From: Alex Ghiti <alex@ghiti.fr>
To: Palmer Dabbelt <palmer@dabbelt.com>
Cc: anup@brainfault.org, linux-kernel@vger.kernel.org,
zong.li@sifive.com, Paul Walmsley <paul.walmsley@sifive.com>,
linux-riscv@lists.infradead.org, Christoph Hellwig <hch@lst.de>
Subject: Re: [RFC PATCH 1/7] riscv: Get rid of compile time logic with MAX_EARLY_MAPPING_SIZE
Date: Tue, 7 Apr 2020 01:12:15 -0400 [thread overview]
Message-ID: <befad912-5fab-897c-48d6-9a703a6b4240@ghiti.fr> (raw)
In-Reply-To: <mhng-ee39eb13-2567-479e-b0f4-5d23dff8496c@palmerdabbelt-glaptop1>
On 4/3/20 11:17 AM, Palmer Dabbelt wrote:
> On Sun, 22 Mar 2020 04:00:22 PDT (-0700), alex@ghiti.fr wrote:
>> There is no need to compare at compile time MAX_EARLY_MAPPING_SIZE value
>> with PGDIR_SIZE since MAX_EARLY_MAPPING_SIZE is set to 128MB which is
>> less
>> than PGDIR_SIZE that is equal to 1GB: that allows to simplify early_pmd
>> definition.
>>
>> Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
>> ---
>> arch/riscv/mm/init.c | 16 ++++------------
>> 1 file changed, 4 insertions(+), 12 deletions(-)
>>
>> diff --git a/arch/riscv/mm/init.c b/arch/riscv/mm/init.c
>> index 238bd0033c3f..18bbb426848e 100644
>> --- a/arch/riscv/mm/init.c
>> +++ b/arch/riscv/mm/init.c
>> @@ -247,13 +247,7 @@ static void __init create_pte_mapping(pte_t *ptep,
>>
>> pmd_t trampoline_pmd[PTRS_PER_PMD] __page_aligned_bss;
>> pmd_t fixmap_pmd[PTRS_PER_PMD] __page_aligned_bss;
>> -
>> -#if MAX_EARLY_MAPPING_SIZE < PGDIR_SIZE
>> -#define NUM_EARLY_PMDS 1UL
>> -#else
>> -#define NUM_EARLY_PMDS (1UL + MAX_EARLY_MAPPING_SIZE /
>> PGDIR_SIZE)
>> -#endif
>> -pmd_t early_pmd[PTRS_PER_PMD * NUM_EARLY_PMDS] __initdata
>> __aligned(PAGE_SIZE);
>> +pmd_t early_pmd[PTRS_PER_PMD] __initdata __aligned(PAGE_SIZE);
>>
>> static pmd_t *__init get_pmd_virt(phys_addr_t pa)
>> {
>> @@ -267,14 +261,12 @@ static pmd_t *__init get_pmd_virt(phys_addr_t pa)
>>
>> static phys_addr_t __init alloc_pmd(uintptr_t va)
>> {
>> - uintptr_t pmd_num;
>> -
>> if (mmu_enabled)
>> return memblock_phys_alloc(PAGE_SIZE, PAGE_SIZE);
>>
>> - pmd_num = (va - PAGE_OFFSET) >> PGDIR_SHIFT;
>> - BUG_ON(pmd_num >= NUM_EARLY_PMDS);
>> - return (uintptr_t)&early_pmd[pmd_num * PTRS_PER_PMD];
>> + BUG_ON((va - PAGE_OFFSET) >> PGDIR_SHIFT);
>> +
>> + return (uintptr_t)early_pmd;
>> }
>>
>> static void __init create_pmd_mapping(pmd_t *pmdp,
>
> My specific worry here was that allyesconfig kernels are quite large,
> and that
> dropping the code to handle large kernels would make it even harder to boot
> them. That said, I can't actually get one to boot so I'm happy to just
> push
> that off until later and drop the code we can't practically use.
>
> Reviewed-by: Palmer Dabbelt <palmerdabbelt@google.com>
>
> Thanks!
>
Thanks,
Alex
next prev parent reply other threads:[~2020-04-07 5:12 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-22 11:00 [RFC PATCH 0/7] Introduce sv48 support Alexandre Ghiti
2020-03-22 11:00 ` [RFC PATCH 1/7] riscv: Get rid of compile time logic with MAX_EARLY_MAPPING_SIZE Alexandre Ghiti
2020-03-26 6:10 ` Anup Patel
2020-04-03 15:17 ` Palmer Dabbelt
2020-04-07 5:12 ` Alex Ghiti [this message]
2020-03-22 11:00 ` [RFC PATCH 2/7] riscv: Allow to dynamically define VA_BITS Alexandre Ghiti
2020-03-26 6:12 ` Anup Patel
2020-04-03 15:17 ` Palmer Dabbelt
2020-04-07 5:12 ` Alex Ghiti
2020-03-22 11:00 ` [RFC PATCH 3/7] riscv: Simplify MAXPHYSMEM config Alexandre Ghiti
2020-03-26 6:22 ` Anup Patel
2020-03-26 6:34 ` Anup Patel
2020-04-03 15:53 ` Palmer Dabbelt
2020-04-07 5:13 ` Alex Ghiti
2020-03-22 11:00 ` [RFC PATCH 4/7] riscv: Implement sv48 support Alexandre Ghiti
2020-03-26 7:00 ` Anup Patel
2020-03-31 16:31 ` Alex Ghiti
2020-04-03 15:53 ` Palmer Dabbelt
2020-04-07 5:14 ` Alex Ghiti
2020-04-07 5:56 ` Anup Patel
2020-04-08 4:39 ` Alex Ghiti
2020-04-08 5:06 ` Anup Patel
2020-03-22 11:00 ` [RFC PATCH 5/7] riscv: Use pgtable_l4_enabled to output mmu type in cpuinfo Alexandre Ghiti
2020-03-26 7:01 ` Anup Patel
2020-04-03 15:53 ` Palmer Dabbelt
2020-04-07 5:14 ` Alex Ghiti
2020-03-22 11:00 ` [RFC PATCH 6/7] dt-bindings: riscv: Remove "riscv,svXX" property from device-tree Alexandre Ghiti
2020-03-26 7:03 ` Anup Patel
2020-04-03 15:53 ` Palmer Dabbelt
2020-04-07 5:14 ` Alex Ghiti
2020-03-22 11:00 ` [RFC PATCH 7/7] riscv: Explicit comment about user virtual address space size Alexandre Ghiti
2020-03-26 7:05 ` Anup Patel
2020-04-03 15:53 ` Palmer Dabbelt
2020-04-07 5:15 ` Alex Ghiti
2020-03-31 19:53 ` [RFC PATCH 0/7] Introduce sv48 support Palmer Dabbelt
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