projects / thirdparty / kernel / stable-queue.git / blame
| Commit | Line | Data |
|---|---|---|
| 8f593f65 GKH |
1 | From 6f913de3231e1d70a871135b38219da7810df218 Mon Sep 17 00:00:00 2001 |
| 2 | From: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> | |
| 3 | Date: Tue, 19 Feb 2019 10:52:24 +0300 | |
| 4 | Subject: x86/boot/compressed/64: Do not read legacy ROM on EFI system | |
| 5 | ||
| 6 | From: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | |
| 7 | ||
| 8 | commit 6f913de3231e1d70a871135b38219da7810df218 upstream. | |
| 9 | ||
| 10 | EFI systems do not necessarily provide a legacy ROM. If the ROM is missing | |
| 11 | the memory is not mapped at all. | |
| 12 | ||
| 13 | Trying to dereference values in the legacy ROM area leads to a crash on | |
| 14 | Macbook Pro. | |
| 15 | ||
| 16 | Only look for values in the legacy ROM area for non-EFI system. | |
| 17 | ||
| 18 | Fixes: 3548e131ec6a ("x86/boot/compressed/64: Find a place for 32-bit trampoline") | |
| 19 | Reported-by: Pitam Mitra <pitamm@gmail.com> | |
| 20 | Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | |
| 21 | Signed-off-by: Thomas Gleixner <tglx@linutronix.de> | |
| 22 | Tested-by: Bockjoo Kim <bockjoo@phys.ufl.edu> | |
| 23 | Cc: bp@alien8.de | |
| 24 | Cc: hpa@zytor.com | |
| 25 | Cc: stable@vger.kernel.org | |
| 26 | Link: https://lkml.kernel.org/r/20190219075224.35058-1-kirill.shutemov@linux.intel.com | |
| 27 | Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202351 | |
| 28 | Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> | |
| 29 | ||
| 30 | --- | |
| 31 | arch/x86/boot/compressed/pgtable_64.c | 19 ++++++++++++++++--- | |
| 32 | 1 file changed, 16 insertions(+), 3 deletions(-) | |
| 33 | ||
| 34 | --- a/arch/x86/boot/compressed/pgtable_64.c | |
| 35 | +++ b/arch/x86/boot/compressed/pgtable_64.c | |
| 36 | @@ -1,5 +1,7 @@ | |
| 37 | +#include <linux/efi.h> | |
| 38 | #include <asm/e820/types.h> | |
| 39 | #include <asm/processor.h> | |
| 40 | +#include <asm/efi.h> | |
| 41 | #include "pgtable.h" | |
| 42 | #include "../string.h" | |
| 43 | ||
| 44 | @@ -37,9 +39,10 @@ int cmdline_find_option_bool(const char | |
| 45 | ||
| 46 | static unsigned long find_trampoline_placement(void) | |
| 47 | { | |
| 48 | - unsigned long bios_start, ebda_start; | |
| 49 | + unsigned long bios_start = 0, ebda_start = 0; | |
| 50 | unsigned long trampoline_start; | |
| 51 | struct boot_e820_entry *entry; | |
| 52 | + char *signature; | |
| 53 | int i; | |
| 54 | ||
| 55 | /* | |
| 56 | @@ -47,8 +50,18 @@ static unsigned long find_trampoline_pla | |
| 57 | * This code is based on reserve_bios_regions(). | |
| 58 | */ | |
| 59 | ||
| 60 | - ebda_start = *(unsigned short *)0x40e << 4; | |
| 61 | - bios_start = *(unsigned short *)0x413 << 10; | |
| 62 | + /* | |
| 63 | + * EFI systems may not provide legacy ROM. The memory may not be mapped | |
| 64 | + * at all. | |
| 65 | + * | |
| 66 | + * Only look for values in the legacy ROM for non-EFI system. | |
| 67 | + */ | |
| 68 | + signature = (char *)&boot_params->efi_info.efi_loader_signature; | |
| 69 | + if (strncmp(signature, EFI32_LOADER_SIGNATURE, 4) && | |
| 70 | + strncmp(signature, EFI64_LOADER_SIGNATURE, 4)) { | |
| 71 | + ebda_start = *(unsigned short *)0x40e << 4; | |
| 72 | + bios_start = *(unsigned short *)0x413 << 10; | |
| 73 | + } | |
| 74 | ||
| 75 | if (bios_start < BIOS_START_MIN || bios_start > BIOS_START_MAX) | |
| 76 | bios_start = BIOS_START_MAX; |