Tailcall in AArch64
In AArch64 (ARM64), for a tail call to work, the current function must tear down its own stack frame before branching to the next function. If it didn't, the stack…
Tag: AARCH64
LDR vs. LDUR in AArch64
In AArch64 (ARMv8-A), the main difference between LDR and LDUR is how they handle the immediate offset from the base address. LDR (Load Register): Uses a scaled positive immediate offset.…
Why the load of main by _start uses got entry, not adrp+add pair?
The _start function uses a Global Offset Table (GOT) entry to load the address of main primarily because _start is defined in a pre-compiled object file (typically Scrt1.o) that was…
AArch64 Pre/Post Indexing
In AArch64 (ARMv8-A 64-bit architecture), Pre-indexing and Post-indexing are memory addressing modes used with Load (LDR) and Store (STR) instructions. Their primary purpose is to perform Writeback: they automatically update…
Enabling PAC and BTI on AArch64 for Linux
https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/enabling-pac-and-bti-on-aarch64 https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/p2-enabling-pac-and-bti-on-aarch64 https://community.arm.com/arm-community-blogs/b/architectures-and-processors-blog/posts/p3-enabling-pac-and-bti-on-aarch64 Source code for the examples can be found at https://gitlab.arm.com/pac-and-bti-blog/blog-example and the tag will be referenced with the "Tag" keyword before source examples. Certain versions of Arm…
How to compile coreutils / binutils for aarch64 in x64
Dockcross git clone https://github.com/dockcross/dockcross.git cd dockcross docker run --rm dockcross/linux-arm64> ./dockcross-linux-arm64 chmod +x ./dockcross-linux-arm64 mv ./dockcross-linux-arm64 ~/bin/ Coreutils / Binutils //Go to the repository diretory dockcross-linux-arm64 bash //In the docker…
How to launch ARM aarch64 VM with QEMU from scratch
https://futurewei-cloud.github.io/ARM-Datacenter/qemu/how-to-launch-aarch64-vm https://ww2.coastal.edu/mmurphy2/oer/qemu/aarch64 The below instructions will allow for bringing up an ARM VM from scratch. To launch an aarch64 VM we first need to install a few dependencies, including QEMU…