linux-kernel - [PATCH 3/9] riscv: Fix check_unaligned_access_all

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Message-ID: <20250207161939.46139-14-ajones@ventanamicro.com>
Date: Fri,  7 Feb 2025 17:19:43 +0100
From: Andrew Jones <ajones@...tanamicro.com>
To: linux-riscv@...ts.infradead.org,
	linux-kernel@...r.kernel.org
Cc: paul.walmsley@...ive.com,
	palmer@...belt.com,
	charlie@...osinc.com,
	jesse@...osinc.com,
	Anup Patel <apatel@...tanamicro.com>
Subject: [PATCH 3/9] riscv: Fix check_unaligned_access_all_cpus

check_vector_unaligned_access_emulated_all_cpus(), like its name
suggests, will return true when all cpus emulate unaligned vector
accesses. If the function returned false it may have been because
vector isn't supported at all (!has_vector()) or because at least
one cpu doesn't emulate unaligned vector accesses. Since false may
be returned for two cases, checking for it isn't sufficient when
attempting to determine if we should proceed with the vector speed
check. Move the !has_vector() functionality to
check_unaligned_access_all_cpus() in order for
check_vector_unaligned_access_emulated_all_cpus() to return false
for a single case.

Fixes: e7c9d66e313b ("RISC-V: Report vector unaligned access speed hwprobe")
Signed-off-by: Andrew Jones <ajones@...tanamicro.com>
---
 arch/riscv/kernel/traps_misaligned.c       |  6 ------
 arch/riscv/kernel/unaligned_access_speed.c | 11 +++++++----
 2 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/arch/riscv/kernel/traps_misaligned.c b/arch/riscv/kernel/traps_misaligned.c
index aacbd9d7196e..4354c87c0376 100644
--- a/arch/riscv/kernel/traps_misaligned.c
+++ b/arch/riscv/kernel/traps_misaligned.c
@@ -609,12 +609,6 @@ bool __init check_vector_unaligned_access_emulated_all_cpus(void)
 {
 	int cpu;
 
-	if (!has_vector()) {
-		for_each_online_cpu(cpu)
-			per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
-		return false;
-	}
-
 	schedule_on_each_cpu(check_vector_unaligned_access_emulated);
 
 	for_each_online_cpu(cpu)
diff --git a/arch/riscv/kernel/unaligned_access_speed.c b/arch/riscv/kernel/unaligned_access_speed.c
index 161964cf2abc..02b485dc4bc4 100644
--- a/arch/riscv/kernel/unaligned_access_speed.c
+++ b/arch/riscv/kernel/unaligned_access_speed.c
@@ -403,13 +403,16 @@ static int __init vec_check_unaligned_access_speed_all_cpus(void *unused __alway
 
 static int __init check_unaligned_access_all_cpus(void)
 {
-	bool all_cpus_emulated, all_cpus_vec_unsupported;
+	bool all_cpus_emulated;
+	int cpu;
 
 	all_cpus_emulated = check_unaligned_access_emulated_all_cpus();
-	all_cpus_vec_unsupported = check_vector_unaligned_access_emulated_all_cpus();
 
-	if (!all_cpus_vec_unsupported &&
-	    IS_ENABLED(CONFIG_RISCV_PROBE_VECTOR_UNALIGNED_ACCESS)) {
+	if (!has_vector()) {
+		for_each_online_cpu(cpu)
+			per_cpu(vector_misaligned_access, cpu) = RISCV_HWPROBE_MISALIGNED_VECTOR_UNSUPPORTED;
+	} else if (!check_vector_unaligned_access_emulated_all_cpus() &&
+		   IS_ENABLED(CONFIG_RISCV_PROBE_VECTOR_UNALIGNED_ACCESS)) {
 		kthread_run(vec_check_unaligned_access_speed_all_cpus,
 			    NULL, "vec_check_unaligned_access_speed_all_cpus");
 	}
-- 
2.48.1