From: Ard Biesheuvel <ardb@kernel.org>
To: linux-efi@vger.kernel.org, Ingo Molnar <mingo@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>
Cc: Ard Biesheuvel <ardb@kernel.org>,
linux-kernel@vger.kernel.org,
Anshuman Khandual <anshuman.khandual@arm.com>,
Arnd Bergmann <arnd@arndb.de>,
Dan Williams <dan.j.williams@intel.com>,
Dave Young <dyoung@redhat.com>,
Saravana Kannan <saravanak@google.com>
Subject: [PATCH 12/13] efi: Fix efi_memmap_alloc() leaks
Date: Mon, 13 Jan 2020 18:22:44 +0100 [thread overview]
Message-ID: <20200113172245.27925-13-ardb@kernel.org> (raw)
In-Reply-To: <20200113172245.27925-1-ardb@kernel.org>
From: Dan Williams <dan.j.williams@intel.com>
With efi_fake_memmap() and efi_arch_mem_reserve() the efi table may be
updated and replaced multiple times. When that happens a previous
dynamically allocated efi memory map can be garbage collected. Use the
new EFI_MEMMAP_{SLAB,MEMBLOCK} flags to detect when a dynamically
allocated memory map is being replaced.
Debug statements in efi_memmap_free() reveal:
efi: __efi_memmap_free:37: phys: 0x23ffdd580 size: 2688 flags: 0x2
efi: __efi_memmap_free:37: phys: 0x9db00 size: 2640 flags: 0x2
efi: __efi_memmap_free:37: phys: 0x9e580 size: 2640 flags: 0x2
...a savings of 7968 bytes on a qemu boot with 2 entries specified to
efi_fake_mem=.
[ ardb: added a comment to clarify that efi_memmap_free() does nothing when
called from efi_clean_memmap(), i.e., with data->flags == 0x0 ]
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
drivers/firmware/efi/memmap.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/drivers/firmware/efi/memmap.c b/drivers/firmware/efi/memmap.c
index 04dfa56b994b..501672166502 100644
--- a/drivers/firmware/efi/memmap.c
+++ b/drivers/firmware/efi/memmap.c
@@ -29,6 +29,28 @@ static phys_addr_t __init __efi_memmap_alloc_late(unsigned long size)
return PFN_PHYS(page_to_pfn(p));
}
+static void __init __efi_memmap_free(u64 phys, unsigned long size, unsigned long flags)
+{
+ if (flags & EFI_MEMMAP_MEMBLOCK) {
+ if (slab_is_available())
+ memblock_free_late(phys, size);
+ else
+ memblock_free(phys, size);
+ } else if (flags & EFI_MEMMAP_SLAB) {
+ struct page *p = pfn_to_page(PHYS_PFN(phys));
+ unsigned int order = get_order(size);
+
+ free_pages((unsigned long) page_address(p), order);
+ }
+}
+
+static void __init efi_memmap_free(void)
+{
+ __efi_memmap_free(efi.memmap.phys_map,
+ efi.memmap.desc_size * efi.memmap.nr_map,
+ efi.memmap.flags);
+}
+
/**
* efi_memmap_alloc - Allocate memory for the EFI memory map
* @num_entries: Number of entries in the allocated map.
@@ -100,6 +122,9 @@ static int __init __efi_memmap_init(struct efi_memory_map_data *data)
return -ENOMEM;
}
+ /* NOP if data->flags & (EFI_MEMMAP_MEMBLOCK | EFI_MEMMAP_SLAB) == 0 */
+ efi_memmap_free();
+
map.phys_map = data->phys_map;
map.nr_map = data->size / data->desc_size;
map.map_end = map.map + data->size;
--
2.20.1
next prev parent reply other threads:[~2020-01-13 17:23 UTC|newest]
Thread overview: 32+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-01-13 17:22 [GIT PULL 00/13] More EFI updates for v5.6 Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 01/13] efi/libstub/x86: use const attribute for efi_is_64bit() Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 02/13] efi/libstub/x86: use mandatory 16-byte stack alignment in mixed mode Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 03/13] efi/libstub/x86: fix unused-variable warning Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 04/13] x86/mm: fix NX bit clearing issue in kernel_map_pages_in_pgd Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 05/13] efi/x86: don't map the entire kernel text RW for mixed mode Ard Biesheuvel
2020-04-08 10:42 ` Jiri Slaby
2020-04-08 10:47 ` Ard Biesheuvel
2020-04-08 10:51 ` Jiri Slaby
2020-04-09 7:51 ` Ard Biesheuvel
2020-04-09 8:06 ` Gary Lin
2020-04-09 8:10 ` Jiri Slaby
2020-04-09 8:19 ` Ard Biesheuvel
2020-04-09 8:34 ` Jiri Slaby
2020-04-09 9:09 ` Ard Biesheuvel
2020-04-09 9:45 ` Ard Biesheuvel
2020-04-09 10:09 ` Jiri Slaby
2020-04-09 10:45 ` Ard Biesheuvel
2020-04-09 11:08 ` Ard Biesheuvel
2020-04-09 11:25 ` Ard Biesheuvel
2020-04-09 11:32 ` Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 06/13] efi/x86: avoid RWX mappings for all of DRAM Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 07/13] efi/x86: limit EFI old memory map to SGI UV machines Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 08/13] efi/arm: defer probe of PCIe backed efifb on DT systems Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 09/13] efi: Fix comment for efi_mem_type() wrt absent physical addresses Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 10/13] efi: Add a flags parameter to efi_memory_map Ard Biesheuvel
2020-01-13 17:22 ` [PATCH 11/13] efi: Add tracking for dynamically allocated memmaps Ard Biesheuvel
2020-01-13 17:22 ` Ard Biesheuvel [this message]
2020-01-13 17:22 ` [PATCH 13/13] efi: Fix handling of multiple efi_fake_mem= entries Ard Biesheuvel
2020-01-20 8:25 ` [GIT PULL 00/13] More EFI updates for v5.6 Ingo Molnar
2020-01-20 8:45 ` Ard Biesheuvel
2020-01-22 7:03 ` Ingo Molnar
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