linux/arch/x86/include/asm/highmem.h
Mike Rapoport (Microsoft) 6faea3422e arch, mm: streamline HIGHMEM freeing
All architectures that support HIGHMEM have their code that frees high
memory pages to the buddy allocator while __free_memory_core() is limited
to freeing only low memory.

There is no actual reason for that.  The memory map is completely ready by
the time memblock_free_all() is called and high pages can be released to
the buddy allocator along with low memory.

Remove low memory limit from __free_memory_core() and drop per-architecture
code that frees high memory pages.

Link: https://lkml.kernel.org/r/20250313135003.836600-12-rppt@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Acked-by: Dave Hansen <dave.hansen@linux.intel.com>	[x86]
Tested-by: Mark Brown <broonie@kernel.org>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Andreas Larsson <andreas@gaisler.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Ard Biesheuvel <ardb@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: Dinh Nguyen <dinguyen@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Gerald Schaefer <gerald.schaefer@linux.ibm.com>
Cc: Guo Ren (csky) <guoren@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: Huacai Chen <chenhuacai@kernel.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: John Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Russel King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Vineet Gupta <vgupta@kernel.org>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-03-17 22:06:53 -07:00

74 lines
2.3 KiB
C

/* SPDX-License-Identifier: GPL-2.0 */
/*
* highmem.h: virtual kernel memory mappings for high memory
*
* Used in CONFIG_HIGHMEM systems for memory pages which
* are not addressable by direct kernel virtual addresses.
*
* Copyright (C) 1999 Gerhard Wichert, Siemens AG
* Gerhard.Wichert@pdb.siemens.de
*
*
* Redesigned the x86 32-bit VM architecture to deal with
* up to 16 Terabyte physical memory. With current x86 CPUs
* we now support up to 64 Gigabytes physical RAM.
*
* Copyright (C) 1999 Ingo Molnar <mingo@redhat.com>
*/
#ifndef _ASM_X86_HIGHMEM_H
#define _ASM_X86_HIGHMEM_H
#ifdef __KERNEL__
#include <linux/interrupt.h>
#include <linux/threads.h>
#include <asm/tlbflush.h>
#include <asm/paravirt.h>
#include <asm/fixmap.h>
#include <asm/pgtable_areas.h>
/* declarations for highmem.c */
extern unsigned long highstart_pfn, highend_pfn;
/*
* Right now we initialize only a single pte table. It can be extended
* easily, subsequent pte tables have to be allocated in one physical
* chunk of RAM.
*/
/*
* Ordering is:
*
* high memory on: high_memory off:
* FIXADDR_TOP FIXADDR_TOP
* fixed addresses fixed addresses
* FIXADDR_START FIXADDR_START
* temp fixed addresses/persistent kmap area VMALLOC_END
* PKMAP_BASE temp fixed addresses/vmalloc area
* VMALLOC_END VMALLOC_START
* vmalloc area high_memory
* VMALLOC_START
* high_memory
*
* The temp fixed area is only used during boot for early_ioremap(), and
* it is unused when the ioremap() is functional. vmalloc/pkmap area become
* available after early boot so the temp fixed area is available for re-use.
*/
#define LAST_PKMAP_MASK (LAST_PKMAP-1)
#define PKMAP_NR(virt) ((virt-PKMAP_BASE) >> PAGE_SHIFT)
#define PKMAP_ADDR(nr) (PKMAP_BASE + ((nr) << PAGE_SHIFT))
#define flush_cache_kmaps() do { } while (0)
#define arch_kmap_local_post_map(vaddr, pteval) \
arch_flush_lazy_mmu_mode()
#define arch_kmap_local_post_unmap(vaddr) \
do { \
flush_tlb_one_kernel((vaddr)); \
arch_flush_lazy_mmu_mode(); \
} while (0)
#endif /* __KERNEL__ */
#endif /* _ASM_X86_HIGHMEM_H */