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* i386: prepare shared kernel/entry.SThomas Gleixner2007-10-111-1112/+0
| | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* i386: prepare shared kernel/syscall_table.SThomas Gleixner2007-10-111-1/+1
| | | | | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Signed-off-by: Ingo Molnar <mingo@elte.hu>
* i386: fixup TRACE_IRQ breakagePeter Zijlstra2007-07-181-2/+0
| | | | | | | | | The TRACE_IRQS_ON function in iret_exc: calls a C function without ensuring that the segments are set properly. Move the trace function and the enabling of interrupt into the C stub. Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* xen: use iret directly when possibleJeremy Fitzhardinge2007-07-181-1/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Most of the time we can simply use the iret instruction to exit the kernel, rather than having to use the iret hypercall - the only exception is if we're returning into vm86 mode, or from delivering an NMI (which we don't support yet). When running native, iret has the behaviour of testing for a pending interrupt atomically with re-enabling interrupts. Unfortunately there's no way to do this with Xen, so there's a window in which we could get a recursive exception after enabling events but before actually returning to userspace. This causes a problem: if the nested interrupt causes one of the task's TIF_WORK_MASK flags to be set, they will not be checked again before returning to userspace. This means that pending work may be left pending indefinitely, until the process enters and leaves the kernel again. The net effect is that a pending signal or reschedule event could be delayed for an unbounded amount of time. To deal with this, the xen event upcall handler checks to see if the EIP is within the critical section of the iret code, after events are (potentially) enabled up to the iret itself. If its within this range, it calls the iret critical section fixup, which adjusts the stack to deal with any unrestored registers, and then shifts the stack frame up to replace the previous invocation. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
* xen: Core Xen implementationJeremy Fitzhardinge2007-07-181-0/+71
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is a rollup of all the core pieces of the Xen implementation, including: - booting and setup - pagetable setup - privileged instructions - segmentation - interrupt flags - upcalls - multicall batching BOOTING AND SETUP The vmlinux image is decorated with ELF notes which tell the Xen domain builder what the kernel's requirements are; the domain builder then constructs the address space accordingly and starts the kernel. Xen has its own entrypoint for the kernel (contained in an ELF note). The ELF notes are set up by xen-head.S, which is included into head.S. In principle it could be linked separately, but it seems to provoke lots of binutils bugs. Because the domain builder starts the kernel in a fairly sane state (32-bit protected mode, paging enabled, flat segments set up), there's not a lot of setup needed before starting the kernel proper. The main steps are: 1. Install the Xen paravirt_ops, which is simply a matter of a structure assignment. 2. Set init_mm to use the Xen-supplied pagetables (analogous to the head.S generated pagetables in a native boot). 3. Reserve address space for Xen, since it takes a chunk at the top of the address space for its own use. 4. Call start_kernel() PAGETABLE SETUP Once we hit the main kernel boot sequence, it will end up calling back via paravirt_ops to set up various pieces of Xen specific state. One of the critical things which requires a bit of extra care is the construction of the initial init_mm pagetable. Because Xen places tight constraints on pagetables (an active pagetable must always be valid, and must always be mapped read-only to the guest domain), we need to be careful when constructing the new pagetable to keep these constraints in mind. It turns out that the easiest way to do this is use the initial Xen-provided pagetable as a template, and then just insert new mappings for memory where a mapping doesn't already exist. This means that during pagetable setup, it uses a special version of xen_set_pte which ignores any attempt to remap a read-only page as read-write (since Xen will map its own initial pagetable as RO), but lets other changes to the ptes happen, so that things like NX are set properly. PRIVILEGED INSTRUCTIONS AND SEGMENTATION When the kernel runs under Xen, it runs in ring 1 rather than ring 0. This means that it is more privileged than user-mode in ring 3, but it still can't run privileged instructions directly. Non-performance critical instructions are dealt with by taking a privilege exception and trapping into the hypervisor and emulating the instruction, but more performance-critical instructions have their own specific paravirt_ops. In many cases we can avoid having to do any hypercalls for these instructions, or the Xen implementation is quite different from the normal native version. The privileged