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Commit d6fbe1c5 authored by Michael Ellerman's avatar Michael Ellerman
Browse files

powerpc/64s: Wire up cpu_show_spectre_v2() 



Add a definition for cpu_show_spectre_v2() to override the generic
version. This has several permuations, though in practice some may not
occur we cater for any combination.

The most verbose is:

  Mitigation: Indirect branch serialisation (kernel only), Indirect
  branch cache disabled, ori31 speculation barrier enabled

We don't treat the ori31 speculation barrier as a mitigation on its
own, because it has to be *used* by code in order to be a mitigation
and we don't know if userspace is doing that. So if that's all we see
we say:

  Vulnerable, ori31 speculation barrier enabled

Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
parent 56986016

arch/powerpc/kernel/security.c

+33 −0
Original line number Diff line number Diff line
@@ -58,3 +58,36 @@ ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, c 


	return sprintf(buf, "Vulnerable\n");

}



ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)

{

	bool bcs, ccd, ori;

	struct seq_buf s;



	seq_buf_init(&s, buf, PAGE_SIZE - 1);



	bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);

	ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);

	ori = security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31);



	if (bcs || ccd) {

		seq_buf_printf(&s, "Mitigation: ");



		if (bcs)

			seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");



		if (bcs && ccd)

			seq_buf_printf(&s, ", ");



		if (ccd)

			seq_buf_printf(&s, "Indirect branch cache disabled");

	} else

		seq_buf_printf(&s, "Vulnerable");



	if (ori)

		seq_buf_printf(&s, ", ori31 speculation barrier enabled");



	seq_buf_printf(&s, "\n");



	return s.len;

}