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Kernel/aarch64: Execute kernel with SP_EL1 instead of SP_EL0

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Until now the kernel was always executing with SP_EL0, as this made the
initial dropping to EL1 a bit easier. This commit changes this behaviour
to use the corresponding SP_ELx for each exception level.

To make sure that the execution of the C++ code can continue, the
current stack pointer is copied into the corresponding SP_ELx just
before dropping an exception level.
This commit is contained in:
Timon Kruiper 2023-01-08 14:01:31 +01:00 • committed by Andreas Kling
parent 05659debd1
commit 247109cee6
5 changed files with 23 additions and 20 deletions
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4
Kernel/Arch/aarch64/Processor.cpp
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@ -252,9 +252,9 @@ FlatPtr Processor::init_context(Thread& thread, bool leave_crit)
saved_program_status_register_el1.I = 0;
saved_program_status_register_el1.F = 0;
// Set exception origin mode to EL1t, so when the context is restored, we'll be executing in EL1 with SP_EL0
// Set exception origin mode to EL1h, so when the context is restored, we'll be executing in EL1 with SP_EL1
// FIXME: This must be EL0t when aarch64 supports userspace applications.
saved_program_status_register_el1.M = Aarch64::SPSR_EL1::Mode::EL1t;
saved_program_status_register_el1.M = Aarch64::SPSR_EL1::Mode::EL1h;
memcpy(&eretframe.spsr_el1, &saved_program_status_register_el1, sizeof(u64));
// Push a TrapFrame onto the stack