From nobody Fri Dec 19 21:50:07 2025 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2740720CCC7; Wed, 4 Dec 2024 15:22:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733325750; cv=none; b=Nt8G+lXtwDcUR956RbGO1Eg0R4l0wqEc2UW8GkRF0KCIP+TwGmFAIvT1Qg0TBsbkaxnaVPk+rOATA7qHM+2aK9O9UDX12wunAL1w97YuIgNgDODRrJ/whhBEg04ZxevppZdtUJK59eI6VZZ3Y/gtCV9ny0PmonVgT+Ixhy+5XZg= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733325750; c=relaxed/simple; bh=A8QKBxilDmxPa7rkbda6zcbE9W7eNHPT2bdz3YleFLw=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=CkVAr+TKMBgMZRpzx8Ctg7YhleInPraAJ2sO1/P8bWnriIyMci6/uMALUoJ3hAmsDHS+CqxzHbKJiNLiH2ApOp9tQbhEsJoWsTIHPEQYacjjWllZl0ikzuE7eZA7gpEKbBh7qs3bq45cHVEI8WrF2QL4Q+sjVnr6tEwAhb5HPrk= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=QNj5hXem; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="QNj5hXem" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F4F9C4CED2; Wed, 4 Dec 2024 15:22:28 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1733325750; bh=A8QKBxilDmxPa7rkbda6zcbE9W7eNHPT2bdz3YleFLw=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=QNj5hXemT+0ygrwbrgagcUNKOZv7DgPtgEFPYb2ASRGxh801B9/Gxxd88fI+jbDvg JXiP3zd1ThdTKB0crkPoFya/IKM/m0aBjYCv7N4DqXshIk17EBw3LMNPR4GsRxCWRd ESiLrVPAn2oXczQspoZnSOFa0AY2xWyM1v7JTtEhAjUacMhtsC6mWdAaQXVg9U35Yf a6VzE0jAv80ZkgP8JErM2iPhqJgas5NSOVaAUpJiQEyCY2rtg8TybLbu+iISNbPm5O 6o5ZWZ4UKPLGy180R+7AvMjUUAdpu3cn7mRDnYXxtfxpFwfzudscBcgI34+mNxa+S4 ZDhyxvNCXkzWQ== From: Mark Brown Date: Wed, 04 Dec 2024 15:20:51 +0000 Subject: [PATCH v2 3/6] arm64/ptrace: Zero FPMR on streaming mode entry/exit Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: quoted-printable Message-Id: <20241204-arm64-sme-reenable-v2-3-bae87728251d@kernel.org> References: <20241204-arm64-sme-reenable-v2-0-bae87728251d@kernel.org> In-Reply-To: <20241204-arm64-sme-reenable-v2-0-bae87728251d@kernel.org> To: Catalin Marinas , Will Deacon Cc: Mark Rutland , Dave Martin , linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org, Mark Brown , stable@vger.kernel.org X-Mailer: b4 0.15-dev-9b746 X-Developer-Signature: v=1; a=openpgp-sha256; l=2536; i=broonie@kernel.org; h=from:subject:message-id; bh=A8QKBxilDmxPa7rkbda6zcbE9W7eNHPT2bdz3YleFLw=; b=owEBbQGS/pANAwAKASTWi3JdVIfQAcsmYgBnUHOqPfutP7bJSiz1k/7SJhcoIeMOBJXZS1GuIf38 grLqUyCJATMEAAEKAB0WIQSt5miqZ1cYtZ/in+ok1otyXVSH0AUCZ1BzqgAKCRAk1otyXVSH0K5oB/ 9g8XrD26deExaGvYbmtEB2rk9DdkgD0udiS0bq/MVMNeUZAP6wa0bz7mKAWRk9vEZ7UQ2XhBC+5JOU Y74TcXmBDAxrhN+kxiv/EwXqzTyvLBQ7dmz4sr6sfRUW2jIkzyawXKXPWByssW6Cqu0+Z+lCylgevf V9tCwn/IbrKcvHinej/SrO4Z1BvUjs4B+ea0iAmbCpTipdlARj8HTOESCozy38MrlHXpktcPv5Nzuh 5Z6YyRTBGFWARBoyqqtAMrB4UKfclQrK1g4flJL01GNB5xki7imPM+Xdf+sclqpAKtOMX1ErxyGIQu ETIrsydK0mSkxcXkHB0+UfZC4CPCFD X-Developer-Key: i=broonie@kernel.org; a=openpgp; fpr=3F2568AAC26998F9E813A1C5C3F436CA30F5D8EB When FPMR and SME are both present then entering and exiting streaming mode clears FPMR in the same manner as it clears the V/Z and P registers. Since entering and exiting streaming mode via ptrace is expected to have the same effect as doing so via SMSTART/SMSTOP it should clear FPMR too but this was missed when FPMR support was added. Add the required reset of FPMR. Since changing the vector length resets SVCR a SME vector length change implemented via a write to ZA can trigger an exit of streaming mode and we need to check when writing to ZA as well. Fixes: 4035c22ef7d4 ("arm64/ptrace: Expose FPMR via ptrace") Signed-off-by: Mark Brown Cc: stable@vger.kernel.org --- arch/arm64/kernel/ptrace.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/arm64/kernel/ptrace.c b/arch/arm64/kernel/ptrace.c index e4437f62a2cda93734052c44b48886db83d75b3e..43a9397d5903ff87b608befdcae= d3f9a7e48f976 100644 --- a/arch/arm64/kernel/ptrace.c +++ b/arch/arm64/kernel/ptrace.c @@ -877,6 +877,7 @@ static int sve_set_common(struct task_struct *target, const void *kbuf, const void __user *ubuf, enum vec_type type) { + u64 old_svcr =3D target->thread.svcr; int ret; struct user_sve_header header; unsigned int vq; @@ -908,8 +909,6 @@ static int sve_set_common(struct task_struct *target, =20 /* Enter/exit streaming mode */ if (system_supports_sme()) { - u64 old_svcr =3D target->thread.svcr; - switch (type) { case ARM64_VEC_SVE: target->thread.svcr &=3D ~SVCR_SM_MASK; @@ -1008,6 +1007,10 @@ static int sve_set_common(struct task_struct *target, start, end); =20 out: + /* If we entered or exited streaming mode then reset FPMR */ + if ((target->thread.svcr & SVCR_SM) !=3D (old_svcr & SVCR_SM)) + target->thread.uw.fpmr =3D 0; + fpsimd_flush_task_state(target); return ret; } @@ -1104,6 +1107,7 @@ static int za_set(struct task_struct *target, unsigned int pos, unsigned int count, const void *kbuf, const void __user *ubuf) { + u64 old_svcr =3D target->thread.svcr; int ret; struct user_za_header header; unsigned int vq; @@ -1184,6 +1188,10 @@ static int za_set(struct task_struct *target, target->thread.svcr |=3D SVCR_ZA_MASK; =20 out: + /* If we entered or exited streaming mode then reset FPMR */ + if ((target->thread.svcr & SVCR_SM) !=3D (old_svcr & SVCR_SM)) + target->thread.uw.fpmr =3D 0; + fpsimd_flush_task_state(target); return ret; } --=20 2.39.5