linux/arch/um/kernel/trap.c, branch v3.0.82

um: print info about fatal segfaults

2011-05-25T15:39:41Z

Print a short info about fatal segfaults like other archs do. Signed-off-by: Richard Weinberger Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Move FAULT_FLAG_xyz into handle_mm_fault() callers

2009-06-21T20:08:22Z

This allows the callers to now pass down the full set of FAULT_FLAG_xyz flags to handle_mm_fault(). All callers have been (mechanically) converted to the new calling convention, there's almost certainly room for architectures to clean up their code and then add FAULT_FLAG_RETRY when that support is added. Signed-off-by: Linus Torvalds

mm: invoke oom-killer from page fault

2009-01-06T23:58:58Z

Rather than have the pagefault handler kill a process directly if it gets a VM_FAULT_OOM, have it call into the OOM killer. With increasingly sophisticated oom behaviour (cpusets, memory cgroups, oom killing throttling, oom priority adjustment or selective disabling, panic on oom, etc), it's silly to unconditionally kill the faulting process at page fault time. Create a hook for pagefault oom path to call into instead. Only converted x86 and uml so far. [akpm@linux-foundation.org: make __out_of_memory() static] [akpm@linux-foundation.org: fix comment] Signed-off-by: Nick Piggin Cc: Jeff Dike Acked-by: Ingo Molnar Cc: Thomas Gleixner Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: kill processes instead of panicing kernel

2008-02-05T17:44:28Z

UML was panicing in the case of failures of libc calls which shouldn't happen. This is an overreaction since a failure from libc doesn't normally mean that kernel data structures are in an unknown state. Instead, the current process should just be killed if there is no way to recover. The case that prompted this was a failure of PTRACE_SETREGS restoring the same state that was read by PTRACE_GETREGS. It appears that when a process tries to load a bogus value into a segment register, it segfaults (as expected) and the value is actually loaded and is seen by PTRACE_GETREGS (not expected). This case is fixed by forcing a fatal SIGSEGV on the process so that it immediately dies. fatal_sigsegv was added for this purpose. It was declared as noreturn, so in order to pursuade gcc that it actually does not return, I added a call to os_dump_core (and declared it noreturn) so that I get a core file if somehow the process survives. All other calls in arch/um/os-Linux/skas/process.c got the same treatment, with failures causing the process to die instead of a kernel panic, with some exceptions. userspace_tramp exits with status 1 if anything goes wrong there. That will cause start_userspace to return an error. copy_context_skas0 and map_stub_pages also now return errors instead of panicing. Callers of thes functions were changed to check for errors and do something appropriate. Usually that's to return an error to their callers. check_skas3_ptrace_faultinfo just exits since that's too early to do anything else. save_registers, restore_registers, and init_registers now return status instead of panicing on failure, with their callers doing something appropriate. There were also duplicate declarations of save_registers and restore_registers in os.h - these are gone. I noticed and fixed up some whitespace damage. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: tidy pgtable.h

2008-02-05T17:44:26Z

Large pieces of include/asm/pgtable.h were unused cruft. This uncovered arch/um/kernel/trap.c needing skas.h in order to get ptrace_faultinfo. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: tidy kern_util.h

2008-02-05T17:44:26Z

Tidy kern_util.h. It turns out that most of the function declarations aren't used, so they can go away. os.h no longer includes kern_util.h, so files which got it through os.h now need to include it directly. A number of other files never needed it, so these includes are deleted. The structure which was used to pass signal handlers from the kernel side to the userspace side is gone. Instead, the handlers are declared here, and used directly from libc code. This allows arch/um/os-Linux/trap.c to be deleted, with its remnants being moved to arch/um/os-Linux/skas/trap.c. arch/um/os-Linux/tty.c had its inclusions changed, and it needed some style attention, so it got tidied. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: further bugs.c tidying

2008-02-05T17:44:25Z

bugs.c, for both i386 and x86_64, can undergo further cleaning - The i386 arch_check_bugs only does one thing, so we might as well inline the cmov checking. The i386 includes can be trimmed down a bit. arch_init_thread wasn't used, so it is deleted. The panics in arch_handle_signal are turned into printks because the process is about to get segfaulted anyway, so something is dying no matter what happens here. Also, the return value was always the same, so it contained no information, so it can be void instead. The name is changed to arch_examine_signal because it doesn't handle anything. The caller of arch_handle_signal, relay_signal, does things in a different order. The kernel-mode signal check is now first, which puts everything else together, making things a bit clearer conceptually. [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid namespaces: define is_global_init() and is_container_init()

2007-10-19T18:53:37Z

is_init() is an ambiguous name for the pid==1 check. Split it into is_global_init() and is_container_init(). A cgroup init has it's tsk->pid == 1. A global init also has it's tsk->pid == 1 and it's active pid namespace is the init_pid_ns. But rather than check the active pid namespace, compare the task structure with 'init_pid_ns.child_reaper', which is initialized during boot to the /sbin/init process and never changes. Changelog: 2.6.22-rc4-mm2-pidns1: - Use 'init_pid_ns.child_reaper' to determine if a given task is the global init (/sbin/init) process. This would improve performance and remove dependence on the task_pid(). 2.6.21-mm2-pidns2: - [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc, ppc,avr32}/traps.c for the _exception() call to is_global_init(). This way, we kill only the cgroup if the cgroup's init has a bug rather than force a kernel panic. [akpm@linux-foundation.org: fix comment] [sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c] [bunk@stusta.de: kernel/pid.c: remove unused exports] [sukadev@us.ibm.com: Fix capability.c to work with threaded init] Signed-off-by: Serge E. Hallyn Signed-off-by: Sukadev Bhattiprolu Acked-by: Pavel Emelianov Cc: Eric W. Biederman Cc: Cedric Le Goater Cc: Dave Hansen Cc: Herbert Poetzel Cc: Kirill Korotaev Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: get rid of do_longjmp

2007-10-16T16:43:05Z

do_longjmp used to be needed when UML didn't have its own implementation of setjmp and longjmp. They came from libc, and couldn't be called directly from kernel code, as the libc jmp_buf couldn't be imported there. do_longjmp was a userspace function which served to provide longjmp access to kernel code. This is gone, and a number of void * pointers can now be jmp_buf *. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: remove code made redundant by CHOOSE_MODE removal

2007-10-16T16:43:05Z

This patch makes a number of simplifications enabled by the removal of CHOOSE_MODE. There were lots of functions that looked like int foo(args){ foo_skas(args); } The bodies of foo_skas are now folded into foo, and their declarations (and sometimes entire header files) are deleted. In addition, the union uml_pt_regs, which was a union between the tt and skas register formats, is now a struct, with the tt-mode arm of the union being removed. It turns out that usr2_handler was unused, so it is gone. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds