- 05 9月, 2005 40 次提交
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Apparently, GDB gets confused when we do an execvp() on ourselves. Since it's simply done to allocate further space for command line arguments (which we'll use to allow gathering the startup command line for guest processes through the host), allow the user to disable that to get a debuggable UML binary. Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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As a follow-up to "UML Support - Ptrace: adds the host SYSEMU support, for UML and general usage" (i.e. uml-support-* in current mm). Avoid unconditionally jumping to work_pending and code copying, just reuse the already existing resume_userspace path. One interesting note, from Charles P. Wright, suggested that the API is improvable with no downsides for UML (except that it will have to support yet another host API, since dropping support for the current API, for UML, is not reasonable from users' point of view). Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> CC: Charles P. Wright <cwright@cs.sunysb.edu> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Bodo Stroesser 提交于
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> This is simply an adjustment for "Ptrace - i386: fix Syscall Audit interaction with singlestep" to work on top of SYSEMU patches, too. On this patch, I have some doubts: I wonder why we need to alter that way ptrace_disable(). I left the patch this way because it has been extensively tested, but I don't understand the reason. The current PTRACE_DETACH handling simply clears child->ptrace; actually this is not enough because entry.S just looks at the thread_flags; actually, do_syscall_trace checks current->ptrace but I don't think depending on that is good, at least for performance, so I think the clearing is done elsewhere. For instance, on PTRACE_CONT it's done, but doing PTRACE_DETACH without PTRACE_CONT is possible (and happens when gdb crashes and one kills it manually). Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> CC: Roland McGrath <roland@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Bodo Stroesser 提交于
This patch implements the new ptrace option PTRACE_SYSEMU_SINGLESTEP, which can be used by UML to singlestep a process: it will receive SINGLESTEP interceptions for normal instructions and syscalls, but syscall execution will be skipped just like with PTRACE_SYSEMU. Signed-off-by: NBodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Bodo Stroesser 提交于
With this patch, we change the way we handle switching from PTRACE_SYSEMU to PTRACE_{SINGLESTEP,SYSCALL}, to free TIF_SYSCALL_EMU from double use as a preparation for PTRACE_SYSEMU_SINGLESTEP extension, without changing the behavior of the host kernel. Signed-off-by: NBodo Stroesser <bstroesser@fujitsu-siemens.com> Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Laurent Vivier 提交于
Jeff Dike <jdike@addtoit.com>, Paolo 'Blaisorblade' Giarrusso <blaisorblade_spam@yahoo.it>, Bodo Stroesser <bstroesser@fujitsu-siemens.com> Adds a new ptrace(2) mode, called PTRACE_SYSEMU, resembling PTRACE_SYSCALL except that the kernel does not execute the requested syscall; this is useful to improve performance for virtual environments, like UML, which want to run the syscall on their own. In fact, using PTRACE_SYSCALL means stopping child execution twice, on entry and on exit, and each time you also have two context switches; with SYSEMU you avoid the 2nd stop and so save two context switches per syscall. Also, some architectures don't have support in the host for changing the syscall number via ptrace(), which is currently needed to skip syscall execution (UML turns any syscall into getpid() to avoid it being executed on the host). Fixing that is hard, while SYSEMU is easier to implement. * This version of the patch includes some suggestions of Jeff Dike to avoid adding any instructions to the syscall fast path, plus some other little changes, by myself, to make it work even when the syscall is executed with SYSENTER (but I'm unsure about them). It has been widely tested for quite a lot of time. * Various fixed were included to handle the various switches between various states, i.e. when for instance a syscall entry is traced with one of PT_SYSCALL / _SYSEMU / _SINGLESTEP and another one is used on exit. Basically, this is done by remembering which one of them was used even after the call to ptrace_notify(). * We're combining TIF_SYSCALL_EMU with TIF_SYSCALL_TRACE or TIF_SINGLESTEP to make do_syscall_trace() notice that the current syscall was started with SYSEMU on entry, so that no notification ought to be done in the exit path; this is a bit of a hack, so this problem is solved in another way in next patches. * Also, the effects of the patch: "Ptrace - i386: fix Syscall Audit