paul Bame <bame at parisc-linux.org>
* Copyright (C) 2000 John Marvin <jsm at parisc-linux.org>
* Copyright (C) 2000 Michael Ang <mang with subcarrier.org>
* Copyright (C) 2002 Randolph Chung <tausq with parisc-linux.org>
* Copyright (C) 2003 James Bottomley <jejb with parisc-linux.org>
* Copyright (C) 2006 Helge Deller <deller@gmx.de>
*
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <asm-generic/vmlinux.lds.h>
/* needed for the processor specific cache alignment size */
#include <asm/cache.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
#include <asm/thread_info.h>
/* ld script to make hppa Linux kernel */
#ifndef CONFIG_64BIT
OUTPUT_FORMAT("elf32-hppa-linux")
OUTPUT_ARCH(hppa)
#else
OUTPUT_FORMAT("elf64-hppa-linux")
OUTPUT_ARCH(hppa:hppa2.0w)
#endif
ENTRY(_stext)
#ifndef CONFIG_64BIT
jiffies = jiffies_64 + 4;
#else
jiffies = jiffies_64;
#endif
SECTIONS
{
. = KERNEL_BINARY_TEXT_START;
_text = .; /* Text and read-only data */
.text ALIGN(16) : {
HEAD_TEXT
TEXT_TEXT
SCHED_TEXT
LOCK_TEXT
KPROBES_TEXT
IRQENTRY_TEXT
*(.text.do_softirq)
*(.text.sys_exit)
*(.text.do_sigaltstack)
*(.text.do_fork)
*(.text.*)
*(.fixup)
*(.lock.text) /* out-of-line lock text */
*(.gnu.warning)
} = 0
/* End of text section */
_etext = .;
RODATA
/* writeable */
/* Make sure this is page aligned so
* that we can properly leave these
* as writable
*/
. = ALIGN(PAGE_SIZE);
data_start = .;
/* unwind info */
.PARISC.unwind : {
__start___unwind = .;
*(.PARISC.unwind)
__stop___unwind = .;
}
EXCEPTION_TABLE(16)
NOTES
/* Data */
RW_DATA_SECTION(L1_CACHE_BYTES, PAGE_SIZE, THREAD_SIZE)
/* PA-RISC locks requires 16-byte alignment */
. = ALIGN(16);
.data..lock_aligned : {
*(.data..lock_aligned)
}
/* End of data section */
_edata = .;
/* BSS */
__bss_start = .;
/* page table entries need to be PAGE_SIZE aligned */
. = ALIGN(PAGE_SIZE);
.data..vmpages : {
*(.data..vm0.pmd)
*(.data..vm0.pgd)
*(.data..vm0.pte)
}
.bss : {
*(.bss)
*(COMMON)
}
__bss_stop = .;
#ifdef CONFIG_64BIT
. = ALIGN(16);
/* Linkage tables */
.opd : {
*(.opd)
} PROVIDE (__gp = .);
.plt : {
*(.plt)
}
.dlt : {
*(.dlt)
}
#endif
/* reserve space for interrupt stack by aligning __init* to 16k */
. = ALIGN(16384);
__init_begin = .;
INIT_TEXT_SECTION(16384)
. = ALIGN(PAGE_SIZE);
INIT_DATA_SECTION(16)
/* we have to discard exit text and such at runtime, not link time */
.exit.text :
{
EXIT_TEXT
}
.exit.data :
{
EXIT_DATA
}
PERCPU(L1_CACHE_BYTES, PAGE_SIZE)
. = ALIGN(PAGE_SIZE);
__init_end = .;
/* freed after init ends here */
_end = . ;
STABS_DEBUG
.note 0 : { *(.note) }
/* Sections to be discarded */
DISCARDS
/DISCARD/ : {
#ifdef CONFIG_64BIT
/* temporary hack until binutils is fixed to not emit these
* for static binaries
*/
*(.interp)
*(.dynsym)
*(.dynstr)
*(.dynamic)
*(.hash)
*(.gnu.hash)
#endif
}
}