- 11 Jun, 2020 40 commits
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Thomas Gleixner authored
Convert KVM specific system vectors to IDTENTRY_SYSVEC*: The two empty stub handlers which only increment the stats counter do no need to run on the interrupt stack. Use IDTENTRY_SYSVEC_SIMPLE for them. The wakeup handler does more work and runs on the interrupt stack. None of these handlers need to save and restore the irq_regs pointer. Signed-off-by:
Thomas Gleixner <tglx@linutronix.de> Signed-off-by:
Ingo Molnar <mingo@kernel.org> Acked-by:
Paolo Bonzini <pbonzini@redhat.com> Acked-by:
Andy Lutomirski <luto@kernel.org> Link: https://lore.kernel.org/r/20200521202119.555715519@linutronix.de
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Thomas Gleixner authored
Convert various system vectors to IDTENTRY_SYSVEC: - Implement the C entry point with DEFINE_IDTENTRY_SYSVEC - Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC - Remove the ASM idtentries in 64-bit - Remove the BUILD_INTERRUPT entries in 32-bit - Remove the old prototypes No functional change. Signed-off-by:
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Thomas Gleixner authored
Convert SMP system vectors to IDTENTRY_SYSVEC: - Implement the C entry point with DEFINE_IDTENTRY_SYSVEC - Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC - Remove the ASM idtentries in 64-bit - Remove the BUILD_INTERRUPT entries in 32-bit - Remove the old prototypes No functional change. Signed-off-by:
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Thomas Gleixner authored
Convert APIC interrupts to IDTENTRY_SYSVEC: - Implement the C entry point with DEFINE_IDTENTRY_SYSVEC - Emit the ASM stub with DECLARE_IDTENTRY_SYSVEC - Remove the ASM idtentries in 64-bit - Remove the BUILD_INTERRUPT entries in 32-bit - Remove the old prototypes No functional change. Signed-off-by:
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Thomas Gleixner authored
Provide IDTENTRY variants for system vectors to consolidate the different mechanisms to emit the ASM stubs for 32- and 64-bit. On 64-bit this also moves the stack switching from ASM to C code. 32-bit will excute the system vectors w/o stack switching as before. The simple variant is meant for "empty" system vectors like scheduler IPI and KVM posted interrupt vectors. These do not need the full glory of irq enter/exit handling with softirq processing and more. Signed-off-by:
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Thomas Gleixner authored
Replace the extra interrupt handling code and reuse the existing idtentry machinery. This moves the irq stack switching on 64-bit from ASM to C code; 32-bit already does the stack switching in C. This requires to remove HAVE_IRQ_EXIT_ON_IRQ_STACK as the stack switch is not longer in the low level entry code. Signed-off-by:
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Thomas Gleixner authored
Provide a seperate IDTENTRY macro for device interrupts. Similar to IDTENTRY_ERRORCODE with the addition of invoking irq_enter/exit_rcu() and providing the errorcode as a 'u8' argument to the C function, which truncates the sign extended vector number. Signed-off-by:
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Thomas Gleixner authored
To consolidate the interrupt entry/exit code vs. the other exceptions make handle_irq() an inline and handle both 64-bit and 32-bit mode. Preparatory change to move irq stack switching for 64-bit to C which allows to consolidate the entry exit handling by reusing the idtentry machinery both in ASM and C. Signed-off-by:
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Thomas Gleixner authored
Device interrupts which go through do_IRQ() or the spurious interrupt handler have their separate entry code on 64 bit for no good reason. Both 32 and 64 bit transport the vector number through ORIG_[RE]AX in pt_regs. Further the vector number is forced to fit into an u8 and is complemented and offset by 0x80 so it's in the signed character range. Otherwise GAS would expand the pushq to a 5 byte instruction for any vector > 0x7F. Treat the vector number like an error code and hand it to the C function as argument. This allows to get rid of the extra entry code in a later step. Simplify the error code push magic by implementing the pushq imm8 via a '.byte 0x6a, vector' sequence so GAS is not able to screw it up. As the pushq imm8 is sign extending the resulting error code needs to be truncated to 8 bits in C code. Originally-by:
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Thomas Gleixner authored
The only difference is the name of the per-CPU variable: irq_regs vs. __irq_regs, but the accessor functions are identical. Remove the pointless copy and use the generic variant. Signed-off-by:
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Thomas Gleixner authored
No more users. Signed-off-by:
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Thomas Gleixner authored
No more users. Signed-off-by:
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Thomas Gleixner authored
xen_failsafe_callback() is invoked from XEN for two cases: 1. Fault while reloading DS, ES, FS or GS 2. Fault while executing IRET #1 retries the IRET after XEN has fixed up the segments. #2 injects a #GP which kills the task For #1 there is no reason to go through the full exception return path because the tasks TIF state is still the same. So just going straight to the IRET path is good enough. Signed-off-by:
