💡Apple's PSCI Implementation Faces Unique Challenges on M1
Apple's M1 cores sleep differently from others
TL;DR
Apple's M1 silicon complicates PSCI implementation due to unique power management requirements. Sven is working on a UEFI Runtime Service-based PSCI conduit to address this.
Apple's M1 silicon complicates the Power State Coordination Interface (PSCI) implementation due to unique power management requirements. The ARM specification mandates cores in WFI loops preserve state, but Apple's cores use a 'deep' WFI mode that sacrifices state. This means Apple's cores do not implement EL3, unlike other ARM cores. Sven is working on a UEFI Runtime Service-based PSCI conduit to address this. Apple's cores also set chicken bits in mBoot and lock down registers starting with the M4 series. This is a big deal for anyone working with Apple Silicon's power management.
Key Points
Apple's cores use a 'deep' WFI mode that sacrifices state, unlike other ARM cores.
Sven is working on a UEFI Runtime Service-based PSCI conduit to address unique challenges.
Apple's cores set chicken bits in mBoot and lock down registers starting with M4 series.
The ARM specification mandates cores in WFI loops preserve all state.
Secure Page Table Monitor (SPTM) isolates pagetable management from the rest of the kernel.
Why It Matters
If you're working with Apple Silicon's power management, the unique challenges and solutions like Sven's UEFI Runtime Service-based PSCI conduit are crucial. This affects developers and sysadmins working with M1 and later Apple Silicon chips, impacting how they manage power and performance.
Frequently Asked Questions
Why does this matter?
If you're working with Apple Silicon's power management, the unique challenges and solutions like Sven's UEFI Runtime Service-based PSCI conduit are crucial. This affects developers and sysadmins working with M1 and later Apple Silicon chips, impacting how they manage power and performance.
What happened?
Apple's M1 silicon complicates PSCI implementation due to unique power management requirements. Sven is working on a UEFI Runtime Service-based PSCI conduit to address this.
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