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bpf, sparc64: remove ld_abs/ld_ind

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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: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Daniel Borkmann 2018-05-04 01:08:18 +02:00 committed by Alexei Starovoitov
parent 816d9ef32a
commit fe83963b7c
4 changed files with 6 additions and 269 deletions
repo.diff.show_diff_stats Download patch file Download diff file Expand all files Collapse all files

5
arch/sparc/net/Makefile
View file

@ -1,4 +1,7 @@
# #
# Arch-specific network modules # 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

29
arch/sparc/net/bpf_jit_64.h
View file

@ -33,35 +33,6 @@
#define I5 0x1d #define I5 0x1d
#define FP 0x1e #define FP 0x1e
#define I7 0x1f #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
#endif /* _BPF_JIT_H */ #endif /* _BPF_JIT_H */

162
arch/sparc/net/bpf_jit_asm_64.S
View file

@ -1,162 +0,0 @@
/* 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

79
arch/sparc/net/bpf_jit_comp_64.c
View file

@ -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 S13(X) ((X) & 0x1fff)
#define S5(X) ((X) & 0x1f) #define S5(X) ((X) & 0x1f)
#define IMMED 0x00002000 #define IMMED 0x00002000
@ -198,7 +194,6 @@ struct jit_ctx {
bool tmp_1_used; bool tmp_1_used;
bool tmp_2_used; bool tmp_2_used;
bool tmp_3_used; bool tmp_3_used;
bool saw_ld_abs_ind;
bool saw_frame_pointer; bool saw_frame_pointer;
bool saw_call; bool saw_call;
bool saw_tail_call; bool saw_tail_call;
@ -207,9 +202,7 @@ struct jit_ctx {
#define TMP_REG_1 (MAX_BPF_JIT_REG + 0) #define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
#define TMP_REG_2 (MAX_BPF_JIT_REG + 1) #define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
#define SKB_HLEN_REG (MAX_BPF_JIT_REG + 2) #define TMP_REG_3 (MAX_BPF_JIT_REG + 2)
#define SKB_DATA_REG (MAX_BPF_JIT_REG + 3)
#define TMP_REG_3 (MAX_BPF_JIT_REG + 4)
/* Map BPF registers to SPARC registers */ /* Map BPF registers to SPARC registers */
static const int bpf2sparc[] = { static const int bpf2sparc[] = {
@ -238,9 +231,6 @@ static const int bpf2sparc[] = {
[TMP_REG_1] = G1, [TMP_REG_1] = G1,
[TMP_REG_2] = G2, [TMP_REG_2] = G2,
[TMP_REG_3] = G3, [TMP_REG_3] = G3,
[SKB_HLEN_REG] = L4,
[SKB_DATA_REG] = L5,
}; };
static void emit(const u32 insn, struct jit_ctx *ctx) 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; 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. */ /* Just skip the save instruction and the ctx register move. */
#define BPF_TAILCALL_PROLOGUE_SKIP 16 #define BPF_TAILCALL_PROLOGUE_SKIP 16
#define BPF_TAILCALL_CNT_SP_OFF (STACK_BIAS + 128) #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); emit_reg_move(I0, O0, ctx);
/* If you add anything here, adjust BPF_TAILCALL_PROLOGUE_SKIP above. */ /* 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) 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; u8 *func = ((u8 *)__bpf_call_base) + imm;
ctx->saw_call = true; 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_call((u32 *)func, ctx);
emit_nop(ctx); emit_nop(ctx);
emit_reg_move(O0, bpf2sparc[BPF_REG_0], 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; break;
} }
@ -1412,43 +1375,6 @@ static int build_insn(const struct bpf_insn *insn, struct jit_ctx *ctx)
emit_nop(ctx); emit_nop(ctx);
break; 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: default:
pr_err_once("unknown opcode %02x\n", code); pr_err_once("unknown opcode %02x\n", code);
@ -1583,12 +1509,11 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
build_epilogue(&ctx); build_epilogue(&ctx);
if (bpf_jit_enable > 1) 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), image_size - (ctx.idx * 4),
ctx.tmp_1_used ? '1' : ' ', ctx.tmp_1_used ? '1' : ' ',
ctx.tmp_2_used ? '2' : ' ', ctx.tmp_2_used ? '2' : ' ',
ctx.tmp_3_used ? '3' : ' ', ctx.tmp_3_used ? '3' : ' ',
ctx.saw_ld_abs_ind ? 'L' : ' ',
ctx.saw_frame_pointer ? 'F' : ' ', ctx.saw_frame_pointer ? 'F' : ' ',
ctx.saw_call ? 'C' : ' ', ctx.saw_call ? 'C' : ' ',
ctx.saw_tail_call ? 'T' : ' '); ctx.saw_tail_call ? 'T' : ' ');