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Thomas Gleixner authored
Now that all exceptions are converted over the sane flag is not longer needed. Also the vector argument of idtentry_body on 64-bit is pointless now. Signed-off-by:
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Thomas Gleixner authored
Convert page fault exceptions to IDTENTRY_RAW: - Implement the C entry point with DEFINE_IDTENTRY_RAW - Add the CR2 read into the exception handler - Add the idtentry_enter/exit_cond_rcu() invocations in in the regular page fault handler and in the async PF part. - Emit the ASM stub with DECLARE_IDTENTRY_RAW - Remove the ASM idtentry in 64-bit - Remove the CR2 read from 64-bit - Remove the open coded ASM entry code in 32-bit - Fix up the XEN/PV code - Remove the old prototypes No functional change. Signed-off-by: -
Thomas Gleixner authored
All C functions which do not have an error code have been converted to the new IDTENTRY interface which does not expect an error code in the arguments. Spare the XORL. Signed-off-by:
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Thomas Gleixner authored
Convert the XEN/PV hypercall to IDTENTRY: - Emit the ASM stub with DECLARE_IDTENTRY - Remove the ASM idtentry in 64-bit - Remove the open coded ASM entry code in 32-bit - Remove the old prototypes The handler stubs need to stay in ASM code as they need corner case handling and adjustment of the stack pointer. Provide a new C function which invokes the entry/exit handling and calls into the XEN handler on the interrupt stack if required. The exit code is slightly different from the regular idtentry_exit() on non-preemptible kernels. If the hypercall is preemptible and need_resched() is set then XEN provides a preempt hypercall scheduling function. Move this functionality into the entry code so it can use the existing idtentry functionality. [ mingo: Build fixes. ] Signed-off-by:
Juergen Gross <jgross@suse.com> Tested-by:
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Thomas Gleixner authored
The XEN PV hypercall requires the ability of conditional rescheduling when preemption is disabled because some hypercalls take ages. Split out the rescheduling code from idtentry_exit_cond_rcu() so it can be reused for that. Signed-off-by:
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Thomas Gleixner authored
The first step to get rid of the ENTER/LEAVE_IRQ_STACK ASM macro maze. Use the new C code helpers to move do_softirq_own_stack() out of ASM code. Signed-off-by:
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Thomas Gleixner authored
Device interrupt handlers and system vector handlers are executed on the interrupt stack. The stack switch happens in the low level assembly entry code. This conflicts with the efforts to consolidate the exit code in C to ensure correctness vs. RCU and tracing. As there is no way to move #DB away from IST due to the MOV SS issue, the requirements vs. #DB and NMI for switching to the interrupt stack do not exist anymore. The only requirement is that interrupts are disabled. That allows the moving of the stack switching to C code, which simplifies the entry/exit handling further, because it allows the switching of stacks after handling the entry and on exit before handling RCU, returning to usermode and kernel preemption in the same way as for regular exceptions. The initial attempt of having the stack switching in inline ASM caused too much headache vs. objtool and the unwinder. After analysing the use cases it was agreed on that having the stack switch in ASM for the price of an indirect call is acceptable, as the main users are indirect call heavy anyway and the few system vectors which are empty shells (scheduler IPI and KVM posted interrupt vectors) can run from the regular stack. Provide helper functions to check whether the interrupt stack is already active and whether stack switching is required. 64-bit only for now, as 32-bit has a variant of that already. Once this is cleaned up, the two implementations might be consolidated as an additional cleanup on top. Signed-off-by:
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Thomas Gleixner authored
Like __irq_enter/exit() but without time accounting. To be used for "empty" system vectors like the scheduler IPI to avoid the overhead. Signed-off-by:
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Thomas Gleixner authored
irq_enter()/exit() currently include RCU handling. To properly separate the RCU handling code, provide variants which contain only the non-RCU related functionality. Signed-off-by:
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Thomas Gleixner authored
Now that everything is converted to conditional RCU handling remove idtentry_enter/exit() and tidy up the conditional functions. This does not remove rcu_irq_exit_preempt(), to avoid conflicts with the RCU tree. Will be removed once all of this hits Linus's tree. Signed-off-by:
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Thomas Gleixner authored
Switch all idtentry_enter/exit() users over to the new conditional RCU handling scheme and make the user mode entries in #DB, #INT3 and #MCE use the user mode idtentry functions. Signed-off-by:
