LoongArch: BPF: Fix stack arguments for indirect trampolines

LoongArch passes arguments beyond a0-a7 at the caller stack pointer. The
trampoline store_args() helper always reads those arguments at FP + 16,
which is correct for a regular fentry trampoline: its prologue leaves FP
16 bytes below the stack pointer at trampoline entry to hold the saved
RA/FP frame record of the parent function.

A struct_ops indirect trampoline is entered through a function pointer
and only saves its own RA and FP before setting FP to the entry stack
pointer. Its stack arguments therefore start at FP rather than FP + 16.
As a result, every stack-passed struct_ops argument is currently read
two slots late.

Select the source offset based on whether the trampoline is indirect.
This also prepares the stack-passed arena argument path to consume the
actual pointer slot.

With this patch the BPF selftest "./test_progs -t struct_ops_multi_args"
passed on LoongArch.

Fixes: c9ebe2016de9 ("LoongArch: BPF: Support up to 12 function arguments for trampoline")
Acked-by: Hengqi Chen <hengqi.chen@gmail.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>

0 files changed, 0 insertions, 0 deletions