[RFC PATCH v1 1/7] powerpc/bpf: Remove classical BPF support for PPC32

From: Christophe Leroy
Date: Wed Dec 16 2020 - 05:11:59 EST

At the time being, PPC32 has Classical BPF support.

The test_bpf module exhibits some failure:

test_bpf: #298 LD_IND byte frag jited:1 ret 202 != 66 FAIL (1 times)
test_bpf: #299 LD_IND halfword frag jited:1 ret 51958 != 17220 FAIL (1 times)
test_bpf: #301 LD_IND halfword mixed head/frag jited:1 ret 51958 != 1305 FAIL (1 times)
test_bpf: #303 LD_ABS byte frag jited:1 ret 202 != 66 FAIL (1 times)
test_bpf: #304 LD_ABS halfword frag jited:1 ret 51958 != 17220 FAIL (1 times)
test_bpf: #306 LD_ABS halfword mixed head/frag jited:1 ret 51958 != 1305 FAIL (1 times)

test_bpf: Summary: 371 PASSED, 7 FAILED, [119/366 JIT'ed]

Fixing this is not worth the effort. Instead, remove support for
classical BPF and prepare for adding Extended BPF support instead.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxxxxxx>
---
arch/powerpc/Kconfig | 1 -
arch/powerpc/net/Makefile | 4 -
arch/powerpc/net/bpf_jit32.h | 139 -------
arch/powerpc/net/bpf_jit_asm.S | 226 -----------
arch/powerpc/net/bpf_jit_comp.c | 683 --------------------------------
5 files changed, 1053 deletions(-)
delete mode 100644 arch/powerpc/net/bpf_jit32.h
delete mode 100644 arch/powerpc/net/bpf_jit_asm.S
delete mode 100644 arch/powerpc/net/bpf_jit_comp.c

