diff mbox series

[bpf,RESEND,1/4] bpf: Adapt 32-bit return value kfunc for 32-bit ARM when zext extension

Message ID 20221103092118.248600-2-yangjihong1@huawei.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series bpf: Support kernel function call in 32-bit ARM | expand

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Context Check Description
bpf/vmtest-bpf-PR fail PR summary
bpf/vmtest-bpf-VM_Test-1 pending Logs for ${{ matrix.test }} on ${{ matrix.arch }} with ${{ matrix.toolchain }}
bpf/vmtest-bpf-VM_Test-2 pending Logs for ShellCheck
bpf/vmtest-bpf-VM_Test-3 fail Logs for build for s390x with gcc
bpf/vmtest-bpf-VM_Test-4 fail Logs for build for x86_64 with gcc
bpf/vmtest-bpf-VM_Test-5 fail Logs for build for x86_64 with llvm-16
bpf/vmtest-bpf-VM_Test-6 success Logs for llvm-toolchain
bpf/vmtest-bpf-VM_Test-7 success Logs for set-matrix
netdev/tree_selection success Clearly marked for bpf
netdev/fixes_present fail Series targets non-next tree, but doesn't contain any Fixes tags
netdev/subject_prefix success Link
netdev/cover_letter success Series has a cover letter
netdev/patch_count success Link
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 10 this patch: 10
netdev/cc_maintainers success CCed 12 of 12 maintainers
netdev/build_clang success Errors and warnings before: 5 this patch: 5
netdev/module_param success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 10 this patch: 10
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 9 lines checked
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Yang Jihong Nov. 3, 2022, 9:21 a.m. UTC 
For ARM32 architecture, if data width of kfunc return value is 32 bits,
need to do explicit zero extension for high 32-bit, insn_def_regno should
return dst_reg for BPF_JMP type of BPF_PSEUDO_KFUNC_CALL. Otherwise,
opt_subreg_zext_lo32_rnd_hi32 returns -EFAULT, resulting in BPF failure.

Signed-off-by: Yang Jihong <yangjihong1@huawei.com>
---
 kernel/bpf/verifier.c | 3 +++
 1 file changed, 3 insertions(+)
diff mbox series

Patch

diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index 7f0a9f6cb889..bac37757ffca 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -2404,6 +2404,9 @@  static int insn_def_regno(const struct bpf_insn *insn)
 {
 	switch (BPF_CLASS(insn->code)) {
 	case BPF_JMP:
+		if (insn->src_reg == BPF_PSEUDO_KFUNC_CALL)
+			return insn->dst_reg;
+		fallthrough;
 	case BPF_JMP32:
 	case BPF_ST:
 		return -1;