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2005-10-29[PATCH] mm: split page table lockHugh Dickins
Christoph Lameter demonstrated very poor scalability on the SGI 512-way, with a many-threaded application which concurrently initializes different parts of a large anonymous area. This patch corrects that, by using a separate spinlock per page table page, to guard the page table entries in that page, instead of using the mm's single page_table_lock. (But even then, page_table_lock is still used to guard page table allocation, and anon_vma allocation.) In this implementation, the spinlock is tucked inside the struct page of the page table page: with a BUILD_BUG_ON in case it overflows - which it would in the case of 32-bit PA-RISC with spinlock debugging enabled. Splitting the lock is not quite for free: another cacheline access. Ideally, I suppose we would use split ptlock only for multi-threaded processes on multi-cpu machines; but deciding that dynamically would have its own costs. So for now enable it by config, at some number of cpus - since the Kconfig language doesn't support inequalities, let preprocessor compare that with NR_CPUS. But I don't think it's worth being user-configurable: for good testing of both split and unsplit configs, split now at 4 cpus, and perhaps change that to 8 later. There is a benefit even for singly threaded processes: kswapd can be attacking one part of the mm while another part is busy faulting. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29[PATCH] mm: uml kill unusedHugh Dickins
In worrying over the various pte operations in different architectures, I came across some unused functions in UML: remove mprotect_kernel_vm, protect_vm_page and addr_pte. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29[PATCH] mm: uml pte atomicityHugh Dickins
There's usually a good reason when a pte is examined without the lock; but it makes me nervous when the pointer is dereferenced more than once. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-29[PATCH] mm: arches skip ptlockHugh Dickins
Convert those few architectures which are calling pud_alloc, pmd_alloc, pte_alloc_map on a user mm, not to take the page_table_lock first, nor drop it after. Each of these can continue to use pte_alloc_map, no need to change over to pte_alloc_map_lock, they're neither racy nor swappable. In the sparc64 io_remap_pfn_range, flush_tlb_range then falls outside of the page_table_lock: that's okay, on sparc64 it's like flush_tlb_mm, and that has always been called from outside of page_table_lock in dup_mmap. Signed-off-by: Hugh Dickins <hugh@veritas.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-28[PATCH] gfp_t: remaining bits of arch/*Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-24[PATCH] uml: fix compile failure for TT modeMiklos Szeredi
Without this patch, uml compile fails with: LD .tmp_vmlinux1 arch/um/kernel/built-in.o: In function `config_gdb_cb': arch/um/kernel/tt/gdb.c:129: undefined reference to `TASK_EXTERN_PID' Tested on i386, but fix needed on x86_64 too AFAICS. Signed-off-by: Miklos Szeredi <miklos@szeredi.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-19[PATCH] build fix for uml/amd64Al Viro
Missing half of the [PATCH] uml: Fix sysrq-r support for skas mode We need to remove these (UPT_[DEFG]S) from the read side as well as the write one - otherwise it simply won't build. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Acked-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Acked-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-12[PATCH] uml: compile-time fix recent patchPaolo 'Blaisorblade' Giarrusso
Give an empty definition for clear_can_do_skas() when it is not needed. Thanks to Junichi Uekawa <dancer@netfort.gr.jp> for reporting the breakage and providing a fix (I re-fixed it in an IMHO cleaner way). Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-12[PATCH] uml: revert block driver use of host AIOJeff Dike
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>
2005-10-10[PATCH] uml: fix x86_64 with !CONFIG_FRAME_POINTERJeff Dike
UML/x86_64 doesn't run when built with frame pointers disabled. There was an implicit frame pointer assumption in the stub segfault handler. With frame pointers disabled, UML dies on handling its first page fault. The container-of part of this is from Paolo Giarrusso <blaisorblade@yahoo.it>. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10[PATCH] uml: cleanup whitespace for COW driverPaolo 'Blaisorblade' Giarrusso
