This patch implements the signal handling on aarch64. I will not be repeating the details of what it changes and why as it is quite well explained in the code changes. But in essence, this patch updates the build_signal_frame() which I believe was based on the x86_64 version of it with the changes specific to aarch64. It also adds missing handling of the SA_ONSTACK flag. Secondly, this patch also enhances entry.S to implement the call_signal_handler_thunk which is probably the most tricky part. The call_signal_handler_thunk is called on exit from a page fault as an effect of build_signal_frame() setting the field `elr` into the exception frame. Unlike on x86_64, the stack pointer register (sp) is not changed automatically based on the content of the frame on exit. To that end, the call_signal_handler_thunk has to carefully switch to SP_EL0 (exception stack) to read the value of the sp field from the exception frame in order to set SP_EL1 which is used normally for non-expection-handling by kernel and apps. Eventually, it calls the call_signal_handler() which is implemented logically in similar fashion as on x86_64 except for different registers. Finally, this patch also enables 3 unit tests to run on aarch64. Fixes cloudius-systems#1154 Fixes cloudius-systems#1151 Fixes cloudius-systems#1152 Fixes cloudius-systems#1153 Signed-off-by: Waldemar Kozaczuk <jwkozaczuk@gmail.com>

tst-elf-permissions.cc fails on aarch64 #1152

Description

Metadata

Assignees

Labels

Type

Projects

Milestone

Relationships

Development

Issue actions