Thread (6 messages) read the whole thread 6 messages, 2 authors, 2021-05-15
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1 review trailer; landed in mainline as 7058f4b13edd on 2021-05-12.

[PATCH v2 3/4] powerpc/pseries: use notrace hcall variant for H_CEDE idle

From: Nicholas Piggin <npiggin@gmail.com>
Date: 2021-05-08 10:16:59
Subsystem: linux for powerpc (32-bit and 64-bit), the rest · Maintainers: Madhavan Srinivasan, Linus Torvalds

Rather than special-case H_CEDE in the hcall trace wrappers, make the
idle H_CEDE call use plpar_hcall_norets_notrace().

Reviewed-by: Naveen N. Rao <redacted>
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
---
 arch/powerpc/include/asm/plpar_wrappers.h |  6 +++++-
 arch/powerpc/platforms/pseries/lpar.c     | 10 ----------
 2 files changed, 5 insertions(+), 11 deletions(-)
diff --git a/arch/powerpc/include/asm/plpar_wrappers.h b/arch/powerpc/include/asm/plpar_wrappers.h
index ece84a430701..83e0f701ebc6 100644
--- a/arch/powerpc/include/asm/plpar_wrappers.h
+++ b/arch/powerpc/include/asm/plpar_wrappers.h
@@ -28,7 +28,11 @@ static inline void set_cede_latency_hint(u8 latency_hint)
 
 static inline long cede_processor(void)
 {
-	return plpar_hcall_norets(H_CEDE);
+	/*
+	 * We cannot call tracepoints inside RCU idle regions which
+	 * means we must not trace H_CEDE.
+	 */
+	return plpar_hcall_norets_notrace(H_CEDE);
 }
 
 static inline long extended_cede_processor(unsigned long latency_hint)
diff --git a/arch/powerpc/platforms/pseries/lpar.c b/arch/powerpc/platforms/pseries/lpar.c
index d79d7410c320..ad1cec80019b 100644
--- a/arch/powerpc/platforms/pseries/lpar.c
+++ b/arch/powerpc/platforms/pseries/lpar.c
@@ -1840,13 +1840,6 @@ notrace void __trace_hcall_entry(unsigned long opcode, unsigned long *args)
 	unsigned long flags;
 	unsigned int *depth;
 
-	/*
-	 * We cannot call tracepoints inside RCU idle regions which
-	 * means we must not trace H_CEDE.
-	 */
-	if (opcode == H_CEDE)
-		return;
-
 	local_irq_save(flags);
 
 	depth = this_cpu_ptr(&hcall_trace_depth);
@@ -1868,9 +1861,6 @@ notrace void __trace_hcall_exit(long opcode, long retval, unsigned long *retbuf)
 	unsigned long flags;
 	unsigned int *depth;
 
-	if (opcode == H_CEDE)
-		return;
-
 	local_irq_save(flags);
 
 	depth = this_cpu_ptr(&hcall_trace_depth);
-- 
2.23.0
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