Fix whitespace - I split this off the previous patch for easier review. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10[PATCH] uml: cleanup byte order macros for COW driverPaolo 'Blaisorblade' Giarrusso
After restoring the existing code, make it work also when included in kernelspace code (which isn't currently the case, but at least this will prevent people from "fixing" it as just happened). Whitespace is fixed in next patch - it cluttered the diff too much. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10[PATCH] uml: restore include breakage, breaking binary format of COW driverPaolo 'Blaisorblade' Giarrusso
Commit 44456d37b59d8e541936ed26d8b6e08d27e88ac1, between 2.6.13-rc3 and -rc4, was a "nice cleanup" which broke something. Revert the offending part. It broke because: a) because this part doesn't fall under the description b) the author didn't know what he was doing here c) the author didn't try to compile the existing code and see that it worked perfectly. d) the author didn't ask us what was happening e) you didn't either, and somebody there should have learned that UML is a bit different. In fact, UML is special in linking to host libc and using its includes. In particular, since host includes always define both __BIG_ENDIAN and __LITTLE_ENDIAN, ntohll() macros started thinking to be in a big-endian world; and on-disk compatibility was broken. Many thanks go to Nix for reporting the problem and correctly diagnosing an endianness problem. Btw, this patch restores the previous code, which worked; but the definitions would be uncorrect if used in kernelspace files. Next patch addresses that. Cc: Nix <nix@esperi.org.uk>, Olaf Hering <olh@suse.de> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10[PATCH] uml: allow building .s/.i/.lst files from userspace filesPaolo 'Blaisorblade' Giarrusso
For files which need to include glibc headers (i.e. userspace files), we specified the correct flags only for .o, not for .s/.lst/.i. Fix this. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-10[PATCH] uml: add mode=skas0 as a synonym of skas0Paolo 'Blaisorblade' Giarrusso
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>
2005-10-10[PATCH] Uml: hide commands when not being verbosePaolo 'Blaisorblade' Giarrusso
Add a missing $(Q) to a "ln" invocation. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-10-04[PATCH] uml: Fix sysrq-r support for skas modeAllan Graves
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>
2005-10-04[PATCH] UML - Fix Al's build tidyingJeff Dike
Al's build tidying missed one bit from me - without this UML doesn't boot. Signed-off-by: Jeff Dike <jdike@addtoit.com> Acked-by: Al Viro <viro@ftp.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30[PATCH] uml: revert "run mconsole "sysrq" in process context"Paolo 'Blaisorblade' Giarrusso
Revert commit 12ebcd73e40e09f0dfddf89e465cc0541e0ff8b1, i.e. [PATCH] uml: run mconsole "sysrq" in process context on request from Jeff Dike. a) sysrq may be run when the scheduler is non-functioning b) the warning I wanted to fix actually came from the fault handler run in atomic context. But I fixed that not to take the semaphore in a separate patch. c) the fault handler is run because of a fault, and that fault was unaffected by this patch. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30[PATCH] uml: clear SKAS0/3 flags when running in TT modePaolo 'Blaisorblade' Giarrusso
SEGV_MAYBE_FIXABLE tests ptrace_faultinfo, and depends on it being 1 only in SKAS3 mode, while currently when running with mode=tt it will be 1 anyway. Fix this, and do the same for proc_mm. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30[PATCH] uml: fix page faults in SKAS3 mode.Paolo 'Blaisorblade' Giarrusso
I hadn't been running a SKAS3 host when testing the "uml: fix hang in TT mode on fault" patch (commit 546fe1cbf91d4d62e3849517c31a2327c992e5c5), and I didn't think enough to the missing trap_no in SKAS3 mode. In fact, the resulting kernel doesn't work at all in SKAS3 mode. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-30[PATCH] useless linux/irq.h includes (arch/um)Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-29[PATCH] uml makefiles sanitizedAl Viro
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>
2005-09-22[PATCH] uml: replace printk with "stack-friendly" printf - to report console ↵Paolo 'Blaisorblade' Giarrusso
