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Message-ID: <0257ee07-8b85-5295-1490-72c7aa14943d@gmail.com>
Date: Mon, 5 Nov 2018 12:51:23 -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 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.
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 :)
--
Florian
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