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powerpc/bpf: Use helper for mapping bpf to ppc registers on PPC64
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Prepare for doing commit 4027203 ("powerpc/bpf: Reallocate BPF
registers to volatile registers when possible on PPC32") on PPC64 in a
later patch. Instead of directly accessing the const b2p[] array for
mapping bpf to ppc registers use bpf_to_ppc() which allows per struct
codegen_context mappings.

Signed-off-by: Jordan Niethe <[email protected]>
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@iamjpn @intel-lab-lkp
iamjpn authored and intel-lab-lkp committed Jul 27, 2021
1 parent f15769c commit 283acec
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Showing 4 changed files with 71 additions and 65 deletions.
5 changes: 5 additions & 0 deletions arch/powerpc/net/bpf_jit.h
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Original file line number Diff line number Diff line change
Expand Up @@ -172,6 +172,11 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx);
void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx);
void bpf_jit_realloc_regs(struct codegen_context *ctx);

static inline int bpf_to_ppc(struct codegen_context *ctx, int reg)
{
return ctx->b2p[reg];
}

#endif

#endif
30 changes: 15 additions & 15 deletions arch/powerpc/net/bpf_jit64.h
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Original file line number Diff line number Diff line change
Expand Up @@ -68,23 +68,23 @@ const int b2p[MAX_BPF_JIT_REG + 2] = {
* WARNING: These can use TMP_REG_2 if the offset is not at word boundary,
* so ensure that it isn't in use already.
*/
#define PPC_BPF_LL(r, base, i) do { \
if ((i) % 4) { \
EMIT(PPC_RAW_LI(b2p[TMP_REG_2], (i)));\
EMIT(PPC_RAW_LDX(r, base, \
b2p[TMP_REG_2])); \
} else \
EMIT(PPC_RAW_LD(r, base, i)); \
#define PPC_BPF_LL(ctx, r, base, i) do { \
if ((i) % 4) { \
EMIT(PPC_RAW_LI(bpf_to_ppc(ctx, TMP_REG_2), (i)));\
EMIT(PPC_RAW_LDX(r, base, \
bpf_to_ppc(ctx, TMP_REG_2))); \
} else \
EMIT(PPC_RAW_LD(r, base, i)); \
} while(0)
#define PPC_BPF_STL(r, base, i) do { \
if ((i) % 4) { \
EMIT(PPC_RAW_LI(b2p[TMP_REG_2], (i)));\
EMIT(PPC_RAW_STDX(r, base, \
b2p[TMP_REG_2])); \
} else \
EMIT(PPC_RAW_STD(r, base, i)); \
#define PPC_BPF_STL(ctx, r, base, i) do { \
if ((i) % 4) { \
EMIT(PPC_RAW_LI(bpf_to_ppc(ctx, TMP_REG_2), (i)));\
EMIT(PPC_RAW_STDX(r, base, \
bpf_to_ppc(ctx, TMP_REG_2))); \
} else \
EMIT(PPC_RAW_STD(r, base, i)); \
} while(0)
#define PPC_BPF_STLU(r, base, i) do { EMIT(PPC_RAW_STDU(r, base, i)); } while(0)
#define PPC_BPF_STLU(ctx, r, base, i) do { EMIT(PPC_RAW_STDU(r, base, i)); } while(0)

#endif /* !__ASSEMBLY__ */

Expand Down
5 changes: 0 additions & 5 deletions arch/powerpc/net/bpf_jit_comp32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -58,11 +58,6 @@ const int b2p[MAX_BPF_JIT_REG + 1] = {
[TMP_REG] = 31, /* 32 bits */
};

static int bpf_to_ppc(struct codegen_context *ctx, int reg)
{
return ctx->b2p[reg];
}

/* PPC NVR range -- update this if we ever use NVRs below r17 */
#define BPF_PPC_NVR_MIN 17
#define BPF_PPC_TC 16
Expand Down
96 changes: 51 additions & 45 deletions arch/powerpc/net/bpf_jit_comp64.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -26,7 +26,7 @@ static inline bool bpf_has_stack_frame(struct codegen_context *ctx)
* - the bpf program uses its stack area
* The latter condition is deduced from the usage of BPF_REG_FP
*/
return ctx->seen & SEEN_FUNC || bpf_is_seen_register(ctx, b2p[BPF_REG_FP]);
return ctx->seen & SEEN_FUNC || bpf_is_seen_register(ctx, bpf_to_ppc(ctx, BPF_REG_FP));
}

/*
Expand Down Expand Up @@ -78,9 +78,9 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
* invoked through a tail call.
*/
if (ctx->seen & SEEN_TAILCALL) {
EMIT(PPC_RAW_LI(b2p[TMP_REG_1], 0));
EMIT(PPC_RAW_LI(bpf_to_ppc(ctx, TMP_REG_1), 0));
/* this goes in the redzone */
PPC_BPF_STL(b2p[TMP_REG_1], 1, -(BPF_PPC_STACK_SAVE + 8));
PPC_BPF_STL(ctx, bpf_to_ppc(ctx, TMP_REG_1), 1, -(BPF_PPC_STACK_SAVE + 8));
} else {
EMIT(PPC_RAW_NOP());
EMIT(PPC_RAW_NOP());
Expand All @@ -95,10 +95,10 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
*/
if (ctx->seen & SEEN_FUNC) {
EMIT(PPC_RAW_MFLR(_R0));
PPC_BPF_STL(0, 1, PPC_LR_STKOFF);
PPC_BPF_STL(ctx, 0, 1, PPC_LR_STKOFF);
}

PPC_BPF_STLU(1, 1, -(BPF_PPC_STACKFRAME + ctx->stack_size));
PPC_BPF_STLU(ctx, 1, 1, -(BPF_PPC_STACKFRAME + ctx->stack_size));
}

/*
Expand All @@ -107,13 +107,14 @@ void bpf_jit_build_prologue(u32 *image, struct codegen_context *ctx)
* in the protected zone below the previous stack frame
*/
for (i = BPF_REG_6; i <= BPF_REG_10; i++)
if (bpf_is_seen_register(ctx, b2p[i]))
PPC_BPF_STL(b2p[i], 1, bpf_jit_stack_offsetof(ctx, b2p[i]));
if (bpf_is_seen_register(ctx, bpf_to_ppc(ctx, i)))
PPC_BPF_STL(ctx, bpf_to_ppc(ctx, i), 1,
bpf_jit_stack_offsetof(ctx, bpf_to_ppc(ctx, i)));

/* Setup frame pointer to point to the bpf stack area */
if (bpf_is_seen_register(ctx, b2p[BPF_REG_FP]))
EMIT(PPC_RAW_ADDI(b2p[BPF_REG_FP], 1,
STACK_FRAME_MIN_SIZE + ctx->stack_size));
if (bpf_is_seen_register(ctx, bpf_to_ppc(ctx, BPF_REG_FP)))
EMIT(PPC_RAW_ADDI(bpf_to_ppc(ctx, BPF_REG_FP), 1,
STACK_FRAME_MIN_SIZE + ctx->stack_size));
}

static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx)
Expand All @@ -122,14 +123,15 @@ static void bpf_jit_emit_common_epilogue(u32 *image, struct codegen_context *ctx

/* Restore NVRs */
for (i = BPF_REG_6; i <= BPF_REG_10; i++)
if (bpf_is_seen_register(ctx, b2p[i]))
PPC_BPF_LL(b2p[i], 1, bpf_jit_stack_offsetof(ctx, b2p[i]));
if (bpf_is_seen_register(ctx, bpf_to_ppc(ctx, i)))
PPC_BPF_LL(ctx, bpf_to_ppc(ctx, i), 1,
bpf_jit_stack_offsetof(ctx, bpf_to_ppc(ctx, i)));

/* Tear down our stack frame */
if (bpf_has_stack_frame(ctx)) {
EMIT(PPC_RAW_ADDI(1, 1, BPF_PPC_STACKFRAME + ctx->stack_size));
if (ctx->seen & SEEN_FUNC) {
PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
PPC_BPF_LL(ctx, 0, 1, PPC_LR_STKOFF);
EMIT(PPC_RAW_MTLR(0));
}
}
Expand All @@ -140,7 +142,7 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
bpf_jit_emit_common_epilogue(image, ctx);

/* Move result to r3 */
EMIT(PPC_RAW_MR(3, b2p[BPF_REG_0]));
EMIT(PPC_RAW_MR(3, bpf_to_ppc(ctx, BPF_REG_0)));

EMIT(PPC_RAW_BLR());
}
Expand All @@ -150,18 +152,18 @@ static void bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx,
{
#ifdef PPC64_ELF_ABI_v1
/* func points to the function descriptor */
PPC_LI64(b2p[TMP_REG_2], func);
PPC_LI64(bpf_to_ppc(ctx, TMP_REG_2), func);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_2], 0);
PPC_BPF_LL(ctx, bpf_to_ppc(ctx, TMP_REG_1), bpf_to_ppc(ctx, TMP_REG_2), 0);
/* ... and move it to CTR */
EMIT(PPC_RAW_MTCTR(b2p[TMP_REG_1]));
EMIT(PPC_RAW_MTCTR(bpf_to_ppc(ctx, TMP_REG_1)));
/*
* Load TOC from function descriptor at offset 8.
* We can clobber r2 since we get called through a
* function pointer (so caller will save/restore r2)
* and since we don't use a TOC ourself.
*/
PPC_BPF_LL(2, b2p[TMP_REG_2], 8);
PPC_BPF_LL(ctx, 2, bpf_to_ppc(ctx, TMP_REG_2), 8);
#else
/* We can clobber r12 */
PPC_FUNC_ADDR(12, func);
Expand Down Expand Up @@ -197,9 +199,9 @@ void bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 fun
* function pointer (so caller will save/restore r2)
* and since we don't use a TOC ourself.
*/
PPC_BPF_LL(2, 12, 8);
PPC_BPF_LL(ctx, 2, 12, 8);
/* Load actual entry point from function descriptor */
PPC_BPF_LL(12, 12, 0);
PPC_BPF_LL(ctx, 12, 12, 0);
#endif

EMIT(PPC_RAW_MTCTR(12));
Expand All @@ -214,54 +216,58 @@ static void bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32
* r4/BPF_REG_2 - pointer to bpf_array
* r5/BPF_REG_3 - index in bpf_array
*/
int b2p_bpf_array = b2p[BPF_REG_2];
int b2p_index = b2p[BPF_REG_3];
int b2p_bpf_array = bpf_to_ppc(ctx, BPF_REG_2);
int b2p_index = bpf_to_ppc(ctx, BPF_REG_3);

/*
* if (index >= array->map.max_entries)
* goto out;
*/
EMIT(PPC_RAW_LWZ(b2p[TMP_REG_1], b2p_bpf_array, offsetof(struct bpf_array, map.max_entries)));
EMIT(PPC_RAW_LWZ(bpf_to_ppc(ctx, TMP_REG_1), b2p_bpf_array,
offsetof(struct bpf_array, map.max_entries)));
EMIT(PPC_RAW_RLWINM(b2p_index, b2p_index, 0, 0, 31));
EMIT(PPC_RAW_CMPLW(b2p_index, b2p[TMP_REG_1]));
EMIT(PPC_RAW_CMPLW(b2p_index, bpf_to_ppc(ctx, TMP_REG_1)));
PPC_BCC(COND_GE, out);

/*
* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
* goto out;
*/
PPC_BPF_LL(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx));
EMIT(PPC_RAW_CMPLWI(b2p[TMP_REG_1], MAX_TAIL_CALL_CNT));
PPC_BPF_LL(ctx, bpf_to_ppc(ctx, TMP_REG_1), 1, bpf_jit_stack_tailcallcnt(ctx));
EMIT(PPC_RAW_CMPLWI(bpf_to_ppc(ctx, TMP_REG_1), MAX_TAIL_CALL_CNT));
PPC_BCC(COND_GT, out);

/*
* tail_call_cnt++;
*/
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], 1));
PPC_BPF_STL(b2p[TMP_REG_1], 1, bpf_jit_stack_tailcallcnt(ctx));
EMIT(PPC_RAW_ADDI(bpf_to_ppc(ctx, TMP_REG_1), bpf_to_ppc(ctx, TMP_REG_1), 1));
PPC_BPF_STL(ctx, bpf_to_ppc(ctx, TMP_REG_1), 1, bpf_jit_stack_tailcallcnt(ctx));

/* prog = array->ptrs[index]; */
EMIT(PPC_RAW_MULI(b2p[TMP_REG_1], b2p_index, 8));
EMIT(PPC_RAW_ADD(b2p[TMP_REG_1], b2p[TMP_REG_1], b2p_bpf_array));
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_array, ptrs));
EMIT(PPC_RAW_MULI(bpf_to_ppc(ctx, TMP_REG_1), b2p_index, 8));
EMIT(PPC_RAW_ADD(bpf_to_ppc(ctx, TMP_REG_1), bpf_to_ppc(ctx, TMP_REG_1), b2p_bpf_array));
PPC_BPF_LL(ctx, bpf_to_ppc(ctx, TMP_REG_1), bpf_to_ppc(ctx, TMP_REG_1),
offsetof(struct bpf_array, ptrs));

