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Message-ID: <7de7d83b-fcd4-a11f-a10d-1e20a871caa4@gmail.com>
Date: Mon, 5 Nov 2018 13:05:12 -0800
From: Florian Fainelli <f.fainelli@...il.com>
To: Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Rob Herring <robh+dt@...nel.org>,
Frank Rowand <frowand.list@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Marc Zyngier <marc.zyngier@....com>,
Russell King <rmk+kernel@...linux.org.uk>,
Andrey Ryabinin <aryabinin@...tuozzo.com>,
Andrey Konovalov <andreyknvl@...gle.com>,
Masahiro Yamada <yamada.masahiro@...ionext.com>,
Robin Murphy <robin.murphy@....com>,
Laura Abbott <labbott@...hat.com>,
Stefan Agner <stefan@...er.ch>,
Johannes Weiner <hannes@...xchg.org>,
Greg Hackmann <ghackmann@...roid.com>,
Kristina Martsenko <kristina.martsenko@....com>,
CHANDAN VN <chandan.vn@...sung.com>,
"moderated list:ARM64 PORT (AARCH64 ARCHITECTURE)"
<linux-arm-kernel@...ts.infradead.org>,
"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE"
<devicetree@...r.kernel.org>, rppt@...ux.ibm.com,
Russell King <linux@...linux.org.uk>, green.hu@...il.com,
deanbo422@...il.com, gxt@....edu.cn,
linux-snps-arc@...ts.infradead.org, vgupta@...opsys.com
Subject: Re: [PATCH v3 4/6] arm64: Utilize phys_initrd_start/phys_initrd_size
On 11/5/18 1:00 PM, Ard Biesheuvel wrote:
> On 5 November 2018 at 21:51, Florian Fainelli <f.fainelli@...il.com> wrote:
>> On 11/5/18 12:44 PM, Ard Biesheuvel wrote:
>>> On 5 November 2018 at 21:41, Florian Fainelli <f.fainelli@...il.com> wrote:
>>>> On 11/5/18 12:39 PM, Ard Biesheuvel wrote:
>>>>> Hi Florian,
>>>>>
>>>>> On 31 October 2018 at 20:28, Florian Fainelli <f.fainelli@...il.com> wrote:
>>>>>> ARM64 is the only architecture that re-defines
>>>>>> __early_init_dt_declare_initrd() in order for that function to populate
>>>>>> initrd_start/initrd_end with physical addresses instead of virtual
>>>>>> addresses. Instead of having an override we can leverage
>>>>>> drivers/of/fdt.c populating phys_initrd_start/phys_initrd_size to
>>>>>> populate those variables for us.
>>>>>>
>>>>>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>>>>>> ---
>>>>>> arch/arm64/mm/init.c | 19 +++++++++----------
>>>>>> 1 file changed, 9 insertions(+), 10 deletions(-)
>>>>>>
>>>>>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>>>>>> index 3cf87341859f..00ef2166bb73 100644
>>>>>> --- a/arch/arm64/mm/init.c
>>>>>> +++ b/arch/arm64/mm/init.c
>>>>>> @@ -72,8 +72,8 @@ static int __init early_initrd(char *p)
>>>>>> if (*endp == ',') {
>>>>>> size = memparse(endp + 1, NULL);
>>>>>>
>>>>>> - initrd_start = start;
>>>>>> - initrd_end = start + size;
>>>>>> + phys_initrd_start = start;
>>>>>> + phys_initrd_size = size;
>>>>>> }
>>>>>> return 0;
>>>>>> }
>>>>>> @@ -408,14 +408,14 @@ void __init arm64_memblock_init(void)
>>>>>> memblock_add(__pa_symbol(_text), (u64)(_end - _text));
>>>>>> }
>>>>>>
>>>>>> - if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && initrd_start) {
>>>>>> + if (IS_ENABLED(CONFIG_BLK_DEV_INITRD) && phys_initrd_size) {
>>>>>> /*
>>>>>> * Add back the memory we just removed if it results in the
>>>>>> * initrd to become inaccessible via the linear mapping.
>>>>>> * Otherwise, this is a no-op
>>>>>> */
>>>>>> - u64 base = initrd_start & PAGE_MASK;
>>>>>> - u64 size = PAGE_ALIGN(initrd_end) - base;
>>>>>> + u64 base = phys_initrd_start & PAGE_MASK;
>>>>>> + u64 size = PAGE_ALIGN(phys_initrd_size);
>>>>>>
>>>>>> /*
>>>>>> * We can only add back the initrd memory if we don't end up
>>>>>> @@ -460,12 +460,11 @@ void __init arm64_memblock_init(void)
>>>>>> */
>>>>>> memblock_reserve(__pa_symbol(_text), _end - _text);
>>>>>> #ifdef CONFIG_BLK_DEV_INITRD
>>>>>> - if (initrd_start) {
>>>>>> - memblock_reserve(initrd_start, initrd_end - initrd_start);
>>>>>> -
>>>>>> + if (phys_initrd_size) {
>>>>>> /* the generic initrd code expects virtual addresses */
>>>>>> - initrd_start = __phys_to_virt(initrd_start);
>>>>>> - initrd_end = __phys_to_virt(initrd_end);
>>>>>> + initrd_start = __phys_to_virt(phys_initrd_start);
>>>>>> + initrd_end = initrd_start + phys_initrd_size;
>>>>>> + initrd_below_start_ok = 0;
>>>>>
>>>>> Where is this assignment coming from?
>>>>
>>>> __early_init_dt_declare_initrd() sets initrd_below_start_ok to 1 though
>>>> after patch #5 this is not necessary any more.
>>>
>>> Yes, but why? The original arm64 version of
>>> __early_init_dt_declare_initrd() does not set it but now you set to 1
>>> in the IS_ENABLED(CONFIG_ARM64) section in the generic code and set it
>>> back to 0 here.
>>
>> Humm, it is an if (!IS_ENABLED(CONFIG_ARM64)) condition, so we would not
>> be taking that branch on an ARM64 kernel.
>>
>
> Right. So now that we are not setting it to 1 on arm64, there is no
> longer a reason to set it to 0 again, no?
Correct, and in fact, this is not a problem either at patch #4 (which
has the custom __early_init_dt_declare_initrd()) or #5 (which removes
it), any other feedback you would like me to address before addressing
Rob's suggestion?
>
>> If you are saying the assignment is not necessary anymore after patch #5
>> , that is true, though this can only be done a part of part #5, not as
>> part of patch #4 in order not to break initrd functionality in-between
>> patches.
>>
>>>
>>> Or am I missing something?
>>>
>>
>> Not sure, I could be too, it's Monday after all :)
>
> Yeah :-)
>
--
Florian
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