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Sat, 5 Dec 2020 19:49:06 +0000 (GMT) Received: from b03ledav005.gho.boulder.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id C9390BE04F; Sat, 5 Dec 2020 19:48:58 +0000 (GMT) Received: from manicouagan.localdomain (unknown [9.85.177.236]) by b03ledav005.gho.boulder.ibm.com (Postfix) with ESMTPS; Sat, 5 Dec 2020 19:48:58 +0000 (GMT) References: <20201204195149.611-1-nramas@linux.microsoft.com> <20201204195149.611-4-nramas@linux.microsoft.com> User-agent: mu4e 1.4.10; emacs 27.1 From: Thiago Jung Bauermann To: Lakshmi Ramasubramanian Cc: zohar@linux.ibm.com, robh@kernel.org, gregkh@linuxfoundation.org, james.morse@arm.com, catalin.marinas@arm.com, sashal@kernel.org, will@kernel.org, mpe@ellerman.id.au, benh@kernel.crashing.org, paulus@samba.org, robh+dt@kernel.org, frowand.list@gmail.com, vincenzo.frascino@arm.com, mark.rutland@arm.com, dmitry.kasatkin@gmail.com, jmorris@namei.org, serge@hallyn.com, pasha.tatashin@soleen.com, allison@lohutok.net, kstewart@linuxfoundation.org, takahiro.akashi@linaro.org, tglx@linutronix.de, masahiroy@kernel.org, bhsharma@redhat.com, mbrugger@suse.com, hsinyi@chromium.org, tao.li@vivo.com, christophe.leroy@c-s.fr, linux-integrity@vger.kernel.org, linux-kernel@vger.kernel.org, devicetree@vger.kernel.org, prsriva@linux.microsoft.com, balajib@linux.microsoft.com Subject: Re: [PATCH v10 3/8] powerpc: Move ima buffer functions to drivers/of/kexec.c In-reply-to: <20201204195149.611-4-nramas@linux.microsoft.com> Date: Sat, 05 Dec 2020 16:48:56 -0300 Message-ID: <87zh2sm3tj.fsf@manicouagan.localdomain> MIME-Version: 1.0 Content-Type: text/plain X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.312,18.0.737 definitions=2020-12-05_15:2020-12-04,2020-12-05 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 lowpriorityscore=0 mlxscore=0 adultscore=0 phishscore=0 mlxlogscore=999 spamscore=0 priorityscore=1501 malwarescore=0 suspectscore=0 clxscore=1015 impostorscore=0 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2012050130 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Lakshmi Ramasubramanian writes: > The functions do_get_kexec_buffer() and get_addr_size_cells(), > defined in arch/powerpc/kexec/ima.c, retrieve the address and size > of the given property from the device tree blob. These functions do > not have architecture specific code, but are currently limited to > powerpc. do_get_kexec_buffer() correctly handles a device tree property > that is a child node of the root node, but not anything other than > the immediate root child nodes. > > Move architecture independent functions get_ima_kexec_buffer() and > get_root_addr_size_cells() to "drivers/of/kexec.c". These functions > retrieve the chosen node "linux,ima-kexec-buffer" from the device tree, > and return the address and size of the buffer used for carrying forward > the IMA measurement log across kexec system call. > > Co-developed-by: Prakhar Srivastava > Signed-off-by: Prakhar Srivastava > Signed-off-by: Lakshmi Ramasubramanian I'd personally squash this patch with the next one, but I'll leave it just as a suggestion since maintainers are the ones who know best what works well in this regard. The code is good, except for a nit below: Reviewed-by: Thiago Jung Bauermann > --- > drivers/of/kexec.c | 70 +++++++++++++++++++++++++++++++++++++++++++ > include/linux/kexec.h | 3 ++ > 2 files changed, 73 insertions(+) > > diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c > index b7d59105fcb8..516b86f7113a 100644 > --- a/drivers/of/kexec.c > +++ b/drivers/of/kexec.c > @@ -59,3 +59,73 @@ int delete_fdt_mem_rsv(void *fdt, unsigned long start, unsigned long size) > > return -ENOENT; > } > + > +/** > + * get_root_addr_size_cells - Get address and size of root node > + * > + * @addr_cells: Return address of the root node > + * @size_cells: Return size of the root node > + * > + * Return: 0 on success, or negative errno on error. > + */ > +int get_root_addr_size_cells(int *addr_cells, int *size_cells) > +{ > + struct device_node *root; > + > + if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC)) > + return -EOPNOTSUPP; > + > + root = of_find_node_by_path("/"); > + if (!root) > + return -EINVAL; > + > + *addr_cells = of_n_addr_cells(root); > + *size_cells = of_n_size_cells(root); > + > + of_node_put(root); > + > + return 0; > +} > + > +/** > + * get_ima_kexec_buffer - Get address and size of IMA kexec buffer > + * > + * @fdt: Flattened Device Tree > + * @chosen_node: Offset of chosen node in the FDT > + * @addr: Return address of the node > + * @size: Return size of the node > + * > + * Return: 0 on success, or negative errno on error. > + */ > +int get_ima_kexec_buffer(void *fdt, int chosen_node, > + unsigned long *addr, size_t *size) > +{ > + const void *prop; > + int addr_cells, size_cells, prop_len; > + int rc; > + > + if (!IS_ENABLED(CONFIG_HAVE_IMA_KEXEC)) > + return -EOPNOTSUPP; > + > + rc = get_root_addr_size_cells(&addr_cells, &size_cells); > + if (rc) > + return rc; > + > + if (fdt) > + prop = fdt_getprop(fdt, chosen_node, > + "linux,ima-kexec-buffer", &prop_len); > + else > + prop = of_get_property(of_chosen, > + "linux,ima-kexec-buffer", &prop_len); > + > + if (!prop) > + return -ENOENT; > + > + if (prop_len < 4 * (addr_cells + size_cells)) > + return -EINVAL; > + > + *addr = of_read_number(prop, addr_cells); > + *size = of_read_number(prop + 4 * addr_cells, size_cells); > + > + return 0; > +} > diff --git a/include/linux/kexec.h b/include/linux/kexec.h > index d0234c4815da..10ff704ab670 100644 > --- a/include/linux/kexec.h > +++ b/include/linux/kexec.h > @@ -408,6 +408,9 @@ static inline int kexec_crash_loaded(void) { return 0; } > #endif /* CONFIG_KEXEC_CORE */ > > #if defined(CONFIG_OF_FLATTREE) > +extern int get_root_addr_size_cells(int *addr_cells, int *size_cells); > +extern int get_ima_kexec_buffer(void *fdt, int chosen_node, > + unsigned long *addr, size_t *size); > extern int delete_fdt_mem_rsv(void *fdt, unsigned long start, > unsigned long size); > #endif /* CONFIG_OF_FLATTREE */ The extern keyword on function prototypes doesn't have any meaning. It's better to drop them (I should have mentioned this on the previous patch as well). -- Thiago Jung Bauermann IBM Linux Technology Center