linux-user: Implement new ARM 64 bit cmpxchg kernel helper
Linux 3.1 will have a new kernel-page helper for ARM implementing
64 bit cmpxchg. Implement this helper in QEMU linux-user mode:
* Provide kernel helper emulation for 64bit cmpxchg
* Allow guest to object to guest offset to ensure it can map a page
* Populate page with kernel helper version
Signed-off-by: Riku Voipio <riku.voipio@linaro.org>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Dr. David Alan Gilbert <david.gilbert@linaro.org>
The dynamic linker from the GNU C library v2.10+ uses the ELF
auxiliary vector AT_RANDOM [1] as a pointer to 16 bytes with random
values to initialize the stack protection mechanism. Technically the
emulated GNU dynamic linker crashes due to a NULL pointer
derefencement if it is built with stack protection enabled and if
AT_RANDOM is not defined by the QEMU ELF loader.
[1] This ELF auxiliary vector was introduced in Linux v2.6.29.
This patch can be tested with the code above:
#include <elf.h> /* Elf*_auxv_t, AT_RANDOM, */
#include <stdio.h> /* printf(3), */
#include <stdlib.h> /* exit(3), EXIT_*, */
#include <stdint.h> /* uint8_t, */
#include <string.h> /* memcpy(3), */
#if defined(__LP64__) || defined(__ILP64__) || defined(__LLP64__)
# define Elf_auxv_t Elf64_auxv_t
#else
# define Elf_auxv_t Elf32_auxv_t
#endif
main(int argc, char* argv[], char* envp[])
{
Elf_auxv_t *auxv;
/* *envp = NULL marks end of envp. */
while (*envp++ != NULL);
/* auxv->a_type = AT_NULL marks the end of auxv. */
for (auxv = (Elf_auxv_t *)envp; auxv->a_type != AT_NULL; auxv++) {
if (auxv->a_type == AT_RANDOM) {
int i;
uint8_t rand_bytes[16];
printf("AT_RANDOM is: 0x%x\n", auxv->a_un.a_val);
memcpy(rand_bytes, (const uint8_t *)auxv->a_un.a_val, sizeof(rand_bytes));
printf("it points to: ");
for (i = 0; i < 16; i++) {
printf("0x%02x ", rand_bytes[i]);
}
printf("\n");
exit(EXIT_SUCCESS);
}
}
exit(EXIT_FAILURE);
}
Changes introduced in v2 and v3:
* Fix typos + thinko (AT_RANDOM is used for stack canary, not for
ASLR)
* AT_RANDOM points to 16 random bytes stored inside the user
stack.
* Add a small test program.
Signed-off-by: Cédric VINCENT <cedric.vincent@st.com>
Signed-off-by: Laurent ALFONSI <laurent.alfonsi@st.com>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
Fix a bug in the linux-user ELF loader code where it was not correctly
handling images where the lowest vaddr to be loaded was not page aligned.
The problem was that the code to probe for a suitable guest base address
was changing the 'loaddr' variable (by rounding it to a page boundary),
which meant that the load bias would then be incorrectly calculated
unless loaddr happened to already be page-aligned.
Binaries generated by gcc with the default linker script do start with
a loadable segment at a page-aligned vaddr, so were unaffected. This
bug was noticed with a binary created by the Google Go toolchain for ARM.
We fix the bug by refactoring the "probe for guest base" code out into
its own self-contained function.
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
This patch fixes a "double free()" due to "realloc(syms, 0)" in the
loader when the ELF file has no "useful" symbol, as with the following
example (compiled with "sh4-linux-gcc -nostdlib"):
.text
.align 1
.global _start
_start:
mov #1, r3
trapa #40 // syscall(__NR_exit)
nop
The bug appears when the log (option "-d") is enabled.
Signed-off-by: Cédric VINCENT <cedric.vincent@st.com>
Signed-off-by: Yves JANIN <yves.janin@st.com>
Signed-off-by: Riku Voipio <riku.voipio@iki.fi>
Reviewed-by: Richard Henderson <rth@twiddle.net>
This patch adds support for running s390x binaries in the linux-user emulation
code.
Signed-off-by: Ulrich Hecht <uli@suse.de>
Signed-off-by: Alexander Graf <agraf@suse.de>
Extract from "man realloc":
"If realloc() fails the original block is left untouched;
it is not freed or moved."
Fix a possible memory leak (reported by cppcheck).
Cc: Riku Voipio <riku.voipio@iki.fi>
Signed-off-by: Stefan Weil <weil@mail.berlios.de>
Signed-off-by: Riku Voipio <riku.voipio@nokia.com>
This requires moving the PT_INTERP extraction and GUEST_BASE
handling into load_elf_image. Key this off a non-null pointer
argument to receive the interpreter name.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Moving toward a single copy of the elf binary loading code.
Fill in the details of the loaded image into a struct image_info.