/*
* if (prog == NULL)
* goto out;
*/
EMIT(PPC_RAW_CMPLDI(b2p[TMP_REG_1], 0));
EMIT(PPC_RAW_CMPLDI(bpf_to_ppc(ctx, TMP_REG_1), 0));
PPC_BCC(COND_EQ, out);

/* goto *(prog->bpf_func + prologue_size); */
PPC_BPF_LL(b2p[TMP_REG_1], b2p[TMP_REG_1], offsetof(struct bpf_prog, bpf_func));
PPC_BPF_LL(ctx, bpf_to_ppc(ctx, TMP_REG_1), bpf_to_ppc(ctx, TMP_REG_1),
offsetof(struct bpf_prog, bpf_func));
#ifdef PPC64_ELF_ABI_v1
/* skip past the function descriptor */
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1],
FUNCTION_DESCR_SIZE + BPF_TAILCALL_PROLOGUE_SIZE));
EMIT(PPC_RAW_ADDI(bpf_to_ppc(ctx, TMP_REG_1), bpf_to_ppc(ctx, TMP_REG_1),
FUNCTION_DESCR_SIZE + BPF_TAILCALL_PROLOGUE_SIZE));
#else
EMIT(PPC_RAW_ADDI(b2p[TMP_REG_1], b2p[TMP_REG_1], BPF_TAILCALL_PROLOGUE_SIZE));
EMIT(PPC_RAW_ADDI(bpf_to_ppc(ctx, TMP_REG_1), bpf_to_ppc(ctx, TMP_REG_1),
BPF_TAILCALL_PROLOGUE_SIZE));
#endif
EMIT(PPC_RAW_MTCTR(b2p[TMP_REG_1]));
EMIT(PPC_RAW_MTCTR(bpf_to_ppc(ctx, TMP_REG_1)));

/* tear down stack, restore NVRs, ... */
bpf_jit_emit_common_epilogue(image, ctx);
Expand All @@ -283,10 +289,10 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *

for (i = 0; i < flen; i++) {
u32 code = insn[i].code;
u32 dst_reg = b2p[insn[i].dst_reg];
u32 src_reg = b2p[insn[i].src_reg];
u32 tmp1_reg = b2p[TMP_REG_1];
u32 tmp2_reg = b2p[TMP_REG_2];
u32 dst_reg = bpf_to_ppc(ctx, insn[i].dst_reg);
u32 src_reg = bpf_to_ppc(ctx, insn[i].src_reg);
u32 tmp1_reg = bpf_to_ppc(ctx, TMP_REG_1);
u32 tmp2_reg = bpf_to_ppc(ctx, TMP_REG_2);
s16 off = insn[i].off;
s32 imm = insn[i].imm;
bool func_addr_fixed;
Expand Down Expand Up @@ -587,7 +593,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
* the instructions generated will remain the
* same across all passes
*/
PPC_BPF_STL(dst_reg, 1, bpf_jit_stack_local(ctx));
PPC_BPF_STL(ctx, dst_reg, 1, bpf_jit_stack_local(ctx));
EMIT(PPC_RAW_ADDI(tmp1_reg, 1, bpf_jit_stack_local(ctx)));
EMIT(PPC_RAW_LDBRX(dst_reg, 0, tmp1_reg));
break;
Expand Down Expand Up @@ -646,7 +652,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
PPC_LI32(tmp1_reg, imm);
src_reg = tmp1_reg;
}
PPC_BPF_STL(src_reg, dst_reg, off);
PPC_BPF_STL(ctx, src_reg, dst_reg, off);
break;

/*
Expand Down Expand Up @@ -714,7 +720,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
break;
/* dst = *(u64 *)(ul) (src + off) */
case BPF_LDX | BPF_MEM | BPF_DW:
PPC_BPF_LL(dst_reg, src_reg, off);
PPC_BPF_LL(ctx, dst_reg, src_reg, off);
break;

/*
Expand Down Expand Up @@ -759,7 +765,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
else
bpf_jit_emit_func_call_rel(image, ctx, func_addr);
/* move return value from r3 to BPF_REG_0 */
EMIT(PPC_RAW_MR(b2p[BPF_REG_0], 3));
EMIT(PPC_RAW_MR(bpf_to_ppc(ctx, BPF_REG_0), 3));
break;

/*
Expand Down

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