From: Dmitry Osipenko <digetx@gmail.com>
To: "Michał Mirosław" <mirq-linux@rere.qmqm.pl>
Cc: "Jens Axboe" <axboe@kernel.dk>,
"Thierry Reding" <thierry.reding@gmail.com>,
"Jonathan Hunter" <jonathanh@nvidia.com>,
"David Heidelberg" <david@ixit.cz>,
"Peter Geis" <pgwipeout@gmail.com>,
"Stephen Warren" <swarren@wwwdotorg.org>,
"Nicolas Chauvet" <kwizart@gmail.com>,
"Ulf Hansson" <ulf.hansson@linaro.org>,
"Adrian Hunter" <adrian.hunter@intel.com>,
"Billy Laws" <blaws05@gmail.com>,
"Nils Östlund" <nils@naltan.com>,
"Christoph Hellwig" <hch@infradead.org>,
"Ard Biesheuvel" <ard.biesheuvel@linaro.org>,
"Davidlohr Bueso" <dave@stgolabs.net>,
linux-tegra@vger.kernel.org, linux-block@vger.kernel.org,
"Andrey Danin" <danindrey@mail.ru>,
"Gilles Grandou" <gilles@grandou.net>,
"Ryan Grachek" <ryan@edited.us>,
linux-mmc@vger.kernel.org, linux-kernel@vger.kernel.org,
"Steve McIntyre" <steve@einval.com>,
"Randy Dunlap" <rdunlap@infradead.org>,
linux-efi <linux-efi@vger.kernel.org>
Subject: Re: [PATCH v5 6/6] soc/tegra: Expose Boot Configuration Table via sysfs
Date: Mon, 18 May 2020 11:00:46 +0300 [thread overview]
Message-ID: <75e7d242-268c-07a3-a4f9-7b8252769140@gmail.com> (raw)
In-Reply-To: <20200518074557.GA12306@qmqm.qmqm.pl>
18.05.2020 10:45, Michał Mirosław пишет:
> On Sat, May 16, 2020 at 06:36:44PM +0300, Dmitry Osipenko wrote:
>> It's quite useful to have unencrypted BCT exposed to userspace for
>> debugging purposes, so let's expose it via sysfs. The BCT data will be
>> present in '/sys/tegra/boot_config_table' binary file if BCT is available.
> [...]
>> +/*
>> + * spare_bct[] will be released once kernel is booted, hence not wasting
>> + * kernel space if BCT is missing. The tegra_bct can't be allocated during
>> + * of BCT setting up because it's too early for the slab allocator.
>> + */
>> +static u8 spare_bct[SZ_8K] __initdata;
>> +static u8 *tegra_bct;
>> +
>> +static ssize_t boot_config_table_read(struct file *filp,
>> + struct kobject *kobj,
>> + struct bin_attribute *bin_attr,
>> + char *buf, loff_t off, size_t count)
>> +{
>> + memcpy(buf, tegra_bct + off, count);
>> + return count;
>> +}
>> +static BIN_ATTR_RO(boot_config_table, 0);
>> +
>> +static int __init tegra_bootdata_bct_sysfs_init(void)
>> +{
>> + if (!bin_attr_boot_config_table.size)
>> + return 0;
>> +
>> + tegra_bct = kmalloc(GFP_KERNEL, bin_attr_boot_config_table.size);
>> + if (!tegra_bct)
>> + return -ENOMEM;
>> +
>> + memcpy(tegra_bct, spare_bct, bin_attr_boot_config_table.size);
>> +
>> + return sysfs_create_bin_file(tegra_soc_kobj,
>> + &bin_attr_boot_config_table);
>
> Should we consider freeing the table if sysfs registration fails?
This is a good suggestion, thank you :)
>> +}
>> +late_initcall(tegra_bootdata_bct_sysfs_init)
>> +
>> +void __init tegra_bootdata_bct_setup(void __iomem *bct_ptr, size_t bct_size)
>> +{
>> + memcpy_fromio(spare_bct, bct_ptr, bct_size);
>> + bin_attr_boot_config_table.size = bct_size;
> [...]
>
> The size isn't checked anywhere. How the maximum is obtained? At least
> a comment would be good if the 8k limit is guaranteed by other means.
Yes, I can add a clarifying comment about the 8K. It also should be
possible to create a union of T20/T30 BCT structs and then use use
sizeof(bct_union). I'll consider this change for the next version, thank
you for the suggestion.
prev parent reply other threads:[~2020-05-18 8:00 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-16 15:36 [PATCH v5 0/6] Introduce NVIDIA Tegra Partition Table Dmitry Osipenko
2020-05-16 15:36 ` [PATCH v5 1/6] mmc: core: Add raw_boot_mult field to mmc_ext_csd Dmitry Osipenko
2020-05-16 15:36 ` [PATCH v5 2/6] mmc: block: Add mmc_bdev_to_card() helper Dmitry Osipenko
2020-05-16 15:36 ` [PATCH v5 3/6] partitions: Introduce NVIDIA Tegra Partition Table Dmitry Osipenko
2020-05-16 15:36 ` [PATCH v5 4/6] partitions/efi: Support GPT entry lookup at a non-standard location Dmitry Osipenko
2020-05-16 15:51 ` Randy Dunlap
2020-05-16 16:50 ` Dmitry Osipenko
2020-05-16 16:58 ` Randy Dunlap
2020-05-17 0:11 ` Dmitry Osipenko
2020-05-17 2:07 ` Randy Dunlap
2020-05-16 15:36 ` [PATCH v5 5/6] partitions/tegra: Support enforced GPT scanning Dmitry Osipenko
2020-05-16 15:52 ` Randy Dunlap
2020-05-16 15:36 ` [PATCH v5 6/6] soc/tegra: Expose Boot Configuration Table via sysfs Dmitry Osipenko
2020-05-18 7:45 ` Michał Mirosław
2020-05-18 8:00 ` Dmitry Osipenko [this message]
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