diff options
Diffstat (limited to 'Documentation')
| -rw-r--r-- | Documentation/arch/arm64/booting.rst | 12 | ||||
| -rw-r--r-- | Documentation/arch/arm64/elf_hwcaps.rst | 7 |
2 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/arch/arm64/booting.rst b/Documentation/arch/arm64/booting.rst index 26efca09aef3..13ef311dace8 100644 --- a/Documentation/arch/arm64/booting.rst +++ b/Documentation/arch/arm64/booting.rst @@ -556,6 +556,18 @@ Before jumping into the kernel, the following conditions must be met: - MDCR_EL3.TPM (bit 6) must be initialized to 0b0 + For CPUs with support for 64-byte loads and stores without status (FEAT_LS64): + + - If the kernel is entered at EL1 and EL2 is present: + + - HCRX_EL2.EnALS (bit 1) must be initialised to 0b1. + + For CPUs with support for 64-byte stores with status (FEAT_LS64_V): + + - If the kernel is entered at EL1 and EL2 is present: + + - HCRX_EL2.EnASR (bit 2) must be initialised to 0b1. + The requirements described above for CPU mode, caches, MMUs, architected timers, coherency and system registers apply to all CPUs. All CPUs must enter the kernel in the same exception level. Where the values documented diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst index a15df4956849..97315ae6c0da 100644 --- a/Documentation/arch/arm64/elf_hwcaps.rst +++ b/Documentation/arch/arm64/elf_hwcaps.rst @@ -444,6 +444,13 @@ HWCAP3_MTE_STORE_ONLY HWCAP3_LSFE Functionality implied by ID_AA64ISAR3_EL1.LSFE == 0b0001 +HWCAP3_LS64 + Functionality implied by ID_AA64ISAR1_EL1.LS64 == 0b0001. Note that + the function of instruction ld64b/st64b requires support by CPU, system + and target (device) memory location and HWCAP3_LS64 implies the support + of CPU. User should only use ld64b/st64b on supported target (device) + memory location, otherwise fallback to the non-atomic alternatives. + 4. Unused AT_HWCAP bits ----------------------- |