linux-kernel - [PATCH 5/5] powerpc64/bpf: jit support for signed division and modulo

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Date: Fri, 17 May 2024 09:56:50 +0200
From: Artem Savkov <asavkov@...hat.com>
To: Michael Ellerman <mpe@...erman.id.au>,
	Nicholas Piggin <npiggin@...il.com>,
	Christophe Leroy <christophe.leroy@...roup.eu>,
	"Naveen N. Rao" <naveen.n.rao@...ux.ibm.com>,
	linuxppc-dev@...ts.ozlabs.org
Cc: Alexei Starovoitov <ast@...nel.org>,
	Daniel Borkmann <daniel@...earbox.net>,
	Andrii Nakryiko <andrii@...nel.org>,
	bpf@...r.kernel.org,
	netdev@...r.kernel.org,
	linux-kernel@...r.kernel.org,
	Artem Savkov <asavkov@...hat.com>
Subject: [PATCH 5/5] powerpc64/bpf: jit support for signed division and modulo

Add jit support for sign division and modulo. Tested using test_bpf
module.

Signed-off-by: Artem Savkov <asavkov@...hat.com>
---
 arch/powerpc/include/asm/ppc-opcode.h |  1 +
 arch/powerpc/net/bpf_jit_comp64.c     | 41 +++++++++++++++++++++------
 2 files changed, 34 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h
index 76cc9a2d82065..b98a9e982c03b 100644
--- a/arch/powerpc/include/asm/ppc-opcode.h
+++ b/arch/powerpc/include/asm/ppc-opcode.h
@@ -536,6 +536,7 @@
 #define PPC_RAW_MULI(d, a, i)		(0x1c000000 | ___PPC_RT(d) | ___PPC_RA(a) | IMM_L(i))
 #define PPC_RAW_DIVW(d, a, b)		(0x7c0003d6 | ___PPC_RT(d) | ___PPC_RA(a) | ___PPC_RB(b))
 #define PPC_RAW_DIVWU(d, a, b)		(0x7c000396 | ___PPC_RT(d) | ___PPC_RA(a) | ___PPC_RB(b))
+#define PPC_RAW_DIVD(d, a, b)		(0x7c0003d2 | ___PPC_RT(d) | ___PPC_RA(a) | ___PPC_RB(b))
 #define PPC_RAW_DIVDU(d, a, b)		(0x7c000392 | ___PPC_RT(d) | ___PPC_RA(a) | ___PPC_RB(b))
 #define PPC_RAW_DIVDE(t, a, b)		(0x7c000352 | ___PPC_RT(t) | ___PPC_RA(a) | ___PPC_RB(b))
 #define PPC_RAW_DIVDE_DOT(t, a, b)	(0x7c000352 | ___PPC_RT(t) | ___PPC_RA(a) | ___PPC_RB(b) | 0x1)
diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 811775cfd3a1b..1f5f93926e424 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -510,20 +510,33 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct code
 		case BPF_ALU | BPF_DIV | BPF_X: /* (u32) dst /= (u32) src */
 		case BPF_ALU | BPF_MOD | BPF_X: /* (u32) dst %= (u32) src */
 			if (BPF_OP(code) == BPF_MOD) {
-				EMIT(PPC_RAW_DIVWU(tmp1_reg, dst_reg, src_reg));
+				if (off)
+					EMIT(PPC_RAW_DIVW(tmp1_reg, dst_reg, src_reg));
+				else
+					EMIT(PPC_RAW_DIVWU(tmp1_reg, dst_reg, src_reg));
+
 				EMIT(PPC_RAW_MULW(tmp1_reg, src_reg, tmp1_reg));
 				EMIT(PPC_RAW_SUB(dst_reg, dst_reg, tmp1_reg));
 			} else
-				EMIT(PPC_RAW_DIVWU(dst_reg, dst_reg, src_reg));
+				if (off)
+					EMIT(PPC_RAW_DIVW(dst_reg, dst_reg, src_reg));
+				else
+					EMIT(PPC_RAW_DIVWU(dst_reg, dst_reg, src_reg));
 			goto bpf_alu32_trunc;
 		case BPF_ALU64 | BPF_DIV | BPF_X: /* dst /= src */
 		case BPF_ALU64 | BPF_MOD | BPF_X: /* dst %= src */
 			if (BPF_OP(code) == BPF_MOD) {
-				EMIT(PPC_RAW_DIVDU(tmp1_reg, dst_reg, src_reg));
+				if (off)
+					EMIT(PPC_RAW_DIVD(tmp1_reg, dst_reg, src_reg));
+				else
+					EMIT(PPC_RAW_DIVDU(tmp1_reg, dst_reg, src_reg));
 				EMIT(PPC_RAW_MULD(tmp1_reg, src_reg, tmp1_reg));
 				EMIT(PPC_RAW_SUB(dst_reg, dst_reg, tmp1_reg));
 			} else
-				EMIT(PPC_RAW_DIVDU(dst_reg, dst_reg, src_reg));
+				if (off)
+					EMIT(PPC_RAW_DIVD(dst_reg, dst_reg, src_reg));
+				else
+					EMIT(PPC_RAW_DIVDU(dst_reg, dst_reg, src_reg));
 			break;
 		case BPF_ALU | BPF_MOD | BPF_K: /* (u32) dst %= (u32) imm */
 		case BPF_ALU | BPF_DIV | BPF_K: /* (u32) dst /= (u32) imm */
@@ -544,19 +557,31 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct code
 			switch (BPF_CLASS(code)) {
 			case BPF_ALU:
 				if (BPF_OP(code) == BPF_MOD) {
-					EMIT(PPC_RAW_DIVWU(tmp2_reg, dst_reg, tmp1_reg));
+					if (off)
+						EMIT(PPC_RAW_DIVW(tmp2_reg, dst_reg, tmp1_reg));
+					else
+						EMIT(PPC_RAW_DIVWU(tmp2_reg, dst_reg, tmp1_reg));
 					EMIT(PPC_RAW_MULW(tmp1_reg, tmp1_reg, tmp2_reg));
 					EMIT(PPC_RAW_SUB(dst_reg, dst_reg, tmp1_reg));
 				} else
-					EMIT(PPC_RAW_DIVWU(dst_reg, dst_reg, tmp1_reg));
+					if (off)
+						EMIT(PPC_RAW_DIVW(dst_reg, dst_reg, tmp1_reg));
+					else
+						EMIT(PPC_RAW_DIVWU(dst_reg, dst_reg, tmp1_reg));
 				break;
 			case BPF_ALU64:
 				if (BPF_OP(code) == BPF_MOD) {
-					EMIT(PPC_RAW_DIVDU(tmp2_reg, dst_reg, tmp1_reg));
+					if (off)
+						EMIT(PPC_RAW_DIVD(tmp2_reg, dst_reg, tmp1_reg));
+					else
+						EMIT(PPC_RAW_DIVDU(tmp2_reg, dst_reg, tmp1_reg));
 					EMIT(PPC_RAW_MULD(tmp1_reg, tmp1_reg, tmp2_reg));
 					EMIT(PPC_RAW_SUB(dst_reg, dst_reg, tmp1_reg));
 				} else
-					EMIT(PPC_RAW_DIVDU(dst_reg, dst_reg, tmp1_reg));
+					if (off)
+						EMIT(PPC_RAW_DIVD(dst_reg, dst_reg, tmp1_reg));
+					else
+						EMIT(PPC_RAW_DIVDU(dst_reg, dst_reg, tmp1_reg));
 				break;
 			}
 			goto bpf_alu32_trunc;
-- 
2.45.0