Adjust create_elf_tables to read from such structures instead
of from a collection of passed arguments. Don't return error
values from load_elf_interp; always exit(-1) with a message to
stderr. Collect elf_interpreter handling in load_elf_binary
to a common spot.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
At the bottom of the a.out support was the unimplemented load_aout_interp
function. There were other portions of the support that didn't look
right; when I went to look in the Linux kernel for clarification, I found
that the support for such interpreters has been removed from binfmt_elf.
There doesn't seem to be any reason to keep this broken support in qemu.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
There are no supported stack-grows-up targets. We were putting
the guard page at the highest address, i.e. the bottom of the stack.
Use the maximum of host and guest page size for the guard size.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Validate more fields of the elf header. Extract those checks
into two common functions to be used in both load_elf_interp
and load_elf_binary.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
First, adjust load_symbols to accept a load_bias parameter. At the same
time, read the entire section header table in one go, use pread instead
f lseek+read for the symbol and string tables, and properly free
allocated structures on error exit paths.
Second, adjust load_elf_interp to compute load_bias. This requires
finding out the built-in load addresses. Which allows us to honor a
pre-linked interpreter image when possible, and eliminate the hard-coded
INTERP_MAP_SIZE value.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Remove ifdefs from code by defining empty inline functions
when byte swapping isn't needed. Push loops over swapping
arrays of structures into the swapping functions.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
The only consideration on this value is the target endianness.
The existing defines were incorrect for alpha and sh4eb.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Define BPRM_BUF_SIZE to 1k and read that amount initially. If the
data we want from the binary is in this buffer, use it instead of
reading from the file again.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
Moving some PPC AT_* constants from elfload.c at the same time.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
I caught padzero not properly initializing the .bss segment
on a statically linked Alpha program. Rather than a minimal
patch, replace the gross code with a single mmap+memset.
Share more code between load_elf_interp and load_elf_binary.
Legally, an ELF program need not have just a single .bss;
and PT_LOAD segment can have memsz > filesz.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
When loading a shared library that requires an executable stack,
glibc uses the mprotext PROT_GROWSDOWN flag to achieve this.
We don't support PROT_GROWSDOWN.
Add a special case to handle changing the stack permissions in this way.
Signed-off-by: Paul Brook <paul@codesourcery.com>
189 was allocated in upstream binutils.
0xbaab was the old temporary value. Still used by some tools and the
linux kernel.
I've seen 115 in older gdb versions, but lets ignore that one.
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>
The usermode PAGE_RESERVED code is not required by the current mmap
implementation, and is already broken when guest_base != 0.
Unfortunately the bsd emulation still uses the old mmap implementation,
so we can't rip it out altogether.
Signed-off-by: Paul Brook <paul@codesourcery.com>
The dynamic linker converts the Linux layout to the AIX layout and is
reentrant so it won't do it a second time if it's already been
converted. In short it work just fine with either register layout.
OTOH, statically linked binaries expect a Linux layout.
Remove code converting the Linux layout to AIX layout so that all
binaries are presented the Linux Layout.
Signed-off-by: Rob Landley <rob@landley.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
The current default stack limit of 512kB is far too small; a fair
number of gcc testsuite failures (for all guests) are directly
attributable to this. Using the -s option in every invocation of
the emulator is annoying to say the least.
A reasonable compromise seems to be to honor the system rlimit.
At least on two Linux distributions, this is set to 8MB and 10MB
respectively. If the system does not limit the stack, then we're
no worse off than before.
At the same time, rename the variable from x86_stack_size and
change the ultimate fallback size from 512kB to 8MB.
Signed-off-by: Richard Henderson <rth@twiddle.net>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
There's no sense in separately declaring target_{elf_greg,uid,gid,pid}_t
for every architecture. Just declare them once with appropriate
USE_UID16 handling.
Signed-off-by: Nathan Froyd <froydnj@codesourcery.com>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
Make an "#if 0"'d printf() in load_elf_binary(), probably left to aid in
debugging, reflect what the actual code does. The current printf() will
only confuse those who "#if 1" it (it certainly confused me enough to
write this trivial patch).
Signed-off-by: Paul Bolle <pebolle@tiscali.nl>
Signed-off-by: Aurelien Jarno <aurelien@aurel32.net>
In the very least, a change like this requires discussion on the list.
The naming convention is goofy and it causes a massive merge problem. Something
like this _must_ be presented on the list first so people can provide input
and cope with it.
This reverts commit 99a0949b72.
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Put space between = and * when dereferencing a pointer,
to avoid confusion with old-style "*="
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
Callers must pass ELF machine, byte swapping and symbol LSB clearing
information to ELF loader. A.out loader needs page size information, pass
that too as a parameter.
Extract prototypes to a separate file. Move loader.[ch] and elf_ops.h under hw.
Adjust callers. Also use target_phys_addr_t instead of target_ulong for
addresses: loader addresses aren't virtual.
Signed-off-by: Blue Swirl <blauwirbel@gmail.com>
