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* [PATCH] uml: close TUN/TAP file descriptorsJeff Dike2006-02-07
| | | | | | | | | | | | | | When UML opens a TUN/TAP device, the file descriptor could be copied into later, long-lived threads, holding the device open even after the interface is taken down, preventing it from being brought up again. This patch makes these descriptors close-on-exec so that they disappear from helper processes, and adds CLONE_FILES to a UML helper thread so that the descriptors are closed in the thread when they are closed elsewhere in UML. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: avoid malloc to sleep in atomic sectionsPaolo 'Blaisorblade' Giarrusso2006-01-18
| | | | | | | | | | | | | | Ugly trick to help make malloc not sleeping - we can't do anything else. But this is not yet optimal, since spinlock don't trigger in_atomic() when preemption is disabled. Also, even if ugly, this was already used in one place, and was even more bogus. Fix it. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: implement soft interruptsJeff Dike2006-01-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch implements soft interrupts. Interrupt enabling and disabling no longer map to sigprocmask. Rather, a flag is set indicating whether interrupts may be handled. If a signal comes in and interrupts are marked as OK, then it is handled normally. If interrupts are marked as off, then the signal handler simply returns after noting that a signal needs handling. When interrupts are enabled later on, this pending signals flag is checked, and the IRQ handlers are called at that point. The point of this is to reduce the cost of local_irq_save et al, since they are very much more common than the signals that they are enabling and disabling. Soft interrupts produce a speed-up of ~25% on a kernel build. Subtleties - UML uses sigsetjmp/siglongjmp to switch contexts. sigsetjmp has been wrapped in a save_flags-like macro which remembers the interrupt state at setjmp time, and restores it when it is longjmp-ed back to. The enable_signals function has to loop because the IRQ handler disables interrupts before returning. enable_signals has to return with signals enabled, and signals may come in between the disabling and the return to enable_signals. So, it loops for as long as there are pending signals, ensuring that signals are enabled when it finally returns, and that there are no pending signals that need to be dealt with. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: eliminate some globalsJeff Dike2006-01-18
| | | | | | | | | | Stop using global variables to hold the file descriptor and offset used to map the skas0 stubs. Instead, calculate them using the page physical addresses. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc-dependent skas process handlingGennady Sharapov2006-01-18
| | | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel/skas dir). This moves all systemcalls from skas/process.c file under os-Linux dir and join skas/process.c and skas/process_kern.c files. Signed-off-by: Gennady Sharapov <gennady.v.sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc-dependent skas memory mapping codeGennady Sharapov2006-01-18
| | | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel/skas dir). This moves all systemcalls from skas/mem_user.c file under os-Linux dir and join skas/mem_user.c and skas/mem.c files. Signed-off-by: Gennady Sharapov <gennady.v.sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: change interface to boot_timer_handlerBodo Stroesser2006-01-18
| | | | | | | | | | | | | | Current implementation of boot_timer_handler isn't usable for s390. So I changed its name to do_boot_timer_handler, taking (struct sigcontext *)sc as argument. do_boot_timer_handler is called from new boot_timer_handler() in arch/um/os-Linux/signal.c, which uses the same mechanisms as other signal handler to find out sigcontext pointer. Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc-dependent time codeGennady Sharapov2006-01-18
| | | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from time.c file under os-Linux dir and joins time.c and tine_kernel.c files Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc-dependent utility proceduresGennady Sharapov2006-01-18
| | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from user_util.c file under os-Linux dir Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: whitespace cleanupJeff Dike2006-01-08
| | | | | | | | | This fixes some mangled whitespace added by the earlier trap_user.c patch. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: merge trap_user.c and trap_kern.cGennady Sharapov2006-01-08
| | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This joins trap_user.c and trap_kernel.c files. Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc-dependent code from trap_user.cGennady Sharapov2006-01-08
| | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from trap_user.c file under os-Linux dir Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc-dependent code from signal_user.cGennady Sharapov2006-01-08
| | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from signal_user.c file under os-Linux dir Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: umid cleanupJeff Dike2006-01-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch cleans up the umid code: - The only_if_set argument to get_umid is gone. - get_umid returns an empty string rather than NULL if there is no umid. - umid_is_random is gone since its users went away. - Some printfs were turned into printks because the code runs late enough that printk is working. - Error paths were cleaned up. - Some functions now return an error and let the caller print the error message rather than printing it themselves. This eliminates the practice of passing a pointer to printf or printk in, depending on where in the boot process we are. - Major tidying of not_dead_yet - mostly error path cleanup, plus a comment explaining why it doesn't react to errors the way you might expect. - Calls to os_* interfaces that were moved under os are changed back to their native libc forms. - snprintf, strlcpy, and their bounds-checking friends are used more often, replacing by-hand bounds checking in some places. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: separate libc-dependent umid codeJeff Dike2006-01-06
| | | | | | | | | | | | | | | | I reworked Gennady's umid OS abstraction patch because the code shouldn't be moved entirely to os. As it turns out, I moved most of it anyway. This patch is the minimal one needed to move the code and have it work. It turns out that the concept of the umid is OS-independent, but almost everything else about the implementation is OS-dependent. This is code movement without cleanup - a follow-on patch tidies everything up without shuffling code around. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: Formatting changesJeff Dike2006-01-06
| | | | | | | | | | | | | | | | | | | This patch makes a bunch of non-functional changes - return(foo); becomes return foo; some statements are broken across lines for readability some trailing whitespace is cleaned up open_one_chan took four arguments, three of which could be deduced from the first. Accordingly, they were eliminated. some examples of "} else {" had a newline added some whitespace cleanup in the indentation lines_init got some control flow cleanup some long lines were broken removed another emacs-specific C formatting comment Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: non-void functions should return somethingJeff Dike2006-01-06
| | | | | | | | | | | There are a few functions which are declared to return something, but don't. These are actually infinite loops which are forced to be declared as non-void. This makes them all return 0. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Hostfs: update for new glibc - add missing symbol exportsPaolo 'Blaisorblade' Giarrusso2005-12-29
| | | | | | | | | | | | Today, when compiling UML, I got warnings for two used unexported symbols: readdir64 and truncate64. Indeed, my glibc headers are aliasing readdir to readdir64 and truncate to truncate64 (and so on). I'm then adding additional exports. Since I've no idea if the symbols where always provided in the supported glibc's, I've added weak definitions too. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: fix random segfaults at bootupPaolo 'Blaisorblade' Giarrusso2005-12-29
| | | | | | | | | | | | | | | | | Don't use printk() where "current_thread_info()" is crap. Until when we switch to running on init_stack, current_thread_info() evaluates to crap. Printk uses "current" at times (in detail, &current is evaluated with CONFIG_DEBUG_SPINLOCK to check the spinlock owner task). And this leads to random segmentation faults. Exactly, what happens is that &current = *(current_thread_info()), i.e. round down $esp and dereference the value. I.e. access the stack below $esp, which causes SIGSEGV on a VM_GROWSDOWN vma (see arch/i386/mm/fault.c). Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: big memory fixesJeff Dike2005-11-07
| | | | | | | | | | | | | | | A number of fixes to improve behavior when large physical memory sizes are specified: - libc files need -D_FILE_OFFSET_BITS=64 because there are unavoidable uses of non-64 interfaces in libc - some %d need to be %u Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: maintain own LDT entriesBodo Stroesser2005-11-07
| | | | | | | | | | | | | | | | | | | | Patch imlements full LDT handling in SKAS: * UML holds it's own LDT table, used to deliver data on modify_ldt(READ) * UML disables the default_ldt, inherited from the host (SKAS3) or resets LDT entries, set by host's clib and inherited in SKAS0 * A new global variable skas_needs_stub is inserted, that can be used to decide, whether stub-pages must be supported or not. * Uses the syscall-stub to replace missing PTRACE_LDT (therefore, write_ldt_entry needs to be modified) Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: separate libc-dependent helper codeJeff Dike2005-11-07
| | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from helper.c file under os-Linux dir Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: separate libc-dependent early initializationJeff Dike2005-11-07
| | | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from main.c file under os-Linux dir and joins mem.c and um_arch.c files. Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: separate libc-dependent uaccess codeGennady Sharapov2005-11-07
| | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from uaccess_user.c file under os-Linux dir Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: revert block driver use of host AIOJeff Dike2005-10-12
| | | | | | | | | | | | | | The patch to use host AIO support that I submitted early after 2.6.13 exposed some problems in the block driver. I have fixes for these, but am not comfortable putting them into 2.6.14 at this late date. So, this patch reverts the use of host AIO. I will resubmit the original patch, plus fixes to the driver after 2.6.14 in order to get a reasonable amount of testing before they're exposed to the general public. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: add mode=skas0 as a synonym of skas0Paolo 'Blaisorblade' Giarrusso2005-10-10
