The touchpad driver crashed the ASUS TUF A15 at boot. Its thread runs the firmware's AML -- _DSM, _PS0, _CRS -- through uACPI at -O0, on an 8 KB kernel stack, and kernel stacks are one array: running off the end lands in the next thread's stack, and the machine dies a moment later in some other code. The thread now runs on a 64 KB stack of its own, through SCFF's call_on_stack(). And a crashed laptop sat with its fans up until somebody held the power button, since the other processors keep running. On an ordinary boot the PSOGM now says it will power off, and does, after three minutes: SLP_TYP from \_S5, read at boot, written straight to PM1 control with no AML, which could sleep or wait on a lock a dead processor holds. A verbose boot keeps the screen up for ever. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
34 lines
1.6 KiB
C
34 lines
1.6 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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#pragma once
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// ACPI, in two layers.
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//
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// kernel/arch/x86_64/acpi.c reads the static tables at boot, before anything
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// else can run: the MADT for the processors and the I/O APIC and its
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// interrupt source overrides, the FADT for the PM timer.
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//
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// kernel/acpi/ is everything that needs AML, which is the firmware's own code
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// and has to be interpreted: uACPI (ports/uacpi) runs it, and aml.c uses it
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// for PCI interrupt routing, the power button, power-off and reset. Every
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// function below that depends on it does nothing, and says so by returning
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// -1, on a machine whose AML could not be loaded.
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// The RSDP's physical address, or 0 if there is none.
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uint64 acpi_rsdp_phys(void);
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// The GSI an ISA IRQ is wired to, after the MADT's interrupt source
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// overrides, and its trigger mode (an IRQ_* from irq.h) in *mode. `dflt` is
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// the mode when the override says "conforms to the bus" or there is none:
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// edge/high for an ISA device, level/low for the SCI.
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int acpi_isa_gsi(int isa, int dflt, int *mode);
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// Load and initialize the namespace. After kinit, before pci_init.
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void acpi_aml_init(void);
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// The worker thread that runs AML on behalf of interrupts. After sinit.
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void acpi_thread_start(void);
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// Route every PCI device's INTx through _PRT. From pci_init, before binding.
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void acpi_pci_route(void);
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int acpi_poweroff(void); // S5; returns only on failure
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void acpi_poweroff_now(void); // S5 from a panic, no AML; returns only on failure
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int acpi_reboot(void); // the FADT reset register; ditto
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