interaction with singlestep" are cancelled; they are restored back in the last patch of this series. Detailed descriptions of the patches doing this kind of processing follow (but I've already summed everything up). * Fix behaviour when changing interception kind #1. In do_syscall_trace(), we check the status of the TIF_SYSCALL_EMU flag only after doing the debugger notification; but the debugger might have changed the status of this flag because he continued execution with PTRACE_SYSCALL, so this is wrong. This patch fixes it by saving the flag status before calling ptrace_notify(). * Fix behaviour when changing interception kind #2: avoid intercepting syscall on return when using SYSCALL again. A guest process switching from using PTRACE_SYSEMU to PTRACE_SYSCALL crashes. The problem is in arch/i386/kernel/entry.S. The current SYSEMU patch inhibits the syscall-handler to be called, but does not prevent do_syscall_trace() to be called after this for syscall completion interception. The appended patch fixes this. It reuses the flag TIF_SYSCALL_EMU to remember "we come from PTRACE_SYSEMU and now are in PTRACE_SYSCALL", since the flag is unused in the depicted situation. * Fix behaviour when changing interception kind #3: avoid intercepting syscall on return when using SINGLESTEP. When testing 2.6.9 and the skas3.v6 patch, with my latest patch and had problems with singlestepping on UML in SKAS with SYSEMU. It looped receiving SIGTRAPs without moving forward. EIP of the traced process was the same for all SIGTRAPs. What's missing is to handle switching from PTRACE_SYSCALL_EMU to PTRACE_SINGLESTEP in a way very similar to what is done for the change from PTRACE_SYSCALL_EMU to PTRACE_SYSCALL_TRACE. I.e., after calling ptrace(PTRACE_SYSEMU), on the return path, the debugger is notified and then wake ups the process; the syscall is executed (or skipped, when do_syscall_trace() returns 0, i.e. when using PTRACE_SYSEMU), and do_syscall_trace() is called again. Since we are on the return path of a SYSEMU'd syscall, if the wake up is performed through ptrace(PTRACE_SYSCALL), we must still avoid notifying the parent of the syscall exit. Now, this behaviour is extended even to resuming with PTRACE_SINGLESTEP. Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Bodo Stroesser 提交于
Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Avoid giving two traps for singlestep instead of one, when syscall auditing is enabled. In fact no singlestep trap is sent on syscall entry, only on syscall exit, as can be seen in entry.S: # Note that in this mask _TIF_SINGLESTEP is not tested !!! <<<<<<<<<<<<<< testb $(_TIF_SYSCALL_TRACE|_TIF_SYSCALL_AUDIT|_TIF_SECCOMP),TI_flags(%ebp) jnz syscall_trace_entry ... syscall_trace_entry: ... call do_syscall_trace But auditing a SINGLESTEP'ed process causes do_syscall_trace to be called, so the tracer will get one more trap on the syscall entry path, which it shouldn't. Signed-off-by: NPaolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> CC: Roland McGrath <roland@redhat.com> Cc: Jeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Jeff Dike 提交于
To the extent that sub-Kconfig files exist elsewhere in the tree, they are named Kconfig.foo, rather than the Kconfig_foo that UML has. This patch brings the names in line with the rest of the tree. Signed-off-by: NJeff Dike <jdike@addtoit.com> Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Jeff Dike 提交于
This eliminates the segfault info ring buffer, which added a system call to each page fault, and which hadn't been useful for debugging in ages. Signed-off-by: NJeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Adrian Bunk 提交于
This patch converts arch/cris/Kconfig.debug to using lib/Kconfig.debug. This should fix a compile error in 2.6.13-rc4 caused by a missing CONFIG_LOG_BUF_SHIFT definition. While I was editing this file, I also converted some spaces to tabs. Signed-off-by: NAdrian Bunk <bunk@stusta.de> Acked-by: NMikael Starvik <starvik@axis.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Roman Zippel 提交于
Use the builtin functions for memset/memclr/memcpy, special optimizations for page operations have dedicated functions now. Uninline memmove/memchr and move all functions into a single file and clean it up a little. Signed-off-by: NRoman Zippel <zippel@linux-m68k.org> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Roman Zippel 提交于
Move a few cache functions into its own file and fix flush_icache_range() so it can handle both kernel and user addresses correctly (assuming context is set correctly). Turn copy_to_user_page/copy_from_user_page into inline functions and add a missing cache flush. Signed-off-by: NRoman Zippel <zippel@linux-m68k.org> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Roman Zippel 提交于
