s390/bpf: fix bpf frame pointer setup

[karo-tx-linux.git] / arch / s390 / net / bpf_jit_comp.c

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index 7690dc8e1ab5bb619bb19ec1be1b12853e1b0589..55423d8be580113d045d30edbf86d26fb74340ff 100644 (file)
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -384,13 +384,16 @@ static void bpf_jit_prologue(struct bpf_jit *jit)
        }
        /* Setup stack and backchain */
        if (jit->seen & SEEN_STACK) {
-               /* lgr %bfp,%r15 (BPF frame pointer) */
-               EMIT4(0xb9040000, BPF_REG_FP, REG_15);
+               if (jit->seen & SEEN_FUNC)
+                       /* lgr %w1,%r15 (backchain) */
+                       EMIT4(0xb9040000, REG_W1, REG_15);
+               /* la %bfp,STK_160_UNUSED(%r15) (BPF frame pointer) */
+               EMIT4_DISP(0x41000000, BPF_REG_FP, REG_15, STK_160_UNUSED);
                /* aghi %r15,-STK_OFF */
                EMIT4_IMM(0xa70b0000, REG_15, -STK_OFF);
                if (jit->seen & SEEN_FUNC)
-                       /* stg %bfp,152(%r15) (backchain) */
-                       EMIT6_DISP_LH(0xe3000000, 0x0024, BPF_REG_FP, REG_0,
+                       /* stg %w1,152(%r15) (backchain) */
+                       EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
                                      REG_15, 152);
        }
        /*
@@ -443,8 +446,11 @@ static void bpf_jit_epilogue(struct bpf_jit *jit)
 
 /*
  * Compile one eBPF instruction into s390x code
+ *
+ * NOTE: Use noinline because for gcov (-fprofile-arcs) gcc allocates a lot of
+ * stack space for the large switch statement.
  */
-static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
+static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
 {
        struct bpf_insn *insn = &fp->insnsi[i];
        int jmp_off, last, insn_count = 1;
@@ -588,8 +594,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
                EMIT4(0xb9160000, dst_reg, rc_reg);
                break;
        }
-       case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / (u32) src */
-       case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % (u32) src */
+       case BPF_ALU64 | BPF_DIV | BPF_X: /* dst = dst / src */
+       case BPF_ALU64 | BPF_MOD | BPF_X: /* dst = dst % src */
        {
                int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
 
@@ -602,10 +608,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
                EMIT4_IMM(0xa7090000, REG_W0, 0);
                /* lgr %w1,%dst */
                EMIT4(0xb9040000, REG_W1, dst_reg);
-               /* llgfr %dst,%src (u32 cast) */
-               EMIT4(0xb9160000, dst_reg, src_reg);
                /* dlgr %w0,%dst */
-               EMIT4(0xb9870000, REG_W0, dst_reg);
+               EMIT4(0xb9870000, REG_W0, src_reg);
                /* lgr %dst,%rc */
                EMIT4(0xb9040000, dst_reg, rc_reg);
                break;
@@ -632,8 +636,8 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
                EMIT4(0xb9160000, dst_reg, rc_reg);
                break;
        }
-       case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / (u32) imm */
-       case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % (u32) imm */
+       case BPF_ALU64 | BPF_DIV | BPF_K: /* dst = dst / imm */
+       case BPF_ALU64 | BPF_MOD | BPF_K: /* dst = dst % imm */
        {
                int rc_reg = BPF_OP(insn->code) == BPF_DIV ? REG_W1 : REG_W0;
 
@@ -649,7 +653,7 @@ static int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i)
                EMIT4(0xb9040000, REG_W1, dst_reg);
                /* dlg %w0,<d(imm)>(%l) */
                EMIT6_DISP_LH(0xe3000000, 0x0087, REG_W0, REG_0, REG_L,
-                             EMIT_CONST_U64((u32) imm));
+                             EMIT_CONST_U64(imm));
                /* lgr %dst,%rc */
                EMIT4(0xb9040000, dst_reg, rc_reg);
                break;