Commit fe83963b authored by Daniel Borkmann's avatar Daniel Borkmann Committed by Alexei Starovoitov
Browse files

bpf, sparc64: remove ld_abs/ld_ind 



Since LD_ABS/LD_IND instructions are now removed from the core and
reimplemented through a combination of inlined BPF instructions and
a slow-path helper, we can get rid of the complexity from sparc64 JIT.

Signed-off-by: default avatarDaniel Borkmann <daniel@iogearbox.net>
Acked-by: default avatarAlexei Starovoitov <ast@kernel.org>
Acked-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 816d9ef3

arch/sparc/net/Makefile

+4 −1
Original line number Diff line number Diff line 
#

# Arch-specific network modules

#

obj-$(CONFIG_BPF_JIT) += bpf_jit_asm_$(BITS).o bpf_jit_comp_$(BITS).o
 
obj-$(CONFIG_BPF_JIT) += bpf_jit_comp_$(BITS).o

ifeq ($(BITS),32)

obj-$(CONFIG_BPF_JIT) += bpf_jit_asm_32.o

endif

arch/sparc/net/bpf_jit_64.h

+0 −29
Original line number Diff line number Diff line
@@ -33,35 +33,6 @@ 
#define I5		0x1d

#define FP		0x1e

#define I7		0x1f



#define r_SKB		L0

#define r_HEADLEN	L4

#define r_SKB_DATA	L5

#define r_TMP		G1

#define r_TMP2		G3



/* assembly code in arch/sparc/net/bpf_jit_asm_64.S */

extern u32 bpf_jit_load_word[];

extern u32 bpf_jit_load_half[];

extern u32 bpf_jit_load_byte[];

extern u32 bpf_jit_load_byte_msh[];

extern u32 bpf_jit_load_word_positive_offset[];

extern u32 bpf_jit_load_half_positive_offset[];

extern u32 bpf_jit_load_byte_positive_offset[];

extern u32 bpf_jit_load_byte_msh_positive_offset[];

extern u32 bpf_jit_load_word_negative_offset[];

extern u32 bpf_jit_load_half_negative_offset[];

extern u32 bpf_jit_load_byte_negative_offset[];

extern u32 bpf_jit_load_byte_msh_negative_offset[];



#else

#define r_RESULT	%o0

#define r_SKB		%o0

#define r_OFF		%o1

#define r_HEADLEN	%l4

#define r_SKB_DATA	%l5

#define r_TMP		%g1

#define r_TMP2		%g3

#endif



#endif /* _BPF_JIT_H */

arch/sparc/net/bpf_jit_asm_64.S

deleted100644 → 0
+0 −162
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0 */

#include <asm/ptrace.h>



#include "bpf_jit_64.h"



#define SAVE_SZ		176

#define SCRATCH_OFF	STACK_BIAS + 128

#define BE_PTR(label)	be,pn %xcc, label

#define SIGN_EXTEND(reg)	sra reg, 0, reg



#define SKF_MAX_NEG_OFF	(-0x200000) /* SKF_LL_OFF from filter.h */



	.text

	.globl	bpf_jit_load_word

bpf_jit_load_word:

	cmp	r_OFF, 0

	bl	bpf_slow_path_word_neg

	 nop

	.globl	bpf_jit_load_word_positive_offset

bpf_jit_load_word_positive_offset:

	sub	r_HEADLEN, r_OFF, r_TMP

	cmp	r_TMP, 3

	ble	bpf_slow_path_word

	 add	r_SKB_DATA, r_OFF, r_TMP

	andcc	r_TMP, 3, %g0

	bne	load_word_unaligned

	 nop

	retl

	 ld	[r_TMP], r_RESULT

load_word_unaligned:

	ldub	[r_TMP + 0x0], r_OFF

	ldub	[r_TMP + 0x1], r_TMP2

	sll	r_OFF, 8, r_OFF

	or	r_OFF, r_TMP2, r_OFF

	ldub	[r_TMP + 0x2], r_TMP2

	sll	r_OFF, 8, r_OFF

	or	r_OFF, r_TMP2, r_OFF

	ldub	[r_TMP + 0x3], r_TMP2

	sll	r_OFF, 8, r_OFF

	retl

	 or	r_OFF, r_TMP2, r_RESULT



	.globl	bpf_jit_load_half

bpf_jit_load_half:

	cmp	r_OFF, 0

	bl	bpf_slow_path_half_neg

	 nop

	.globl	bpf_jit_load_half_positive_offset

bpf_jit_load_half_positive_offset:

	sub	r_HEADLEN, r_OFF, r_TMP

	cmp	r_TMP, 1

	ble	bpf_slow_path_half

	 add	r_SKB_DATA, r_OFF, r_TMP

	andcc	r_TMP, 1, %g0

	bne	load_half_unaligned

	 nop

	retl

	 lduh	[r_TMP], r_RESULT

load_half_unaligned:

	ldub	[r_TMP + 0x0], r_OFF

	ldub	[r_TMP + 0x1], r_TMP2

	sll	r_OFF, 8, r_OFF

	retl

	 or	r_OFF, r_TMP2, r_RESULT



	.globl	bpf_jit_load_byte

bpf_jit_load_byte:

