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Date: Mon, 29 Oct 2018 14:52:37 -0700
From: Florian Fainelli <f.fainelli@...il.com>
To: Rob Herring <robh+dt@...nel.org>,
Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc: "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
rppt@...ux.ibm.com, Catalin Marinas <catalin.marinas@....com>,
Will Deacon <will.deacon@....com>,
Frank Rowand <frowand.list@...il.com>,
Andrew Morton <akpm@...ux-foundation.org>,
Marc Zyngier <marc.zyngier@....com>,
Russell King <rmk+kernel@...linux.org.uk>,
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>, ghackmann@...roid.com,
Kristina Martsenko <kristina.martsenko@....com>,
chandan.vn@...sung.com,
"moderated list:ARM/FREESCALE IMX / MXC ARM ARCHITECTURE"
<linux-arm-kernel@...ts.infradead.org>, devicetree@...r.kernel.org,
Russell King <linux@...linux.org.uk>
Subject: Re: [PATCH 1/2 v5] arm64: Get rid of __early_init_dt_declare_initrd()
On 10/29/18 12:59 PM, Rob Herring wrote:
> +Ard who last touched this.
>
> On Mon, Oct 29, 2018 at 2:23 PM 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, just get rid of that
>> implementation and perform the virtual to physical conversion of these
>> addresses in arm64_memblock_init() where relevant.
>>
>> Signed-off-by: Florian Fainelli <f.fainelli@...il.com>
>> Signed-off-by: Mike Rapoport <rppt@...ux.ibm.com>
>> ---
>> arch/arm64/include/asm/memory.h | 8 -------
>> arch/arm64/mm/init.c | 42 +++++++++++++++++++++------------
>> 2 files changed, 27 insertions(+), 23 deletions(-)
>>
>> diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h
>> index b96442960aea..dc3ca21ba240 100644
>> --- a/arch/arm64/include/asm/memory.h
>> +++ b/arch/arm64/include/asm/memory.h
>> @@ -168,14 +168,6 @@
>> #define IOREMAP_MAX_ORDER (PMD_SHIFT)
>> #endif
>>
>> -#ifdef CONFIG_BLK_DEV_INITRD
>> -#define __early_init_dt_declare_initrd(__start, __end) \
>> - do { \
>> - initrd_start = (__start); \
>> - initrd_end = (__end); \
>> - } while (0)
>> -#endif
>> -
>> #ifndef __ASSEMBLY__
>>
>> #include <linux/bitops.h>
>> diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
>> index 3cf87341859f..292570b08f85 100644
>> --- a/arch/arm64/mm/init.c
>> +++ b/arch/arm64/mm/init.c
>> @@ -62,6 +62,8 @@
>> s64 memstart_addr __ro_after_init = -1;
>> phys_addr_t arm64_dma_phys_limit __ro_after_init;
>>
>> +static phys_addr_t phys_initrd_start, phys_initrd_end;
>> +
>> #ifdef CONFIG_BLK_DEV_INITRD
>> static int __init early_initrd(char *p)
>> {
>> @@ -72,8 +74,8 @@ 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_end = start + size;
>> }
>> return 0;
>> }
>> @@ -364,6 +366,7 @@ static void __init fdt_enforce_memory_region(void)
>> void __init arm64_memblock_init(void)
>> {
>> const s64 linear_region_size = -(s64)PAGE_OFFSET;
>> + u64 __maybe_unused base, size;
>>
>> /* Handle linux,usable-memory-range property */
>> fdt_enforce_memory_region();
>> @@ -408,14 +411,25 @@ 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) &&
>> + (initrd_start || phys_initrd_start)) {
>
> I've tried to explain already that this is broken. The problem is
> __early_init_dt_declare_initrd using __va() which happens before this
> function is called. __va() uses PHYS_OFFSET which in turn is defined
> as memstart_addr. However, memstart_addr may be changed just above
> this hunk, so the earlier conversion to a VA may not be valid at this
> point. This is explained if you read Ard's commit that added all this
> mess.
Thanks for explaining this again, looks like I had overlooked that
explanation in the "other branch" of the thread last time I read it.
>
> You could fix this by converting back to a PA before adjusting
> memstart_addr, but that's 2 wrongs making a right and fragile. The
> better solution is the other proposal making the DT code set
> phys_initrd_* (whatever the ARM code calls them).
OK, that sounds reasonable, will cook something doing that. Thanks!
>
>> /*
>> * 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;
>> + if (phys_initrd_start) {
>> + /* Command line specified the initrd location */
>> + initrd_start = __phys_to_virt(phys_initrd_start);
>> + initrd_end = __phys_to_virt(phys_initrd_end);
>> + } else if (initrd_start) {
>> + /* FDT specified the initrd location */
>> + phys_initrd_start = __pa(initrd_start);
>> + phys_initrd_end = __pa(initrd_end);
>
> Kind of inconsistent to mix __phys_to_virt and __pa flavors.
>
> Rob
>
--
Florian
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