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Kernel/aarch64: Do not trap floating-point instructions

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This requires setting the FPEN field of the Architectural Feature Access
Control Register (CPACR_EL1) to 0b11.
This commit is contained in:
Timon Kruiper 2023-01-30 16:06:24 +01:00 • committed by Jelle Raaijmakers
parent dfc6555fec
commit e57d35ff53
2 changed files with 27 additions and 0 deletions
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7
Kernel/Arch/aarch64/Exceptions.cpp
View file

@ -78,6 +78,13 @@ static void setup_el1()
Aarch64::SCTLR_EL1::write(system_control_register_el1);
Aarch64::CPACR_EL1 cpacr_el1 = {};
cpacr_el1.ZEN = 0; // Trap SVE instructions at EL1 and EL0
cpacr_el1.FPEN = 0b11; // Don't trap Advanced SIMD and floating-point instructions
cpacr_el1.SMEN = 0; // Trap SME instructions at EL1 and EL0
cpacr_el1.TTA = 0; // Don't trap access to trace registers
Aarch64::CPACR_EL1::write(cpacr_el1);
Aarch64::Asm::load_el1_vector_table(&vector_table_el1);
}

20
Kernel/Arch/aarch64/Registers.h
View file

@ -1344,4 +1344,24 @@ struct alignas(u64) PMCCNTR_EL0 {
};
static_assert(sizeof(PMCCNTR_EL0) == 8);
// D17.2.30 CPACR_EL1, Architectural Feature Access Control Register
struct alignas(u64) CPACR_EL1 {
int _reserved0 : 16 = 0;
int ZEN : 2;
int _reserved18 : 2 = 0;
int FPEN : 2;
int _reserved22 : 2 = 0;
int SMEN : 2;
int _reserved26 : 2 = 0;
int TTA : 1;
int _reserved29 : 3 = 0;
int _reserved32 : 32 = 0;
static inline void write(CPACR_EL1 cpacr_el1)
{
asm("msr cpacr_el1, %[value]" ::[value] "r"(cpacr_el1));
}
};
static_assert(sizeof(CPACR_EL1) == 8);
}