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2020-06-11x86/int3: Inline bsearch()Peter Zijlstra2-4/+9
Avoid calling out to bsearch() by inlining it, for normal kernel configs this was the last external call and poke_int3_handler() is now fully self sufficient -- no calls to external code. Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11lib/bsearch: Provide __always_inline variantPeter Zijlstra2-22/+26
For code that needs the ultimate performance (it can inline the @cmp function too) or simply needs to avoid calling external functions for whatever reason, provide an __always_inline variant of bsearch(). [ tglx: Renamed to __inline_bsearch() as suggested by Andy ] Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/int3: Avoid atomic instrumentationPeter Zijlstra1-3/+3
Use arch_atomic_*() and __READ_ONCE() to ensure nothing untoward creeps in and ruins things. That is; this is the INT3 text poke handler, strictly limit the code that runs in it, lest it inadvertenly hits yet another INT3. Reported-by: Thomas Gleixner <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Masami Hiramatsu <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/int3: Ensure that poke_int3_handler() is not tracedThomas Gleixner3-12/+14
In order to ensure poke_int3_handler() is completely self contained -- this is called while modifying other text, imagine the fun of hitting another INT3 -- ensure that everything it uses is not traced. The primary means here is to force inlining; bsearch() is notrace because all of lib/ is. Signed-off-by: Thomas Gleixner <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/32: Convert IRET exception to IDTENTRY_SWThomas Gleixner5-16/+21
Convert the IRET exception handler to IDTENTRY_SW. This is slightly different than the conversions of hardware exceptions as the IRET exception is invoked via an exception table when IRET faults. So it just uses the IDTENTRY_SW mechanism for consistency. It does not emit ASM code as it does not fit the other idtentry exceptions. - Implement the C entry point with DEFINE_IDTENTRY_SW() which maps to DEFINE_IDTENTRY() - Fixup the XEN/PV code - Remove the old prototypes - Remove the RCU warning as the new entry macro ensures correctness No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert SIMD coprocessor error exception to IDTENTRYThomas Gleixner8-33/+21
Convert #XF to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - Emit the ASM stub with DECLARE_IDTENTRY - Handle INVD_BUG in C - Remove the ASM idtentry in 64bit - Remove the open coded ASM entry code in 32bit - Fixup the XEN/PV code - Remove the old prototypes - Remove the RCU warning as the new entry macro ensures correctness No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Alignment check exception to IDTENTRYThomas Gleixner8-16/+5
Convert #AC to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - 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 - Remove the RCU warning as the new entry macro ensures correctness No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Coprocessor error exception to IDTENTRYThomas Gleixner8-17/+6
Convert #MF to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - 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 - Remove the RCU warning as the new entry macro ensures correctness No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Spurious interrupt bug exception to IDTENTRYThomas Gleixner8-16/+5
Convert #SPURIOUS to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - 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: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert General protection exception to IDTENTRYThomas Gleixner8-20/+9
Convert #GP to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - 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 - Remove the RCU warning as the new entry macro ensures correctness No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Stack segment exception to IDTENTRYThomas Gleixner8-21/+8
Convert #SS to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - 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: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Segment not present exception to IDTENTRYThomas Gleixner8-14/+10
Convert #NP to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - 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: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Invalid TSS exception to IDTENTRYThomas Gleixner8-14/+12
Convert #TS to IDTENTRY_ERRORCODE: - Implement the C entry point with DEFINE_IDTENTRY - 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: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/idtentry: Provide IDTENTRY_ERRORCODEThomas Gleixner1-0/+46
Same as IDTENTRY but the C entry point has an error code argument. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Coprocessor segment overrun exception to IDTENTRYThomas Gleixner8-15/+10
Convert #OLD_MF to IDTENTRY: - Implement the C entry point with DEFINE_IDTENTRY - 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: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Device not available exception to IDTENTRYThomas Gleixner8-20/+6
