From: Peter Zijlstra <peterz@infradead.org>
From: Peter Zijlstra <peterz@infradead.org>
To: David Woodhouse <dwmw2@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Josh Poimboeuf <jpoimboe@redhat.com>
Cc: linux-kernel@vger.kernel.org, Dave Hansen <dave.hansen@intel.com>,
Ashok Raj <ashok.raj@intel.com>,
Tim Chen <tim.c.chen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Linus Torvalds <torvalds@linux-foundation.org>,
Greg KH <gregkh@linuxfoundation.org>,
Andrea Arcangeli <aarcange@redhat.com>,
Andi Kleen <ak@linux.intel.com>,
Arjan Van De Ven <arjan.van.de.ven@intel.com>,
Dan Williams <dan.j.williams@intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Jun Nakajima <jun.nakajima@intel.com>,
Asit Mallick <asit.k.mallick@intel.com>,
Jason Baron <jbaron@akamai.com>,
Peter Zijlstra <peterz@infradead.org>
Subject: [PATCH 23/35] x86/speculation: Add basic speculation control code
Date: Thu, 18 Jan 2018 14:48:23 +0100 [thread overview]
Message-ID: <20180118140152.830682032@infradead.org> (raw)
In-Reply-To: 20180118134800.711245485@infradead.org
[-- Attachment #1: x86-speculation--Add-basic-speculation-control-code.patch --]
[-- Type: text/plain, Size: 5641 bytes --]
From: Thomas Gleixner <tglx@linutronix.de>
Add the minimal infrastructure to control the speculation control feature.
- Integrate it into the spectre_v2 coammand line parser and the mitigation
selector function. The conditional selector function is a placeholder
right now, which needs to be expanded with CPU specific decision
functions.
- Provide a static key for the actual code control.
- Provide a init function which is called after jump label patching is
functional.
- Provide an interface for the late micro code loader to allow late
discovery of the IBRS support. Not yet functional.
[peterz: fixed Makefile]
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
---
Documentation/admin-guide/kernel-parameters.txt | 1
arch/x86/include/asm/nospec-branch.h | 5 +++
arch/x86/kernel/cpu/Makefile | 1
arch/x86/kernel/cpu/bugs.c | 26 +++++++++++++++++-
arch/x86/kernel/cpu/specctrl.c | 33 ++++++++++++++++++++++++
5 files changed, 64 insertions(+), 2 deletions(-)
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -3932,6 +3932,7 @@
retpoline - replace indirect branches
retpoline,generic - google's original retpoline
retpoline,amd - AMD-specific minimal thunk
+ ibrs - Intel: Indirect Branch Restricted Speculation
Not specifying this option is equivalent to
spectre_v2=auto.
--- a/arch/x86/include/asm/nospec-branch.h
+++ b/arch/x86/include/asm/nospec-branch.h
@@ -214,5 +214,10 @@ static inline void vmexit_fill_RSB(void)
: "r" (loops) : "memory" );
#endif
}
+
+bool specctrl_force_enable_ibrs(void);
+bool specctrl_cond_enable_ibrs(bool full_retpoline);
+bool is_skylake_era(void);
+
#endif /* __ASSEMBLY__ */
#endif /* __NOSPEC_BRANCH_H__ */
--- a/arch/x86/kernel/cpu/Makefile
+++ b/arch/x86/kernel/cpu/Makefile
@@ -24,6 +24,7 @@ obj-y += match.o
obj-y += bugs.o
obj-$(CONFIG_CPU_FREQ) += aperfmperf.o
obj-y += cpuid-deps.o
+obj-y += specctrl.o
obj-$(CONFIG_PROC_FS) += proc.o
obj-$(CONFIG_X86_FEATURE_NAMES) += capflags.o powerflags.o
--- a/arch/x86/kernel/cpu/bugs.c
+++ b/arch/x86/kernel/cpu/bugs.c
@@ -79,6 +79,7 @@ enum spectre_v2_mitigation_cmd {
SPECTRE_V2_CMD_RETPOLINE,
SPECTRE_V2_CMD_RETPOLINE_GENERIC,
SPECTRE_V2_CMD_RETPOLINE_AMD,
+ SPECTRE_V2_CMD_IBRS,
};
static const char *spectre_v2_strings[] = {
@@ -87,6 +88,7 @@ static const char *spectre_v2_strings[]
[SPECTRE_V2_RETPOLINE_MINIMAL_AMD] = "Vulnerable: Minimal AMD ASM retpoline",
[SPECTRE_V2_RETPOLINE_GENERIC] = "Mitigation: Full generic retpoline",
[SPECTRE_V2_RETPOLINE_AMD] = "Mitigation: Full AMD retpoline",
+ [SPECTRE_V2_IBRS] = "Mitigation: Indirect Branch Restricted Speculation",
};
#undef pr_fmt
@@ -144,6 +146,8 @@ static enum spectre_v2_mitigation_cmd __
} else if (match_option(arg, ret, "retpoline,generic")) {
spec2_print_if_insecure("generic retpoline selected on command line.");
return SPECTRE_V2_CMD_RETPOLINE_GENERIC;
+ } else if (match_option(arg, ret, "ibrs")) {
+ return SPECTRE_V2_CMD_IBRS;
} else if (match_option(arg, ret, "auto")) {
return SPECTRE_V2_CMD_AUTO;
}
@@ -156,8 +160,8 @@ static enum spectre_v2_mitigation_cmd __
return SPECTRE_V2_CMD_NONE;
}
-/* Check for Skylake-like CPUs (for RSB handling) */
-static bool __init is_skylake_era(void)
+/* Check for Skylake-like CPUs (for RSB and IBRS handling) */
+bool __init is_skylake_era(void)
{
if (boot_cpu_data.x86_vendor == X86_VENDOR_INTEL &&
boot_cpu_data.x86 == 6) {
@@ -175,6 +179,7 @@ static bool __init is_skylake_era(void)
static void __init spectre_v2_select_mitigation(void)
{
+ bool full_retpoline = IS_ENABLED(CONFIG_RETPOLINE) && retp_compiler();
enum spectre_v2_mitigation_cmd cmd = spectre_v2_parse_cmdline();
enum spectre_v2_mitigation mode = SPECTRE_V2_NONE;
@@ -190,9 +195,25 @@ static void __init spectre_v2_select_mit
case SPECTRE_V2_CMD_NONE:
return;
+ case SPECTRE_V2_CMD_IBRS:
+ /* Command line requested IBRS. Try to enable it */
+ if (specctrl_force_enable_ibrs()) {
+ mode = SPECTRE_V2_IBRS;
+ goto set_mode;
+ }
+ /* FALLTRHU */
+
case SPECTRE_V2_CMD_FORCE:
/* FALLTRHU */
case SPECTRE_V2_CMD_AUTO:
+ /*
+ * Check whether the CPU prefers to have IBRS or IBRS is
+ * the only available mitigation.
+ */
+ if (specctrl_cond_enable_ibrs(full_retpoline)) {
+ mode = SPECTRE_V2_IBRS;
+ goto set_mode;
+ }
goto retpoline_auto;
case SPECTRE_V2_CMD_RETPOLINE_AMD:
@@ -229,6 +250,7 @@ static void __init spectre_v2_select_mit
setup_force_cpu_cap(X86_FEATURE_RETPOLINE);
}
+set_mode:
spectre_v2_enabled = mode;
pr_info("%s\n", spectre_v2_strings[mode]);
--- /dev/null
+++ b/arch/x86/kernel/cpu/specctrl.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <asm/cpufeature.h>
+#include <asm/cpufeatures.h>
+#include <asm/nospec-branch.h>
+
+static inline void specctrl_enable_ibrs(void)
+{
+ setup_force_cpu_cap(X86_FEATURE_IBRS);
+}
+
+bool __init specctrl_force_enable_ibrs(void)
+{
+ if (!boot_cpu_has(X86_FEATURE_SPEC_CTRL))
+ return false;
+ specctrl_enable_ibrs();
+ return true;
+}
+
+bool __init specctrl_cond_enable_ibrs(bool full_retpoline)
+{
+ if (!boot_cpu_has(X86_FEATURE_SPEC_CTRL))
+ return false;
+ /*
+ * IBRS is only required by SKL or as fallback if retpoline is not
+ * fully supported.
+ */
+ if (!is_skylake_era() && full_retpoline)
+ return false;
+
+ specctrl_enable_ibrs();
+ return true;
+}
next prev parent reply other threads:[~2018-01-18 15:01 UTC|newest]
Thread overview: 65+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-18 13:48 [PATCH 00/35] jump_label, objtool, IBRS and IBPB Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 01/35] jump_label: Add branch hints to static_branch_{un,}likely() Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 02/35] sched: Optimize ttwu_stat() Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 03/35] x86: Reindent _static_cpu_has Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 04/35] x86: Update _static_cpu_has to use all named variables Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 05/35] x86: Add a type field to alt_instr Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 06/35] objtool: Implement base jump_assert support Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 07/35] x86: Annotate static_cpu_has alternative Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 08/35] objtool: Implement jump_assert for _static_cpu_has() Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 09/35] objtool: Introduce special_type Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 10/35] x86/jump_label: Implement arch_static_assert() Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 11/35] objtool: Add retpoline validation Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 12/35] x86/paravirt: Annotate indirect calls Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 13/35] x86,nospec: Annotate indirect calls/jumps Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 14/35] x86: Annotate indirect jump in head_64.S Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 15/35] objtool: More complex static jump implementation Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 16/35] objtool: Use existing global variables for options Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 17/35] objtool: Even more complex static block checks Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 18/35] objtool: Another static block fail Peter Zijlstra, Peter Zijlstra
2018-01-19 16:42 ` Peter Zijlstra
2018-01-29 18:01 ` Josh Poimboeuf
2018-01-29 18:24 ` Peter Zijlstra
2018-01-18 13:48 ` [PATCH 19/35] objtool: Skip static assert when KCOV/KASAN Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 20/35] x86: Force asm-goto Peter Zijlstra, Peter Zijlstra
2018-01-18 16:25 ` David Woodhouse
2018-01-18 13:48 ` [PATCH 21/35] x86: Remove FAST_FEATURE_TESTS Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 22/35] x86/cpufeatures: Detect Speculation control feature Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` Peter Zijlstra, Peter Zijlstra [this message]
2018-01-18 16:37 ` [PATCH 23/35] x86/speculation: Add basic speculation control code Josh Poimboeuf
2018-01-18 17:08 ` Dave Hansen
2018-01-18 17:12 ` Paolo Bonzini
2018-01-18 18:24 ` Josh Poimboeuf
2018-01-18 19:08 ` Andrea Arcangeli
2018-01-18 23:25 ` Andy Lutomirski
2018-01-18 23:35 ` Andrew Cooper
2018-01-19 1:41 ` Andrea Arcangeli
2018-01-19 4:10 ` Andy Lutomirski
2018-01-19 4:15 ` Van De Ven, Arjan
2018-01-19 15:47 ` Andrea Arcangeli
2018-01-18 13:48 ` [PATCH 24/35] x86/msr: Move native_*msr macros out of microcode.h Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 25/35] x86/speculation: Add inlines to control Indirect Branch Speculation Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 26/35] x86/enter: Create macros to stop/restart " Peter Zijlstra, Peter Zijlstra
2018-01-18 19:44 ` Tim Chen
2018-01-18 13:48 ` [PATCH 27/35] x86/enter: Use IBRS on syscall and interrupts Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 28/35] x86/idle: Control Indirect Branch Speculation in idle Peter Zijlstra, Peter Zijlstra
2018-01-18 19:52 ` Andrew Cooper
2018-01-18 13:48 ` [PATCH 29/35] x86/speculation: Add IPBP support Peter Zijlstra, Peter Zijlstra
2018-01-18 16:22 ` Josh Poimboeuf
2018-01-18 18:31 ` Borislav Petkov
2018-01-18 18:35 ` Josh Poimboeuf
2018-01-18 18:46 ` Borislav Petkov
2018-01-18 13:48 ` [PATCH 30/35] x86/speculation: Use Indirect Branch Prediction Barrier in context switch Peter Zijlstra, Peter Zijlstra
2018-01-19 0:38 ` Tim Chen
2018-01-19 4:03 ` Kevin Easton
2018-01-19 20:26 ` Tim Chen
2018-01-18 13:48 ` [PATCH 31/35] x86/ibrs: Add new helper macros to save/restore MSR_IA32_SPEC_CTRL Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 32/35] x86/vmx: Direct access to MSR_IA32_SPEC_CTRL Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 33/35] x86/svm: " Peter Zijlstra, Peter Zijlstra
2018-01-18 13:48 ` [PATCH 34/35] x86/kvm: Add IBPB support Peter Zijlstra, Peter Zijlstra
2018-01-18 15:32 ` Paolo Bonzini
2018-01-19 15:25 ` Paolo Bonzini
2018-01-19 16:08 ` David Woodhouse
2018-01-19 16:27 ` Andy Lutomirski
2018-01-19 16:48 ` Paolo Bonzini
2018-01-18 13:48 ` [PATCH 35/35] x86/nospec: Add static assertions Peter Zijlstra, Peter Zijlstra
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20180118140152.830682032@infradead.org \
--to=peterz@infradead.org \
--cc=aarcange@redhat.com \
--cc=ak@linux.intel.com \
--cc=arjan.van.de.ven@intel.com \
--cc=ashok.raj@intel.com \
--cc=asit.k.mallick@intel.com \
--cc=dan.j.williams@intel.com \
--cc=dave.hansen@intel.com \
--cc=dwmw2@infradead.org \
--cc=gregkh@linuxfoundation.org \
--cc=jbaron@akamai.com \
--cc=jpoimboe@redhat.com \
--cc=jun.nakajima@intel.com \
--cc=linux-kernel@vger.kernel.org \
--cc=luto@kernel.org \
--cc=pbonzini@redhat.com \
--cc=tglx@linutronix.de \
--cc=tim.c.chen@linux.intel.com \
--cc=torvalds@linux-foundation.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).