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index cf328e199308..6d1454d31a53 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -191,7 +191,6 @@ config PPC
select HAVE_ARCH_TRACEHOOK
select HAVE_ASM_MODVERSIONS
select HAVE_C_RECORDMCOUNT
- select HAVE_CBPF_JIT if !PPC64
select HAVE_STACKPROTECTOR if PPC64 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r13)
select HAVE_STACKPROTECTOR if PPC32 && $(cc-option,-mstack-protector-guard=tls -mstack-protector-guard-reg=r2)
select HAVE_CONTEXT_TRACKING if PPC64
diff --git a/arch/powerpc/net/Makefile b/arch/powerpc/net/Makefile
index c2dec3a68d4c..52c939cef5b2 100644
--- a/arch/powerpc/net/Makefile
+++ b/arch/powerpc/net/Makefile
@@ -2,8 +2,4 @@
#
# Arch-specific network modules
#
-ifdef CONFIG_PPC64
obj-$(CONFIG_BPF_JIT) += bpf_jit_comp64.o
-else
-obj-$(CONFIG_BPF_JIT) += bpf_jit_asm.o bpf_jit_comp.o
-endif
diff --git a/arch/powerpc/net/bpf_jit32.h b/arch/powerpc/net/bpf_jit32.h
deleted file mode 100644
index 448dfd4d98e1..000000000000
--- a/arch/powerpc/net/bpf_jit32.h
+++ /dev/null
@@ -1,139 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/*
- * bpf_jit32.h: BPF JIT compiler for PPC
- *
- * Copyright 2011 Matt Evans <matt@xxxxxxxxxx>, IBM Corporation
- *
- * Split from bpf_jit.h
- */
-#ifndef _BPF_JIT32_H
-#define _BPF_JIT32_H
-
-#include <asm/asm-compat.h>
-#include "bpf_jit.h"
-
-#ifdef CONFIG_PPC64
-#define BPF_PPC_STACK_R3_OFF 48
-#define BPF_PPC_STACK_LOCALS 32
-#define BPF_PPC_STACK_BASIC (48+64)
-#define BPF_PPC_STACK_SAVE (18*8)
-#define BPF_PPC_STACKFRAME (BPF_PPC_STACK_BASIC+BPF_PPC_STACK_LOCALS+ \
- BPF_PPC_STACK_SAVE)
-#define BPF_PPC_SLOWPATH_FRAME (48+64)
-#else
-#define BPF_PPC_STACK_R3_OFF 24
-#define BPF_PPC_STACK_LOCALS 16
-#define BPF_PPC_STACK_BASIC (24+32)
-#define BPF_PPC_STACK_SAVE (18*4)
-#define BPF_PPC_STACKFRAME (BPF_PPC_STACK_BASIC+BPF_PPC_STACK_LOCALS+ \
- BPF_PPC_STACK_SAVE)
-#define BPF_PPC_SLOWPATH_FRAME (24+32)
-#endif
-
-#define REG_SZ (BITS_PER_LONG/8)
-
-/*
- * Generated code register usage:
- *
- * As normal PPC C ABI (e.g. r1=sp, r2=TOC), with:
- *
- * skb r3 (Entry parameter)
- * A register r4
- * X register r5
- * addr param r6
- * r7-r10 scratch
- * skb->data r14
- * skb headlen r15 (skb->len - skb->data_len)
- * m[0] r16
- * m[...] ...
- * m[15] r31
- */
-#define r_skb 3
-#define r_ret 3
-#define r_A 4
-#define r_X 5
-#define r_addr 6
-#define r_scratch1 7
-#define r_scratch2 8
-#define r_D 14
-#define r_HL 15
-#define r_M 16
-
-#ifndef __ASSEMBLY__
-
-/*
- * Assembly helpers from arch/powerpc/net/bpf_jit.S:
- */
-#define DECLARE_LOAD_FUNC(func) \
- extern u8 func[], func##_negative_offset[], func##_positive_offset[]
-
-DECLARE_LOAD_FUNC(sk_load_word);
-DECLARE_LOAD_FUNC(sk_load_half);
-DECLARE_LOAD_FUNC(sk_load_byte);
-DECLARE_LOAD_FUNC(sk_load_byte_msh);
-
-#define PPC_LBZ_OFFS(r, base, i) do { if ((i) < 32768) EMIT(PPC_RAW_LBZ(r, base, i)); \
- else { EMIT(PPC_RAW_ADDIS(r, base, IMM_HA(i))); \
- EMIT(PPC_RAW_LBZ(r, r, IMM_L(i))); } } while(0)
-
-#define PPC_LD_OFFS(r, base, i) do { if ((i) < 32768) EMIT(PPC_RAW_LD(r, base, i)); \
- else { EMIT(PPC_RAW_ADDIS(r, base, IMM_HA(i))); \
- EMIT(PPC_RAW_LD(r, r, IMM_L(i))); } } while(0)
-
-#define PPC_LWZ_OFFS(r, base, i) do { if ((i) < 32768) EMIT(PPC_RAW_LWZ(r, base, i)); \
- else { EMIT(PPC_RAW_ADDIS(r, base, IMM_HA(i))); \
- EMIT(PPC_RAW_LWZ(r, r, IMM_L(i))); } } while(0)
-
-#define PPC_LHZ_OFFS(r, base, i) do { if ((i) < 32768) EMIT(PPC_RAW_LHZ(r, base, i)); \
- else { EMIT(PPC_RAW_ADDIS(r, base, IMM_HA(i))); \
- EMIT(PPC_RAW_LHZ(r, r, IMM_L(i))); } } while(0)
-
-#ifdef CONFIG_PPC64
-#define PPC_LL_OFFS(r, base, i) do { PPC_LD_OFFS(r, base, i); } while(0)
-#else
-#define PPC_LL_OFFS(r, base, i) do { PPC_LWZ_OFFS(r, base, i); } while(0)
-#endif
-
-#ifdef CONFIG_SMP
-#ifdef CONFIG_PPC64
-#define PPC_BPF_LOAD_CPU(r) \
- do { BUILD_BUG_ON(sizeof_field(struct paca_struct, paca_index) != 2); \
