The Linux kernel puts the filename argument of execve() into the new
address space. Many developers are surprised to learn this. Those who
know and could use it, object "But it's not documented."
Those who want to use it dislike the expression
(char *)(1+ strlen(env[-1+ n_env]) + env[-1+ n_env])
because it requires locating the last original environment variable,
and assumes that the filename follows the characters.
This patch documents the insertion of the filename, and makes it easier
to find by adding a new tag AT_EXECFN in the ElfXX_auxv_t; see <elf.h>.
In many cases readlink("/proc/self/exe",) gives the same answer. But if
all the original pages get unmapped, then the kernel erases the symlink
for /proc/self/exe. This can happen when a program decompressor does a
good job of cleaning up after uncompressing directly to memory, so that
the address space of the target program looks the same as if compression
had never happened. One example is http://upx.sourceforge.net .
One notable use of the underlying concept (what path containED the
executable) is glibc expanding $ORIGIN in DT_RUNPATH. In practice for
the near term, it may be a good idea for user-mode code to use both
/proc/self/exe and AT_EXECFN as fall-back methods for each other.
/proc/self/exe can fail due to unmapping, AT_EXECFN can fail because it
won't be present on non-new systems. The auxvec or {AT_EXECFN}.d_val
also can get overwritten, although in nearly all cases this would be the
result of a bug.
The runtime cost is one NEW_AUX_ENT using two words of stack space. The
underlying value is maintained already as bprm->exec; setup_arg_pages()
in fs/exec.c slides it for stack_shift, etc.
Signed-off-by: John Reiser <jreiser@BitWagon.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
I tested tip/master and found an issue (patch attached)
for x2apic support. This is not because of the recent merges we had, but
because of something(where we still access memory based interface after
enabling x2apic mode) that slipped through my earlier tests.
Probably it is a good idea to unmap the memory mapped interface, once we switch
to x2apic mode. That will catch the issues much earlier. I will
post another patch for this.
ack_APIC_irq() is used at too many generic places (and not just during
irq_chip handling!) to use the native_apic_mem_write(). For ex, this will
break x2apic based systems.
Fix ack_APIC_irq() to use the generic apic_write() even for 64-bit.
Signed-off-by: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: suresh.b.siddha@intel.com
Cc: yong.y.wang@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Declare time_init() in asm-x86/time.h
Also did cleanup in asm-x86/timer.h :
timer_ack is only required for X86_32
int recalibrate_cpu_khz(void) is for X86_32
Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>
Moved DECLARE_PER_CPU(int, cpu_number) from CONFIG_X86_32_SMP to CONFIG_X86_32
because cpu_number is required for both.
And include asm/smp.h in process_32.c
Signed-off-by: Jaswinder Singh <jaswinder@infradead.org>
currently if you use PTRACE_SINGLEBLOCK on AMD K6-3 (i586) it will crash.
Kernel now wrongly assumes existing DEBUGCTLMSR MSR register there.
Removed the assumption also for some other non-K6 CPUs but I am not sure there
(but it can only bring small inefficiency there if my assumption is wrong).
Based on info from Roland McGrath, Chuck Ebbert and Mikulas Patocka.
More info at:
https://bugzilla.redhat.com/show_bug.cgi?id=456175
Signed-off-by: Jan Kratochvil <jan.kratochvil@redhat.com>
Cc: <stable@kernel.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Always compile request_module when the kernel allows modules.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
textsearch algorithms can be loaded, make the code depend
on CONFIG_MODULES instead of CONFIG_KMOD.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
One place is just a comment, the other a conditional, unused
inclusion of linux/kmod.h.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: David S. Miller <davem@davemloft.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This reworks try_then_request_module to only invoke the "lookup"
function "x" once when the kernel is not modular.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Also includes a few Kconfig files (xtensa, blackfin)
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Michael Kerrisk <mtk.manpages@gmail.com>
Cc: linux-doc@vger.kernel.org
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Randy Dunlap <rdunlap@xenotime.net>
... as preparation for removing it completely, make it an
invisible bool defaulting to yes.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This patch keeps track of the boundaries of module allocation, in
order to speed up module_text_address().
Inspired by Arjan's version, which required arch-specific defines:
Various pieces of the kernel (lockdep, latencytop, etc) tend
to store backtraces, sometimes at a relatively high
frequency. In itself this isn't a big performance deal (after
all you're using diagnostics features), but there have been
some complaints from people who have over 100 modules loaded
that this is a tad too slow.
This is due to the new backtracer code which looks at every
slot on the stack to see if it's a kernel/module text address,
so that's 1024 slots. 1024 times 100 modules... that's a lot
of list walking.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
This shrinks module.o and each *.ko file.
And finally, structure members which hold length of module
code (four such members there) and count of symbols
are converted from longs to ints.
We cannot possibly have a module where 32 bits won't
be enough to hold such counts.
