Re: [PATCH v5] kernel/trace: Add DISALLOW_TRACE_PRINTK make option

[Steven Rostedt]

On Tue, 25 Aug 2020 08:38:27 +0800
Nicolas Boichat <drinkcat@xxxxxxxxxxxx> wrote:

> This already works. I'll be honest, I'm not 100% sure why (and if
> fully intentional)...
> 
> The CFLAGS end up in 3 generated assembly files:
> # grep -R DISALLOW_TRACE_PRINTK * | grep -v ".cmd:"
> arch/x86/kernel/asm-offsets.s:# -imultiarch x86_64-linux-gnu -D
> __KERNEL__ -D DISALLOW_TRACE_PRINTK
> kernel/bounds.s:# -imultiarch x86_64-linux-gnu -D __KERNEL__ -D
> DISALLOW_TRACE_PRINTK
> scripts/mod/devicetable-offsets.s:# -D DISALLOW_TRACE_PRINTK
> (along with all *.cmd files)
> 
> and I suspect some/all of those force a complete kernel rebuild.

Yeah, I believe that the modification of CFLAGS causes a recompile of
the entire kernel.

Thanks!

-- Steve