Re: [PATCH] x86/mm: Simplify RESERVE_BRK()

[Peter Zijlstra]

On Thu, Apr 28, 2022 at 01:04:25PM -0700, Josh Poimboeuf wrote:
> RESERVE_BRK() reserves data in the .brk_reservation section.  The data
> is initialized to zero, like BSS, so the macro specifies 'nobits' to
> prevent the data from taking up space in the vmlinux binary.  The only
> way to get the compiler to do that (without putting the variable in .bss
> proper) is to use inline asm.
> 
> The macro also has a hack which encloses the inline asm in a discarded
> function, which allows the size to be passed (global inline asm doesn't
> allow inputs).
> 
> Remove the need for the discarded function hack by just stringifying the
> size rather than supplying it as an input to the inline asm.
> 
> Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>

Tested-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>