From: Will Deacon <will@kernel.org>
To: linux-kernel@vger.kernel.org
Cc: linux-arm-kernel@lists.infradead.org,
Will Deacon <will@kernel.org>,
Sami Tolvanen <samitolvanen@google.com>,
Kees Cook <keescook@chromium.org>,
Catalin Marinas <catalin.marinas@arm.com>,
Mark Rutland <mark.rutland@am.com>, Jann Horn <jannh@google.com>,
Ard Biesheuvel <ardb@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
kernel-team@android.com
Subject: [PATCH 4/6] scs: Move scs_overflow_check() out of architecture code
Date: Fri, 15 May 2020 18:27:54 +0100 [thread overview]
Message-ID: <20200515172756.27185-5-will@kernel.org> (raw)
In-Reply-To: <20200515172756.27185-1-will@kernel.org>
There is nothing architecture-specific about scs_overflow_check() as
it's just a trivial wrapper around scs_corrupted().
For parity with task_stack_end_corrupted(), rename scs_corrupted() to
task_scs_end_corrupted() and call it from schedule_debug() when
CONFIG_SCHED_STACK_END_CHECK_is enabled. Finally, remove the unused
scs_overflow_check() function entirely.
This has absolutely no impact on architectures that do not support SCS
(currently arm64 only).
Signed-off-by: Will Deacon <will@kernel.org>
---
arch/arm64/include/asm/scs.h | 18 ------------------
arch/arm64/kernel/process.c | 2 --
arch/arm64/kernel/scs.c | 2 +-
include/linux/scs.h | 4 ++--
kernel/sched/core.c | 3 +++
kernel/scs.c | 3 ++-
6 files changed, 8 insertions(+), 24 deletions(-)
diff --git a/arch/arm64/include/asm/scs.h b/arch/arm64/include/asm/scs.h
index d46efdd2060a..eaa2cd92e4c1 100644
--- a/arch/arm64/include/asm/scs.h
+++ b/arch/arm64/include/asm/scs.h
@@ -24,24 +24,6 @@
.endm
#endif /* CONFIG_SHADOW_CALL_STACK */
-#else /* __ASSEMBLY__ */
-
-#include <linux/scs.h>
-
-#ifdef CONFIG_SHADOW_CALL_STACK
-
-static inline void scs_overflow_check(struct task_struct *tsk)
-{
- if (unlikely(scs_corrupted(tsk)))
- panic("corrupted shadow stack detected inside scheduler\n");
-}
-
-#else /* CONFIG_SHADOW_CALL_STACK */
-
-static inline void scs_overflow_check(struct task_struct *tsk) {}
-
-#endif /* CONFIG_SHADOW_CALL_STACK */
-
#endif /* __ASSEMBLY __ */
#endif /* _ASM_SCS_H */
diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c
index a35d3318492c..56be4cbf771f 100644
--- a/arch/arm64/kernel/process.c
+++ b/arch/arm64/kernel/process.c
@@ -52,7 +52,6 @@
#include <asm/mmu_context.h>
#include <asm/processor.h>
#include <asm/pointer_auth.h>
-#include <asm/scs.h>
#include <asm/stacktrace.h>
#if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK)
@@ -516,7 +515,6 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
entry_task_switch(next);
uao_thread_switch(next);
ssbs_thread_switch(next);
- scs_overflow_check(next);
/*
* Complete any pending TLB or cache maintenance on this CPU in case
diff --git a/arch/arm64/kernel/scs.c b/arch/arm64/kernel/scs.c
index adc97f826fab..955875dff9e1 100644
--- a/arch/arm64/kernel/scs.c
+++ b/arch/arm64/kernel/scs.c
@@ -6,7 +6,7 @@
*/
#include <linux/percpu.h>
-#include <asm/scs.h>
+#include <linux/scs.h>
/* Allocate a static per-CPU shadow stack */
#define DEFINE_SCS(name) \
diff --git a/include/linux/scs.h b/include/linux/scs.h
index 0eb2485ef832..2fd3df50e93e 100644
--- a/include/linux/scs.h
+++ b/include/linux/scs.h
@@ -47,7 +47,7 @@ static inline unsigned long *__scs_magic(void *s)
return (unsigned long *)(s + SCS_SIZE) - 1;
}
-static inline bool scs_corrupted(struct task_struct *tsk)
+static inline bool task_scs_end_corrupted(struct task_struct *tsk)
{
unsigned long *magic = __scs_magic(task_scs(tsk));
unsigned long sz = task_scs_sp(tsk) - task_scs(tsk);
@@ -60,8 +60,8 @@ static inline bool scs_corrupted(struct task_struct *tsk)
static inline void scs_init(void) {}
static inline void scs_task_reset(struct task_struct *tsk) {}
static inline int scs_prepare(struct task_struct *tsk, int node) { return 0; }
-static inline bool scs_corrupted(struct task_struct *tsk) { return false; }
static inline void scs_release(struct task_struct *tsk) {}
+static inline bool task_scs_end_corrupted(struct task_struct *tsk) { return false; }
#endif /* CONFIG_SHADOW_CALL_STACK */
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 934e03cfaec7..a1d815a11b90 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -3878,6 +3878,9 @@ static inline void schedule_debug(struct task_struct *prev, bool preempt)
#ifdef CONFIG_SCHED_STACK_END_CHECK
if (task_stack_end_corrupted(prev))
panic("corrupted stack end detected inside scheduler\n");
+
+ if (task_scs_end_corrupted(prev))
+ panic("corrupted shadow stack detected inside scheduler\n");
#endif
#ifdef CONFIG_DEBUG_ATOMIC_SLEEP
diff --git a/kernel/scs.c b/kernel/scs.c
index aea841cd7586..faf0ecd7b893 100644
--- a/kernel/scs.c
+++ b/kernel/scs.c
@@ -98,7 +98,8 @@ void scs_release(struct task_struct *tsk)
if (!s)
return;
- WARN(scs_corrupted(tsk), "corrupted shadow stack detected when freeing task\n");
+ WARN(task_scs_end_corrupted(tsk),
+ "corrupted shadow stack detected when freeing task\n");
scs_check_usage(tsk);
scs_free(s);
}
--
2.26.2.761.g0e0b3e54be-goog
next prev parent reply other threads:[~2020-05-15 17:28 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-15 17:27 [PATCH 0/6] Clean up Shadow Call Stack patches for 5.8 Will Deacon
2020-05-15 17:27 ` [PATCH 1/6] arm64: scs: Store absolute SCS stack pointer value in thread_info Will Deacon
2020-05-18 11:37 ` Mark Rutland
2020-05-18 13:37 ` Will Deacon
2020-05-15 17:27 ` [PATCH 2/6] scs: Move accounting into alloc/free functions Will Deacon
2020-05-18 11:38 ` Mark Rutland
2020-05-18 13:39 ` Will Deacon
2020-05-15 17:27 ` [PATCH 3/6] arm64: scs: Use 'scs_sp' register alias for x18 Will Deacon
2020-05-18 11:55 ` Mark Rutland
2020-05-18 13:03 ` Will Deacon
2020-05-18 13:13 ` Mark Rutland
2020-05-15 17:27 ` Will Deacon [this message]
2020-05-18 12:12 ` [PATCH 4/6] scs: Move scs_overflow_check() out of architecture code Mark Rutland
2020-05-18 13:23 ` Will Deacon
2020-05-18 13:32 ` Mark Rutland
2020-05-18 15:31 ` Kees Cook
2020-05-18 16:44 ` Will Deacon
2020-05-15 17:27 ` [PATCH 5/6] scs: Remove references to asm/scs.h from core code Will Deacon
2020-05-18 12:15 ` Mark Rutland
2020-05-15 17:27 ` [PATCH 6/6] scs: Move DEFINE_SCS macro into " Will Deacon
2020-05-18 12:14 ` Mark Rutland
2020-05-18 13:26 ` Will Deacon
2020-05-18 13:37 ` Mark Rutland
2020-05-15 20:42 ` [PATCH 0/6] Clean up Shadow Call Stack patches for 5.8 Sami Tolvanen
2020-05-18 13:52 ` Will Deacon
2020-05-18 15:43 ` Sami Tolvanen
2020-05-18 16:49 ` Will Deacon
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