Messages in this thread | | | From | Thomas Gleixner <> | Subject | Re: [patch V4 part 1 20/36] vmlinux.lds.h: Create section for protection against instrumentation | Date | Wed, 06 May 2020 18:57:38 +0200 |
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Peter Zijlstra <peterz@infradead.org> writes: > On Wed, May 06, 2020 at 09:08:31AM -0700, Sean Christopherson wrote: >> On Tue, May 05, 2020 at 03:16:22PM +0200, Thomas Gleixner wrote: >> > Provide also a set of markers: instr_begin()/end() >> > >> > These are used to mark code inside a noinstr function which calls >> > into regular instrumentable text section as safe. >> >> ... >> >> > --- a/include/linux/compiler.h >> > +++ b/include/linux/compiler.h >> > @@ -120,10 +120,27 @@ void ftrace_likely_update(struct ftrace_ >> > /* Annotate a C jump table to allow objtool to follow the code flow */ >> > #define __annotate_jump_table __section(.rodata..c_jump_table) >> > >> > +/* Begin/end of an instrumentation safe region */ >> > +#define instr_begin() ({ \ >> > + asm volatile("%c0:\n\t" \ >> > + ".pushsection .discard.instr_begin\n\t" \ >> > + ".long %c0b - .\n\t" \ >> > + ".popsection\n\t" : : "i" (__COUNTER__)); \ >> > +}) >> > + >> > +#define instr_end() ({ \ >> > + asm volatile("%c0:\n\t" \ >> > + ".pushsection .discard.instr_end\n\t" \ >> > + ".long %c0b - .\n\t" \ >> > + ".popsection\n\t" : : "i" (__COUNTER__)); \ >> > +}) >> >> Any chance we could spell these out, i.e. instrumentation_begin/end()? I >> can't help but read these as "instruction_begin/end". At a glance, the >> long names shouldn't cause any wrap/indentation issues. > > The kernel naming convention is insn for instruction, not instr. That > said, you're not the first to be confused by this.
I'm happy to spell it out. Was just lazy I guess.
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