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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: Tiezhu Yang <yangtiezhu@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
This commit is contained in:
Tiezhu Yang 2025-08-05 19:00:22 +08:00 committed by Huacai Chen
parent f9b6b41f0c
commit 6abf17d690
1 changed files with 49 additions and 24 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

27
arch/loongarch/net/bpf_jit.c
View File

@ -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: