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authorJosh Poimboeuf <jpoimboe@kernel.org>2023-02-25 16:01:36 -0800
committerThomas Gleixner <tglx@linutronix.de>2023-03-21 11:53:16 +0100
commitf87d28673b71b35b248231a2086f9404afbb7f28 (patch)
treebb9ce4fd1fd483cf1547b115f11356219c9f66cb
parente8d018dd0257f744ca50a729e3d042cf2ec9da65 (diff)
entry: Fix noinstr warning in __enter_from_user_mode()
__enter_from_user_mode() is triggering noinstr warnings with CONFIG_DEBUG_PREEMPT due to its call of preempt_count_add() via ct_state(). The preemption disable isn't needed as interrupts are already disabled. And the context_tracking_enabled() check in ct_state() also isn't needed as that's already being done by the CT_WARN_ON(). Just use __ct_state() instead. Fixes the following warnings: vmlinux.o: warning: objtool: enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0xf9: call to preempt_count_add() leaves .noinstr.text section vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0xc7: call to preempt_count_add() leaves .noinstr.text section vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section Fixes: 171476775d32 ("context_tracking: Convert state to atomic_t") Signed-off-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Link: https://lore.kernel.org/r/d8955fa6d68dc955dda19baf13ae014ae27926f5.1677369694.git.jpoimboe@kernel.org
-rw-r--r--include/linux/context_tracking.h1
-rw-r--r--include/linux/context_tracking_state.h2
-rw-r--r--kernel/entry/common.c2
3 files changed, 4 insertions, 1 deletions
diff --git a/include/linux/context_tracking.h b/include/linux/context_tracking.h
index d4afa8508a80..3a7909ed5498 100644
--- a/include/linux/context_tracking.h
+++ b/include/linux/context_tracking.h
@@ -96,6 +96,7 @@ static inline void user_exit_irqoff(void) { }
static inline int exception_enter(void) { return 0; }
static inline void exception_exit(enum ctx_state prev_ctx) { }
static inline int ct_state(void) { return -1; }
+static inline int __ct_state(void) { return -1; }
static __always_inline bool context_tracking_guest_enter(void) { return false; }
static inline void context_tracking_guest_exit(void) { }
#define CT_WARN_ON(cond) do { } while (0)
diff --git a/include/linux/context_tracking_state.h b/include/linux/context_tracking_state.h
index 4a4d56f77180..fdd537ea513f 100644
--- a/include/linux/context_tracking_state.h
+++ b/include/linux/context_tracking_state.h
@@ -46,7 +46,9 @@ struct context_tracking {
#ifdef CONFIG_CONTEXT_TRACKING
DECLARE_PER_CPU(struct context_tracking, context_tracking);
+#endif
+#ifdef CONFIG_CONTEXT_TRACKING_USER
static __always_inline int __ct_state(void)
{
return arch_atomic_read(this_cpu_ptr(&context_tracking.state)) & CT_STATE_MASK;
diff --git a/kernel/entry/common.c b/kernel/entry/common.c
index 846add8394c4..1314894d2efa 100644
--- a/kernel/entry/common.c
+++ b/kernel/entry/common.c
@@ -21,7 +21,7 @@ static __always_inline void __enter_from_user_mode(struct pt_regs *regs)
arch_enter_from_user_mode(regs);
lockdep_hardirqs_off(CALLER_ADDR0);
- CT_WARN_ON(ct_state() != CONTEXT_USER);
+ CT_WARN_ON(__ct_state() != CONTEXT_USER);
user_exit_irqoff();
instrumentation_begin();