instructions fall into the broad classes of: Segmentation: setting up the GDT and the GDT entries, LDT, TLS and so on. Xen doesn't allow the GDT to be directly modified; all GDT updates are done via hypercalls where the new entries can be validated. This is important because Xen uses segment limits to prevent the guest kernel from damaging the hypervisor itself. Traps and exceptions: Xen uses a special format for trap entrypoints, so when the kernel wants to set an IDT entry, it needs to be converted to the form Xen expects. Xen sets int 0x80 up specially so that the trap goes straight from userspace into the guest kernel without going via the hypervisor. sysenter isn't supported. Kernel stack: The esp0 entry is extracted from the tss and provided to Xen. TLB operations: the various TLB calls are mapped into corresponding Xen hypercalls. Control registers: all the control registers are privileged. The most important is cr3, which points to the base of the current pagetable, and we handle it specially. Another instruction we treat specially is CPUID, even though its not privileged. We want to control what CPU features are visible to the rest of the kernel, and so CPUID ends up going into a paravirt_op. Xen implements this mainly to disable the ACPI and APIC subsystems. INTERRUPT FLAGS Xen maintains its own separate flag for masking events, which is contained within the per-cpu vcpu_info structure. Because the guest kernel runs in ring 1 and not 0, the IF flag in EFLAGS is completely ignored (and must be, because even if a guest domain disables interrupts for itself, it can't disable them overall). (A note on terminology: "events" and interrupts are effectively synonymous. However, rather than using an "enable flag", Xen uses a "mask flag", which blocks event delivery when it is non-zero.) There are paravirt_ops for each of cli/sti/save_fl/restore_fl, which are implemented to manage the Xen event mask state. The only thing worth noting is that when events are unmasked, we need to explicitly see if there's a pending event and call into the hypervisor to make sure it gets delivered. UPCALLS Xen needs a couple of upcall (or callback) functions to be implemented by each guest. One is the event upcalls, which is how events (interrupts, effectively) are delivered to the guests. The other is the failsafe callback, which is used to report errors in either reloading a segment register, or caused by iret. These are implemented in i386/kernel/entry.S so they can jump into the normal iret_exc path when necessary. MULTICALL BATCHING Xen provides a multicall mechanism, which allows multiple hypercalls to be issued at once in order to mitigate the cost of trapping into the hypervisor. This is particularly useful for context switches, since the 4-5 hypercalls they would normally need (reload cr3, update TLS, maybe update LDT) can be reduced to one. This patch implements a generic batching mechanism for hypercalls, which gets used in many places in the Xen code. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Cc: Ian Pratt <ian.pratt@xensource.com> Cc: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Cc: Adrian Bunk <bunk@stusta.de>
* i386: fix regression, endless loop in ptrace singlestep over an int80Jason Wessel2007-07-061-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The commit 635cf99a80f4ebee59d70eb64bb85ce829e4591f introduced a regression. Executing a ptrace single step after certain int80 accesses will infinitely loop and never advance the PC. The TIF_SINGLESTEP check should be done on the return from the syscall and not before it. I loops on each single step on the pop right after the int80 which writes out to the console. At that point you can issue as many single steps as you want and it will not advance any further. The test case is below: /* Test whether singlestep through an int80 syscall works. */ #define _GNU_SOURCE #include <stdio.h> #include <unistd.h> #include <fcntl.h> #include <sys/ptrace.h> #include <sys/wait.h> #include <sys/mman.h> #include <asm/user.h> #include <string.h> static int child, status; static struct user_regs_struct regs; static void do_child() { char str[80] = "child: int80 test\n"; ptrace(PTRACE_TRACEME, 0, 0, 0); kill(getpid(), SIGUSR1); write(fileno(stdout),str,strlen(str)); asm ("int $0x80" : : "a" (20)); /* getpid */ } static void do_parent() { unsigned long eip, expected = 0; again: waitpid(child, &status, 0); if (WIFEXITED(status) || WIFSIGNALED(status)) return; if (WIFSTOPPED(status)) { ptrace(PTRACE_GETREGS, child, 0, &regs); eip = regs.eip; if (expected) fprintf(stderr, "child stop @ %08lx, expected %08lx %s\n", eip, expected, eip == expected ? "" : " <== ERROR"); if (*(unsigned short *)eip == 0x80cd) { fprintf(stderr, "int 0x80 at %08x\n", (unsigned int)eip); expected = eip + 2; } else expected = 0; ptrace(PTRACE_SINGLESTEP, child, NULL, NULL); } goto again; } int main(int argc, char * const argv[]) { child = fork(); if (child) do_parent(); else do_child(); return 0; } Signed-off-by: Jason Wessel <jason.wessel@windriver.com> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: <stable@kernel.org> Cc: Chuck Ebbert <76306.1226@compuserve.com> Acked-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* [PATCH] i386: fix wrong comment for syscall stack layoutAndi Kleen2007-05-021-1/+1
| | | | | | | | `ret_from_sys_call' label no longer exist and `syscall_exit' label was introduced instead. Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Convert VMI timer to use clock eventsZachary Amsden2007-05-021-5/+0
| | | | | | | | | | | | | | | Convert VMI timer to use clock events, making it properly able to use the NO_HZ infrastructure. On UP systems, with no local APIC, we just continue to route these events through the PIT. On systems with a local APIC, or SMP, we provide a single source interrupt chip which creates the local timer IRQ. It actually gets delivered by the APIC hardware, but we don't want to use the same local APIC clocksource processing, so we create our own handler here. Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de> CC: Dan Hecht <dhecht@vmware.com> CC: Ingo Molnar <mingo@elte.hu> CC: Thomas Gleixner <tglx@linutronix.de>
* [PATCH] i386: Convert PDA into the percpu sectionJeremy Fitzhardinge2007-05-021-3/+2
| | | | | | | | | | | | | | | | | | | | | | | | Currently x86 (similar to x84-64) has a special per-cpu structure called "i386_pda" which can be easily and efficiently referenced via the %fs register. An ELF section is more flexible than a structure, allowing any piece of code to use this area. Indeed, such a section already exists: the per-cpu area. So this patch: (1) Removes the PDA and uses per-cpu variables for each current member. (2) Replaces the __KERNEL_PDA segment with __KERNEL_PERCPU. (3) Creates a per-cpu mirror of __per_cpu_offset called this_cpu_off, which can be used to calculate addresses for this CPU's variables. (4) Simplifies startup, because %fs doesn't need to be loaded with a special segment at early boot; it can be deferred until the first percpu area is allocated (or never for UP). The result is less code and one less x86-specific concept. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de>
* [PATCH] i386: Page-align the GDTJeremy Fitzhardinge2007-05-021-1/+1
| | | | | | | | | | | Xen wants a dedicated page for the GDT. I believe VMI likes it too. lguest, KVM and native don't care. Simple transformation to page-aligned "struct gdt_page". Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Jeremy Fitzhardinge <jeremy@xensource.com>
* [PATCH] i386: PARAVIRT: Fix patch site clobbers to include return registerJeremy Fitzhardinge2007-05-021-1/+1
| | | | | | | | | | | | | | Fix a few clobbers to include the return register. The clobbers set is the set of all registers modified (or may be modified) by the code snippet, regardless of whether it was deliberate or accidental. Also, make sure that callsites which are used in contexts which don't allow clobbers actually save and restore all clobberable registers. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Zachary Amsden <zach@vmware.com>
* [PATCH] i386: Relocate VDSO ELF headers to match mapped location with ↵Jeremy Fitzhardinge2007-05-021-4/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | COMPAT_VDSO Some versions of libc can't deal with a VDSO which doesn't have its ELF headers matching its mapped address. COMPAT_VDSO maps the VDSO at a specific system-wide fixed address. Previously this was all done at build time, on the grounds that the fixed VDSO address is always at the top of the address space. However, a hypervisor may reserve some of that address space, pushing the fixmap address down. This patch does the adjustment dynamically at runtime, depending on the runtime location of the VDSO fixmap. [ Patch has been through several hands: Jan Beulich wrote the orignal version; Zach reworked it, and Jeremy converted it to relocate phdrs as well as sections. ] Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Zachary Amsden <zach@vmware.com> Cc: "Jan Beulich" <JBeulich@novell.com> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: Andi Kleen <ak@suse.de> Cc: Ingo Molnar <mingo@elte.hu> Cc: Roland McGrath <roland@redhat.com>
* [PATCH] i386: cleanup GDT AccessRusty Russell2007-05-021-2/+1
| | | | | | | | | | | | | Now we have an explicit per-cpu GDT variable, we don't need to keep the descriptors around to use them to find the GDT: expose cpu_gdt directly. We could go further and make load_gdt() pack the descriptor for us, or even assume it means "load the current cpu's GDT" which is what it always does. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* [PATCH] i386: No need to use -traditional for processing asm in i386/kernel/Jeremy Fitzhardinge2007-05-021-1/+1
| | | | | | | No need to use -traditional for processing asm in i386/kernel/ Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: entry.S END/ENDPROC annotationsJan Beulich2007-02-131-4/+37
| | | | | | | | | | Annotate i386/kernel/entry.S with END/ENDPROC to assist disassemblers and other analysis tools. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
* [PATCH] i386: vMI timer patchesZachary Amsden2007-02-131-0/+5
| | | | | | | | | | | | | | | | | | | | VMI timer code. It works by taking over the local APIC clock when APIC is configured, which requires a couple hooks into the APIC code. The backend timer code could be commonized into the timer infrastructure, but there are some pieces missing (stolen time, in particular), and the exact semantics of when to do accounting for NO_IDLE need to be shared between different hypervisors as well. So for now, VMI timer is a separate module. [Adrian Bunk: cleanups] Subject: VMI timer patches Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Andi Kleen <ak@suse.de> Cc: Jeremy Fitzhardinge <jeremy@xensource.com> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] i386: Convert i386 PDA code to use %fsJeremy Fitzhardinge2007-02-131-16/+16
| | | | | | | | | | | | | | | | | | | | | | | | | | | Convert the PDA code to use %fs rather than %gs as the segment for per-processor data. This is because some processors show a small but measurable performance gain for reloading a NULL segment selector (as %fs generally is in user-space) versus a non-NULL one (as %gs generally is). On modern processors the difference is very small, perhaps undetectable. Some old AMD "K6 3D+" processors are noticably slower when %fs is used rather than %gs; I have no idea why this might be, but I think they're sufficiently rare that it doesn't matter much. This patch also fixes the math emulator, which had not been adjusted to match the changed struct pt_regs. [frederik.deweerdt@gmail.com: fixit with gdb] [mingo@elte.hu: Fix KVM too] Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Ian Campbell <Ian.Campbell@XenSource.com> Acked-by: Ingo Molnar <mingo@elte.hu> Acked-by: Zachary Amsden <zach@vmware.com> Cc: Eric Dumazet <dada1@cosmosbay.com> Signed-off-by: Frederik Deweerdt <frederik.deweerdt@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] Fix CONFIG_COMPAT_VDSORoland McGrath2007-01-261-0/+4
| | | | | | | | | | | | | | | | | | | | I wouldn't mind if CONFIG_COMPAT_VDSO went away entirely. But if it's there, it should work properly. Currently it's quite haphazard: both real vma and fixmap are mapped, both are put in the two different AT_* slots, sysenter returns to the vma address rather than the fixmap address, and core dumps yet are another story. This patch makes CONFIG_COMPAT_VDSO disable the real vma and use the fixmap area consistently. This makes it actually compatible with what the old vdso implementation did. Signed-off-by: Roland McGrath <roland@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Paul Mackerras <paulus@samba.org> Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Remove stack unwinder for nowLinus Torvalds2006-12-151-32/+0
| | | | | | | | | | It has caused more problems than it ever really solved, and is apparently not getting cleaned up and fixed. We can put it back when it's stable and isn't likely to make warning or bug events worse. In the meantime, enable frame pointers for more readable stack traces. Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] paravirt: Patch inline replacements for paravirt interceptsRusty Russell2006-12-071-13/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | It turns out that the most called ops, by several orders of magnitude, are the interrupt manipulation ops. These are obvious candidates for patching, so mark them up and create infrastructure for it. The method used is that the ops structure has a patch function, which is called for each place which needs to be patched: this returns a number of instructions (the rest are NOP-padded). Usually we can spare a register (%eax) for the binary patched code to use, but in a couple of critical places in entry.S we can't: we make the clobbers explicit at the call site, and manually clobber the allowed registers in debug mode as an extra check. And: Don't abuse CONFIG_DEBUG_KERNEL, add CONFIG_DEBUG_PARAVIRT. And: AK: Fix warnings in x86-64 alternative.c build And: AK: Fix compilation with defconfig And: ^From: Andrew Morton <akpm@osdl.org> Some binutlises still like to emit references to __stop_parainstructions and __start_parainstructions. And: AK: Fix warnings about unused variables when PARAVIRT is disabled. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] paravirt: header and stubs for paravirtualisationRusty Russell2006-12-071-7/+27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Create a paravirt.h header for all the critical operations which need to be replaced with hypervisor calls, and include that instead of defining native operations, when CONFIG_PARAVIRT. This patch does the dumbest possible replacement of paravirtualized instructions: calls through a "paravirt_ops" structure. Currently these are function implementations of native hardware: hypervisors will override the ops structure with their own variants. All the pv-ops functions are declared "fastcall" so that a specific register-based ABI is used, to make inlining assember easier. And: +From: Andy Whitcroft <apw@shadowen.org> The paravirt ops introduce a 'weak' attribute onto memory_setup(). Code ordering leads to the following warnings on x86: arch/i386/kernel/setup.c:651: warning: weak declaration of `memory_setup' after first use results in unspecified behavior Move memory_setup() to avoid this. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Jeremy Fitzhardinge <jeremy@goop.org> Cc: Zachary Amsden <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andy Whitcroft <apw@shadowen.org>
