From: Thomas Gleixner <tglx@linutronix.de>
To: LKML <linux-kernel@vger.kernel.org>
Cc: x86@kernel.org, Peter Zijlstra <peterz@infradead.org>,
Andy Lutomirski <luto@kernel.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Will Deacon <will@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Marc Zyngier <maz@kernel.org>,
Paolo Bonzini <pbonzini@redhat.com>,
kvm@vger.kernel.org, linux-arch@vger.kernel.org
Subject: [RFC patch 01/15] entry: Provide generic syscall entry functionality
Date: Thu, 19 Sep 2019 17:03:15 +0200 [thread overview]
Message-ID: <20190919150808.521907403@linutronix.de> (raw)
In-Reply-To: 20190919150314.054351477@linutronix.de
On syscall entry certain work needs to be done conditionally like tracing,
seccomp etc. This code is duplicated in all architectures.
Provide a generic version.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/Kconfig | 3 +
include/linux/entry-common.h | 122 +++++++++++++++++++++++++++++++++++++++++++
kernel/Makefile | 1
kernel/entry/Makefile | 3 +
kernel/entry/common.c | 33 +++++++++++
5 files changed, 162 insertions(+)
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -27,6 +27,9 @@ config HAVE_IMA_KEXEC
config HOTPLUG_SMT
bool
+config GENERIC_ENTRY
+ bool
+
config OPROFILE
tristate "OProfile system profiling"
depends on PROFILING
--- /dev/null
+++ b/include/linux/entry-common.h
@@ -0,0 +1,122 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __LINUX_ENTRYCOMMON_H
+#define __LINUX_ENTRYCOMMON_H
+
+#include <linux/tracehook.h>
+#include <linux/syscalls.h>
+#include <linux/seccomp.h>
+#include <linux/sched.h>
+#include <linux/audit.h>
+
+#include <asm/entry-common.h>
+
+/*
+ * Define dummy _TIF work flags if not defined by the architecture or for
+ * disabled functionality.
+ */
+#ifndef _TIF_SYSCALL_TRACE
+# define _TIF_SYSCALL_TRACE (0)
+#endif
+
+#ifndef _TIF_SYSCALL_EMU
+# define _TIF_SYSCALL_EMU (0)
+#endif
+
+#ifndef _TIF_SYSCALL_TRACEPOINT
+# define _TIF_SYSCALL_TRACEPOINT (0)
+#endif
+
+#ifndef _TIF_SECCOMP
+# define _TIF_SECCOMP (0)
+#endif
+
+#ifndef _TIF_AUDIT
+# define _TIF_AUDIT (0)
+#endif
+
+/*
+ * TIF flags handled in syscall_enter_from_usermode()
+ */
+#ifndef ARCH_SYSCALL_ENTER_WORK
+# define ARCH_SYSCALL_ENTER_WORK (0)
+#endif
+
+#define SYSCALL_ENTER_WORK \
+ (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_AUDIT | TIF_SECCOMP | \
+ _TIF_SYSCALL_TRACEPOINT | _TIF_SYSCALL_EMU | \
+ ARCH_SYSCALL_ENTER_WORK)
+
+/**
+ * arch_syscall_enter_tracehook - Wrapper around tracehook_report_syscall_entry()
+ *
+ * Defaults to tracehook_report_syscall_entry(). Can be replaced by
+ * architecture specific code.
+ *
+ * Invoked from syscall_enter_from_usermode()
+ */
+static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs);
+
+#ifndef arch_syscall_enter_tracehook
+static inline __must_check int arch_syscall_enter_tracehook(struct pt_regs *regs)
+{
+ return tracehook_report_syscall_entry(regs);
+}
+#endif
+
+/**
+ * arch_syscall_enter_seccomp - Architecture specific seccomp invocation
+ * @regs: Pointer to currents pt_regs
+ *
+ * Invoked from syscall_enter_from_usermode(). Can be replaced by
+ * architecture specific code.
+ */
+static inline long arch_syscall_enter_seccomp(struct pt_regs *regs);
+
+#ifndef arch_syscall_enter_seccomp
+static inline long arch_syscall_enter_seccomp(struct pt_regs *regs)
+{
+ return secure_computing(NULL);
+}
+#endif
+
+/**
+ * arch_syscall_enter_audit - Architecture specific audit invocation
+ * @regs: Pointer to currents pt_regs
+ *
+ * Invoked from syscall_enter_from_usermode(). Must be replaced by
+ * architecture specific code if the architecture supports audit.
+ */
+static inline void arch_syscall_enter_audit(struct pt_regs *regs);
+
+#ifndef arch_syscall_enter_audit
+static inline void arch_syscall_enter_audit(struct pt_regs *regs) { }
+#endif
+
+/* Common syscall enter function */
+long core_syscall_enter_from_usermode(struct pt_regs *regs, long syscall);
+
+/**
+ * syscall_enter_from_usermode - Check and handle work before invoking
+ * a syscall
+ * @regs: Pointer to currents pt_regs
+ * @syscall: The syscall number
+ *
+ * Invoked from architecture specific syscall entry code with interrupts
+ * enabled.
