[PATCH] Documentation: Add powerpc options for spec_store_bypass_disable
From: Michael Ellerman <mpe@ellerman.id.au>
Date: 2018-07-10 02:08:53
Also in:
linuxppc-dev, lkml
Subsystem:
documentation, the rest · Maintainers:
Jonathan Corbet, Linus Torvalds
Document the support for spec_store_bypass_disable that was added for
powerpc in commit a048a07d7f45 ("powerpc/64s: Add support for a store
forwarding barrier at kernel entry/exit").
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
---
Documentation/admin-guide/kernel-parameters.txt | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)
I tried documenting the differences between the PPC options and X86 ones in one
section, but it got quite messy, so I went with this instead. Happy to take
advice on how better to structure it if anyone has opinions.
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index efc7aa7a0670..f320c7168b04 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt@@ -4060,6 +4060,8 @@ This parameter controls whether the Speculative Store Bypass optimization is used. + On x86 the options are: + on - Unconditionally disable Speculative Store Bypass off - Unconditionally enable Speculative Store Bypass auto - Kernel detects whether the CPU model contains an
@@ -4075,12 +4077,20 @@ seccomp - Same as "prctl" above, but all seccomp threads will disable SSB unless they explicitly opt out. - Not specifying this option is equivalent to - spec_store_bypass_disable=auto. - Default mitigations: X86: If CONFIG_SECCOMP=y "seccomp", otherwise "prctl" + On powerpc the options are: + + on,auto - On Power8 and Power9 insert a store-forwarding + barrier on kernel entry and exit. On Power7 + perform a software flush on kernel entry and + exit. + off - No action. + + Not specifying this option is equivalent to + spec_store_bypass_disable=auto. + spia_io_base= [HW,MTD] spia_fio_base= spia_pedr=
--
2.14.1
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