| | | | | | | | Too many people were confused by skas0 and tried using "mode=skas0". And after all, they are right - accept this. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: Fix sysrq-r support for skas modeAllan Graves2005-10-04
| | | | | | | | | | | The old code had the IP and SP coming from the registers in the thread struct, which are completely wrong since those are the userspace registers. This fixes that by pulling the correct values from the jmp_buf in which the kernel state of each thread is stored. Signed-off-by: Allan Graves <allan.graves@oracle.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml makefiles sanitizedAl Viro2005-09-29
| | | | | | | | | | | | | | | UML makefiles sanitized: - number of generated headers reduced to 2 (from user-offsets.c and kernel-offsets.c resp.). The rest is made constant and simply includes those two. - mk_... helpers are gone now that we don't need to generate these headers - arch/um/include2 removed since everything under arch/um/include/sysdep is constant now and symlink can point straight to source tree. - dependencies seriously simplified. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: comment about cast build fixPaolo 'Blaisorblade' Giarrusso2005-09-21
| | | | | | | | | | Explain why the casting we do to silence this warning is indeed safe. It is because the field we're casting from, though being 64-bit wide, was filled with a pointer in first place by ourselves. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: readd removed unistd.h inclusionPaolo 'Blaisorblade' Giarrusso2005-09-21
| | | | | | | | Readd this header (deleted in 60d339f6fe0831060600c62418b71a62ad26c281). A warning is spit out here about undeclared getpgrp(). Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: fix bogus HOST_ELF_CLASS symbol namePaolo 'Blaisorblade' Giarrusso2005-09-21
| | | | | | | | | | | | | | | | Even if with a bit of misunderstanding, Al fixed this in commit 95608261dae863bc43292e6fbd946a3abd3aa49f. Well, the symbol was intended to come from userspace (it exists there on normal host), but since some hosts may miss that, using the kernel one is just as fine. However, rename it to be named consistently with the rest. Actually, he missed converting ELFCLASS32 to coming from kernel headers. For consistence, add ELFCLASS64 too. Cc: Al Viro <viro@ZenIV.linux.org.uk> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: remove include of asm/elf.hJeff Dike2005-09-17
| | | | | | | | | | asm/elf.h is bad on x86_64, and i386 doesn't need it any more after Al's cleanup. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: return a real error codeJeff Dike2005-09-17
| | | | | | | | | do_aio used to return -1 on error instead of errno. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc code out of mem_user.c and tempfile.cJeff Dike2005-09-17
| | | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all system calls from mem_user.c and tempfile.c files under os-Linux dir. Signed-off-by: Gennady Sharapov <Gennady.V.Sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: preserve errno in error pathsJeff Dike2005-09-17
| | | | | | | | | | | | | | | | | | | | | | | | | The poster child for this patch is the third tuntap_user hunk. When an ioctl fails, it properly closes the opened file descriptor and returns. However, the close resets errno to 0, and the 'return errno' that follows returns 0 rather than the value that ioctl set. This caused the caller to believe that the device open succeeded and had opened file descriptor 0, which caused no end of interesting behavior. The rest of this patch is a pass through the UML sources looking for places where errno could be reset before being passed back out. A common culprit is printk, which could call write, being called before errno is returned. In some cases, where the code ends up being much smaller, I just deleted the printk. There was another case where a caller of run_helper looked at errno after a failure, rather than the return value of run_helper, which was the errno value that it wanted. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: Remove some build warningsJeff Dike2005-09-17
| | | | | | | | | These ugly double-casts are the result of gdb complaining about size Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] bogus symbol used in arch/um/os-Linux/elf_aux.cviro@ZenIV.linux.org.uk2005-09-07
| | | | | | | | elf_aux is userland code; it uses symbol (ELF_CLASS) that doesn't exist in userland headers; pulled into kernel-offsets.h, switched elf_aux to using it. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: fix advanced sysemu checkBodo Stroesser2005-09-05
| | | | | | | | | | cleanup and fix the check for advanced sysemu (PTRACE_SYSEMU_SINGLESTEP option) Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: allow host capability usage to be disabledBodo Stroesser2005-09-05
| | | | | | | | | | | | | Add new cmdline setups: - noprocmm - noptracefaultinfo In case of testing, they can be used to switch off usage of /proc/mm and PTRACE_FAULTINFO independently. Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: move libc-dependent startup and signal codeGennady Sharapov2005-09-05
