181 lines
7.6 KiB
Diff
181 lines
7.6 KiB
Diff
From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
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Date: Wed, 9 Dec 2015 15:41:08 -0800
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Subject: x86/efi-bgrt: Fix kernel panic when mapping BGRT data
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Origin: https://git.kernel.org/cgit/linux/kernel/git/mfleming/efi.git/commit?id=50a0cb565246f20d59cdb161778531e4b19d35ac
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Bug-Debian: https://bugs.debian.org/815125
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Starting with this commit 35eb8b81edd4 ("x86/efi: Build our own page
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table structures") efi regions have a separate page directory called
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"efi_pgd". In order to access any efi region we have to first shift %cr3
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to this page table. In the bgrt code we are trying to copy bgrt_header
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and image, but these regions fall under "EFI_BOOT_SERVICES_DATA"
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and to access these regions we have to shift %cr3 to efi_pgd and not
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doing so will cause page fault as shown below.
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[ 0.251599] Last level dTLB entries: 4KB 64, 2MB 0, 4MB 0, 1GB 4
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[ 0.259126] Freeing SMP alternatives memory: 32K (ffffffff8230e000 - ffffffff82316000)
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[ 0.271803] BUG: unable to handle kernel paging request at fffffffefce35002
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[ 0.279740] IP: [<ffffffff821bca49>] efi_bgrt_init+0x144/0x1fd
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[ 0.286383] PGD 300f067 PUD 0
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[ 0.289879] Oops: 0000 [#1] SMP
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[ 0.293566] Modules linked in:
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[ 0.297039] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 4.4.0-rc1-eywa-eywa-built-in-47041+ #2
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[ 0.306619] Hardware name: Intel Corporation Skylake Client platform/Skylake Y LPDDR3 RVP3, BIOS SKLSE2R1.R00.B104.B01.1511110114 11/11/2015
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[ 0.320925] task: ffffffff820134c0 ti: ffffffff82000000 task.ti: ffffffff82000000
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[ 0.329420] RIP: 0010:[<ffffffff821bca49>] [<ffffffff821bca49>] efi_bgrt_init+0x144/0x1fd
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[ 0.338821] RSP: 0000:ffffffff82003f18 EFLAGS: 00010246
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[ 0.344852] RAX: fffffffefce35000 RBX: fffffffefce35000 RCX: fffffffefce2b000
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[ 0.352952] RDX: 000000008a82b000 RSI: ffffffff8235bb80 RDI: 000000008a835000
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[ 0.361050] RBP: ffffffff82003f30 R08: 000000008a865000 R09: ffffffffff202850
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[ 0.369149] R10: ffffffff811ad62f R11: 0000000000000000 R12: 0000000000000000
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[ 0.377248] R13: ffff88016dbaea40 R14: ffffffff822622c0 R15: ffffffff82003fb0
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[ 0.385348] FS: 0000000000000000(0000) GS:ffff88016d800000(0000) knlGS:0000000000000000
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[ 0.394533] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
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[ 0.401054] CR2: fffffffefce35002 CR3: 000000000300c000 CR4: 00000000003406f0
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[ 0.409153] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
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[ 0.417252] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
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[ 0.425350] Stack:
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[ 0.427638] ffffffffffffffff ffffffff82256900 ffff88016dbaea40 ffffffff82003f40
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[ 0.436086] ffffffff821bbce0 ffffffff82003f88 ffffffff8219c0c2 0000000000000000
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[ 0.444533] ffffffff8219ba4a ffffffff822622c0 0000000000083000 00000000ffffffff
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[ 0.452978] Call Trace:
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[ 0.455763] [<ffffffff821bbce0>] efi_late_init+0x9/0xb
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[ 0.461697] [<ffffffff8219c0c2>] start_kernel+0x463/0x47f
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[ 0.467928] [<ffffffff8219ba4a>] ? set_init_arg+0x55/0x55
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[ 0.474159] [<ffffffff8219b120>] ? early_idt_handler_array+0x120/0x120
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[ 0.481669] [<ffffffff8219b5ee>] x86_64_start_reservations+0x2a/0x2c
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[ 0.488982] [<ffffffff8219b72d>] x86_64_start_kernel+0x13d/0x14c
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[ 0.495897] Code: 00 41 b4 01 48 8b 78 28 e8 09 36 01 00 48 85 c0 48 89 c3 75 13 48 c7 c7 f8 ac d3 81 31 c0 e8 d7 3b fb fe e9 b5 00 00 00 45 84 e4 <44> 8b 6b 02 74 0d be 06 00 00 00 48 89 df e8 ae 34 0$
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[ 0.518151] RIP [<ffffffff821bca49>] efi_bgrt_init+0x144/0x1fd
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[ 0.524888] RSP <ffffffff82003f18>
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[ 0.528851] CR2: fffffffefce35002
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[ 0.532615] ---[ end trace 7b06521e6ebf2aea ]---
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[ 0.537852] Kernel panic - not syncing: Attempted to kill the idle task!
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As said above one way to fix this bug is to shift %cr3 to efi_pgd but we
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are not doing that way because it leaks inner details of how we switch
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to EFI page tables into a new call site and it also adds duplicate code.