- create helper function singlestep_disable() - move variable definitions to the top of the function - use "out_eio" label as common error destination - don't clear failure value for PTRACE_SETREGS/PTRACE_GETREGS Signed-off-by: NRoman Zippel <zippel@linux-m68k.org> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Roman Zippel 提交于
This reformats and properly indents sys_ptrace (only whitespace changes). Signed-off-by: NRoman Zippel <zippel@linux-m68k.org> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Shaohua Li 提交于
The timers lack .suspend/.resume methods. Because of this, jiffies got a big compensation after a S3 resume. And then softlockup watchdog reports an oops. This occured with HPET enabled, but it's also possible for other timers. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
Clean code up a bit, and only show suspend to disk as available when it is configured in. Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
If process freezing fails, some processes are frozen, and rest are left in "were asked to be frozen" state. Thats wrong, we should leave it in some consistent state. Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
Drop printing during normal boot (when no image exists in swap), print message when drivers fail, fix error paths and consolidate near-identical functions in disk.c (and functions with just one statement). Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Shaohua Li 提交于
It is trying to protect swsusp_resume_device and software_resume() from two users banging it from userspace at the same time. Signed-off-by: NShaohua Li <shaohua.li@intel.com> Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Andreas Steinmetz 提交于
The attached patch contains a mini howto for using dm-crypt together with swsusp. Signed-off-by: NAndreas Steinmetz <ast@domdv.de> Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Michal Schmidt 提交于
The function calc_nr uses an iterative algorithm to calculate the number of pages needed for the image and the pagedir. Exactly the same result can be obtained with a one-line expression. Note that this was even proved correct ;-). Signed-off-by: NMichal Schmidt <xschmi00@stud.feec.vutbr.cz> Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Michal Schmidt 提交于
Stop the disks from spinning down and up on suspend. Signed-off-by: NMichal Schmidt <xschmi00@stud.feec.vutbr.cz> Cc: Pavel Machek <pavel@ucw.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Andreas Steinmetz 提交于
The patch protects from leaking sensitive data after resume from suspend. During suspend a temporary key is created and this key is used to encrypt the data written to disk. When, during resume, the data was read back into memory the temporary key is destroyed which simply means that all data written to disk during suspend are then inaccessible so they can't be stolen lateron. Think of the following: you suspend while an application is running that keeps sensitive data in memory. The application itself prevents the data from being swapped out. Suspend, however, must write these data to swap to be able to resume lateron. Without suspend encryption your sensitive data are then stored in plaintext on disk. This means that after resume your sensitive data are accessible to all applications having direct access to the swap device which was used for suspend. If you don't need swap after resume these data can remain on disk virtually forever. Thus it can happen that your system gets broken in weeks later and sensitive data which you thought were encrypted and protected are retrieved and stolen from the swap device. Signed-off-by: NAndreas Steinmetz <ast@domdv.de> Acked-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
This should bits from -mm tree that are affected by pm_message_t conversion. [I'm not 100% sure I got all of them, but I certainly got all the errors on make allyesconfig build, and most of warnings, too. I'll go through the buildlog tommorow and fix any remaining bits]. Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
This adds type-checking to pm_message_t, so that people can't confuse it with int or u32. It also allows us to fix "disk yoyo" during suspend (disk spinning down/up/down). [We've tried that before; since that cpufreq problems were fixed and I've tried make allyes config and fixed resulting damage.] Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAlexander Nyberg <alexn@telia.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
Fix remaining bits of u32 vs. pm_message confusion. Should not break anything. Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NRafael J. Wysocki <rjw@sisk.pl> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
Update suspend documentation. Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pierre Ossman 提交于