| | | | | | | | | | | | The serial UML OS-abstraction layer patch (um/kernel dir). This moves all systemcalls from process.c file under os-Linux dir and join process.c and process_kern.c files. Signed-off-by: Gennady Sharapov <gennady.v.sharapov@intel.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: add host AIO support to block driverJeff Dike2005-09-05
| | | | | | | | | | | | | | | | | | | | This adds AIO support to the ubd driver. The driver breaks a struct request into IO requests to the host, based on the hardware segments in the request and on any COW blocks covered by the request. The ubd IO thread is gone, since there is now an equivalent thread in the AIO module. There is provision for multiple outstanding requests now. Requests aren't retired until all pieces of it have been completed. The AIO requests have a shared count, which is decremented as IO operations come in until it reaches 0. This can be possibly moved to the request struct - haven't looked at this yet. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: use host AIO supportJeff Dike2005-09-05
| | | | | | | | | | This patch makes UML use host AIO support when it (and /usr/include/linux/aio_abi.h) are present. This is only the support, with no consumers - a consumer is coming in the next patch. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: fix the x86_64 buildAl Viro2005-08-18
| | | | | | | | asm/elf.h breaks the x86_64 build. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: fix vsyscall brokennessJeff Dike2005-07-29
| | | | | | | | | | | | | The #if/#ifdef cleanup exposed a bug in UML's ELF header processing. With this bug fixed, UML recognizes the vsyscall info coming from the host. On FC4, there is a vsyscall page low in the address space, which UML doesn't provide. This causes an infinite page fault loop and a hang on boot. This patch works around that by making this look like a no-vsyscall system. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: implement hostfs syncingPaolo 'Blaisorblade' Giarrusso2005-07-29
| | | | | | | | | Actually implement the hostfs "sync" method. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] turn many #if $undefined_string into #ifdef $undefined_stringOlaf Hering2005-07-27
| | | | | | | | | turn many #if $undefined_string into #ifdef $undefined_string to fix some warnings after -Wno-def was added to global CFLAGS Signed-off-by: Olaf Hering <olh@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: skas0 - separate kernel address space on stock hostsJeff Dike2005-07-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | UML has had two modes of operation - an insecure, slow mode (tt mode) in which the kernel is mapped into every process address space which requires no host kernel modifications, and a secure, faster mode (skas mode) in which the UML kernel is in a separate host address space, which requires a patch to the host kernel. This patch implements something very close to skas mode for hosts which don't support skas - I'm calling this skas0. It provides the security of the skas host patch, and some of the performance gains. The two main things that are provided by the skas patch, /proc/mm and PTRACE_FAULTINFO, are implemented in a way that require no host patch. For the remote address space changing stuff (mmap, munmap, and mprotect), we set aside two pages in the process above its stack, one of which contains a little bit of code which can call mmap et al. To update the address space, the system call information (system call number and arguments) are written to the stub page above the code. The %esp is set to the beginning of the data, the %eip is set the the start of the stub, and it repeatedly pops the information into its registers and makes the system call until it sees a system call number of zero. This is to amortize the cost of the context switch across multiple address space updates. When the updates are done, it SIGSTOPs itself, and the kernel process continues what it was doing. For a PTRACE_FAULTINFO replacement, we set up a SIGSEGV handler in the child, and let it handle segfaults rather than nullifying them. The handler is in the same page as the mmap stub. The second page is used as the stack. The handler reads cr2 and err from the sigcontext, sticks them at the base of the stack in a faultinfo struct, and SIGSTOPs itself. The kernel then reads the faultinfo and handles the fault. A complication on x86_64 is that this involves resetting the registers to the segfault values when the process is inside the kill system call. This breaks on x86_64 because %rcx will contain %rip because you tell SYSRET where to return to by putting the value in %rcx. So, this corrupts $rcx on return from the segfault. To work around this, I added an arch_finish_segv, which on x86 does nothing, but which on x86_64 ptraces the child back through the sigreturn. This causes %rcx to be restored by sigreturn and avoids the corruption. Ultimately, I think I will replace this with the trick of having it send itself a blocked signal which will be unblocked by the sigreturn. This will allow it to be stopped just after the sigreturn, and PTRACE_SYSCALLed without all the back-and-forth of PTRACE_SYSCALLing it through sigreturn. This runs on a stock host, so theoretically (and hopefully), tt mode isn't needed any more. We need to make sure that this is better in every way than tt mode, though. I'm concerned about the speed of address space updates and page fault handling, since they involve extra round-trips to the child. We can amortize the round-trip cost for large address space updates by writing all of the