From 6fa0d03840d0be5f91bfd00afc43177cda46ab1a Mon Sep 17 00:00:00 2001 From: Sang-Heon Jeon Date: Thu, 9 Jul 2026 02:06:45 +0900 Subject: [PATCH] mm/early_ioremap: clarify early_ioremap_reset() semantics 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 Cc: Albert Ou Cc: Alexandre Ghiti Cc: Catalin Marinas Cc: David Hildenbrand Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Michal Hocko Cc: Mike Rapoport Cc: Palmer Dabbelt Cc: Suren Baghdasaryan Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- mm/early_ioremap.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/mm/early_ioremap.c b/mm/early_ioremap.c index 96c29b9dc85d..6215b90dfef3 100644 --- a/mm/early_ioremap.c +++ b/mm/early_ioremap.c @@ -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,