linux-kernel - Re: [PATCH v3 02/12] powerpc/kexec

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <87ft9quh1o.fsf@morokweng.localdomain>
Date:   Fri, 17 Jul 2020 15:34:27 -0300
From:   Thiago Jung Bauermann <bauerman@...ux.ibm.com>
To:     Hari Bathini <hbathini@...ux.ibm.com>
Cc:     Pingfan Liu <piliu@...hat.com>, Nayna Jain <nayna@...ux.ibm.com>,
        Kexec-ml <kexec@...ts.infradead.org>,
        Mahesh J Salgaonkar <mahesh@...ux.ibm.com>,
        Mimi Zohar <zohar@...ux.ibm.com>,
        lkml <linux-kernel@...r.kernel.org>,
        linuxppc-dev <linuxppc-dev@...abs.org>,
        Sourabh Jain <sourabhjain@...ux.ibm.com>,
        Petr Tesarik <ptesarik@...e.cz>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Dave Young <dyoung@...hat.com>,
        Vivek Goyal <vgoyal@...hat.com>,
        Eric Biederman <ebiederm@...ssion.com>
Subject: Re: [PATCH v3 02/12] powerpc/kexec_file: mark PPC64 specific code


Hari Bathini <hbathini@...ux.ibm.com> writes:

> On 16/07/20 7:19 am, Thiago Jung Bauermann wrote:
>> 
>> I didn't forget about this patch. I just wanted to see more of the
>> changes before comenting on it.
>> 
>> Hari Bathini <hbathini@...ux.ibm.com> writes:
>> 
>>> Some of the kexec_file_load code isn't PPC64 specific. Move PPC64
>>> specific code from kexec/file_load.c to kexec/file_load_64.c. Also,
>>> rename purgatory/trampoline.S to purgatory/trampoline_64.S in the
>>> same spirit.
>> 
>> There's only a 64 bit implementation of kexec_file_load() so this is a
>> somewhat theoretical exercise, but there's no harm in getting the code
>> organized, so:
>> 
>> Reviewed-by: Thiago Jung Bauermann <bauerman@...ux.ibm.com>
>> 
>> I have just one question below.
>
> <snip>
>
>>> +/**
>>> + * setup_new_fdt_ppc64 - Update the flattend device-tree of the kernel
>>> + *                       being loaded.
>>> + * @image:               kexec image being loaded.
>>> + * @fdt:                 Flattened device tree for the next kernel.
>>> + * @initrd_load_addr:    Address where the next initrd will be loaded.
>>> + * @initrd_len:          Size of the next initrd, or 0 if there will be none.
>>> + * @cmdline:             Command line for the next kernel, or NULL if there will
>>> + *                       be none.
>>> + *
>>> + * Returns 0 on success, negative errno on error.
>>> + */
>>> +int setup_new_fdt_ppc64(const struct kimage *image, void *fdt,
>>> +			unsigned long initrd_load_addr,
>>> +			unsigned long initrd_len, const char *cmdline)
>>> +{
>>> +	int chosen_node, ret;
>>> +
>>> +	/* Remove memory reservation for the current device tree. */
>>> +	ret = delete_fdt_mem_rsv(fdt, __pa(initial_boot_params),
>>> +				 fdt_totalsize(initial_boot_params));
>>> +	if (ret == 0)
>>> +		pr_debug("Removed old device tree reservation.\n");
>>> +	else if (ret != -ENOENT) {
>>> +		pr_err("Failed to remove old device-tree reservation.\n");
>>> +		return ret;
>>> +	}
>>> +
>>> +	ret = setup_new_fdt(image, fdt, initrd_load_addr, initrd_len,
>>> +			    cmdline, &chosen_node);
>>> +	if (ret)
>>> +		return ret;
>>> +
>>> +	ret = fdt_setprop(fdt, chosen_node, "linux,booted-from-kexec", NULL, 0);
>>> +	if (ret)
>>> +		pr_err("Failed to update device-tree with linux,booted-from-kexec\n");
>>> +
>>> +	return ret;
>>> +}
>> 
>> For setup_purgatory_ppc64() you start with an empty function and build
>> from there, but for setup_new_fdt_ppc64() you moved some code here. Is
>> the code above 64 bit specific?
>
> Actually, I was not quiet sure if fdt updates like in patch 6 & patch 9 can be
> done after setup_ima_buffer() call. If you can confirm, I will move them back
> to setup_purgatory()

Hari and I discussed this off-line and we came to the conclusion that
theis code can be moved back to setup_new_fdt().

-- 
Thiago Jung Bauermann
IBM Linux Technology Center