linux-toradex.git/arch/um/os-Linux, branch tegra

um: Save FPU registers between task switches

2011-09-15T01:09:37+00:00

Some time ago Jeff prepared 42daba316557 ("uml: stop saving process FP
state") for UML to stop saving the process FP state between task
switches.  The assumption was that since with SKAS0 every guest process
runs inside a host process context the host OS will take care of keeping
the proper FP state.

Unfortunately this is not true for multi-threaded applications, where
all guest threads share a single host process context yet all may use
the FPU on their own.  Although I haven't verified it I suspect things
to be even worse in SKAS3 mode where all guest processes run inside a
single host process.

The patch reintroduces the saving and restoring of the FP context
between task switches.

[richard@nod.at: Ingo posted this patch in 2009, sadly it was never applied
and got lost. Now in 2011 the problem was reported by Gunnar.]

Signed-off-by: Ingo van Lil 
Signed-off-by: Richard Weinberger 
Reported-by: 
Tested-by: 
Cc: Stanislav Meduna 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: disable scan_elf_aux() on x86_64

2011-07-26T03:57:13+00:00

Reusing the host's vDSO makes only sense on x86_32.

Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

uml: free resources

2011-07-26T03:57:13+00:00

When creating the temp file there's a memory and file descriptor leak upon
error.

Signed-off-by: Davidlohr Bueso 
Signed-off-by: Richard Weinberger 
Reviewed-by: Vitaliy Ivanov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

uml: helper.c warning corrections

2011-07-26T03:57:13+00:00

Fix this warning:

  arch/um/os-Linux/helper.c: In function `helper_child':
  arch/um/os-Linux/helper.c:38:7: warning: ignoring return value of `write', declared with attribute warn_unused_result

[richard@nod.at: happens only with -D_FORTIFY_SOURCE=2]
Signed-off-by: Vitaliy Ivanov 
Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: fix _FORTIFY_SOURCE=2 support for kernel modules

2011-07-26T03:57:12+00:00

When UML is compiled with _FORTIFY_SOURCE we have to export all _chk()
functions which are used in modules.  For now it's only the case for
__sprintf_chk().

Tested-by: Florian Fainelli 
Reported-by: Florian Fainelli 
Signed-off-by: Richard Weinberger 
Acked-by: Vitaliy Ivanov 
Cc: Geert Uytterhoeven 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: fix crash while os_dump_core()

2011-05-25T15:39:42+00:00

os_dump_core() emits SIGTERM to terminate all UML processes.  Kernel
threads have to exit on SIGTERM instead of calling last_ditch_exit().
Multiple calls to last_ditch_exit() can cause a crash.

Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: add earlyprintk support

2011-05-25T15:39:41+00:00

User Mode Linux can also benefit from earlyprintk.  UML's earlyprintk
writes kernel messages directly to stdout.

Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: remove SIGHUP handler

2011-05-25T15:39:40+00:00

The UML kernel ignores SIGHUP anyway.  This handler is in vain.

Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: fix UML_LIB_PATH

2011-05-25T15:39:40+00:00

UML_LIB_PATH is hardcoded to /usr/lib/uml/, on 64bit systems UML_LIB_PATH
needs to be /usr/lib64/uml/.

Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

um: fix abort

2011-05-18T09:55:23+00:00

os_dump_core() uses abort() to terminate UML in case of an fatal error.

glibc's abort() calls raise(SIGABRT) which makes use of tgkill().
tgkill() has no effect within UML's kernel threads because they are not
pthreads.  As fallback abort() executes an invalid instruction to
terminate the process.  Therefore UML gets killed by SIGSEGV and leaves a
ugly log entry in the host's kernel ring buffer.

To get rid of this we use our own abort routine.

Signed-off-by: Richard Weinberger 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds