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From: Thiago Jung Bauermann <bauerman@linux.ibm.com>
To: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>
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
Date: Sat, 05 Dec 2020 16:48:56 -0300	[thread overview]
Message-ID: <87zh2sm3tj.fsf@manicouagan.localdomain> (raw)
In-Reply-To: <20201204195149.611-4-nramas@linux.microsoft.com>


Lakshmi Ramasubramanian <nramas@linux.microsoft.com> 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 <prsriva@linux.microsoft.com>
> Signed-off-by: Prakhar Srivastava <prsriva@linux.microsoft.com>
> Signed-off-by: Lakshmi Ramasubramanian <nramas@linux.microsoft.com>

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 <bauerman@linux.ibm.com>

> ---
>  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

  reply	other threads:[~2020-12-05 19:50 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-04 19:51 [PATCH v10 0/8] Carry forward IMA measurement log on kexec on ARM64 Lakshmi Ramasubramanian
2020-12-04 19:51 ` [PATCH v10 1/8] powerpc: fix compiler warnings and errors Lakshmi Ramasubramanian
2020-12-05  1:20   ` Thiago Jung Bauermann
2020-12-04 19:51 ` [PATCH v10 2/8] powerpc: Move delete_fdt_mem_rsv() to drivers/of/kexec.c Lakshmi Ramasubramanian
2020-12-05  2:22   ` Thiago Jung Bauermann
2020-12-07  1:50     ` Lakshmi Ramasubramanian
2020-12-11 16:37       ` Lakshmi Ramasubramanian
2020-12-11 18:19         ` Thiago Jung Bauermann
2020-12-11 19:25           ` Lakshmi Ramasubramanian
2020-12-12  1:14             ` Thiago Jung Bauermann
2020-12-04 19:51 ` [PATCH v10 3/8] powerpc: Move ima buffer functions " Lakshmi Ramasubramanian
2020-12-05 19:48   ` Thiago Jung Bauermann [this message]
2020-12-07  1:53     ` Lakshmi Ramasubramanian
2020-12-04 19:51 ` [PATCH v10 4/8] powerpc: Use ima kexec node functions Lakshmi Ramasubramanian
2020-12-05 19:51   ` Thiago Jung Bauermann
2020-12-07  1:54     ` Lakshmi Ramasubramanian
2020-12-04 19:51 ` [PATCH v10 5/8] powerpc: Move remove_ima_buffer() to drivers/of/kexec.c Lakshmi Ramasubramanian
2020-12-05 20:14   ` Thiago Jung Bauermann
2020-12-07  1:57     ` Lakshmi Ramasubramanian
2020-12-04 19:51 ` [PATCH v10 6/8] powerpc: Move ima_get_kexec_buffer() and ima_free_kexec_buffer() to ima Lakshmi Ramasubramanian
2020-12-05 21:02   ` Thiago Jung Bauermann
2020-12-07  1:58     ` Lakshmi Ramasubramanian
2020-12-04 19:51 ` [PATCH v10 7/8] powerpc: Move arch_ima_add_kexec_buffer " Lakshmi Ramasubramanian
2020-12-05 21:36   ` Thiago Jung Bauermann
2020-12-07  2:03     ` Lakshmi Ramasubramanian
2020-12-07 14:57       ` Mimi Zohar
2020-12-04 19:51 ` [PATCH v10 8/8] arm64: Add IMA log information in kimage used for kexec Lakshmi Ramasubramanian
2020-12-05 21:44   ` Thiago Jung Bauermann
2020-12-07  2:05     ` Lakshmi Ramasubramanian

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