* [PATCH] i386: Fix entry.S code with !CONFIG_VM86Joe Korty2006-12-071-2/+4
| | | | | | | | | | | | | | | The entry.S code at work_notifysig is surely wrong. It drops into unrelated code if the branch to work_notifysig_v86 is taken, and CONFIG_VM86=n. [PATCH] Make vm86 support optional tree 9b5daef5280800a0006343a17f63072658d91a1d pushed to git Jan 8, 2006, and first appears in 2.6.16 The 'fix' here is to also compile out the vm86 test & branch when CONFIG_VM86=n. Signed-off-by: Joe Korty <joe.korty@ccur.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Implement smp_processor_id() with the PDAJeremy Fitzhardinge2006-12-071-2/+1
| | | | | | | | | | | | | | | Use the cpu_number in the PDA to implement raw_smp_processor_id. This is a little simpler than using thread_info, though the cpu field in thread_info cannot be removed since it is used for things other than getting the current CPU in common code. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden <zach@vmware.com> Cc: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] i386: Use %gs as the PDA base-segment in the kernelJeremy Fitzhardinge2006-12-071-22/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch is the meat of the PDA change. This patch makes several related changes: 1: Most significantly, %gs is now used in the kernel. This means that on entry, the old value of %gs is saved away, and it is reloaded with __KERNEL_PDA. 2: entry.S constructs the stack in the shape of struct pt_regs, and this is passed around the kernel so that the process's saved register state can be accessed. Unfortunately struct pt_regs doesn't currently have space for %gs (or %fs). This patch extends pt_regs to add space for gs (no space is allocated for %fs, since it won't be used, and it would just complicate the code in entry.S to work around the space). 3: Because %gs is now saved on the stack like %ds, %es and the integer registers, there are a number of places where it no longer needs to be handled specially; namely context switch, and saving/restoring the register state in a signal context. 4: And since kernel threads run in kernel space and call normal kernel code, they need to be created with their %gs == __KERNEL_PDA. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Chuck Ebbert <76306.1226@compuserve.com> Cc: Zachary Amsden <zach@vmware.com> Cc: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@suse.de> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] i386: Use asm-offsets for the offsets of registers into the pt_regs ↵Jeremy Fitzhardinge2006-12-071-68/+52
| | | | | | | | | | | | | | | | struct Use asm-offsets for the offsets of registers into the pt_regs struct, rather than having hard-coded constants I left the constants in the comments of entry.S because they're useful for reference; the code in entry.S is very dependent on the layout of pt_regs, even when using asm-offsets. Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andi Kleen <ak@suse.de> Cc: Keith Owens <kaos@ocs.com.au> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] i386: espfix cleanupStas Sergeev2006-12-071-40/+33
| | | | | | | | | | | | | | | | | | | | | | | | Clean up the espfix code: - Introduced PER_CPU() macro to be used from asm - Introduced GET_DESC_BASE() macro to be used from asm - Rewrote the fixup code in asm, as calling a C code with the altered %ss appeared to be unsafe - No longer altering the stack from a .fixup section - 16bit per-cpu stack is no longer used, instead the stack segment base is patched the way so that the high word of the kernel and user %esp are the same. - Added the limit-patching for the espfix segment. (Chuck Ebbert) [jeremy@goop.org: use the x86 scaling addressing mode rather than shifting] Signed-off-by: Stas Sergeev <stsp@aknet.ru> Signed-off-by: Andi Kleen <ak@suse.de> Acked-by: Zachary Amsden <zach@vmware.com> Acked-by: Chuck Ebbert <76306.1226@compuserve.com> Acked-by: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Jeremy Fitzhardinge <jeremy@goop.org> Signed-off-by: Andrew Morton <akpm@osdl.org>
