On 2022/10/18 18:12, Xi Ruoyao wrote:
On Tue, 2022-10-18 at 18:04 +0800, WANG Xuerui wrote:
/* snip */
+The system call number is placed in the register ``a7``.
+Parameters, if present, are placed from ``a0`` through ``a6`` as needed,
+as if calling a function with the respective arguments.
+Upon return, ``a0`` contains the return value, and ``t0-t8`` should be
+considered clobbered; all other registers are preserved.
Hmm, are a1-a7 guaranteed to be preserved?
Yes, you can find the relevant code here: [1] [2].
Thanks.
[1]:
https://github.com/torvalds/linux/blob/master/arch/loongarch/kernel/entry.S#L43-L50
[2]:
https://github.com/torvalds/linux/blob/master/arch/loongarch/kernel/entry.S#L68
