diff options
Diffstat (limited to 'Documentation/arm64')
| -rw-r--r-- | Documentation/arm64/booting.rst | 33 | ||||
| -rw-r--r-- | Documentation/arm64/elf_hwcaps.rst | 2 | ||||
| -rw-r--r-- | Documentation/arm64/tagged-address-abi.rst | 6 |
3 files changed, 39 insertions, 2 deletions
diff --git a/Documentation/arm64/booting.rst b/Documentation/arm64/booting.rst index 4fcc00add117..18b8cc1bf32c 100644 --- a/Documentation/arm64/booting.rst +++ b/Documentation/arm64/booting.rst @@ -277,9 +277,40 @@ Before jumping into the kernel, the following conditions must be met: - SCR_EL3.FGTEn (bit 27) must be initialised to 0b1. + For CPUs with Advanced SIMD and floating point support: + + - If EL3 is present: + + - CPTR_EL3.TFP (bit 10) must be initialised to 0b0. + + - If EL2 is present and the kernel is entered at EL1: + + - CPTR_EL2.TFP (bit 10) must be initialised to 0b0. + + For CPUs with the Scalable Vector Extension (FEAT_SVE) present: + + - if EL3 is present: + + - CPTR_EL3.EZ (bit 8) must be initialised to 0b1. + + - ZCR_EL3.LEN must be initialised to the same value for all CPUs the + kernel is executed on. + + - If the kernel is entered at EL1 and EL2 is present: + + - CPTR_EL2.TZ (bit 8) must be initialised to 0b0. + + - CPTR_EL2.ZEN (bits 17:16) must be initialised to 0b11. + + - ZCR_EL2.LEN must be initialised to the same value for all CPUs the + kernel will execute on. + 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. +enter the kernel in the same exception level. Where the values documented +disable traps it is permissible for these traps to be enabled so long as +those traps are handled transparently by higher exception levels as though +the values documented were set. The boot loader is expected to enter the kernel on each CPU in the following manner: diff --git a/Documentation/arm64/elf_hwcaps.rst b/Documentation/arm64/elf_hwcaps.rst index 87821662eeb2..ec1a5a63c1d0 100644 --- a/Documentation/arm64/elf_hwcaps.rst +++ b/Documentation/arm64/elf_hwcaps.rst @@ -74,7 +74,7 @@ HWCAP_ASIMD HWCAP_EVTSTRM The generic timer is configured to generate events at a frequency of - approximately 100KHz. + approximately 10KHz. HWCAP_AES Functionality implied by ID_AA64ISAR0_EL1.AES == 0b0001. diff --git a/Documentation/arm64/tagged-address-abi.rst b/Documentation/arm64/tagged-address-abi.rst index cbc4d4500241..459e6b66ff68 100644 --- a/Documentation/arm64/tagged-address-abi.rst +++ b/Documentation/arm64/tagged-address-abi.rst @@ -113,6 +113,12 @@ ABI relaxation: - ``shmat()`` and ``shmdt()``. +- ``brk()`` (since kernel v5.6). + +- ``mmap()`` (since kernel v5.6). + +- ``mremap()``, the ``new_address`` argument (since kernel v5.6). + Any attempt to use non-zero tagged pointers may result in an error code being returned, a (fatal) signal being raised, or other modes of failure. |