kernel.git/arch/um/include/os.h, branch linux-2.6.25.y

uml: deal with inaccessible address space start

2008-08-20T18:15:37Z

commit 40fb16a360d9c6459afee91dc793c1e3374feb94 upstream This patch makes os_get_task_size locate the bottom of the address space, as well as the top. This is for systems which put a lower limit on mmap addresses. It works by manually scanning pages from zero onwards until a valid page is found. Because the bottom of the address space may not be zero, it's not sufficient to assume the top of the address space is the size of the address space. The size is the difference between the top address and bottom address. [jdike@addtoit.com: changed the name to reflect that this function is supposed to return the top of the process address space, not its size and changed the return value to reflect that. Also some minor formatting changes] Signed-off-by: Tom Spink Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

uml: runtime host VMSPLIT detection

2008-02-08T17:22:42Z

Calculate TASK_SIZE at run-time by figuring out the host's VMSPLIT - this is needed on i386 if UML is to run on hosts with varying VMSPLITs without recompilation. TASK_SIZE is now defined in terms of a variable, task_size. This gets rid of an include of pgtable.h from processor.h, which can cause include loops. On i386, task_size is calculated early in boot by probing the address space in a binary search to figure out where the boundary between usable and non-usable memory is. This tries to make sure that a page that is considered to be in userspace is, or can be made, read-write. I'm concerned about a system-global VDSO page in kernel memory being hit and considered to be a userspace page. On x86_64, task_size is just the old value of CONFIG_TOP_ADDR. A bunch of config variable are gone now. CONFIG_TOP_ADDR is directly replaced by TASK_SIZE. NEST_LEVEL is gone since the relocation of the stubs makes it irrelevant. All the HOST_VMSPLIT stuff is gone. All references to these in arch/um/Makefile are also gone. I noticed and fixed a missing extern in os.h when adding os_get_task_size. Note: This has been revised to fix the 32-bit UML on 64-bit host bug that Miklos ran into. Signed-off-by: Jeff Dike Cc: Miklos Szeredi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: remove init_irq_signals

2008-02-05T17:44:30Z

init_irq_signals doesn't need to be called from the context of a new process. It initializes handlers, which are useless in process context. With that call gone, init_irq_signals has only one caller, so it can be inlined into init_new_thread_signals. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: move sig_handler_common_skas

2008-02-05T17:44:30Z

This patch moves sig_handler_common_skas from arch/um/os-Linux/skas/trap.c to its only caller in arch/um/os-Linux/signal.c. trap.c is now empty, so it can be removed. This is code movement only - the significant cleanup needed here is done in the next patch. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: tidy helper code

2008-02-05T17:44:30Z

Style fixes to arch/um/os/helper.c and tidying up the breakpoint fix a bit. helper.c gets all the usual style fixes - updated copyright all printks get severities Also - errval changes to err in helper_child fixed an obsolete comment run_helper was killing a child process which is guaranteed to be dead or dying anyway Removed the nohang and pname arguments from helper_wait and fixed the declaration and callers. nohang was used only in the slirp driver and I don't think it was needed. I think pname was a bit of overkill in putting out an error message when something goes wrong. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: eliminate setjmp_wrapper

2008-02-05T17:44:29Z

setjmp_wrapper existed to provide setjmp to kernel code when UML used libc's setjmp and longjmp. Now that UML has its own implementation, this isn't needed and kernel code can invoke setjmp directly. do_buffer_op is massively cleaned up since it is no longer a callback from setjmp_wrapper and given a va_list from which it must extract its arguments. The actual setjmp is moved from buffer_op to do_op_one_page because the copy operation is inside an atomic section (kmap_atomic to kunmap_atomic) and it shouldn't be longjmp-ed out of. Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: style fixes in file.c

2008-02-05T17:44:29Z

arch/um/os-Linux/file.c needed some style work - updated the copyright cleaned up the includes CodingStyle fixes added some missing CATCH_EINTRs os_set_owner was unused, so it is gone all printks now have severities fcntl(F_GETFL) was being called without checking the return removed an obsolete comment Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

uml: miscellaneous code cleanups

2008-02-05T17:44:29Z

Code tidying - the pid field of struct irq_fd isn't used, so it is removed os_set_fd_async needed to read flags before changing them, it doesn't need a pid passed in because it can call getpid itself, and a block of unused code needed deleting os_get_exec_close was unused, so it is removed ptrace_child called _exit for historical reasons which are no longer valid, so just calls exit instead Signed-off-by: Jeff Dike 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: convert functions to void

2008-02-05T17:44:26Z

This patch changes a few functions into returning void. The return values were not used anyway, so I think it should not be a problem. Also removed a little leftover bit from TT mode. Signed-off-by: Karol Swietlicki Signed-off-by: Jeff Dike Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds