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authorLinus Torvalds <torvalds@linux-foundation.org>2018-12-01 23:35:48 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-12-01 23:35:48 +0300
commit4b78317679c4f3782a3cff0ddb269c1fcfde7621 (patch)
treefd3d202ef58da346528625067bc139bc19b28726 /include
parent880584176ed7875117a5ba76cf316cb60f7ad30b (diff)
parent55a974021ec952ee460dc31ca08722158639de72 (diff)
downloadlinux-4b78317679c4f3782a3cff0ddb269c1fcfde7621.tar.xz
Merge branch 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull STIBP fallout fixes from Thomas Gleixner: "The performance destruction department finally got it's act together and came up with a cure for the STIPB regression: - Provide a command line option to control the spectre v2 user space mitigations. Default is either seccomp or prctl (if seccomp is disabled in Kconfig). prctl allows mitigation opt-in, seccomp enables the migitation for sandboxed processes. - Rework the code to handle the conditional STIBP/IBPB control and remove the now unused ptrace_may_access_sched() optimization attempt - Disable STIBP automatically when SMT is disabled - Optimize the switch_to() logic to avoid MSR writes and invocations of __switch_to_xtra(). - Make the asynchronous speculation TIF updates synchronous to prevent stale mitigation state. As a general cleanup this also makes retpoline directly depend on compiler support and removes the 'minimal retpoline' option which just pretended to provide some form of security while providing none" * 'x86-pti-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (31 commits) x86/speculation: Provide IBPB always command line options x86/speculation: Add seccomp Spectre v2 user space protection mode x86/speculation: Enable prctl mode for spectre_v2_user x86/speculation: Add prctl() control for indirect branch speculation x86/speculation: Prepare arch_smt_update() for PRCTL mode x86/speculation: Prevent stale SPEC_CTRL msr content x86/speculation: Split out TIF update ptrace: Remove unused ptrace_may_access_sched() and MODE_IBRS x86/speculation: Prepare for conditional IBPB in switch_mm() x86/speculation: Avoid __switch_to_xtra() calls x86/process: Consolidate and simplify switch_to_xtra() code x86/speculation: Prepare for per task indirect branch speculation control x86/speculation: Add command line control for indirect branch speculation x86/speculation: Unify conditional spectre v2 print functions x86/speculataion: Mark command line parser data __initdata x86/speculation: Mark string arrays const correctly x86/speculation: Reorder the spec_v2 code x86/l1tf: Show actual SMT state x86/speculation: Rework SMT state change sched/smt: Expose sched_smt_present static key ...
Diffstat (limited to 'include')
-rw-r--r--include/linux/ptrace.h17
-rw-r--r--include/linux/sched.h9
-rw-r--r--include/linux/sched/smt.h20
-rw-r--r--include/uapi/linux/prctl.h1
4 files changed, 30 insertions, 17 deletions
diff --git a/include/linux/ptrace.h b/include/linux/ptrace.h
index 6c2ffed907f5..de20ede2c5c8 100644
--- a/include/linux/ptrace.h
+++ b/include/linux/ptrace.h
@@ -64,15 +64,12 @@ extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
#define PTRACE_MODE_NOAUDIT 0x04
#define PTRACE_MODE_FSCREDS 0x08
#define PTRACE_MODE_REALCREDS 0x10
-#define PTRACE_MODE_SCHED 0x20
-#define PTRACE_MODE_IBPB 0x40
/* shorthands for READ/ATTACH and FSCREDS/REALCREDS combinations */
#define PTRACE_MODE_READ_FSCREDS (PTRACE_MODE_READ | PTRACE_MODE_FSCREDS)
#define PTRACE_MODE_READ_REALCREDS (PTRACE_MODE_READ | PTRACE_MODE_REALCREDS)
#define PTRACE_MODE_ATTACH_FSCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_FSCREDS)
#define PTRACE_MODE_ATTACH_REALCREDS (PTRACE_MODE_ATTACH | PTRACE_MODE_REALCREDS)
-#define PTRACE_MODE_SPEC_IBPB (PTRACE_MODE_ATTACH_REALCREDS | PTRACE_MODE_IBPB)
/**
* ptrace_may_access - check whether the caller is permitted to access
@@ -90,20 +87,6 @@ extern void exit_ptrace(struct task_struct *tracer, struct list_head *dead);
*/
extern bool ptrace_may_access(struct task_struct *task, unsigned int mode);
-/**
- * ptrace_may_access - check whether the caller is permitted to access
- * a target task.