Convert #NM to IDTENTRY: - Implement the C entry point with DEFINE_IDTENTRY - 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 - Remove the RCU warning as the new entry macro ensures correctness No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Invalid Opcode exception to IDTENTRYThomas Gleixner9-16/+25
Convert #UD to IDTENTRY: - Implement the C entry point with DEFINE_IDTENTRY - 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 - Fixup the FOOF bug call in fault.c - Remove the old prototypes No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Bounds exception to IDTENTRYThomas Gleixner8-19/+8
Convert #BR to IDTENTRY: - Implement the C entry point with DEFINE_IDTENTRY - 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 - Remove the RCU warning as the new entry macro ensures correctness No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Overflow exception to IDTENTRYThomas Gleixner8-15/+9
Convert #OF to IDTENTRY: - Implement the C entry point with DEFINE_IDTENTRY - 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: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Convert Divide Error to IDTENTRYThomas Gleixner8-15/+26
Convert #DE to IDTENTRY: - Implement the C entry point with DEFINE_IDTENTRY - 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 No functional change. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/traps: Prepare for using DEFINE_IDTENTRYThomas Gleixner1-0/+15
Prepare for using IDTENTRY to define the C exception/trap entry points. It would be possible to glue this into the existing macro maze, but it's simpler and better to read at the end to just make them distinct. Provide a trivial inline helper to read the trap address and add a comment explaining the logic behind it. The existing macros will be removed once all instances are converted. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/common: Provide idtentry_enter/exit()Thomas Gleixner2-0/+102
Provide functions which handle the low level entry and exit similar to enter/exit from user mode. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/idtentry: Provide macros to define/declare IDT entry pointsThomas Gleixner4-1/+80
Provide DECLARE/DEFINE_IDTENTRY() macros. DEFINE_IDTENTRY() provides a wrapper which acts as the function definition. The exception handler body is just appended to it with curly brackets. The entry point is marked noinstr so that irq tracing and the enter_from_user_mode() can be moved into the C-entry point. As all C-entries use the same macro (or a later variant) the necessary entry handling can be implemented at one central place. DECLARE_IDTENTRY() provides the function prototypes: - The C entry point cfunc - The ASM entry point asm_cfunc - The XEN/PV entry point xen_asm_cfunc They all follow the same naming convention. When included from ASM code DECLARE_IDTENTRY() is a macro which emits the low level entry point in assembly by instantiating idtentry. IDTENTRY is the simplest variant which just has a pt_regs argument. It's going to be used for all exceptions which have no error code. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/32: Provide macro to emit IDT entry stubsThomas Gleixner1-0/+68
32 and 64 bit have unnecessary different ways to populate the exception entry code. Provide a idtentry macro which allows to consolidate all of that. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/64: Provide sane error entry/exitThomas Gleixner1-3/+19
For gradual conversion provide a macro parameter and the required code which allows to handle instrumentation and interrupt flags tracking in C. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Distangle idtentryThomas Gleixner1-183/+220
idtentry is a completely unreadable maze. Split it into distinct idtentry variants which only contain the minimal code: - idtentry for regular exceptions - idtentry_mce_debug for #MCE and #DB - idtentry_df for #DF The generated binary code is equivalent. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/64: Reorder idtentriesThomas Gleixner1-19/+17
Move them all together so verifying the cleanup patches for binary equivalence will be easier. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/traps: Split trap numbers out in a separate headerThomas Gleixner2-25/+32
So they can be used in ASM code. For this it is also necessary to convert them to defines. Will be used for the rework of the entry code. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Andy Lutomirski <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/traps: Make interrupt enable/disable symmetric in C codeThomas Gleixner2-11/+32
Traps enable interrupts conditionally but rely on the ASM return code to disable them again. That results in redundant interrupt disable and trace calls. Make the trap handlers disable interrupts before returning to avoid that, which allows simplification of the ASM entry code in follow up changes. Originally-by: Peter Zijlstra <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/64: Use native swapgs in asm_load_gs_index()Thomas Gleixner1-3/+3
