static void bpf_jit_emit_func_call(u32 *image, struct codegen_context *ctx, u64 func)
{
unsigned int i, ctx_idx = ctx->idx;
/* Load function address into r12 */
PPC_LI64(12, func);
/* For bpf-to-bpf function calls, the callee's address is unknown
* until the last extra pass. As seen above, we use PPC_LI64() to
* load the callee's address, but this may optimize the number of
* instructions required based on the nature of the address.
*
* Since we don't want the number of instructions emitted to change,
* we pad the optimized PPC_LI64() call with NOPs to guarantee that
* we always have a five-instruction sequence, which is the maximum
* that PPC_LI64() can emit.
*/
for (i = ctx->idx - ctx_idx; i < 5; i++)
PPC_NOP();
#ifdef PPC64_ELF_ABI_v1
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
* function pointer (so caller will save/restore r2)
* and since we don't use a TOC ourself.
*/
PPC_BPF_LL(2, 12, 8);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(12, 12, 0);
#endif
PPC_MTLR(12);
PPC_BLRL();
}
static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx)
{
int i;
/* Restore NVRs */
for (i = BPF_REG_6; i <= BPF_REG_10; i++)
if (bpf_is_seen_register(ctx, i))
PPC_BPF_LL(b2p[i], 1, bpf_jit_stack_offsetof(ctx, b2p[i]));
/* Tear down our stack frame */
if (bpf_has_stack_frame(ctx)) {
PPC_ADDI(1, 1, BPF_PPC_STACKFRAME + ctx->stack_size);
if (ctx->seen & SEEN_FUNC) {
PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
PPC_MTLR(0);
}
}
}
static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
{
int i;
if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) {
PPC_ADDI(1, 1, BPF_PPC_STACKFRAME);
if (ctx->seen & SEEN_DATAREF) {
PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
PPC_MTLR(0);
PPC_BPF_LL(r_D, 1, -(REG_SZ*(32-r_D)));
PPC_BPF_LL(r_HL, 1, -(REG_SZ*(32-r_HL)));
}
if (ctx->seen & SEEN_MEM) {
/* Restore any saved non-vol registers */
for (i = r_M; i < (r_M+16); i++) {
if (ctx->seen & (1 << (i-r_M)))
PPC_BPF_LL(i, 1, -(REG_SZ*(32-i)));
}
}
}
/* The RETs have left a return value in R3. */
PPC_BLR();
}
static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
u64 func)
{
#ifdef PPC64_ELF_ABI_v1
/* func points to the function descriptor */
PPC_LI64(b2p[TMP_REG_2], func);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
/* ... and move it to LR */
PPC_MTLR(b2p[TMP_REG_1]);
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
* function pointer (so caller will save/restore r2)
* and since we don't use a TOC ourself.
*/
PPC_BPF_LL(2, b2p[TMP_REG_2], 8);
#else
/* We can clobber r12 */
PPC_FUNC_ADDR(12, func);
PPC_MTLR(12);
#endif
PPC_BLRL();
}
