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mm/early_ioremap: clarify early_ioremap_reset() semantics

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Patch series "mm/early_ioremap: clarify and clean up
early_ioremap_reset()".

__late_set_fixmap() and __late_clear_fixmap() are only used after
early_ioremap_reset() has been called, but the comment above them does not
say anything about that.  So arm64, riscv and powerpc, whose
__set_fixmap() works before and after paging_init(), describe the same
situation in three different ways:

                 calls reset    defines the macros
        arm64    yes            yes
        riscv    no             yes
        powerpc  no             no

Patch 1 documents when early_ioremap_reset() needs to be called and that
only architectures calling it need to define the macros.

Patches 2 and 3 remove the unneeded riscv macros, which are unreachable,
and the arm64 reset call and macros, which change nothing.

No functional change.


This patch (of 3):

__late_set_fixmap() and __late_clear_fixmap() are only used after
early_ioremap_reset() has been called.

arm64, riscv and powerpc all have a __set_fixmap() that works before and
after paging_init(), so they do not need to call early_ioremap_reset() or
define the macros, but they describe the same situation in three different
ways:

                 calls reset    defines the macros
        arm64    yes            yes
        riscv    no             yes
        powerpc  no             no

The existing comment is vague and allows all three.  Replace it with
comments that make it clear when the reset and the macros are needed.

No functional change.

Link: https://lore.kernel.org/20260708170647.362562-1-ekffu200098@gmail.com
Link: https://lore.kernel.org/20260708170647.362562-2-ekffu200098@gmail.com
Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Sang-Heon Jeon 2026-07-09 02:06:45 +09:00 committed by Andrew Morton
parent 9922d4ced6
commit 6fa0d03840
1 changed files with 7 additions and 3 deletions
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10
mm/early_ioremap.c
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@ -47,15 +47,19 @@ pgprot_t __init __weak early_memremap_pgprot_adjust(resource_size_t phys_addr,
return prot;
}
/*
* Only architectures whose early_ioremap() must stop using __early_set_fixmap()
* after paging_init() need to call this.
*/
void __init early_ioremap_reset(void)
{
after_paging_init = 1;
}
/*
* Generally, ioremap() is available after paging_init() has been called.
* Architectures wanting to allow early_ioremap after paging_init() can
* define __late_set_fixmap and __late_clear_fixmap to do the right thing.
* Only architectures that call early_ioremap_reset() need to define
* __late_set_fixmap() and __late_clear_fixmap(), which early_ioremap() uses
* instead of __early_set_fixmap() after the reset.
*/
#ifndef __late_set_fixmap
static inline void __init __late_set_fixmap(enum fixed_addresses idx,