Merge branch 'ppc-fix'

Daniel Borkmann says:

====================
This set adds a ppc64 JIT fix for xadd as well as a missing test
case for verifying whether xadd messes with src/dst reg. Thanks!
====================

Signed-off-by: Alexei Starovoitov <ast@kernel.org>

2 files changed, 45 insertions, 24 deletions

diff --git a/arch/powerpc/net/bpf_jit_comp64.c b/arch/powerpc/net/bpf_jit_comp64.c
index 380cbf9a40d9..c0a9bcd28356 100644
--- a/arch/powerpc/net/bpf_jit_comp64.c
+++ b/arch/powerpc/net/bpf_jit_comp64.c
@@ -286,6 +286,7 @@ static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
                 u64 imm64;
                 u8 *func;
                 u32 true_cond;
+                u32 tmp_idx;
 
                 /*
                  * addrs[] maps a BPF bytecode address into a real offset from
@@ -637,11 +638,7 @@ emit_clear:
                 case BPF_STX | BPF_XADD | BPF_W:
                         /* Get EA into TMP_REG_1 */
                         PPC_ADDI(b2p[TMP_REG_1], dst_reg, off);
-                        /* error if EA is not word-aligned */
-                        PPC_ANDI(b2p[TMP_REG_2], b2p[TMP_REG_1], 0x03);
-                        PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + 12);
-                        PPC_LI(b2p[BPF_REG_0], 0);
-                        PPC_JMP(exit_addr);
+                        tmp_idx = ctx->idx * 4;
                         /* load value from memory into TMP_REG_2 */
                         PPC_BPF_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
                         /* add value from src_reg into this */
@@ -649,32 +646,16 @@ emit_clear:
                         /* store result back */
                         PPC_BPF_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
                         /* we're done if this succeeded */
-                        PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + (7*4));
-                        /* otherwise, let's try once more */
-                        PPC_BPF_LWARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
-                        PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
-                        PPC_BPF_STWCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
-                        /* exit if the store was not successful */
-                        PPC_LI(b2p[BPF_REG_0], 0);
-                        PPC_BCC(COND_NE, exit_addr);
+                        PPC_BCC_SHORT(COND_NE, tmp_idx);
                         break;
                 /* *(u64 *)(dst + off) += src */
                 case BPF_STX | BPF_XADD | BPF_DW:
                         PPC_ADDI(b2p[TMP_REG_1], dst_reg, off);
-                        /* error if EA is not doubleword-aligned */
-                        PPC_ANDI(b2p[TMP_REG_2], b2p[TMP_REG_1], 0x07);
-                        PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + (3*4));
-                        PPC_LI(b2p[BPF_REG_0], 0);
-                        PPC_JMP(exit_addr);
-                        PPC_BPF_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
-                        PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
-                        PPC_BPF_STDCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
-                        PPC_BCC_SHORT(COND_EQ, (ctx->idx * 4) + (7*4));
+                        tmp_idx = ctx->idx * 4;
                         PPC_BPF_LDARX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1], 0);
                         PPC_ADD(b2p[TMP_REG_2], b2p[TMP_REG_2], src_reg);
                         PPC_BPF_STDCX(b2p[TMP_REG_2], 0, b2p[TMP_REG_1]);
-                        PPC_LI(b2p[BPF_REG_0], 0);
-                        PPC_BCC(COND_NE, exit_addr);
+                        PPC_BCC_SHORT(COND_NE, tmp_idx);
                         break;
 
                 /*
diff --git a/tools/testing/selftests/bpf/test_verifier.c b/tools/testing/selftests/bpf/test_verifier.c
index f5f7bcc96046..41106d9d5cc7 100644
--- a/tools/testing/selftests/bpf/test_verifier.c
+++ b/tools/testing/selftests/bpf/test_verifier.c
@@ -12005,6 +12005,46 @@ static struct bpf_test tests[] = {
                 .prog_type = BPF_PROG_TYPE_XDP,
         },
         {
+                "xadd/w check whether src/dst got mangled, 1",
+                .insns = {
+                        BPF_MOV64_IMM(BPF_REG_0, 1),
+                        BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
+                        BPF_STX_MEM(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+                        BPF_STX_XADD(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+                        BPF_STX_XADD(BPF_DW, BPF_REG_10, BPF_REG_0, -8),
+                        BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_0, 3),
+                        BPF_JMP_REG(BPF_JNE, BPF_REG_7, BPF_REG_10, 2),
+                        BPF_LDX_MEM(BPF_DW, BPF_REG_0, BPF_REG_10, -8),
+                        BPF_EXIT_INSN(),
+                        BPF_MOV64_IMM(BPF_REG_0, 42),
+                        BPF_EXIT_INSN(),
+                },
+                .result = ACCEPT,
+                .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+                .retval = 3,
+        },
+        {
+                "xadd/w check whether src/dst got mangled, 2",
+                .insns = {
+                        BPF_MOV64_IMM(BPF_REG_0, 1),
+                        BPF_MOV64_REG(BPF_REG_6, BPF_REG_0),
+                        BPF_MOV64_REG(BPF_REG_7, BPF_REG_10),
+                        BPF_STX_MEM(BPF_W, BPF_REG_10, BPF_REG_0, -8),
+                        BPF_STX_XADD(BPF_W, BPF_REG_10, BPF_REG_0, -8),
+                        BPF_STX_XADD(BPF_W, BPF_REG_10, BPF_REG_0, -8),
+                        BPF_JMP_REG(BPF_JNE, BPF_REG_6, BPF_REG_0, 3),
+                        BPF_JMP_REG(BPF_JNE, BPF_REG_7, BPF_REG_10, 2),
+                        BPF_LDX_MEM(BPF_W, BPF_REG_0, BPF_REG_10, -8),
+                        BPF_EXIT_INSN(),
+                        BPF_MOV64_IMM(BPF_REG_0, 42),
+                        BPF_EXIT_INSN(),
+                },
+                .result = ACCEPT,
+                .prog_type = BPF_PROG_TYPE_SCHED_CLS,
+                .retval = 3,
+        },
+        {
                 "bpf_get_stack return R0 within range",
                 .insns = {
                         BPF_MOV64_REG(BPF_REG_6, BPF_REG_1),