operations to the data page and having the child execute them all at the same time. This will help fork and exec, but not page faults, since they involve only one page. I can't think of any way to help page faults, except to add something like PTRACE_FAULTINFO to the host. There is PTRACE_SIGINFO, but UML doesn't use siginfo for SIGSEGV (or anything else) because there isn't enough information in the siginfo struct to handle page faults (the faulting operation type is missing). Adding that would make PTRACE_SIGINFO a usable equivalent to PTRACE_FAULTINFO. As for the code itself: - The system call stub is in arch/um/kernel/sys-$(SUBARCH)/stub.S. It is put in its own section of the binary along with stub_segv_handler in arch/um/kernel/skas/process.c. This is manipulated with run_syscall_stub in arch/um/kernel/skas/mem_user.c. syscall_stub will execute any system call at all, but it's only used for mmap, munmap, and mprotect. - The x86_64 stub calls sigreturn by hand rather than allowing the normal sigreturn to happen, because the normal sigreturn is a SA_RESTORER in UML's address space provided by libc. Needless to say, this is not available in the child's address space. Also, it does a couple of odd pops before that which restore the stack to the state it was in at the time the signal handler was called. - There is a new field in the arch mmu_context, which is now a union. This is the pid to be manipulated rather than the /proc/mm file descriptor. Code which deals with this now checks proc_mm to see whether it should use the usual skas code or the new code. - userspace_tramp is now used to create a new host process for every UML process, rather than one per UML processor. It checks proc_mm and ptrace_faultinfo to decide whether to map in the pages above its stack. - start_userspace now makes CLONE_VM conditional on proc_mm since we need separate address spaces now. - switch_mm_skas now just sets userspace_pid[0] to the new pid rather than PTRACE_SWITCH_MM. There is an addition to userspace which updates its idea of the pid being manipulated each time around the loop. This is important on exec, when the pid will change underneath userspace(). - The stub page has a pte, but it can't be mapped in using tlb_flush because it is part of tlb_flush. This is why it's required for it to be mapped in by userspace_tramp. Other random things: - The stub section in uml.lds.S is page aligned. This page is written out to the backing vm file in setup_physmem because it is mapped from there into user processes. - There's some confusion with TASK_SIZE now that there are a couple of extra pages that the process can't use. TASK_SIZE is considered by the elf code to be the usable process memory, which is reasonable, so it is decreased by two pages. This confuses the definition of USER_PGDS_IN_LAST_PML4, making it too small because of the rounding down of the uneven division. So we round it to the nearest PGDIR_SIZE rather than the lower one. - I added a missing PT_SYSCALL_ARG6_OFFSET macro. - um_mmu.h was made into a userspace-usable file. - proc_mm and ptrace_faultinfo are globals which say whether the host supports these features. - There is a bad interaction between the mm.nr_ptes check at the end of exit_mmap, stack randomization, and skas0. exit_mmap will stop freeing pages at the PGDIR_SIZE boundary after the last vma. If the stack isn't on the last page table page, the last pte page won't be freed, as it should be since the stub ptes are there, and exit_mmap will BUG because there is an unfreed page. To get around this, TASK_SIZE is set to the next lowest PGDIR_SIZE boundary and mm->nr_ptes is decremented after the calls to init_stub_pte. This ensures that we know the process stack (and all other process mappings) will be below the top page table page, and thus we know that mm->nr_ptes will be one too many, and can be decremented. Things that need fixing: - We may need better assurrences that the stub code is PIC. - The stub pte is set up in init_new_context_skas. - alloc_pgdir is probably the right place. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: compile fixes for gcc 4Jeff Dike2005-06-08
| | | | | | | | | | | This is a bunch of compile fixes provoked by building UML with gcc 4. There are a bunch of signedness mismatches, a couple of uninitialized references, and a botched C99 structure initialization which had somehow gone unnoticed. Signed-off-by: Jeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: s390 preparation, sighandler interface abstractionBodo Stroesser2005-05-05
| | | | | | | | | | | | | | s390 passes parameters in registers. So the only safe way to find out the address of signal context, error-address and error-type (trap_no), which are passed to signal handlers as parameters, is to declare these parameters. So I inserted an subarch-specific macro which holds the declaration of parameters for signal handlers. Signed-off-by: Bodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: Fix SIGWINCH relayingJeff Dike2005-05-05
| | | | | | | | | | | | | This makes SIGWINCH work again, and fixes a couple of SIGWINCH-associated crashes. First, the sigio thread disables SIGWINCH because all hell breaks loose if it ever gets one and tries to call the signal handling code. Second, there was a problem with deferencing tty structs after they were freed. The SIGWINCH support for a tty wasn't being turned off or freed after the tty went away. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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