When PARAVIRT_XXL is in use, then load_gs_index() uses xen_load_gs_index() and asm_load_gs_index() is unused. It's therefore pointless to use the paravirtualized SWAPGS implementation in asm_load_gs_index(). Switch it to a plain swapgs. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Steven Rostedt (VMware) <[email protected]> Acked-by: Juergen Gross <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Disable interrupts for native_load_gs_index() in C codeThomas Gleixner2-10/+15
There is absolutely no point in doing this in ASM code. Move it to C. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/traps: Mark sync_regs() noinstrThomas Gleixner1-2/+1
Replace the notrace and NOKPROBE annotations with noinstr. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Reviewed-by: Masami Hiramatsu <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/traps: Mark fixup_bad_iret() noinstrThomas Gleixner1-7/+9
This is called from deep entry ASM in a situation where instrumentation will cause more harm than providing useful information. Switch from memmove() to memcpy() because memmove() can't be called from noinstr code. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Reviewed-by: Masami Hiramatsu <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Make entry_64_compat.S objtool cleanPeter Zijlstra2-7/+20
Currently entry_64_compat is exempt from objtool, but with vmlinux mode there is no hiding it. Make the following changes to make it pass: - change entry_SYSENTER_compat to STT_NOTYPE; it's not a function and doesn't have function type stack setup. - mark all STT_NOTYPE symbols with UNWIND_HINT_EMPTY; so we do validate them and don't treat them as unreachable. - don't abuse RSP as a temp register, this confuses objtool mightily as it (rightfully) thinks we're doing unspeakable things to the stack. Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/speculation/mds: Mark mds_user_clear_cpu_buffers() __always_inlineThomas Gleixner1-2/+2
Prevent the compiler from uninlining and creating traceable/probable functions as this is invoked _after_ context tracking switched to CONTEXT_USER and rcu idle. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Move irq flags tracing to prepare_exit_to_usermode()Thomas Gleixner4-22/+27
This is another step towards more C-code and less convoluted ASM. Similar to the entry path, invoke the tracer before context tracking which might turn off RCU and invoke lockdep as the last step before going back to user space. Annotate the code sections in exit_to_user_mode() accordingly so objtool won't complain about the tracer invocation. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Move irq tracing on syscall entry to C-codeThomas Gleixner4-34/+19
Now that the C entry points are safe, move the irq flags tracing code into the entry helper: - Invoke lockdep before calling into context tracking - Use the safe trace_hardirqs_on_prepare() trace function after context tracking established state and RCU is watching. enter_from_user_mode() is also still invoked from the exception/interrupt entry code which still contains the ASM irq flags tracing. So this is just a redundant and harmless invocation of tracing / lockdep until these are removed as well. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/common: Protect against instrumentationThomas Gleixner1-44/+89
Mark the various syscall entries with noinstr to protect them against instrumentation and add the noinstrumentation_begin()/end() annotations to mark the parts of the functions which are safe to call out into instrumentable code. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Mark enter_from_user_mode() noinstrThomas Gleixner1-1/+1
Both the callers in the low level ASM code and __context_tracking_exit() which is invoked from enter_from_user_mode() via user_exit_irqoff() are marked NOKPROBE. Allowing enter_from_user_mode() to be probed is inconsistent at best. Aside of that while function tracing per se is safe the function trace entry/exit points can be used via BPF as well which is not safe to use before context tracking has reached CONTEXT_KERNEL and adjusted RCU. Mark it noinstr which moves it into the instrumentation protected text section and includes notrace. Note, this needs further fixups in context tracking to ensure that the full call chain is protected. Will be addressed in follow up changes. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Masami Hiramatsu <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/32: Move non entry code into .text sectionThomas Gleixner1-0/+9
All ASM code which is not part of the entry functionality can move out into the .text section. No reason to keep it in the non-instrumentable entry section. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/64: Move non entry code into .text sectionThomas Gleixner2-5/+15
All ASM code which is not part of the entry functionality can move out into the .text section. No reason to keep it in the non-instrumentable entry section. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Steven Rostedt (VMware) <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/idt: Remove update_intr_gate()Thomas Gleixner2-9/+0
No more users. Signed-off-by: Thomas Gleixner <[email protected]>