	cmp	r_OFF, 0

	bl	bpf_slow_path_byte_neg

	 nop

	.globl	bpf_jit_load_byte_positive_offset

bpf_jit_load_byte_positive_offset:

	cmp	r_OFF, r_HEADLEN

	bge	bpf_slow_path_byte

	 nop

	retl

	 ldub	[r_SKB_DATA + r_OFF], r_RESULT



#define bpf_slow_path_common(LEN)	\

	save	%sp, -SAVE_SZ, %sp;	\

	mov	%i0, %o0;		\

	mov	%i1, %o1;		\

	add	%fp, SCRATCH_OFF, %o2;	\

	call	skb_copy_bits;		\

	 mov	(LEN), %o3;		\

	cmp	%o0, 0;			\

	restore;



bpf_slow_path_word:

	bpf_slow_path_common(4)

	bl	bpf_error

	 ld	[%sp + SCRATCH_OFF], r_RESULT

	retl

	 nop

bpf_slow_path_half:

	bpf_slow_path_common(2)

	bl	bpf_error

	 lduh	[%sp + SCRATCH_OFF], r_RESULT

	retl

	 nop

bpf_slow_path_byte:

	bpf_slow_path_common(1)

	bl	bpf_error

	 ldub	[%sp + SCRATCH_OFF], r_RESULT

	retl

	 nop



#define bpf_negative_common(LEN)			\

	save	%sp, -SAVE_SZ, %sp;			\

	mov	%i0, %o0;				\

	mov	%i1, %o1;				\

	SIGN_EXTEND(%o1);				\

	call	bpf_internal_load_pointer_neg_helper;	\

	 mov	(LEN), %o2;				\

	mov	%o0, r_TMP;				\

	cmp	%o0, 0;					\

	BE_PTR(bpf_error);				\

	 restore;



bpf_slow_path_word_neg:

	sethi	%hi(SKF_MAX_NEG_OFF), r_TMP

	cmp	r_OFF, r_TMP

	bl	bpf_error

	 nop

	.globl	bpf_jit_load_word_negative_offset

bpf_jit_load_word_negative_offset:

	bpf_negative_common(4)

	andcc	r_TMP, 3, %g0

	bne	load_word_unaligned

	 nop

	retl

	 ld	[r_TMP], r_RESULT



bpf_slow_path_half_neg:

	sethi	%hi(SKF_MAX_NEG_OFF), r_TMP

	cmp	r_OFF, r_TMP

	bl	bpf_error

	 nop

	.globl	bpf_jit_load_half_negative_offset

bpf_jit_load_half_negative_offset:

	bpf_negative_common(2)

	andcc	r_TMP, 1, %g0

	bne	load_half_unaligned

	 nop

	retl

	 lduh	[r_TMP], r_RESULT



bpf_slow_path_byte_neg:

	sethi	%hi(SKF_MAX_NEG_OFF), r_TMP

	cmp	r_OFF, r_TMP

	bl	bpf_error

	 nop

	.globl	bpf_jit_load_byte_negative_offset

bpf_jit_load_byte_negative_offset:

	bpf_negative_common(1)

	retl

	 ldub	[r_TMP], r_RESULT



bpf_error:

	/* Make the JIT program itself return zero. */

	ret

	restore	%g0, %g0, %o0

arch/sparc/net/bpf_jit_comp_64.c

+2 −77
Original line number Diff line number Diff line
@@ -48,10 +48,6 @@ static void bpf_flush_icache(void *start_, void *end_) 
	}

}



#define SEEN_DATAREF 1 /* might call external helpers */

#define SEEN_XREG    2 /* ebx is used */

#define SEEN_MEM     4 /* use mem[] for temporary storage */



#define S13(X)		((X) & 0x1fff)

#define S5(X)		((X) & 0x1f)

#define IMMED		0x00002000
@@ -198,7 +194,6 @@ struct jit_ctx { 
	bool 			tmp_1_used;

	bool 			tmp_2_used;

	bool 			tmp_3_used;

	bool			saw_ld_abs_ind;

	bool			saw_frame_pointer;

	bool			saw_call;

	bool			saw_tail_call;
@@ -207,9 +202,7 @@ struct jit_ctx { 


#define TMP_REG_1	(MAX_BPF_JIT_REG + 0)

#define TMP_REG_2	(MAX_BPF_JIT_REG + 1)

#define SKB_HLEN_REG	(MAX_BPF_JIT_REG + 2)

#define SKB_DATA_REG	(MAX_BPF_JIT_REG + 3)

#define TMP_REG_3	(MAX_BPF_JIT_REG + 4)

#define TMP_REG_3	(MAX_BPF_JIT_REG + 2)



/* Map BPF registers to SPARC registers */

static const int bpf2sparc[] = {
@@ -238,9 +231,6 @@ static const int bpf2sparc[] = { 
	[TMP_REG_1] = G1,

