From: Ard Biesheuvel <ardb+git@google.com>
To: linux-kernel@vger.kernel.org
Cc: linux-efi@vger.kernel.org, x86@kernel.org,
Ard Biesheuvel <ardb@kernel.org>,
"Mike Rapoport (Microsoft)" <rppt@kernel.org>,
Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: [PATCH v2 19/19] x86/efi: Free unused tail of the EFI memory map
Date: Thu, 19 Mar 2026 10:05:49 +0100 [thread overview]
Message-ID: <20260319090529.1091660-40-ardb+git@google.com> (raw)
In-Reply-To: <20260319090529.1091660-21-ardb+git@google.com>
From: Ard Biesheuvel <ardb@kernel.org>
After moving the relevant entries to the start of the map, the remainder
can be handed back to the page allocator.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
arch/x86/platform/efi/quirks.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/platform/efi/quirks.c b/arch/x86/platform/efi/quirks.c
index 8f2dc477eee0..3b3652c4b90e 100644
--- a/arch/x86/platform/efi/quirks.c
+++ b/arch/x86/platform/efi/quirks.c
@@ -443,6 +443,10 @@ static int __init efi_free_boot_services(void)
efi.memmap.num_valid_entries = (new_md - efi.memmap.map) / efi.memmap.desc_size;
+ /* Free the part of the memory map allocation that has become unused */
+ free_reserved_area(new_md, efi.memmap.map_end, -1, NULL);
+ freed += (void *)efi.memmap.map_end - new_md;
+
if (freed)
pr_info("Freeing EFI boot services memory: %ldK\n", freed / SZ_1K);
--
2.53.0.851.ga537e3e6e9-goog
next prev parent reply other threads:[~2026-03-19 9:06 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-19 9:05 [PATCH v2 00/19] efi/x86: Avoid the need to mangle the EFI memory map Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 01/19] memblock: Permit existing reserved regions to be marked RSRV_KERN Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 02/19] efi: Tag memblock reservations of boot services regions as RSRV_KERN Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 03/19] x86/efi: Unmap kernel-reserved boot regions from EFI page tables Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 04/19] x86/efi: Drop EFI_MEMORY_RUNTIME check from __ioremap_check_other() Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 05/19] x86/efi: Omit RSRV_KERN memblock reservations when freeing boot regions Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 06/19] x86/efi: Defer sub-1M check from unmap to free stage Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 07/19] x86/efi: Simplify real mode trampoline allocation quirk Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 08/19] x86/efi: Omit redundant kernel image overlap check Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 09/19] x86/efi: Drop redundant EFI_PARAVIRT check Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 10/19] x86/efi: Do not rely on EFI_MEMORY_RUNTIME bit and avoid entry splitting Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 11/19] efi: Use nr_map not map_end to find the last valid memory map entry Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 12/19] x86/efi: Only merge EFI memory map entries on 32-bit systems Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 13/19] x86/efi: Clean the memory map using iterator and filter API Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 14/19] x86/efi: Update the runtime map in place Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 15/19] x86/efi: Use iterator API when mapping EFI regions for runtime Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 16/19] x86/efi: Reuse memory map instead of reallocating it Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 17/19] x86/efi: Defer compaction of the EFI memory map Ard Biesheuvel
2026-03-19 9:05 ` [PATCH v2 18/19] x86/efi: Do not abuse RUNTIME bit to mark boot regions as reserved Ard Biesheuvel
2026-03-19 9:05 ` Ard Biesheuvel [this message]
2026-03-24 9:50 ` [PATCH v2 00/19] efi/x86: Avoid the need to mangle the EFI memory map Ard Biesheuvel
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