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Fri, 10 Feb 2023 08:04:22 +0000 (GMT) Received: from jarvis-ozlabs-ibm-com.ozlabs.ibm.com (haven.au.ibm.com [9.192.254.114]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ozlabs.au.ibm.com (Postfix) with ESMTPSA id AD6496097C; Fri, 10 Feb 2023 19:04:15 +1100 (AEDT) From: Andrew Donnellan To: linuxppc-dev@lists.ozlabs.org, linux-integrity@vger.kernel.org Cc: ruscur@russell.cc, bgray@linux.ibm.com, nayna@linux.ibm.com, gcwilson@linux.ibm.com, gjoyce@linux.ibm.com, brking@linux.ibm.com, stefanb@linux.ibm.com, sudhakar@linux.ibm.com, erichte@linux.ibm.com, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, zohar@linux.ibm.com, joel@jms.id.au, npiggin@gmail.com, Michael Ellerman Subject: [PATCH v6 19/26] powerpc/pseries: Make caller pass buffer to plpks_read_var() Date: Fri, 10 Feb 2023 19:03:54 +1100 Message-Id: <20230210080401.345462-20-ajd@linux.ibm.com> X-Mailer: git-send-email 2.39.1 In-Reply-To: <20230210080401.345462-1-ajd@linux.ibm.com> References: <20230210080401.345462-1-ajd@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: cLu69oJZdV381eQpsVGXsipFvgqjakQl X-Proofpoint-GUID: fzGdSvGR4RZCvgD071gHJ7LqnUpJyl3P X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.930,Hydra:6.0.562,FMLib:17.11.170.22 definitions=2023-02-10_03,2023-02-09_03,2023-02-09_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 priorityscore=1501 phishscore=0 impostorscore=0 bulkscore=0 adultscore=0 suspectscore=0 mlxscore=0 clxscore=1015 lowpriorityscore=0 mlxlogscore=999 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2302100070 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" Currently, plpks_read_var() allocates a buffer to pass to the H_PKS_READ_OBJECT hcall, then allocates another buffer into which the data is copied, and returns that buffer to the caller. This is a bit over the top - while we probably still want to allocate a separate buffer to pass to the hypervisor in the hcall, we can let the caller allocate the final buffer and specify the size. Don't allocate var->data in plpks_read_var(), instead expect the caller to allocate it. If the caller needs to discover the size, it can set var->data to NULL and var->datalen will be populated. Update header file to document this. Suggested-by: Michael Ellerman Signed-off-by: Andrew Donnellan Signed-off-by: Russell Currey Reviewed-by: Stefan Berger --- v3: New patch (mpe) v6: Reword commit message (stefanb) --- arch/powerpc/include/asm/plpks.h | 12 ++++++++++++ arch/powerpc/platforms/pseries/plpks.c | 11 ++++------- 2 files changed, 16 insertions(+), 7 deletions(-) diff --git a/arch/powerpc/include/asm/plpks.h b/arch/powerpc/include/asm/pl= pks.h index e7204e6c0ca4..0c49969b0864 100644 --- a/arch/powerpc/include/asm/plpks.h +++ b/arch/powerpc/include/asm/plpks.h @@ -88,16 +88,28 @@ int plpks_remove_var(char *component, u8 varos, =20 /** * Returns the data for the specified os variable. + * + * Caller must allocate a buffer in var->data with length in var->datalen. + * If no buffer is provided, var->datalen will be populated with the objec= t's + * size. */ int plpks_read_os_var(struct plpks_var *var); =20 /** * Returns the data for the specified firmware variable. + * + * Caller must allocate a buffer in var->data with length in var->datalen. + * If no buffer is provided, var->datalen will be populated with the objec= t's + * size. */ int plpks_read_fw_var(struct plpks_var *var); =20 /** * Returns the data for the specified bootloader variable. + * + * Caller must allocate a buffer in var->data with length in var->datalen. + * If no buffer is provided, var->datalen will be populated with the objec= t's + * size. */ int plpks_read_bootloader_var(struct plpks_var *var); =20 diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platform= s/pseries/plpks.c index e5755443d4a4..926b6a927326 100644 --- a/arch/powerpc/platforms/pseries/plpks.c +++ b/arch/powerpc/platforms/pseries/plpks.c @@ -581,17 +581,14 @@ static int plpks_read_var(u8 consumer, struct plpks_v= ar *var) goto out_free_output; } =20 - if (var->datalen =3D=3D 0 || var->datalen > retbuf[0]) + if (!var->data || var->datalen > retbuf[0]) var->datalen =3D retbuf[0]; =20 - var->data =3D kzalloc(var->datalen, GFP_KERNEL); - if (!var->data) { - rc =3D -ENOMEM; - goto out_free_output; - } var->policy =3D retbuf[1]; =20 - memcpy(var->data, output, var->datalen); + if (var->data) + memcpy(var->data, output, var->datalen); + rc =3D 0; =20 out_free_output: --=20 2.39.1