linux/tools/objtool/arch, branch v5.8

objtool: Fix noinstr vs KCOV

2020-06-18T15:36:33Z

Since many compilers cannot disable KCOV with a function attribute, help it to NOP out any __sanitizer_cov_*() calls injected in noinstr code. This turns: 12: e8 00 00 00 00 callq 17 13: R_X86_64_PLT32 __sanitizer_cov_trace_pc-0x4 into: 12: 0f 1f 44 00 00 nopl 0x0(%rax,%rax,1) 13: R_X86_64_NONE __sanitizer_cov_trace_pc-0x4 Just like recordmcount does. Signed-off-by: Peter Zijlstra (Intel) Acked-by: Dmitry Vyukov

objtool: Add support for intra-function calls

2020-04-30T18:14:33Z

Change objtool to support intra-function calls. On x86, an intra-function call is represented in objtool as a push onto the stack (of the return address), and a jump to the destination address. That way the stack information is correctly updated and the call flow is still accurate. Signed-off-by: Alexandre Chartre Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200414103618.12657-4-alexandre.chartre@oracle.com

objtool: Move the IRET hack into the arch decoder

2020-04-30T18:14:33Z

Quoting Julien: "And the other suggestion is my other email was that you don't even need to add INSN_EXCEPTION_RETURN. You can keep IRET as INSN_CONTEXT_SWITCH by default and x86 decoder lookups the symbol conaining an iret. If it's a function symbol, it can just set the type to INSN_OTHER so that it caries on to the next instruction after having handled the stack_op." Suggested-by: Julien Thierry Signed-off-by: Miroslav Benes Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200428191659.913283807@infradead.org

objtool: Remove INSN_STACK

2020-04-30T18:14:33Z

With the unconditional use of handle_insn_ops(), INSN_STACK has lost its purpose. Remove it. Suggested-by: Julien Thierry Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200428191659.854203028@infradead.org

objtool: Rework allocating stack_ops on decode

2020-04-30T18:14:32Z

Wrap each stack_op in a macro that allocates and adds it to the list. This simplifies trying to figure out what to do with the pre-allocated stack_op at the end. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Alexandre Chartre Reviewed-by: Miroslav Benes Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200428191659.736151601@infradead.org

objtool: Constify arch_decode_instruction()

2020-04-23T06:34:18Z

Mostly straightforward constification, except that WARN_FUNC() needs a writable pointer while we have read-only pointers, so deflect this to WARN(). Acked-by: Josh Poimboeuf Signed-off-by: Ingo Molnar Cc: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Sami Tolvanen Cc: Thomas Gleixner Link: https://lore.kernel.org/r/20200422103205.61900-4-mingo@kernel.org

objtool: Rename struct cfi_state

2020-04-22T08:53:50Z

There's going to be a new struct cfi_state, rename this one to make place. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Reviewed-by: Alexandre Chartre Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200416115118.986441913@infradead.org Signed-off-by: Ingo Molnar

objtool: Better handle IRET

2020-04-22T08:53:50Z

Teach objtool a little more about IRET so that we can avoid using the SAVE/RESTORE annotation. In particular, make the weird corner case in insn->restore go away. The purpose of that corner case is to deal with the fact that UNWIND_HINT_RESTORE lands on the instruction after IRET, but that instruction can end up being outside the basic block, consider: if (cond) sync_core() foo(); Then the hint will land on foo(), and we'll encounter the restore hint without ever having seen the save hint. By teaching objtool about the arch specific exception frame size, and assuming that any IRET in an STT_FUNC symbol is an exception frame sized POP, we can remove the use of save/restore hints for this code. Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Reviewed-by: Alexandre Chartre Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200416115118.631224674@infradead.org Signed-off-by: Ingo Molnar

objtool: Support multiple stack_op per instruction

2020-04-22T08:53:50Z

Instruction sets can include more or less complex operations which might not fit the currently defined set of stack_ops. Combining more than one stack_op provides more flexibility to describe the behaviour of an instruction. This also reduces the need to define new stack_ops specific to a single instruction set. Allow instruction decoders to generate multiple stack_op per instruction. Signed-off-by: Julien Thierry Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Reviewed-by: Alexandre Chartre Acked-by: Josh Poimboeuf Link: https://lkml.kernel.org/r/20200327152847.15294-11-jthierry@redhat.com Signed-off-by: Ingo Molnar

objtool: Split out arch-specific CFI definitions

2020-04-22T08:53:49Z

Some CFI definitions used by generic objtool code have no reason to vary from one architecture to another. Keep those definitions in generic code and move the arch-specific ones to a new arch-specific header. Signed-off-by: Julien Thierry Acked-by: Peter Zijlstra (Intel) Reviewed-by: Miroslav Benes Signed-off-by: Josh Poimboeuf Signed-off-by: Ingo Molnar