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Message-ID: <1451941361-32347-1-git-send-email-cmetcalf@ezchip.com>
Date: Mon, 4 Jan 2016 16:02:41 -0500
From: Chris Metcalf <cmetcalf@...hip.com>
To: Gilad Ben Yossef <giladb@...hip.com>,
Steven Rostedt <rostedt@...dmis.org>,
Ingo Molnar <mingo@...nel.org>,
Peter Zijlstra <peterz@...radead.org>,
Andrew Morton <akpm@...ux-foundation.org>,
"Rik van Riel" <riel@...hat.com>, Tejun Heo <tj@...nel.org>,
Frederic Weisbecker <fweisbec@...il.com>,
Thomas Gleixner <tglx@...utronix.de>,
"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>,
Christoph Lameter <cl@...ux.com>,
Viresh Kumar <viresh.kumar@...aro.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Andy Lutomirski <luto@...capital.net>,
"H. Peter Anvin" <hpa@...or.com>, <x86@...nel.org>,
<linux-kernel@...r.kernel.org>
CC: Chris Metcalf <cmetcalf@...hip.com>
Subject: [PATCH v9bis 07/13] arch/x86: enable task isolation functionality
In prepare_exit_to_usermode(), call task_isolation_ready()
when we are checking the thread-info flags, and after we've handled
the other work, call task_isolation_enter() unconditionally.
In syscall_trace_enter_phase1(), we add the necessary support for
strict-mode detection of syscalls.
We add strict reporting for the kernel exception types that do
not result in signals, namely non-signalling page faults and
non-signalling MPX fixups.
Signed-off-by: Chris Metcalf <cmetcalf@...hip.com>
---
Oops! In v9 I sent a version of this patch that didn't have the
semantic merge to 4.4 from Andy's commit 39b48e575e92 ("x86/entry:
Split and inline prepare_exit_to_usermode()"). This "v9bis" version
adds the necessary extra check to get into exit_to_usermode_loop()
in the first place when running in task-isolation mode.
arch/x86/entry/common.c | 18 ++++++++++++++++--
arch/x86/kernel/traps.c | 2 ++
arch/x86/mm/fault.c | 2 ++
3 files changed, 20 insertions(+), 2 deletions(-)
diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index a89fdbc1f0be..477d8cafaaf2 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -21,6 +21,7 @@
#include <linux/context_tracking.h>
#include <linux/user-return-notifier.h>
#include <linux/uprobes.h>
+#include <linux/isolation.h>
#include <asm/desc.h>
#include <asm/traps.h>
@@ -91,6 +92,10 @@ unsigned long syscall_trace_enter_phase1(struct pt_regs *regs, u32 arch)
*/
if (work & _TIF_NOHZ) {
enter_from_user_mode();
+ if (task_isolation_check_syscall(regs->orig_ax)) {
+ regs->orig_ax = -1;
+ return 0;
+ }
work &= ~_TIF_NOHZ;
}
#endif
@@ -254,17 +259,26 @@ static void exit_to_usermode_loop(struct pt_regs *regs, u32 cached_flags)
if (cached_flags & _TIF_USER_RETURN_NOTIFY)
fire_user_return_notifiers();
+ task_isolation_enter();
+
/* Disable IRQs and retry */
local_irq_disable();
cached_flags = READ_ONCE(pt_regs_to_thread_info(regs)->flags);
- if (!(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
+ if (!(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS) &&
+ task_isolation_ready())
break;
}
}
+#ifdef CONFIG_TASK_ISOLATION
+# define EXIT_TO_USERMODE_FLAGS (EXIT_TO_USERMODE_LOOP_FLAGS | _TIF_NOHZ)
+#else
+# define EXIT_TO_USERMODE_FLAGS EXIT_TO_USERMODE_LOOP_FLAGS
+#endif
+
/* Called with IRQs disabled. */
__visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
{
@@ -278,7 +292,7 @@ __visible inline void prepare_exit_to_usermode(struct pt_regs *regs)
cached_flags =
READ_ONCE(pt_regs_to_thread_info(regs)->flags);
- if (unlikely(cached_flags & EXIT_TO_USERMODE_LOOP_FLAGS))
+ if (unlikely(cached_flags & EXIT_TO_USERMODE_FLAGS))
exit_to_usermode_loop(regs, cached_flags);
user_enter();
diff --git a/arch/x86/kernel/traps.c b/arch/x86/kernel/traps.c
index ade185a46b1d..82bf53ec1e98 100644
--- a/arch/x86/kernel/traps.c
+++ b/arch/x86/kernel/traps.c
@@ -36,6 +36,7 @@
#include <linux/mm.h>
#include <linux/smp.h>
#include <linux/io.h>
+#include <linux/isolation.h>
#ifdef CONFIG_EISA
#include <linux/ioport.h>
@@ -398,6 +399,7 @@ dotraplinkage void do_bounds(struct pt_regs *regs, long error_code)
case 2: /* Bound directory has invalid entry. */
if (mpx_handle_bd_fault())
goto exit_trap;
+ task_isolation_check_exception("bounds check");
break; /* Success, it was handled */
case 1: /* Bound violation. */
info = mpx_generate_siginfo(regs);
diff --git a/arch/x86/mm/fault.c b/arch/x86/mm/fault.c
index eef44d9a3f77..7b23487a3bd7 100644
--- a/arch/x86/mm/fault.c
+++ b/arch/x86/mm/fault.c
@@ -14,6 +14,7 @@
#include <linux/prefetch.h> /* prefetchw */
#include <linux/context_tracking.h> /* exception_enter(), ... */
#include <linux/uaccess.h> /* faulthandler_disabled() */
+#include <linux/isolation.h> /* task_isolation_check_exception */
#include <asm/traps.h> /* dotraplinkage, ... */
#include <asm/pgalloc.h> /* pgd_*(), ... */
@@ -1148,6 +1149,7 @@ __do_page_fault(struct pt_regs *regs, unsigned long error_code,
local_irq_enable();
error_code |= PF_USER;
flags |= FAULT_FLAG_USER;
+ task_isolation_check_exception("page fault at %#lx", address);
} else {
if (regs->flags & X86_EFLAGS_IF)
local_irq_enable();
--
2.1.2
--
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