mirror of https://github.com/acidanthera/audk.git
f32bfe6d06
If PcdDxeNxMemoryProtectionPolicy is set to enable protection for memory of EfiBootServicesCode, EfiConventionalMemory, the BIOS will hang at a page fault exception during MP initialization. The root cause is that the AP wake up buffer, which is below 1MB and used to hold both AP init code and data, is type of EfiConventionalMemory (not really allocated because of potential conflict with legacy code), and is marked as non-executable. During the transition from real address mode to long mode, the AP init code has to enable paging which will then cause itself a page fault exception because it's just running in non-executable memory. The solution is splitting AP wake up buffer into two part: lower part is still below 1MB and shared with legacy system, higher part is really allocated memory of BootServicesCode type. The init code in the memory below 1MB will not enable paging but just switch to protected mode and jump to higher memory, in which the init code will enable paging and switch to long mode. Cc: Jiewen Yao <jiewen.yao@intel.com> Cc: Ruiyu Ni <ruiyu.ni@intel.com> Cc: Eric Dong <eric.dong@intel.com> Cc: Laszlo Ersek <lersek@redhat.com> Contributed-under: TianoCore Contribution Agreement 1.1 Signed-off-by: Jian J Wang <jian.j.wang@intel.com> Reviewed-by: Eric Dong <eric.dong@intel.com> |
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| .. | ||
| MpEqu.inc | ||
| MpFuncs.nasm | ||