* [PATCH] i386/x86-64: Work around gcc bug with noreturn functions in unwinderJan Beulich2006-09-261-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | Current gcc generates calls not jumps to noreturn functions. When that happens the return address can point to the next function, which confuses the unwinder. This patch works around it by marking asynchronous exception frames in contrast normal call frames in the unwind information. Then teach the unwinder to decode this. For normal call frames the unwinder now subtracts one from the address which avoids this problem. The standard libgcc unwinder uses the same trick. It doesn't include adjustment of the printed address (i.e. for the original example, it'd still be kernel_math_error+0 that gets displayed, but the unwinder wouldn't get confused anymore. This only works with binutils 2.6.17+ and some versions of H.J.Lu's 2.6.16 unfortunately because earlier binutils don't support .cfi_signal_frame [AK: added automatic detection of the new binutils and wrote description] Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Allow a kernel not to be in ring 0Rusty Russell2006-09-261-4/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We allow for the fact that the guest kernel may not run in ring 0. This requires some abstraction in a few places when setting %cs or checking privilege level (user vs kernel). This is Chris' [RFC PATCH 15/33] move segment checks to subarch, except rather than using #define USER_MODE_MASK which depends on a config option, we use Zach's more flexible approach of assuming ring 3 == userspace. I also used "get_kernel_rpl()" over "get_kernel_cs()" because I think it reads better in the code... 1) Remove the hardcoded 3 and introduce #define SEGMENT_RPL_MASK 3 2) Add a get_kernel_rpl() macro, and don't assume it's zero. And: Clean up of patch for letting kernel run other than ring 0: a. Add some comments about the SEGMENT_IS_*_CODE() macros. b. Add a USER_RPL macro. (Code was comparing a value to a mask in some places and to the magic number 3 in other places.) c. Add macros for table indicator field and use them. d. Change the entry.S tests for LDT stack segment to use the macros Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Zachary Amsden <zach@vmware.com> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Abstract sensitive instructionsRusty Russell2006-09-261-16/+22
| | | | | | | | | | | | | | Abstract sensitive instructions in assembler code, replacing them with macros (which currently are #defined to the native versions). We use long names: assembler is case-insensitive, so if something goes wrong and macros do not expand, it would assemble anyway. Resulting object files are exactly the same as before. Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: annotate FIX_STACK() and the rest of nmi()Chuck Ebbert2006-09-261-3/+15
| | | | | | | | | In i386's entry.S, FIX_STACK() needs annotation because it replaces the stack pointer. And the rest of nmi() needs annotation in order to compile with these new annotations. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: Disallow kprobes on NMI handlersFernando Luis Vázquez Cao2006-09-261-1/+2
| | | | | | | | | | | | | | | | A kprobe executes IRET early and that could cause NMI recursion and stack corruption. Note: This problem was originally spotted and solved by Andi Kleen in the x86_64 architecture. This patch is an adaption of his patch for i386. AK: Merged with current code which was a bit different. AK: Removed printk in nmi handler that shouldn't be there in the first time AK: Added missing include. AK: added KPROBES_END Signed-off-by: Fernando Vazquez <fernando@intellilink.co.jp> Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] i386: move kernel_thread_helper into entry.SAndi Kleen2006-09-261-0/+13
| | | | | | | | | | | And add proper CFI annotation to it which was previously impossible. This prevents "stuck" messages by the dwarf2 unwinder when reaching the top of a kernel stack. Includes feedback from Jan Beulich Cc: jbeulich@novell.com Signed-off-by: Andi Kleen <ak@suse.de>
* [PATCH] x86: error_code is not safe for kprobesPrasanna S.P2006-09-261-12/+13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch moves the entry.S:error_entry to .kprobes.text section, since code marked unsafe for kprobes jumps directly to entry.S::error_entry, that must be marked unsafe as well. This patch also moves all the ".previous.text" asm directives to ".previous" for kprobes section. AK: Following a similar i386 patch from Chuck Ebbert AK: Also merged Jeremy's fix in. +From: Jeremy Fitzhardinge <jeremy@goop.org> KPROBE_ENTRY does a .section .kprobes.text, and expects its users to do a .previous at the end of the function. Unfortunately, if any code within the function switches sections, for example .fixup, then the .previous ends up putting all subsequent code into .fixup. Worse, any subsequent .fixup code gets intermingled with the code its supposed to be fixing (which is also in .fixup). It's surprising this didn't cause more havok. The fix is to use .pushsection/.popsection, so this stuff nests properly. A further cleanup would be to get rid of all .section/.previous pairs, since they're inherently fragile. +From: Chuck Ebbert <76306.1226@compuserve.com> Because code marked unsafe for kprobes jumps directly to entry.S::error_code, that must be marked unsafe as well. The easiest way to do that is to move the page fault entry point to just before error_code and let it inherit the same section. Also moved all the ".previous" asm directives for kprobes sections to column 1 and removed ".text" from them. Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andi Kleen <ak@suse.de>
* x86: save/restore eflags in context switchLinus Torvalds2006-09-181-0/+4