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Instead, we remove the call to efi_lookup_mapped_addr() and always
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perform early_mem*() instead of early_io*() because we want to remap RAM
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regions and not I/O regions. We also delete efi_lookup_mapped_addr()
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because we are no longer using it.
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Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
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Reported-by: Wendy Wang <wendy.wang@intel.com>
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Cc: Borislav Petkov <bp@suse.de>
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Cc: Josh Triplett <josh@joshtriplett.org>
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Cc: Ricardo Neri <ricardo.neri@intel.com>
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Cc: Ravi Shankar <ravi.v.shankar@intel.com>
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Signed-off-by: Matt Fleming <matt@codeblueprint.co.uk>
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---
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arch/x86/platform/efi/efi-bgrt.c | 39 ++++++++++++++-------------------------
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drivers/firmware/efi/efi.c | 32 --------------------------------
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2 files changed, 14 insertions(+), 57 deletions(-)
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--- a/arch/x86/platform/efi/efi-bgrt.c
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+++ b/arch/x86/platform/efi/efi-bgrt.c
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@@ -28,8 +28,7 @@ struct bmp_header {
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void __init efi_bgrt_init(void)
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{
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acpi_status status;
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- void __iomem *image;
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- bool ioremapped = false;
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+ void *image;
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struct bmp_header bmp_header;
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if (acpi_disabled)
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@@ -70,20 +69,14 @@ void __init efi_bgrt_init(void)
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return;
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}
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- image = efi_lookup_mapped_addr(bgrt_tab->image_address);
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+ image = early_memremap(bgrt_tab->image_address, sizeof(bmp_header));
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if (!image) {
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- image = early_ioremap(bgrt_tab->image_address,
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- sizeof(bmp_header));
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- ioremapped = true;
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- if (!image) {
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- pr_err("Ignoring BGRT: failed to map image header memory\n");
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- return;
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- }
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+ pr_err("Ignoring BGRT: failed to map image header memory\n");
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+ return;
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}
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- memcpy_fromio(&bmp_header, image, sizeof(bmp_header));
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- if (ioremapped)
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- early_iounmap(image, sizeof(bmp_header));
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+ memcpy(&bmp_header, image, sizeof(bmp_header));
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+ early_memunmap(image, sizeof(bmp_header));
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bgrt_image_size = bmp_header.size;
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bgrt_image = kmalloc(bgrt_image_size, GFP_KERNEL | __GFP_NOWARN);
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@@ -93,18 +86,14 @@ void __init efi_bgrt_init(void)
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return;
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}
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- if (ioremapped) {
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- image = early_ioremap(bgrt_tab->image_address,
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- bmp_header.size);
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- if (!image) {
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- pr_err("Ignoring BGRT: failed to map image memory\n");
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- kfree(bgrt_image);
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- bgrt_image = NULL;
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- return;
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- }
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+ image = early_memremap(bgrt_tab->image_address, bmp_header.size);
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+ if (!image) {
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+ pr_err("Ignoring BGRT: failed to map image memory\n");
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+ kfree(bgrt_image);
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+ bgrt_image = NULL;
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+ return;
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}
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- memcpy_fromio(bgrt_image, image, bgrt_image_size);
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- if (ioremapped)
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- early_iounmap(image, bmp_header.size);
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+ memcpy(bgrt_image, image, bgrt_image_size);
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+ early_memunmap(image, bmp_header.size);
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}
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--- a/drivers/firmware/efi/efi.c
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+++ b/drivers/firmware/efi/efi.c
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@@ -324,38 +324,6 @@ u64 __init efi_mem_desc_end(efi_memory_d
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return end;
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}
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-/*
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- * We can't ioremap data in EFI boot services RAM, because we've already mapped
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- * it as RAM. So, look it up in the existing EFI memory map instead. Only
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- * callable after efi_enter_virtual_mode and before efi_free_boot_services.
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- */
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-void __iomem *efi_lookup_mapped_addr(u64 phys_addr)
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-{
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- struct efi_memory_map *map;
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- void *p;
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- map = efi.memmap;
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- if (!map)
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- return NULL;
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- if (WARN_ON(!map->map))
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- return NULL;
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- for (p = map->map; p < map->map_end; p += map->desc_size) {
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- efi_memory_desc_t *md = p;
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- u64 size = md->num_pages << EFI_PAGE_SHIFT;
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- u64 end = md->phys_addr + size;
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- if (!(md->attribute & EFI_MEMORY_RUNTIME) &&
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- md->type != EFI_BOOT_SERVICES_CODE &&
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- md->type != EFI_BOOT_SERVICES_DATA)
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- continue;
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- if (!md->virt_addr)
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- continue;
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- if (phys_addr >= md->phys_addr && phys_addr < end) {
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- phys_addr += md->virt_addr - md->phys_addr;
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- return (__force void __iomem *)(unsigned long)phys_addr;
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- }
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- }
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- return NULL;
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-}
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-
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static __initdata efi_config_table_type_t common_tables[] = {
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{ACPI_20_TABLE_GUID, "ACPI 2.0", &efi.acpi20},
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{ACPI_TABLE_GUID, "ACPI", &efi.acpi},
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