failure User get *a lot* confused when consoles don't work but we don't report anything. And, as reported in the comment, using printk to report "your console doesn't work" isn't likely to go that far. Fix the problem on the base of this: stack consumption by host printf(). Use kernel sprintf() and os_write_file, using a wild guess that one page will be enough for the message, to preallocate the buffer with kmalloc(). 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>
2005-09-22[PATCH] uml: use GFP_ATOMIC for allocations under spinlocks.Paolo 'Blaisorblade' Giarrusso
setup_initial_poll is only called with sigio_lock() held, so use appropriate allocation. Also, parse_chan() can also be called when holding a spinlock (see line_open() -> parse_chan_pair()). I have sporadic problems (spinlock taken twice, with spinlock debugging on UP) which could be caused by a sequence like "take spinlock, alloc and go to sleep, take again the spinlock in the other thread". 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>
2005-09-22[PATCH] uml: Fix GFP_ flags usagePaolo 'Blaisorblade' Giarrusso
GFP_ATOMIC | GFP_KERNEL is meaningless and won't work. Actually it never worked, even in 2.4. 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>
2005-09-22[PATCH] uml: avoid fixing faults while atomicPaolo 'Blaisorblade' Giarrusso
Following i386, we should maybe refuse trying to fault in pages when we're doing atomic operations, because to handle the fault we could need to take already taken spinlocks. Also, if we're doing an atomic operation (in the sense of in_atomic()) we're surely in kernel mode and we're surely going to handle adequately the failed fault, so it's safe to behave this way. Currently, on UML SMP is rarely used, and we don't support PREEMPT, so this is unlikely to create problems right now, but it might in the future. 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>
2005-09-22[PATCH] uml: run mconsole "sysrq" in process contextPaolo 'Blaisorblade' Giarrusso
Things are breaking horribly with sysrq called in interrupt context. I want to try to fix it, but probably this is simpler. To tell the truth, sysrq is normally run in interrupt context, so there shouldn't be any problem. There's also a warning from the fault handler because it's run in atomic context (I have a patch for that, only I deferred it). This is why I'm doing this. 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>
2005-09-22[PATCH] uml: fix condition in tlb flushPaolo 'Blaisorblade' Giarrusso
Avoid setting w = 0 twice. Spotted this (trivial) thing which is needed for another patch. 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>
2005-09-22[PATCH] uml: fix hang in TT mode on faultPaolo 'Blaisorblade' Giarrusso
The current code doesn't handle well general protection faults on the host - it thinks that cr2 is always the address of a page fault. While actually, on general protection faults, that address is not accessible, so we'd better assume we couldn't satisfy the fault. Currently instead we think we've fixed it, so we go back, retry the instruction and fault again endlessly. This leads to the kernel hanging when doing copy_from_user(dest, -1, ...) in TT mode, since reading *(-1) causes a GFP, and we don't support kernel preemption. Thanks to Luo Xin for testing UML with LTP and reporting the failures he got. Cc: Luo Xin <luothing@sina.com> 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>
2005-09-22[PATCH] strlcat: use for uml umid.cPaolo 'Blaisorblade' Giarrusso
Simplify the code by using strlcat() instead of strncat() and manual appending. 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>
2005-09-22[PATCH] uml: don't remove umid files in conflict casePaolo 'Blaisorblade' Giarrusso
Only remove the UML pidfile and management socket if we created them. Currently in case two UMLs are started with the same umid, the second will remove the first's ones. Probably we should also panic() at that point, not sure however. 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>
2005-09-21[PATCH] uml: fix compile warning after consolidation patchPaolo 'Blaisorblade' Giarrusso