| | | | | | | | | | | (And reset it on new thread creation) It turns out that eflags is important to save and restore not just because of iopl, but due to the magic bits like the NT bit, which we don't want leaking between different threads. Tested-by: Mike Galbraith <efault@gmx.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Fix trivial unwind info bugMarkus Armbruster2006-07-311-1/+1
| | | | | | | | | | | CFA needs to be adjusted upwards for push, and downwards for pop. arch/i386/kernel/entry.S gets it wrong in one place. Signed-off-by: Markus Armbruster <armbru@redhat.com> Acked-by: Jan Beulich <jbeulich@novell.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] lockdep: irqtrace subsystem, i386 supportIngo Molnar2006-07-031-3/+33
| | | | | | | | Add irqflags-tracing support to i386. Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* Remove obsolete #include <linux/config.h>Jörn Engel2006-06-301-1/+0
| | | | | Signed-off-by: Jörn Engel <joern@wohnheim.fh-wedel.de> Signed-off-by: Adrian Bunk <bunk@stusta.de>
* [PATCH] vdso: randomize the i386 vDSO by moving it into a vmaIngo Molnar2006-06-271-1/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Move the i386 VDSO down into a vma and thus randomize it. Besides the security implications, this feature also helps debuggers, which can COW a vma-backed VDSO just like a normal DSO and can thus do single-stepping and other debugging features. It's good for hypervisors (Xen, VMWare) too, which typically live in the same high-mapped address space as the VDSO, hence whenever the VDSO is used, they get lots of guest pagefaults and have to fix such guest accesses up - which slows things down instead of speeding things up (the primary purpose of the VDSO). There's a new CONFIG_COMPAT_VDSO (default=y) option, which provides support for older glibcs that still rely on a prelinked high-mapped VDSO. Newer distributions (using glibc 2.3.3 or later) can turn this option off. Turning it off is also recommended for security reasons: attackers cannot use the predictable high-mapped VDSO page as syscall trampoline anymore. There is a new vdso=[0|1] boot option as well, and a runtime /proc/sys/vm/vdso_enabled sysctl switch, that allows the VDSO to be turned on/off. (This version of the VDSO-randomization patch also has working ELF coredumping, the previous patch crashed in the coredumping code.) This code is a combined work of the exec-shield VDSO randomization code and Gerd Hoffmann's hypervisor-centric VDSO patch. Rusty Russell started this patch and i completed it. [akpm@osdl.org: cleanups] [akpm@osdl.org: compile fix] [akpm@osdl.org: compile fix 2] [akpm@osdl.org: compile fix 3] [akpm@osdl.org: revernt MAXMEM change] Signed-off-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Cc: Gerd Hoffmann <kraxel@suse.de> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Zachary Amsden <zach@vmware.com> Cc: Andi Kleen <ak@muc.de> Cc: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] fix broken vm86 interrupt/signal handlingAleksey Gorelov2006-06-271-2/+9
| | | | | | | | | | | | | | | | | | | | | | | | | | | Commit c3ff8ec31c1249d268cd11390649768a12bec1b9 ("[PATCH] i386: Don't miss pending signals returning to user mode after signal processing") meant that vm86 interrupt/signal handling got broken for the case when vm86 is called from kernel space. In this scenario, if signal is pending because of vm86 interrupt, do_notify_resume/do_signal exits immediately due to user_mode() check, without processing any signals. Thus, resume_userspace handler is spinning in a tight loop with signal pending and TIF_SIGPENDING is set. Previously everything worked Ok. No in-tree usage of vm86() from kernel space exists, but I've heard about a number of projects out there which use vm86 calls from kernel, one of them being this, for instance: http://dev.gentoo.org/~spock/projects/vesafb-tng/ The following patch fixes the issue. Signed-off-by: Aleksey Gorelov <aleksey_gorelov@phoenix.com> Cc: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Cc: Roland McGrath <roland@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86: increase interrupt vector rangeRusty Russell2006-06-271-2/+2
| | | | | | | | | | | | | | | | | | | | | Remove the limit of 256 interrupt vectors by changing the value stored in orig_{e,r}ax to be the complemented interrupt vector. The orig_{e,r}ax needs to be < 0 to allow the signal code to distinguish between return from interrupt and return from syscall. With this change applied, NR_IRQS can be > 256. Xen extends the IRQ numbering space to include room for dynamically allocated virtual interrupts (in the range 256-511), which requires a more permissive interface to do_IRQ. Signed-off-by: Ian Pratt <ian.pratt@xensource.com> Signed-off-by: Christian Limpach <Christian.Limpach@cl.cam.ac.uk> Signed-off-by: Chris Wright <chrisw@sous-sol.org> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> Cc: "Protasevich, Natalie" <Natalie.Protasevich@UNISYS.com> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] i386: reliable stack trace support i386 entry.SJan Beulich2006-06-261-11/+223