+ *
+ * Returns: The original or a modified syscall number
+ */
+static inline long syscall_enter_from_usermode(struct pt_regs *regs,
+ long syscall)
+{
+ unsigned long ti_work = READ_ONCE(current_thread_info()->flags);
+
+ if (IS_ENABLED(CONFIG_DEBUG_ENTRY))
+ BUG_ON(regs != task_pt_regs(current));
+
+ if (ti_work & SYSCALL_ENTER_WORK)
+ syscall = core_syscall_enter_from_usermode(regs, syscall);
+ return syscall;
+}
+
+#endif
--- a/kernel/Makefile
+++ b/kernel/Makefile
@@ -43,6 +43,7 @@ obj-y += irq/
obj-y += rcu/
obj-y += livepatch/
obj-y += dma/
+obj-y += entry/
obj-$(CONFIG_CHECKPOINT_RESTORE) += kcmp.o
obj-$(CONFIG_FREEZER) += freezer.o
--- /dev/null
+++ b/kernel/entry/Makefile
@@ -0,0 +1,3 @@
+# SPDX-License-Identifier: GPL-2.0
+
+obj-$(CONFIG_GENERIC_ENTRY) += common.o
--- /dev/null
+++ b/kernel/entry/common.c
@@ -0,0 +1,33 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <linux/context_tracking.h>
+#include <linux/entry-common.h>
+
+#define CREATE_TRACE_POINTS
+#include <trace/events/syscalls.h>
+
+long core_syscall_enter_from_usermode(struct pt_regs *regs, long syscall)
+{
+ unsigned long ti_work = READ_ONCE(current_thread_info()->flags);
+ unsigned long ret = 0;
+
+ if (ti_work & (_TIF_SYSCALL_TRACE | _TIF_SYSCALL_EMU)) {
+ ret = arch_syscall_enter_tracehook(regs);
+ if (ret || (ti_work & _TIF_SYSCALL_EMU))
+ return -1L;
+ }
+
+ /* Do seccomp after ptrace, to catch any tracer changes. */
+ if (ti_work & _TIF_SECCOMP) {
+ ret = arch_syscall_enter_seccomp(regs);
+ if (ret == -1L)
+ return ret;
+ }
+
+ if (unlikely(test_thread_flag(TIF_SYSCALL_TRACEPOINT)))
+ trace_sys_enter(regs, syscall);
+
+ arch_syscall_enter_audit(regs);
+
+ return ret ? : syscall;
+}
next prev parent reply other threads:[~2019-09-19 15:11 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-09-19 15:03 [RFC patch 00/15] entry: Provide generic implementation for host and guest entry/exit work Thomas Gleixner
2019-09-19 15:03 ` Thomas Gleixner [this message]
2019-09-20 23:38 ` [RFC patch 01/15] entry: Provide generic syscall entry functionality Andy Lutomirski
2019-10-20 11:49 ` Thomas Gleixner
2019-09-23 9:05 ` Mike Rapoport
2019-09-19 15:03 ` [RFC patch 02/15] x86/entry: Remove _TIF_NOHZ from _TIF_WORK_SYSCALL_ENTRY Thomas Gleixner
2019-09-20 23:39 ` Andy Lutomirski
2019-09-23 20:43 ` Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 03/15] x86/entry: Use generic syscall entry function Thomas Gleixner
2019-09-20 23:41 ` Andy Lutomirski
2019-09-23 8:31 ` Peter Zijlstra
2019-09-23 8:40 ` Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 04/15] arm64/entry: " Thomas Gleixner
2019-09-20 12:21 ` Catalin Marinas
2019-09-19 15:03 ` [RFC patch 05/15] entry: Provide generic syscall exit function Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 06/15] x86/entry: Use generic syscall exit functionality Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 07/15] arm64/syscall: Remove obscure flag check Thomas Gleixner
2019-09-20 14:29 ` Catalin Marinas
2019-09-19 15:03 ` [RFC patch 08/15] arm64/syscall: Use generic syscall exit functionality Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 09/15] entry: Provide generic exit to usermode functionality Thomas Gleixner
2019-09-23 8:30 ` Peter Zijlstra
2019-09-19 15:03 ` [RFC patch 10/15] x86/entry: Move irq tracing to C code Thomas Gleixner
2019-09-23 8:47 ` Peter Zijlstra
2019-09-23 10:27 ` Thomas Gleixner
2019-09-23 11:49 ` Peter Zijlstra
2019-09-23 11:55 ` Peter Zijlstra
2019-09-23 12:10 ` Peter Zijlstra
2019-09-23 17:24 ` Andy Lutomirski
2019-09-26 2:59 ` Josh Poimboeuf
2019-09-19 15:03 ` [RFC patch 11/15] x86/entry: Use generic exit to usermode Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 12/15] arm64/entry: " Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 13/15] arm64/entry: Move FPU restore out of exit_to_usermode() loop Thomas Gleixner
2019-09-19 15:03 ` [RFC patch 14/15] workpending: Provide infrastructure for work before entering a guest Thomas Gleixner
2019-09-19 15:40 ` Paolo Bonzini
2019-09-20 11:48 ` Thomas Gleixner
2019-09-23 18:17 ` Andy Lutomirski
2019-09-26 11:35 ` Miroslav Benes
2019-09-19 15:03 ` [RFC patch 15/15] x86/kvm: Use GENERIC_EXIT_WORKPENDING Thomas Gleixner
2019-09-19 15:40 ` Paolo Bonzini
2019-09-20 15:12 ` [RFC patch 00/15] entry: Provide generic implementation for host and guest entry/exit work Mark Rutland
2019-09-23 20:50 ` Thomas Gleixner
2019-09-23 18:18 ` Andy Lutomirski
2019-09-24 6:50 ` Christian Borntraeger
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