The header declaring this function wasn't included, so the function declaration was totally bogus wrt. the proto - even if this wasn't going to fail at all. It was so bad that the compile warning I got was "control reaches end of non-void function", i.e. missing return. Actually, this has been there for ages, the consolidation patch just added the warning which was needed to clean it up. Nice. Really. Cc: Allan Graves <allan.graves@gmail.com> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-21[PATCH] uml: comment about cast build fixPaolo 'Blaisorblade' Giarrusso
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>
2005-09-21[PATCH] uml: readd removed unistd.h inclusionPaolo 'Blaisorblade' Giarrusso
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>
2005-09-21[PATCH] uml: fix bogus HOST_ELF_CLASS symbol namePaolo 'Blaisorblade' Giarrusso
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>
2005-09-21[PATCH] uml: Fix conflict between libc and ipv6Paolo 'Blaisorblade' Giarrusso
gcc is now complaining during link on some hosts - fix it as for other things. Reported by Antoine Martin <antoine@nagafix.co.uk>. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-21[PATCH] uml: fix uname output on 32-bit binary on 64-bit hostPaolo 'Blaisorblade' Giarrusso
Translate uname output taken from the host if needed. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-21[PATCH] uml: fix modify_ldt - missing break in switchPaolo 'Blaisorblade' Giarrusso
I am a lamer :-(. Luckily, Luo Xin performed LTP testing and found this failure. Btw, the fact that the patch in which I introduced this was merged shows that: a) I'm really trusted by people b) sometimes they're wrong about point a). c) lack of time for reviewers. CC: Luo Xin <luothing@sina.com> Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-21[PATCH] uml: remove verify_area_{tt,skas}Paolo 'Blaisorblade' Giarrusso
When removing verify_area, verify_area_{tt,skas} were forgotten. Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-17[PATCH] uml: UML/i386 cmpxchg fixJeff Dike
Using native cmpxchg offers a slight performance improvement in uml/i386. Signed-off-by: Jeff Dike <jdike@addtoit.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2005-09-17[PATCH] uml: remove include of asm/elf.hJeff Dike
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>
2005-09-17[PATCH] uml: return a real error codeJeff Dike
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>
2005-09-17[PATCH] uml: merge mem_user.c and mem.cJeff Dike
The serial UML OS-abstraction layer patch (um/kernel dir). This joins mem_user.c and mem.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>
2005-09-17[PATCH] uml: move libc code out of mem_user.c and tempfile.cJeff Dike
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>
2005-09-17[PATCH] uml: preserve errno in error pathsJeff Dike
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>
2005-09-17[PATCH] uml: Remove some build warningsJeff Dike
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>
2005-09-17[PATCH] uml: Remove a useless includeJeff Dike
linux/inet.h isn't needed, and on my system, is empty. 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>
2005-09-17[PATCH] uml: Remove an unused fileJeff Dike
This removes a file which is no longer used. 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>
2005-09-17[PATCH] uml: breakpoint an arbitrary threadJeff Dike
This patch implements a stack trace for a thread, not unlike sysrq-t does. The advantage to this is that a break point can be placed on showreqs, so that upon showing the stack, you jump immediately into the debugger. While sysrq-t does the same thing, sysrq-t shows *all* threads stacks. It also doesn't work right now. In the future, I thought it might be acceptable to make this show all pids stacks, but perhaps leaving well enough alone and just using sysrq-t would be okay. For now, upon receiving the stack command, UML switches context to that thread, dumps its registers, and then switches context back to the original thread. Since UML compacts all threads into one of 4 host threads, this sort of mechanism could be expanded in the future to include other debugging helpers that sysrq does not cover. Note by jdike - The main benefit to this is that it brings an arbitrary thread back into context, where it can be examined by gdb. The fact that it dumps it stack is secondary. This provides the capability to examine a sleeping thread, which has existed in tt mode, but not in skas mode until now. Also, the other threads, that sysrq doesn't cover, can be gdb-ed directly anyway. Signed-off-by: Allan Graves<allan.graves@gmail.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>