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Thomas Gleixner authored
As there are exceptions which already handle entry from user mode and from kernel mode separately, providing explicit user entry/exit handling callbacks makes sense and makes the code easier to understand. Signed-off-by:
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Thomas Gleixner authored
After a lengthy discussion [1] it turned out that RCU does not need a full rcu_irq_enter/exit() when RCU is already watching. All it needs if NOHZ_FULL is active is to check whether the tick needs to be restarted. This allows to avoid a separate variant for the pagefault handler which cannot invoke rcu_irq_enter() on a kernel pagefault which might sleep. The cond_rcu argument is only temporary and will be removed once the existing users of idtentry_enter/exit() have been cleaned up. After that the code can be significantly simplified. [ mingo: Simplified the control flow ] Signed-off-by:
"Paul E. McKenney" <paulmck@kernel.org> Acked-by:
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Thomas Gleixner authored
The hardware latency tracer calls into instrumentable functions. Move the calls into the RCU watching sections and annotate them. Signed-off-by:
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Ingo Molnar authored
The following commit: 095b7a3e7745 ("x86/entry: Convert double fault exception to IDTENTRY_DF") introduced a new build warning on 64-bit allnoconfig kernels, that have CONFIG_VMAP_STACK disabled: arch/x86/kernel/traps.c:332:16: warning: unused variable ‘address’ [-Wunused-variable] This variable is only used if CONFIG_VMAP_STACK is defined, so make it dependent on that, not CONFIG_X86_64. Signed-off-by: -
Thomas Gleixner authored
Convert #DF to IDTENTRY_DF - Implement the C entry point with DEFINE_IDTENTRY_DF - Emit the ASM stub with DECLARE_IDTENTRY_DF on 64bit - Remove the ASM idtentry in 64bit - Adjust the 32bit shim code - Fixup the XEN/PV code - Remove the old prototypes No functional change. Signed-off-by:
Alexandre Chartre <alexandre.chartre@oracle.com> Acked-by:
Peter Zijlstra <peterz@infradead.org> Acked-by:
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Thomas Gleixner authored
Provide a separate macro for #DF as this needs to emit paranoid only code and has also a special ASM stub in 32bit. Signed-off-by:
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Thomas Gleixner authored
Mark the relevant functions noinstr, use the plain non-instrumented MSR accessors. The only odd part is the instrumentation_begin()/end() pair around the indirect machine_check_vector() call as objtool can't figure that out. The possible invoked functions are annotated correctly. Also use notrace variant of nmi_enter/exit(). If MCEs happen then hardware latency tracing is the least of the worries. Signed-off-by:
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Thomas Gleixner authored
The functions invoked from handle_debug() can be instrumented. Tell objtool about it. Signed-off-by:
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Thomas Gleixner authored
Now that there are separate entry points, move the kernel/user_mode specifc checks into the entry functions so the common handling code does not need the extra mode checks. Make the code more readable while at it. Signed-off-by:
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Thomas Gleixner authored
The MCE entry point uses the same mechanism as the IST entry point for now. For #DB split the inner workings and just keep the nmi_enter/exit() magic in the IST variant. Fixup the ASM code to emit the proper noist_##cfunc call. Signed-off-by:
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Thomas Gleixner authored
Provide NOIST entry point macros which allows to implement NOIST variants of the C entry points. These are invoked when #DB or #MC enter from user space. This allows explicit handling of the difference between user mode and kernel mode entry later. Signed-off-by:
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Thomas Gleixner authored
The C entry points do not expect an error code. Signed-off-by:
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Thomas Gleixner authored
Convert #DB to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY_DB - Emit the ASM stub with DECLARE_IDTENTRY - Remove the ASM idtentry in 64bit - Remove the open coded ASM entry code in 32bit - Fixup the XEN/PV code - Remove the old prototypes No functional change. Signed-off-by:
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Peter Zijlstra authored
DR6/7 should be handled before nmi_enter() is invoked and restore after nmi_exit() to minimize the exposure. Split it out into helper inlines and bring it into the correct order. Signed-off-by:
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Thomas Gleixner authored
Mark all functions in the fragile code parts noinstr or force inlining so they can't be instrumented. Also make the hardware latency tracer invocation explicit outside of non-instrumentable section. Signed-off-by:
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Thomas Gleixner authored
Convert #NMI to IDTENTRY_NMI: - Implement the C entry point with DEFINE_IDTENTRY_NMI - Fixup the XEN/PV code - Remove the old prototypes No functional change. Signed-off-by:
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