diff mbox series

[RFC,bpf-next,v2,07/16] MIPS: eBPF: fix MOD64 insn on R6 ISA

Message ID ee566ff333843f6ff734f4c12a3c6c86793c9101.1633392335.git.Tony.Ambardar@gmail.com (mailing list archive)
State RFC
Delegated to: BPF
Headers show
Series MIPS: eBPF: refactor code, add MIPS32 JIT | expand

Checks

Context Check Description
bpf/vmtest-bpf-next pending VM_Test
bpf/vmtest-bpf-next-PR pending PR summary
netdev/cover_letter success Series has a cover letter
netdev/fixes_present success Fixes tag not required for -next series
netdev/patch_count fail Series longer than 15 patches (and no cover letter)
netdev/tree_selection success Clearly marked for bpf-next
netdev/subject_prefix success Link
netdev/cc_maintainers success CCed 14 of 14 maintainers
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/module_param success Was 0 now: 0
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/kdoc success Errors and warnings before: 4 this patch: 4
netdev/verify_fixes success Fixes tag looks correct
netdev/checkpatch warning CHECK: From:/Signed-off-by: email comments mismatch: 'From: Tony Ambardar <tony.ambardar@gmail.com>' != 'Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>'
netdev/build_allmodconfig_warn success Errors and warnings before: 0 this patch: 0
netdev/header_inline success No static functions without inline keyword in header files

Commit Message

Tony Ambardar Oct. 5, 2021, 8:26 a.m. UTC 
The BPF_ALU64 | BPF_MOD implementation is broken on MIPS64R6 due to use of
a 32-bit "modu" insn, as shown by the test_verifier failures:

  455/p MOD64 overflow, check 1 FAIL retval 0 != 1 (run 1/1)
  456/p MOD64 overflow, check 2 FAIL retval 0 != 1 (run 1/1)

Resolve by using the 64-bit "dmodu" instead.

Fixes: 6c2c8a188868 ("MIPS: eBPF: Provide eBPF support for MIPS64R6")
Signed-off-by: Tony Ambardar <Tony.Ambardar@gmail.com>
---
 arch/mips/net/ebpf_jit.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)
diff mbox series

Patch

diff --git a/arch/mips/net/ebpf_jit.c b/arch/mips/net/ebpf_jit.c
index b8dc6cebefab..00dc20bc0def 100644
--- a/arch/mips/net/ebpf_jit.c
+++ b/arch/mips/net/ebpf_jit.c
@@ -800,7 +800,7 @@  static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 			if (bpf_op == BPF_DIV)
 				emit_instr(ctx, ddivu_r6, dst, dst, MIPS_R_AT);
 			else
-				emit_instr(ctx, modu, dst, dst, MIPS_R_AT);
+				emit_instr(ctx, dmodu, dst, dst, MIPS_R_AT);
 			break;
 		}
 		emit_instr(ctx, ddivu, dst, MIPS_R_AT);
@@ -882,7 +882,7 @@  static int build_one_insn(const struct bpf_insn *insn, struct jit_ctx *ctx,
 					emit_instr(ctx, ddivu_r6,
 							dst, dst, src);
 				else
-					emit_instr(ctx, modu, dst, dst, src);
+					emit_instr(ctx, dmodu, dst, dst, src);
 				break;
 			}
 			emit_instr(ctx, ddivu, dst, src);