For one, module loading checks module size for sanity
before loading, so such insanely big module will fail
that test first.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
module.c and module.h conatains code for finding
exported symbols which are declared with EXPORT_UNUSED_SYMBOL,
and this code is compiled in even if CONFIG_UNUSED_SYMBOLS is not set
and thus there can be no EXPORT_UNUSED_SYMBOLs in modules anyway
(because EXPORT_UNUSED_SYMBOL(x) are compiled out to nothing then).
This patch adds required #ifdefs.
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
reorder struct module to save space on 64 bit builds.
saves 1 cacheline_size (128 on default x86_64 & 64 on AMD
Opteron/athlon) when CONFIG_MODULE_UNLOAD=y.
Signed-off-by: Richard Kennedy <richard@rsk.demon.co.uk>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Introduce an each_symbol() iterator to avoid duplicating the knowledge
about the 5 different sections containing symbols. Currently only
used by find_symbol(), but will be used by symbol_put_addr() too.
(Includes NULL ptr deref fix by Jiri Kosina <jkosina@suse.cz>)
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Cc: Jiri Kosina <jkosina@suse.cz>
rmmod has a little-used "-w" option, meaning that instead of failing if the
module is in use, it should block until the module becomes unused.
In this case, we don't need to use stop_machine: Max Krasnyansky
indicated that would be useful for SystemTap which loads/unloads new
modules frequently.
Cc: Max Krasnyansky <maxk@qualcomm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
PTE_PFN_MASK was getting lonely, so I made it a friend.
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Rusty, in his peevish way, complained that macros defining constants
should have a name which somewhat accurately reflects the actual
purpose of the constant.
Aside from the fact that PTE_MASK gives no clue as to what's actually
being masked, and is misleadingly similar to the functionally entirely
different PMD_MASK, PUD_MASK and PGD_MASK, I don't really see what the
problem is.
But if this patch silences the incessent noise, then it will have
achieved its goal (TODO: write test-case).
Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
(Jeremy said:
rusty: use PTE_MASK
rusty: use PTE_MASK
rusty: use PTE_MASK
When I asked:
jsgf: does that include the NX flag?
He responded eloquently:
rusty: use PTE_MASK
rusty: use PTE_MASK
yes, it's the official constant of masking flags out of ptes
)
Change a15af1c9ea 'x86/paravirt: add
pte_flags to just get pte flags' removed lguest's private pte_flags()
in favor of a generic one.
Unfortunately, the generic one doesn't filter out the non-flags bits:
this results in lguest creating corrupt shadow page tables and blowing
up host memory.
Since noone is supposed to use the pfn part of pte_flags(), it seems
safest to always do the filtering.
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Acked-by: Jeremy Fitzhardinge <jeremy@goop.org>
Signed-off-and-morning-tea-spilled-by: Ingo Molnar <mingo@elte.hu>
Add documentation about how to describe SPI busses in the device tree.
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Segher Boessenkool <segher@kernel.crashing.org>
If an I2C device node does not specify an interrupt, the .irq member of the
board_info struct was set to -1. This caused crashes on following
irq_dispose_mappings. Leave it NO_IRQ as returned from irq_of_parse_and_map.
(Suggesting -1 as 'i2c-no-irq' used to be a bug in linux/i2c.h.)
Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
Acked-by: Sean MacLennan <smaclennan@pikatech.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
introducing an APIC handling probing abstraction:
static struct genapic *apic_probe[] __initdata = {
&apic_x2apic_uv_x,
&apic_x2apic_phys,
&apic_x2apic_cluster,
&apic_physflat,
NULL,
};
This way we can remove UV, x2apic specific code from genapic_64.c and
move them to their specific genapic files.
[ v2: fix compiling when CONFIG_ACPI is not set ]
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
beauty fix: /proc/cpuinfo will still show apic feature even if
we booted up with it disabled.
Signed-off-by: Yinghai Lu <yhlu.kernel@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This converts all instances of bus_id in the sparc core kernel to use
either dev_set_name(), or dev_name() depending on the need.
This is done in anticipation of removing the bus_id field from struct
driver.
Cc: Kay Sievers <kay.sievers@vrfy.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This changes vortex_prob1() to handle pci_name() now returning a
constant string.
Cc: Steffen Klassert <klassert@mathematik.tu-chemnitz.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This changes the MTD core to handle pci_name() now returning a constant
string.
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
A driver for the HP iLO/iLO2 management processor, which allows userspace
programs to query the management processor. Programs can open a channel
to the device (/dev/hpilo/dXccbN), and use this to send/receive queries.
The O_EXCL open flag is used to indicate that a particular channel cannot
be shared between processes. This driver will replace various packages
HP has shipped, including hprsm and hp-ilo.
Signed-off-by: David Altobelli <david.altobelli@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Use the new generic int attribute accessors for the x86 mce tolerant
attribute. Simple example to illustrate the new macros.
There are much more places all over the tree that could be converted
like this.
Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
