// SPDX-License-Identifier: GPL-2.0 /* callx through pointers to functions in .rodata, loaded by light skeleton */ #include #include #include /* set by user space before the programs are loaded, it's in .rodata too */ const volatile int bias = 1; int op_idx; #ifdef __clang__ const volatile bool skip = false; typedef int (*op_fn)(int); static __noinline int add_bias(int x) { return x + bias; } static __noinline int mul3(int x) { return x * 3; } /* volatile, so that the compiler doesn't replace the table with direct calls */ static op_fn const volatile ops[] = { add_bias, mul3 }; SEC("socket") int select_op(void *ctx) { unsigned int i = op_idx; if (i >= sizeof(ops) / sizeof(ops[0])) return -1; return ops[i](10); } /* functions have other offsets in this program */ SEC("socket") int both_ops(void *ctx) { return ops[1](ops[0](4)); } #else /* gcc doesn't support indirect calls */ const volatile bool skip = true; SEC("socket") int select_op(void *ctx) { return 0; } SEC("socket") int both_ops(void *ctx) { return 0; } #endif /* no callx here */ SEC("socket") int read_bias(void *ctx) { return bias; } char _license[] SEC("license") = "GPL";