2020-06-11bug: Annotate WARN/BUG/stackfail as noinstr safeThomas Gleixner3-3/+13
Warnings, bugs and stack protection fails from noinstr sections, e.g. low level and early entry code, are likely to be fatal. Mark them as "safe" to be invoked from noinstr protected code to avoid annotating all usage sites. Getting the information out is important. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11lib/smp_processor_id: Move it into noinstr sectionThomas Gleixner1-5/+5
That code is already not traceable. Move it into the noinstr section so the objtool section validation does not trigger. Annotate the warning code as "safe". While it might be not under all circumstances, getting the information out is important enough. Should this ever trigger from the sensitive code which is shielded against instrumentation, e.g. low level entry, then the printk is the least of the worries. Addresses the objtool warnings: vmlinux.o: warning: objtool: context_tracking_recursion_enter()+0x7: call to __this_cpu_preempt_check() leaves .noinstr.text section vmlinux.o: warning: objtool: __context_tracking_exit()+0x17: call to __this_cpu_preempt_check() leaves .noinstr.text section vmlinux.o: warning: objtool: __context_tracking_enter()+0x2a: call to __this_cpu_preempt_check() leaves .noinstr.text section Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11context_tracking: Ensure that the critical path cannot be instrumentedThomas Gleixner3-12/+14
context tracking lacks a few protection mechanisms against instrumentation: - While the core functions are marked NOKPROBE they lack protection against function tracing which is required as the function entry/exit points can be utilized by BPF. - static functions invoked from the protected functions need to be marked as well as they can be instrumented otherwise. - using plain inline allows the compiler to emit traceable and probable functions. Fix this by marking the functions noinstr and converting the plain inlines to __always_inline. The NOKPROBE_SYMBOL() annotations are removed as the .noinstr.text section is already excluded from being probed. Cures the following objtool warnings: vmlinux.o: warning: objtool: enter_from_user_mode()+0x34: call to __context_tracking_exit() leaves .noinstr.text section vmlinux.o: warning: objtool: prepare_exit_to_usermode()+0x29: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_return_slowpath()+0x29: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_syscall_64()+0x7f: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_int80_syscall_32()+0x3d: call to __context_tracking_enter() leaves .noinstr.text section vmlinux.o: warning: objtool: do_fast_syscall_32()+0x9c: call to __context_tracking_enter() leaves .noinstr.text section and generates new ones... Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Masami Hiramatsu <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Exclude low level entry code from sanitizingPeter Zijlstra1-0/+8
The sanitizers are not really applicable to the fragile low level entry code. Entry code needs to carefully setup a normal 'runtime' environment. Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry: Remove the unused LOCKDEP_SYSEXIT cruftThomas Gleixner2-29/+0
No users left since two years due to commit 21d375b6b34f ("x86/entry/64: Remove the SYSCALL64 fast path") Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/entry/64: Avoid pointless code when CONTEXT_TRACKING=nThomas Gleixner1-0/+2
GAS cannot optimize out the test and conditional jump when context tracking is disabled and CALL_enter_from_user_mode is an empty macro. Wrap it in #ifdeffery. Will go away once all this is moved to C. Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Frederic Weisbecker <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Acked-by: Peter Zijlstra <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/doublefault: Remove memmove() callPeter Zijlstra1-1/+6
Use of memmove() in #DF is problematic considered tracing and other instrumentation. Remove the memmove() call and simply write out what needs doing; this even clarifies the code, win-win! The code copies from the espfix64 stack to the normal task stack, there is no possible way for that to overlap. Survives selftests/x86, specifically sigreturn_64. Suggested-by: Borislav Petkov <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Acked-by: Andy Lutomirski <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
2020-06-11x86/hw_breakpoint: Prevent data breakpoints on cpu_entry_areaAndy Lutomirski1-0/+25
A data breakpoint near the top of an IST stack will cause unrecoverable recursion. A data breakpoint on the GDT, IDT, or TSS is terrifying. Prevent either of these from happening. Co-developed-by: Peter Zijlstra <[email protected]> Signed-off-by: Andy Lutomirski <[email protected]> Signed-off-by: Peter Zijlstra (Intel) <[email protected]> Signed-off-by: Thomas Gleixner <[email protected]> Reviewed-by: Borislav Petkov <[email protected]> Reviewed-by: Lai Jiangshan <[email protected]> Reviewed-by: Alexandre Chartre <[email protected]> Link: https://lkml.kernel.org/r/[email protected]
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