Re: [RFC PATCH] asm/generic: introduce if_nospec and nospec_barrier

Jiri Kosina
2018-01-04T02:00:41Z

On Wed, 3 Jan 2018, Dan Williams wrote:

> Speaking from a purely Linux kernel maintenance process perspective we
> play wack-a-mole with missed endian conversions and other bugs that
> coccinelle, sparse, etc help us catch.

Fully agreed.

> So this is in that same category, but yes, it's inconvenient.

Disagreed, violently. CPU has to execute the instructions I ask it to
execute, and if it executes *anything* else that reveals any information
about the instructions that have *not* been executed, it's flawed.

> Elena has done the work of auditing static analysis reports to a dozen
> or so locations that need some 'nospec' handling.

How exactly is that related (especially in longer-term support terms) to
BPF anyway?

Thanks,

--
Jiri Kosina
SUSE Labs