	[TMP_REG_2] = G2,

	[TMP_REG_3] = G3,



	[SKB_HLEN_REG] = L4,

	[SKB_DATA_REG] = L5,

};



static void emit(const u32 insn, struct jit_ctx *ctx)
@@ -800,25 +790,6 @@ static int emit_compare_and_branch(const u8 code, const u8 dst, u8 src, 
	return 0;

}



static void load_skb_regs(struct jit_ctx *ctx, u8 r_skb)

{

	const u8 r_headlen = bpf2sparc[SKB_HLEN_REG];

	const u8 r_data = bpf2sparc[SKB_DATA_REG];

	const u8 r_tmp = bpf2sparc[TMP_REG_1];

	unsigned int off;



	off = offsetof(struct sk_buff, len);

	emit(LD32I | RS1(r_skb) | S13(off) | RD(r_headlen), ctx);



	off = offsetof(struct sk_buff, data_len);

	emit(LD32I | RS1(r_skb) | S13(off) | RD(r_tmp), ctx);



	emit(SUB | RS1(r_headlen) | RS2(r_tmp) | RD(r_headlen), ctx);



	off = offsetof(struct sk_buff, data);

	emit(LDPTRI | RS1(r_skb) | S13(off) | RD(r_data), ctx);

}



/* Just skip the save instruction and the ctx register move.  */

#define BPF_TAILCALL_PROLOGUE_SKIP	16

#define BPF_TAILCALL_CNT_SP_OFF		(STACK_BIAS + 128)
@@ -857,9 +828,6 @@ static void build_prologue(struct jit_ctx *ctx) 


	emit_reg_move(I0, O0, ctx);

	/* If you add anything here, adjust BPF_TAILCALL_PROLOGUE_SKIP above. */



	if (ctx->saw_ld_abs_ind)

		load_skb_regs(ctx, bpf2sparc[BPF_REG_1]);

}



static void build_epilogue(struct jit_ctx *ctx)
@@ -1225,16 +1193,11 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) 
		u8 *func = ((u8 *)__bpf_call_base) + imm;



		ctx->saw_call = true;

		if (ctx->saw_ld_abs_ind && bpf_helper_changes_pkt_data(func))

			emit_reg_move(bpf2sparc[BPF_REG_1], L7, ctx);



		emit_call((u32 *)func, ctx);

		emit_nop(ctx);



		emit_reg_move(O0, bpf2sparc[BPF_REG_0], ctx);



		if (ctx->saw_ld_abs_ind && bpf_helper_changes_pkt_data(func))

			load_skb_regs(ctx, L7);

		break;

	}
@@ -1412,43 +1375,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx) 
		emit_nop(ctx);

		break;

	}

#define CHOOSE_LOAD_FUNC(K, func) \

		((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)



	/* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + imm)) */

	case BPF_LD | BPF_ABS | BPF_W:

		func = CHOOSE_LOAD_FUNC(imm, bpf_jit_load_word);

		goto common_load;

	case BPF_LD | BPF_ABS | BPF_H:

		func = CHOOSE_LOAD_FUNC(imm, bpf_jit_load_half);

		goto common_load;

	case BPF_LD | BPF_ABS | BPF_B:

		func = CHOOSE_LOAD_FUNC(imm, bpf_jit_load_byte);

		goto common_load;

	/* R0 = ntohx(*(size *)(((struct sk_buff *)R6)->data + src + imm)) */

	case BPF_LD | BPF_IND | BPF_W:

		func = bpf_jit_load_word;

		goto common_load;

	case BPF_LD | BPF_IND | BPF_H:

		func = bpf_jit_load_half;

		goto common_load;



	case BPF_LD | BPF_IND | BPF_B:

		func = bpf_jit_load_byte;

	common_load:

		ctx->saw_ld_abs_ind = true;



		emit_reg_move(bpf2sparc[BPF_REG_6], O0, ctx);

		emit_loadimm(imm, O1, ctx);



		if (BPF_MODE(code) == BPF_IND)

			emit_alu(ADD, src, O1, ctx);



		emit_call(func, ctx);

		emit_alu_K(SRA, O1, 0, ctx);



		emit_reg_move(O0, bpf2sparc[BPF_REG_0], ctx);

		break;



	default:

		pr_err_once("unknown opcode %02x\n", code);
@@ -1583,12 +1509,11 @@ skip_init_ctx: 
		build_epilogue(&ctx);



		if (bpf_jit_enable > 1)

			pr_info("Pass %d: shrink = %d, seen = [%c%c%c%c%c%c%c]\n", pass,

			pr_info("Pass %d: shrink = %d, seen = [%c%c%c%c%c%c]\n", pass,

				image_size - (ctx.idx * 4),

				ctx.tmp_1_used ? '1' : ' ',

				ctx.tmp_2_used ? '2' : ' ',

				ctx.tmp_3_used ? '3' : ' ',

				ctx.saw_ld_abs_ind ? 'L' : ' ',

				ctx.saw_frame_pointer ? 'F' : ' ',

				ctx.saw_call ? 'C' : ' ',

				ctx.saw_tail_call ? 'T' : ' ');

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