Reset the ISA DMA controller into a known state after a suspend. Primary concern was reenabling the cascading DMA channel (4). Signed-off-by: NPierre Ossman <drzeus@drzeus.cx> Cc: Andi Kleen <ak@muc.de> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pierre Ossman 提交于
Reset the ISA DMA controller into a known state after a suspend. Primary concern was reenabling the cascading DMA channel (4). Signed-off-by: NPierre Ossman <drzeus@drzeus.cx> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Pavel Machek 提交于
This should make refrigerator sleep properly, not busywait after the first schedule() returns. Signed-off-by: NPavel Machek <pavel@suse.cz> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Benjamin LaHaise 提交于
This patch moves the common code in x86 and x86-64's semaphore.c into a single file in lib/semaphore-sleepers.c. The arch specific asm stubs are left in the arch tree (in semaphore.c for i386 and in the asm for x86-64). There should be no changes in code/functionality with this patch. Signed-off-by: NBenjamin LaHaise <benjamin.c.lahaise@intel.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: NJeff Dike <jdike@addtoit.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zwane Mwaikambo 提交于
for_each_cpu walks through all processors in cpu_possible_map, which is defined as cpu_callout_map on i386 and isn't initialised until all processors have been booted. This breaks things which do for_each_cpu iterations early during boot. So, define cpu_possible_map as a bitmap with NR_CPUS bits populated. This was triggered by a patch i'm working on which does alloc_percpu before bringing up secondary processors. From: Alexander Nyberg <alexn@telia.com> i386-boottime-for_each_cpu-broken.patch i386-boottime-for_each_cpu-broken-fix.patch The SMP version of __alloc_percpu checks the cpu_possible_map before allocating memory for a certain cpu. With the above patches the BSP cpuid is never set in cpu_possible_map which breaks CONFIG_SMP on uniprocessor machines (as soon as someone tries to dereference something allocated via __alloc_percpu, which in fact is never allocated since the cpu is not set in cpu_possible_map). Signed-off-by: NZwane Mwaikambo <zwane@arm.linux.org.uk> Signed-off-by: NAlexander Nyberg <alexn@telia.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zachary Amsden 提交于
Add a clone operation for pgd updates. This helps complete the encapsulation of updates to page tables (or pages about to become page tables) into accessor functions rather than using memcpy() to duplicate them. This is both generally good for consistency and also necessary for running in a hypervisor which requires explicit updates to page table entries. The new function is: clone_pgd_range(pgd_t *dst, pgd_t *src, int count); dst - pointer to pgd range anwhere on a pgd page src - "" count - the number of pgds to copy. dst and src can be on the same page, but the range must not overlap and must not cross a page boundary. Note that I ommitted using this call to copy pgd entries into the software suspend page root, since this is not technically a live paging structure, rather it is used on resume from suspend. CC'ing Pavel in case he has any feedback on this. Thanks to Chris Wright for noticing that this could be more optimal in PAE compiles by eliminating the memset. Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 George Anzinger 提交于
This patch adds a notify to the die_nmi notify that the system is about to be taken down. If the notify is handled with a NOTIFY_STOP return, the system is given a new lease on life. We also change the nmi watchdog to carry on if die_nmi returns. This give debug code a chance to a) catch watchdog timeouts and b) possibly allow the system to continue, realizing that the time out may be due to debugger activities such as single stepping which is usually done with "other" cpus held. Signed-off-by: George Anzinger<george@mvista.com> Cc: Keith Owens <kaos@ocs.com.au> Signed-off-by: NGeorge Anzinger <george@mvista.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zachary Amsden 提交于
Introduce a write acessor for updating the current LDT. This is required for hypervisors like Xen that do not allow LDT pages to be directly written. Testing - here's a fun little LDT test that can be trivially modified to test limits as well. /* * Copyright (c) 2005, Zachary Amsden (zach@vmware.com) * This is licensed under the GPL. */ #include <stdio.h> #include <signal.h> #include <asm/ldt.h> #include <asm/segment.h> #include <sys/types.h> #include <unistd.h> #include <sys/mman.h> #define __KERNEL__ #include <asm/page.h> void main(void) { struct user_desc desc; char *code; unsigned long long tsc; code = (char *)mmap(0, 8192, PROT_EXEC|PROT_READ|PROT_WRITE, MAP_PRIVATE | MAP_ANONYMOUS, -1, 0); desc.entry_number = 0; desc.base_addr = code; desc.limit = 1; desc.seg_32bit = 1; desc.contents = MODIFY_LDT_CONTENTS_CODE; desc.read_exec_only = 0; desc.limit_in_pages = 1; desc.seg_not_present = 0; desc.useable = 1; if (modify_ldt(1, &desc, sizeof(desc)) != 0) { perror("modify_ldt"); } printf("code base is 0x%08x\n", (unsigned)code); code[0x0ffe] = 0x0f; /* rdtsc */ code[0x0fff] = 0x31; code[0x1000] = 0xcb; /* lret */ __asm__ __volatile("lcall $7,$0xffe" : "=A" (tsc)); printf("TSC is 0x%016llx\n", tsc); } Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zachary Amsden 提交于
