Commit 6abf17d6 authored by Tiezhu Yang's avatar Tiezhu Yang Committed by Huacai Chen
Browse files

LoongArch: BPF: Add struct ops support for trampoline 



Use BPF_TRAMP_F_INDIRECT flag to detect struct ops and emit proper
prologue and epilogue for this case.

With this patch, all of the struct_ops related testcases (except
struct_ops_multi_pages) passed on LoongArch.

The testcase struct_ops_multi_pages failed is because the actual
image_pages_cnt is 40 which is bigger than MAX_TRAMP_IMAGE_PAGES.

Before:

  $ sudo ./test_progs -t struct_ops -d struct_ops_multi_pages
  ...
  WATCHDOG: test case struct_ops_module/struct_ops_load executes for 10 seconds...

After:

  $ sudo ./test_progs -t struct_ops -d struct_ops_multi_pages
  ...
  #15      bad_struct_ops:OK
  ...
  #399     struct_ops_autocreate:OK
  ...
  #400     struct_ops_kptr_return:OK
  ...
  #401     struct_ops_maybe_null:OK
  ...
  #402     struct_ops_module:OK
  ...
  #404     struct_ops_no_cfi:OK
  ...
  #405     struct_ops_private_stack:SKIP
  ...
  #406     struct_ops_refcounted:OK
  Summary: 8/25 PASSED, 3 SKIPPED, 0 FAILED

Signed-off-by: default avatarTiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: default avatarHuacai Chen <chenhuacai@loongson.cn>
parent f9b6b41f

arch/loongarch/net/bpf_jit.c

+50 −25
Original line number Diff line number Diff line
@@ -1423,6 +1423,7 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i 
	int i, ret, save_ret;

	int stack_size = 0, nargs = 0;

	int retval_off, args_off, nargs_off, ip_off, run_ctx_off, sreg_off;

	bool is_struct_ops = flags & BPF_TRAMP_F_INDIRECT;

	void *orig_call = func_addr;

	struct bpf_tramp_links *fentry = &tlinks[BPF_TRAMP_FENTRY];

	struct bpf_tramp_links *fexit = &tlinks[BPF_TRAMP_FEXIT];
@@ -1500,7 +1501,21 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i 


	stack_size = round_up(stack_size, 16);



	/* For the trampoline called from function entry */

	if (is_struct_ops) {

		/*

		 * For the trampoline called directly, just handle

		 * the frame of trampoline.

		 */

		emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, -stack_size);

		emit_insn(ctx, std, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, stack_size - 8);

		emit_insn(ctx, std, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_size - 16);

		emit_insn(ctx, addid, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_size);

	} else {

		/*

		 * For the trampoline called from function entry,

		 * the frame of traced function and the frame of

		 * trampoline need to be considered.

		 */

		/* RA and FP for parent function */

		emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, -16);

		emit_insn(ctx, std, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, 8);
@@ -1512,6 +1527,7 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i 
		emit_insn(ctx, std, LOONGARCH_GPR_T0, LOONGARCH_GPR_SP, stack_size - 8);

		emit_insn(ctx, std, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_size - 16);

		emit_insn(ctx, addid, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_size);

	}



	/* callee saved register S1 to pass start time */

	emit_insn(ctx, std, LOONGARCH_GPR_S1, LOONGARCH_GPR_FP, -sreg_off);
@@ -1599,6 +1615,14 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i 


	emit_insn(ctx, ldd, LOONGARCH_GPR_S1, LOONGARCH_GPR_FP, -sreg_off);



	if (is_struct_ops) {

		/* trampoline called directly */

		emit_insn(ctx, ldd, LOONGARCH_GPR_RA, LOONGARCH_GPR_SP, stack_size - 8);

		emit_insn(ctx, ldd, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_size - 16);

		emit_insn(ctx, addid, LOONGARCH_GPR_SP, LOONGARCH_GPR_SP, stack_size);



		emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_RA, 0);

	} else {

		/* trampoline called from function entry */

		emit_insn(ctx, ldd, LOONGARCH_GPR_T0, LOONGARCH_GPR_SP, stack_size - 8);

		emit_insn(ctx, ldd, LOONGARCH_GPR_FP, LOONGARCH_GPR_SP, stack_size - 16);
@@ -1614,6 +1638,7 @@ static int __arch_prepare_bpf_trampoline(struct jit_ctx *ctx, struct bpf_tramp_i 
		else

			/* return to traced function */

			emit_insn(ctx, jirl, LOONGARCH_GPR_ZERO, LOONGARCH_GPR_T0, 0);

	}



	ret = ctx->idx;

out: