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fault. The previous method zero'd out the page tables, invalidated the TLB, and then entered a spin loop. The idea was that the instruction after the TLB invalidate would result in a page fault and the page fault and subsequent double fault wouldn't be able to determine the physical page for their fault handlers' first instruction. This stopped working when PGE (PG_G PTE/PDE bit) support was added as a TLB invalidate via %cr3 reload doesn't clear TLB entries with PG_G set. Thus, the CPU was still able to map the virtual address for the spin loop and happily performed its infinite loop. The triple fault now uses a much more deterministic sledge-hammer approach to generate a triple fault. First, the IDT descriptor is set to point to an empty IDT, so any interrupts (including a double fault) will instantly fault. Second, we trigger a int 3 breakpoint to force an interrupt and kick off a triple fault. MFC after: 3 days |
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| linux | ||
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| xbox | ||
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