arch/x86: Changed system call ABI#9
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Instead of pushing and popping arguments on the stack, arguments are passed in registers as on Linux x86 and Tock RISC-V. This new ABI simplifies the implementation of virtual memory. Signed-off-by: Ioan-Cristian CÎRSTEA <ioan.cirstea@oxidos.io>
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Pull Request Overview
This pull request changes the system call ABI on x86. Instead of passing arguments and return values on the stack, they are passed in registers. The following registers are used for argument/return values:
ebx,ecx,edx,edi.This change is needed to simplify the implementation of the MMU on the x86 architecture, where the virtual address space of a process doesn't match the virtual address space of the kernel. In that case, writing/reading from stack led to page faults due to missing pages.
The new system call ABI mimics the Linux kernel's ABI and Tock's RISC-V ABI.
Testing Strategy
This pull request was tested by running two
libtock-rsapplications on QEMU.TODO or Help Wanted
No help needed.
Documentation Updated
Formatting
make prepush.