1 files changed, 18 insertions, 19 deletions

diff --git a/arch/s390/net/bpf_jit_comp.c b/arch/s390/net/bpf_jit_comp.c
index b15cd2f0320f..9557d8b516df 100644
--- a/arch/s390/net/bpf_jit_comp.c
+++ b/arch/s390/net/bpf_jit_comp.c
@@ -55,8 +55,7 @@ struct bpf_jit {
 #define SEEN_LITERAL	8	/* code uses literals */
 #define SEEN_FUNC	16	/* calls C functions */
 #define SEEN_TAIL_CALL	32	/* code uses tail calls */
-#define SEEN_SKB_CHANGE	64	/* code changes skb data */
-#define SEEN_REG_AX	128	/* code uses constant blinding */
+#define SEEN_REG_AX	64	/* code uses constant blinding */
 #define SEEN_STACK	(SEEN_FUNC | SEEN_MEM | SEEN_SKB)
 
 /*
@@ -320,12 +319,12 @@ static void save_regs(struct bpf_jit *jit, u32 rs, u32 re)
 /*
  * Restore registers from "rs" (register start) to "re" (register end) on stack
  */
-static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re)
+static void restore_regs(struct bpf_jit *jit, u32 rs, u32 re, u32 stack_depth)
 {
 	u32 off = STK_OFF_R6 + (rs - 6) * 8;
 
 	if (jit->seen & SEEN_STACK)
-		off += STK_OFF;
+		off += STK_OFF + stack_depth;
 
 	if (rs == re)
 		/* lg %rs,off(%r15) */
@@ -369,7 +368,7 @@ static int get_end(struct bpf_jit *jit, int start)
  * Save and restore clobbered registers (6-15) on stack.
  * We save/restore registers in chunks with gap >= 2 registers.
  */
-static void save_restore_regs(struct bpf_jit *jit, int op)
+static void save_restore_regs(struct bpf_jit *jit, int op, u32 stack_depth)
 {
 
 	int re = 6, rs;
@@ -382,7 +381,7 @@ static void save_restore_regs(struct bpf_jit *jit, int op)
 		if (op == REGS_SAVE)
 			save_regs(jit, rs, re);
 		else
-			restore_regs(jit, rs, re);
+			restore_regs(jit, rs, re, stack_depth);
 		re++;
 	} while (re <= 15);
 }
@@ -414,7 +413,7 @@ static void emit_load_skb_data_hlen(struct bpf_jit *jit)
  * Save registers and create stack frame if necessary.
  * See stack frame layout desription in "bpf_jit.h"!
  */
-static void bpf_jit_prologue(struct bpf_jit *jit)
+static void bpf_jit_prologue(struct bpf_jit *jit, u32 stack_depth)
 {
 	if (jit->seen & SEEN_TAIL_CALL) {
 		/* xc STK_OFF_TCCNT(4,%r15),STK_OFF_TCCNT(%r15) */
@@ -427,7 +426,7 @@ static void bpf_jit_prologue(struct bpf_jit *jit)
 	/* Tail calls have to skip above initialization */
 	jit->tail_call_start = jit->prg;
 	/* Save registers */
-	save_restore_regs(jit, REGS_SAVE);
+	save_restore_regs(jit, REGS_SAVE, stack_depth);
 	/* Setup literal pool */
 	if (jit->seen & SEEN_LITERAL) {
 		/* basr %r13,0 */
@@ -442,24 +441,24 @@ static void bpf_jit_prologue(struct bpf_jit *jit)
 		/* 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);
+		EMIT4_IMM(0xa70b0000, REG_15, -(STK_OFF + stack_depth));
 		if (jit->seen & SEEN_FUNC)
 			/* stg %w1,152(%r15) (backchain) */
 			EMIT6_DISP_LH(0xe3000000, 0x0024, REG_W1, REG_0,
 				      REG_15, 152);
 	}
-	if (jit->seen & SEEN_SKB)
+	if (jit->seen & SEEN_SKB) {
 		emit_load_skb_data_hlen(jit);
-	if (jit->seen & SEEN_SKB_CHANGE)
 		/* stg %b1,ST_OFF_SKBP(%r0,%r15) */
 		EMIT6_DISP_LH(0xe3000000, 0x0024, BPF_REG_1, REG_0, REG_15,
 			      STK_OFF_SKBP);
+	}
 }
 
 /*
  * Function epilogue
  */
-static void bpf_jit_epilogue(struct bpf_jit *jit)
+static void bpf_jit_epilogue(struct bpf_jit *jit, u32 stack_depth)
 {
 	/* Return 0 */
 	if (jit->seen & SEEN_RET0) {
@@ -471,7 +470,7 @@ static void bpf_jit_epilogue(struct bpf_jit *jit)
 	/* Load exit code: lgr %r2,%b0 */
 	EMIT4(0xb9040000, REG_2, BPF_REG_0);
 	/* Restore registers */
-	save_restore_regs(jit, REGS_RESTORE);
+	save_restore_regs(jit, REGS_RESTORE, stack_depth);
 	/* br %r14 */
 	_EMIT2(0x07fe);
 }
@@ -983,8 +982,8 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
 		EMIT2(0x0d00, REG_14, REG_W1);
 		/* lgr %b0,%r2: load return value into %b0 */
 		EMIT4(0xb9040000, BPF_REG_0, REG_2);
-		if (bpf_helper_changes_pkt_data((void *)func)) {
-			jit->seen |= SEEN_SKB_CHANGE;
+		if ((jit->seen & SEEN_SKB) &&
+		    bpf_helper_changes_pkt_data((void *)func)) {
 			/* lg %b1,ST_OFF_SKBP(%r15) */
 			EMIT6_DISP_LH(0xe3000000, 0x0004, BPF_REG_1, REG_0,
 				      REG_15, STK_OFF_SKBP);
@@ -1019,7 +1018,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
 		 */
 
 		if (jit->seen & SEEN_STACK)
-			off = STK_OFF_TCCNT + STK_OFF;
+			off = STK_OFF_TCCNT + STK_OFF + fp->aux->stack_depth;
 		else
 			off = STK_OFF_TCCNT;
 		/* lhi %w0,1 */
@@ -1047,7 +1046,7 @@ static noinline int bpf_jit_insn(struct bpf_jit *jit, struct bpf_prog *fp, int i
 		/*
 		 * Restore registers before calling function
 		 */
-		save_restore_regs(jit, REGS_RESTORE);
+		save_restore_regs(jit, REGS_RESTORE, fp->aux->stack_depth);
 
 		/*
 		 * goto *(prog->bpf_func + tail_call_start);
@@ -1273,7 +1272,7 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp)
 	jit->lit = jit->lit_start;
 	jit->prg = 0;
 
-	bpf_jit_prologue(jit);
+	bpf_jit_prologue(jit, fp->aux->stack_depth);
 	for (i = 0; i < fp->len; i += insn_count) {
 		insn_count = bpf_jit_insn(jit, fp, i);
 		if (insn_count < 0)
@@ -1281,7 +1280,7 @@ static int bpf_jit_prog(struct bpf_jit *jit, struct bpf_prog *fp)
 		/* Next instruction address */
 		jit->addrs[i + insn_count] = jit->prg;
 	}
-	bpf_jit_epilogue(jit);
+	bpf_jit_epilogue(jit, fp->aux->stack_depth);
 
 	jit->lit_start = jit->prg;
 	jit->size = jit->lit;