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Wed, 18 Jan 2023 17:11:08 +1100 (AEDT) From: Andrew Donnellan To: linuxppc-dev@lists.ozlabs.org, linux-integrity@vger.kernel.org Cc: gregkh@linuxfoundation.org, gcwilson@linux.ibm.com, linux-kernel@vger.kernel.org, nayna@linux.ibm.com, ruscur@russell.cc, zohar@linux.ibm.com, mpe@ellerman.id.au, gjoyce@linux.ibm.com, sudhakar@linux.ibm.com, bgray@linux.ibm.com, erichte@linux.ibm.com Subject: [PATCH v3 18/24] powerpc/pseries: Make caller pass buffer to plpks_read_var() Date: Wed, 18 Jan 2023 17:10:43 +1100 Message-Id: <20230118061049.1006141-19-ajd@linux.ibm.com> X-Mailer: git-send-email 2.39.0 In-Reply-To: <20230118061049.1006141-1-ajd@linux.ibm.com> References: <20230118061049.1006141-1-ajd@linux.ibm.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: OCTt7Kb0VNL5SntzAwEFLQUM3J0JRG7N X-Proofpoint-GUID: OCTt7Kb0VNL5SntzAwEFLQUM3J0JRG7N X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.219,Aquarius:18.0.923,Hydra:6.0.562,FMLib:17.11.122.1 definitions=2023-01-18_01,2023-01-17_01,2022-06-22_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 phishscore=0 bulkscore=0 priorityscore=1501 impostorscore=0 mlxscore=0 suspectscore=0 adultscore=0 clxscore=1015 spamscore=0 mlxlogscore=999 lowpriorityscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2212070000 definitions=main-2301180051 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, of the caller's preferred size if necessary, 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 --- v3: New patch (mpe) --- 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 96a026a37285..5d9c6a3b2014 100644 --- a/arch/powerpc/platforms/pseries/plpks.c +++ b/arch/powerpc/platforms/pseries/plpks.c @@ -578,17 +578,14 @@ 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 2.39.0