The kernel makes the high vector page visible to user space. This page
contains (amongst others) small code segments that can be executed in
user space. Make this page visible through ptrace and /proc/<pid>/mem
in order to let gdb perform code parsing needed for proper unwinding.
For example, the ERESTART_RESTARTBLOCK handler actually has a stack
frame -- it returns to a PC value stored on the user's stack. To
unwind after a "sleep" system call was interrupted twice, GDB would
have to recognize this situation and understand that stack frame
layout -- which it currently cannot do.
We could fix this by hard-coding addresses in the vector page range into
GDB, but that isn't really portable as not all of those addresses are
guaranteed to remain stable across kernel releases. And having the gdb
process make an exception for this page and get content from its own
address space for it looks strange, and it is not future proof either.
Being located above PAGE_OFFSET, this vma cannot be deleted by
user space code.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
The patch adds handling case for the R_ARM_THM_MOVW_ABS_NC and
R_ARM_THM_MOVT_ABS relocations in arch/arm/kernel/module.c. Such
relocations may appear in Thumb-2 compiled kernel modules.
Reported-by: Kyungmin Park <kmpark@infradead.org>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
CC kernel/elfcore.o
In file included from include/linux/elf.h:7,
from kernel/elfcore.c:1:
arch/arm/include/asm/elf.h:124: warning: 'struct mm_struct' declared inside parameter list
arch/arm/include/asm/elf.h:124: warning: its scope is only this definition or declaration, which is probably not what you want
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
For this feature to take effect, CONFIG_COMPAT_BRK must be turned
off. This can safely be turned off for any EABI user space versions.
Signed-off-by: Nicolas Pitre <nicolas.pitre@linaro.org>
iop32x_defconfig:
In file included from include/linux/elf.h:7,
from kernel/elfcore.c:1:
arch/arm/include/asm/elf.h:101: warning: "struct task_struct" declared inside parameter list
arch/arm/include/asm/elf.h:101: warning: its scope is only this definition or declaration, which is probably not what you want
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
2.6.34-rc1 added kernel/elfcore.c which includes <asm/elf.h>.
On ARM, this results in:
In file included from include/linux/elf.h:7,
from kernel/elfcore.c:1:
/tmp/linux-2.6.34-rc1/arch/arm/include/asm/elf.h:101: warning: 'struct task_struct' declared inside parameter list
/tmp/linux-2.6.34-rc1/arch/arm/include/asm/elf.h:101: warning: its scope is only this definition or declaration, which is probably not what you want
Including <linux/sched.h> seems a bit heavyweight, so this patch just
adds a tentative declaration of struct task_struct in <asm/elf.h>.
Signed-off-by: Mikael Pettersson <mikpe@it.uu.se>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Currently all architectures but microblaze unconditionally define
USE_ELF_CORE_DUMP. The microblaze omission seems like an error to me, so
let's kill this ifdef and make sure we are the same everywhere.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Cc: <linux-arch@vger.kernel.org>
Cc: Michal Simek <michal.simek@petalogix.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Defines ELF_CORE_COPY_TASK_REGS so that CPU register information
of every thread is included in coredump. Without this, only the faulting
thread is coredumped.
Cc: Roger Quadros <ext-roger.quadros@nokia.com>
Cc: linux-arm-kernel@lists.infradead.org
Signed-off-by: Mika Westerberg <mika.westerberg@iki.fi>
Signed-off-by: Artem Bityutskiy <Artem.Bityutskiy@nokia.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Modules compiled to Thumb-2 have two additional relocations needing to
be resolved at load time, R_ARM_THM_CALL and R_ARM_THM_JUMP24, for BL
and B.W instructions. The maximum Thumb-2 addressing range is +/-2^24
(+/-16MB) therefore the MODULES_VADDR macro in asm/memory.h is set to
(MODULES_END - 8MB) for the Thumb-2 compiled kernel.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
From: Bruce Ashfield <bruce.ashfield@windriver.com>
To fully support the armv7-a instruction set/optimizations, support
for the R_ARM_MOVW_ABS_NC and R_ARM_MOVT_ABS relocation types is
required.
The MOVW and MOVT are both load-immediate instructions, MOVW loads 16
bits into the bottom half of a register, and MOVT loads 16 bits into the
top half of a register.
The relocation information for these instructions has a full 32 bit
value, plus an addend which is stored in the 16 immediate bits in the
instruction itself. The immediate bits in the instruction are not
contiguous (the register # splits it into a 4 bit and 12 bit value),
so the addend has to be extracted accordingly and added to the value.
The value is then split and put into the instruction; a MOVW uses the
bottom 16 bits of the value, and a MOVT uses the top 16 bits.
Signed-off-by: David Borman <david.borman@windriver.com>
Signed-off-by: Bruce Ashfield <bruce.ashfield@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
It would seem when building kernel modules with modern binutils
(required by modern GCC) for ARM v4T targets (specifically observed
with the Samsung 24xx SoC which is an 920T) R_ARM_V4BX relocations
are emitted for function epilogues.
This manifests at module load time with an "unknown relocation: 40"
error message.
The following patch adds the R_ARM_V4BX relocation to the ARM kernel
module loader. The relocation operation is taken from that within the
binutils bfd library.
Signed-off-by: Simtec Linux Team <linux@simtec.co.uk>
Signed-off-by: Vincent Sanders <vince@simtec.co.uk>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
This patch adds ELF section parsing for the unwinding tables in loadable
modules together with the PREL31 relocation symbol resolving.
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
The SET_PERSONALITY macro is always called with a second argument of 0.
Remove the ibcs argument and the various tests to set the PER_SVR4
personality.
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Add support for detecting non-executable stack binaries, and adjust
permissions to prevent execution from data and stack areas. Also,
ensure that READ_IMPLIES_EXEC is enabled for older CPUs where that
is true, and for any executable-stack binary.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Move platform independent header files to arch/arm/include/asm, leaving
those in asm/arch* and asm/plat* alone.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Nicolas Pitre