When reviewing GDT updates, I found the code: set_tss_desc(cpu,t); /* This just modifies memory; ... */ per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS].b &= 0xfffffdff; This second line is unnecessary, since set_tss_desc() has already cleared the busy bit. Commented disassembly, line 1: c028b8bd: 8b 0c 86 mov (%esi,%eax,4),%ecx c028b8c0: 01 cb add %ecx,%ebx c028b8c2: 8d 0c 39 lea (%ecx,%edi,1),%ecx => %ecx = per_cpu(cpu_gdt_table, cpu) c028b8c5: 8d 91 80 00 00 00 lea 0x80(%ecx),%edx => %edx = &per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS] c028b8cb: 66 c7 42 00 73 20 movw $0x2073,0x0(%edx) c028b8d1: 66 89 5a 02 mov %bx,0x2(%edx) c028b8d5: c1 cb 10 ror $0x10,%ebx c028b8d8: 88 5a 04 mov %bl,0x4(%edx) c028b8db: c6 42 05 89 movb $0x89,0x5(%edx) => ((char *)%edx)[5] = 0x89 (equivalent) ((char *)per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS])[5] = 0x89 c028b8df: c6 42 06 00 movb $0x0,0x6(%edx) c028b8e3: 88 7a 07 mov %bh,0x7(%edx) c028b8e6: c1 cb 10 ror $0x10,%ebx => other bits Commented disassembly, line 2: c028b8e9: 8b 14 86 mov (%esi,%eax,4),%edx c028b8ec: 8d 04 3a lea (%edx,%edi,1),%eax => %eax = per_cpu(cpu_gdt_table, cpu) c028b8ef: 81 a0 84 00 00 00 ff andl $0xfffffdff,0x84(%eax) => per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS].b &= 0xfffffdff; (equivalent) ((char *)per_cpu(cpu_gdt_table, cpu)[GDT_ENTRY_TSS])[5] &= 0xfd Note that (0x89 & ~0xfd) == 0; i.e, set_tss_desc(cpu,t) has already stored the type field in the GDT with the busy bit clear. Eliminating redundant and obscure code is always a good thing; in fact, I pointed out this same optimization many moons ago in arch/i386/setup.c, back when it used to be called that. Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zachary Amsden 提交于
The pushf/popf in switch_to are ONLY used to switch IOPL. Making this explicit in C code is more clear. This pushf/popf pair was added as a bugfix for leaking IOPL to unprivileged processes when using sysenter/sysexit based system calls (sysexit does not restore flags). When requesting an IOPL change in sys_iopl(), it is just as easy to change the current flags and the flags in the stack image (in case an IRET is required), but there is no reason to force an IRET if we came in from the SYSENTER path. This change is the minimal solution for supporting a paravirtualized Linux kernel that allows user processes to run with I/O privilege. Other solutions require radical rewrites of part of the low level fault / system call handling code, or do not fully support sysenter based system calls. Unfortunately, this added one field to the thread_struct. But as a bonus, on P4, the fastest time measured for switch_to() went from 312 to 260 cycles, a win of about 17% in the fast case through this performance critical path. Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zachary Amsden 提交于
Privilege checking cleanup. Originally, these diffs were much greater, but recent cleanups in Linux have already done much of the cleanup. I added some explanatory comments in places where the reasoning behind certain tests is rather subtle. Also, in traps.c, we can skip the user_mode check in handle_BUG(). The reason is, there are only two call chains - one via die_if_kernel() and one via do_page_fault(), both entering from die(). Both of these paths already ensure that a kernel mode failure has happened. Also, the original check here, if (user_mode(regs)) was insufficient anyways, since it would not rule out BUG faults from V8086 mode execution. Saving the %ss segment in show_regs() rather than assuming a fixed value also gives better information about the current kernel state in the register dump. Signed-off-by: NZachary Amsden <zach@vmware.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Zachary Amsden 提交于
Some more assembler cleanups I noticed along the way. Signed-off-by: NZachary Amsden <zach@vmware.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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由 Ingo Molnar 提交于
Noticed by Chuck Ebbert: the .ldt entry of the TSS was set up incorrectly. It never mattered since this was a leftover from old times, so remove it. Signed-off-by: NIngo Molnar <mingo@elte.hu> Signed-off-by: NAdrian Bunk <bunk@stusta.de> Signed-off-by: NAndrew Morton <akpm@osdl.org> Signed-off-by: NLinus Torvalds <torvalds@osdl.org>
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