| | | | | | | | | To increase the usefulness of reliable stack unwinding, this adds CFI unwind annotations to many low-level i386 routines. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] i386: reliable stack trace support (i386)Jan Beulich2006-06-261-0/+29
| | | | | | | | | | These are the i386-specific pieces to enable reliable stack traces. This is going to be even more useful once CFI annotations get added to he assembly code, namely to entry.S. Signed-off-by: Jan Beulich <jbeulich@novell.com> Signed-off-by: Andi Kleen <ak@suse.de> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] i386: fix singlestep through an int80 syscallChuck Ebbert2006-03-231-0/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Using PTRACE_SINGLESTEP on a child that does an int80 syscall misses the SIGTRAP that should be delivered upon syscall exit. Fix that by setting TIF_SINGLESTEP when entering the kernel via int80 with TF set. /* Test whether singlestep through an int80 syscall works. */ #define _GNU_SOURCE #include <stdio.h> #include <unistd.h> #include <fcntl.h> #include <sys/ptrace.h> #include <sys/wait.h> #include <sys/mman.h> #include <asm/user.h> static int child, status; static struct user_regs_struct regs; static void do_child() { ptrace(PTRACE_TRACEME, 0, 0, 0); kill(getpid(), SIGUSR1); asm ("int $0x80" : : "a" (20)); /* getpid */ } static void do_parent() { unsigned long eip, expected = 0; again: waitpid(child, &status, 0); if (WIFEXITED(status) || WIFSIGNALED(status)) return; if (WIFSTOPPED(status)) { ptrace(PTRACE_GETREGS, child, 0, &regs); eip = regs.eip; if (expected) fprintf(stderr, "child stop @ %08x, expected %08x %s\n", eip, expected, eip == expected ? "" : " <== ERROR"); if (*(unsigned short *)eip == 0x80cd) { fprintf(stderr, "int 0x80 at %08x\n", (unsigned int)eip); expected = eip + 2; } else expected = 0; ptrace(PTRACE_SINGLESTEP, child, NULL, NULL); } goto again; } int main(int argc, char * const argv[]) { child = fork(); if (child) do_parent(); else do_child(); return 0; } Signed-off-by: Chuck Ebbert <76306.1226@compuserve.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Make vm86 support optionalMatt Mackall2006-01-081-0/+2
| | | | | | | | | | | | | | | | | | | This adds an option to remove vm86 support under CONFIG_EMBEDDED. Saves about 5k. This version eliminates most of the #ifdefs of the previous version and instead uses function stubs in vm86.h. Also, release_vm86_irqs is moved from asm-i386/irq.h to a more appropriate home in vm86.h so that the stubs can live together. $ size vmlinux-baseline vmlinux-novm86 text data bss dec hex filename 2920821 523232 190652 3634705 377611 vmlinux-baseline 2916268 523100 190492 3629860 376324 vmlinux-novm86 Signed-off-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] x86/x86_64: mark rodata section read-only: make some datastructures ↵Arjan van de Ven2006-01-061-0/+1
| | | | | | | | | | | | | | | | | const Mark some key kernel datastructures readonly. This patch was previously posted on Jun 28th but was back then not merged because nothing was enforcing rodata anyway.. well that changed now :) Patch by Christoph Lameter <christoph@lameter.com> and Dave Jones <davej@redhat.com> Signed-off-by: Arjan van de Ven <arjan@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu> Cc: Andi Kleen <ak@muc.de> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] i386: NMI pointer comparison fixJan Beulich2005-11-131-4/+3
| | | | | | | | | | | | | Instruction pointer comparisons for the NMI on debug stack check/fixup were incorrect. From: Jan Beulich <jbeulich@novell.com> Cc: "Eric W. Biederman" <ebiederm@xmission.com> Cc: Zwane Mwaikambo <zwane@holomorphy.com> Acked-by: "Seth, Rohit" <rohit.seth@intel.com> Cc: Zachary Amsden <zach@vmware.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] i386: Don't miss pending signals returning to user mode after signal ↵Roland McGrath2005-09-121-2/+2
| | | | | | | | | processing Signed-off-by: Roland McGrath <roland@redhat.com> Acked-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Acked-by: Ingo Molnar <mingo@elte.hu> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] kprobes: prevent possible race conditions i386 changesPrasanna S Panchamukhi2005-09-071-5/+8
| | | | | | | | | This patch contains the i386 architecture specific changes to prevent the possible race conditions. Signed-off-by: Prasanna S Panchamukhi <prasanna@in.ibm.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] uml: SYSEMU: slight cleanup and speedupPaolo 'Blaisorblade' Giarrusso2005-09-051-7/+1
| | | | | | | | | | | | | | | | | | 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: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it> CC: Charles P. Wright <cwright@cs.sunysb.edu> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
* [PATCH] Uml support: reorganize PTRACE_SYSEMU supportBodo Stroesser2005-09-051-1/+7
| | | | | | | | | | | | | 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: Bodo Stroesser <bstroesser@fujitsu-siemens.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>
generated by cgit v1.1 at 2024-10-31 10:49:27 +0000