- * @task: target task
- * @mode: selects type of access and caller credentials
- *
- * Returns true on success, false on denial.
- *
- * Similar to ptrace_may_access(). Only to be called from context switch
- * code. Does not call into audit and the regular LSM hooks due to locking
- * constraints.
- */
-extern bool ptrace_may_access_sched(struct task_struct *task, unsigned int mode);
-
static inline int ptrace_reparented(struct task_struct *child)
{
return !same_thread_group(child->real_parent, child->parent);
diff --git a/include/linux/sched.h b/include/linux/sched.h
index d6183a55e8eb..291a9bd5b97f 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -1454,6 +1454,8 @@ static inline bool is_percpu_thread(void)
#define PFA_SPREAD_SLAB 2 /* Spread some slab caches over cpuset */
#define PFA_SPEC_SSB_DISABLE 3 /* Speculative Store Bypass disabled */
#define PFA_SPEC_SSB_FORCE_DISABLE 4 /* Speculative Store Bypass force disabled*/
+#define PFA_SPEC_IB_DISABLE 5 /* Indirect branch speculation restricted */
+#define PFA_SPEC_IB_FORCE_DISABLE 6 /* Indirect branch speculation permanently restricted */
#define TASK_PFA_TEST(name, func) \
static inline bool task_##func(struct task_struct *p) \
@@ -1485,6 +1487,13 @@ TASK_PFA_CLEAR(SPEC_SSB_DISABLE, spec_ssb_disable)
TASK_PFA_TEST(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
TASK_PFA_SET(SPEC_SSB_FORCE_DISABLE, spec_ssb_force_disable)
+TASK_PFA_TEST(SPEC_IB_DISABLE, spec_ib_disable)
+TASK_PFA_SET(SPEC_IB_DISABLE, spec_ib_disable)
+TASK_PFA_CLEAR(SPEC_IB_DISABLE, spec_ib_disable)
+
+TASK_PFA_TEST(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
+TASK_PFA_SET(SPEC_IB_FORCE_DISABLE, spec_ib_force_disable)
+
static inline void
current_restore_flags(unsigned long orig_flags, unsigned long flags)
{
diff --git a/include/linux/sched/smt.h b/include/linux/sched/smt.h
new file mode 100644
index 000000000000..59d3736c454c
--- /dev/null
+++ b/include/linux/sched/smt.h
@@ -0,0 +1,20 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _LINUX_SCHED_SMT_H
+#define _LINUX_SCHED_SMT_H
+
+#include <linux/static_key.h>
+
+#ifdef CONFIG_SCHED_SMT
+extern struct static_key_false sched_smt_present;
+
+static __always_inline bool sched_smt_active(void)
+{
+ return static_branch_likely(&sched_smt_present);
+}
+#else
+static inline bool sched_smt_active(void) { return false; }
+#endif
+
+void arch_smt_update(void);
+
+#endif
diff --git a/include/uapi/linux/prctl.h b/include/uapi/linux/prctl.h
index c0d7ea0bf5b6..b17201edfa09 100644
--- a/include/uapi/linux/prctl.h
+++ b/include/uapi/linux/prctl.h
@@ -212,6 +212,7 @@ struct prctl_mm_map {
#define PR_SET_SPECULATION_CTRL 53
/* Speculation control variants */
# define PR_SPEC_STORE_BYPASS 0
+# define PR_SPEC_INDIRECT_BRANCH 1
/* Return and control values for PR_SET/GET_SPECULATION_CTRL */
# define PR_SPEC_NOT_AFFECTED 0
# define PR_SPEC_PRCTL (1UL << 0)