- PPC_LHZ_OFFS(r, 13, offsetof(struct paca_struct, paca_index)); \
- } while (0)
-#else
-#define PPC_BPF_LOAD_CPU(r) \
- do { BUILD_BUG_ON(sizeof_field(struct task_struct, cpu) != 4); \
- PPC_LHZ_OFFS(r, 2, offsetof(struct task_struct, cpu)); \
- } while(0)
-#endif
-#else
-#define PPC_BPF_LOAD_CPU(r) do { EMIT(PPC_RAW_LI(r, 0)); } while(0)
-#endif
-
-#define PPC_LHBRX_OFFS(r, base, i) \
- do { PPC_LI32(r, i); EMIT(PPC_RAW_LHBRX(r, r, base)); } while(0)
-#ifdef __LITTLE_ENDIAN__
-#define PPC_NTOHS_OFFS(r, base, i) PPC_LHBRX_OFFS(r, base, i)
-#else
-#define PPC_NTOHS_OFFS(r, base, i) PPC_LHZ_OFFS(r, base, i)
-#endif
-
-#define PPC_BPF_LL(r, base, i) do { EMIT(PPC_RAW_LWZ(r, base, i)); } while(0)
-#define PPC_BPF_STL(r, base, i) do { EMIT(PPC_RAW_STW(r, base, i)); } while(0)
-#define PPC_BPF_STLU(r, base, i) do { EMIT(PPC_RAW_STWU(r, base, i)); } while(0)
-
-#define SEEN_DATAREF 0x10000 /* might call external helpers */
-#define SEEN_XREG 0x20000 /* X reg is used */
-#define SEEN_MEM 0x40000 /* SEEN_MEM+(1<<n) = use mem[n] for temporary
- * storage */
-#define SEEN_MEM_MSK 0x0ffff
-
-struct codegen_context {
- unsigned int seen;
- unsigned int idx;
- int pc_ret0; /* bpf index of first RET #0 instruction (if any) */
-};
-
-#endif
-
-#endif
diff --git a/arch/powerpc/net/bpf_jit_asm.S b/arch/powerpc/net/bpf_jit_asm.S
deleted file mode 100644
index 2f5030d8383f..000000000000
--- a/arch/powerpc/net/bpf_jit_asm.S
+++ /dev/null
@@ -1,226 +0,0 @@
-/* SPDX-License-Identifier: GPL-2.0-only */
-/* bpf_jit.S: Packet/header access helper functions
- * for PPC64 BPF compiler.
- *
- * Copyright 2011 Matt Evans <matt@xxxxxxxxxx>, IBM Corporation
- */
-
-#include <asm/ppc_asm.h>
-#include <asm/asm-compat.h>
-#include "bpf_jit32.h"
-
-/*
- * All of these routines are called directly from generated code,
- * whose register usage is:
- *
- * r3 skb
- * r4,r5 A,X
- * r6 *** address parameter to helper ***
- * r7-r10 scratch
- * r14 skb->data
- * r15 skb headlen
- * r16-31 M[]
- */
-
-/*
- * To consider: These helpers are so small it could be better to just
- * generate them inline. Inline code can do the simple headlen check
- * then branch directly to slow_path_XXX if required. (In fact, could
- * load a spare GPR with the address of slow_path_generic and pass size
- * as an argument, making the call site a mtlr, li and bllr.)
- */
- .globl sk_load_word
-sk_load_word:
- PPC_LCMPI r_addr, 0
- blt bpf_slow_path_word_neg
- .globl sk_load_word_positive_offset
-sk_load_word_positive_offset:
- /* Are we accessing past headlen? */
- subi r_scratch1, r_HL, 4
- PPC_LCMP r_scratch1, r_addr
- blt bpf_slow_path_word
- /* Nope, just hitting the header. cr0 here is eq or gt! */
-#ifdef __LITTLE_ENDIAN__
- lwbrx r_A, r_D, r_addr
-#else
- lwzx r_A, r_D, r_addr
-#endif
- blr /* Return success, cr0 != LT */
-
- .globl sk_load_half
-sk_load_half:
- PPC_LCMPI r_addr, 0
- blt bpf_slow_path_half_neg
- .globl sk_load_half_positive_offset
-sk_load_half_positive_offset:
- subi r_scratch1, r_HL, 2
- PPC_LCMP r_scratch1, r_addr
- blt bpf_slow_path_half
-#ifdef __LITTLE_ENDIAN__
- lhbrx r_A, r_D, r_addr
-#else
- lhzx r_A, r_D, r_addr
-#endif
- blr
-
- .globl sk_load_byte
-sk_load_byte:
- PPC_LCMPI r_addr, 0
- blt bpf_slow_path_byte_neg
- .globl sk_load_byte_positive_offset
-sk_load_byte_positive_offset:
- PPC_LCMP r_HL, r_addr
- ble bpf_slow_path_byte
- lbzx r_A, r_D, r_addr
- blr
-
-/*
- * BPF_LDX | BPF_B | BPF_MSH: ldxb 4*([offset]&0xf)
- * r_addr is the offset value
- */
- .globl sk_load_byte_msh
-sk_load_byte_msh:
- PPC_LCMPI r_addr, 0
- blt bpf_slow_path_byte_msh_neg
- .globl sk_load_byte_msh_positive_offset
-sk_load_byte_msh_positive_offset:
- PPC_LCMP r_HL, r_addr
- ble bpf_slow_path_byte_msh
- lbzx r_X, r_D, r_addr
- rlwinm r_X, r_X, 2, 32-4-2, 31-2
- blr
-
-/* Call out to skb_copy_bits:
- * We'll need to back up our volatile regs first; we have
- * local variable space at r1+(BPF_PPC_STACK_BASIC).
- * Allocate a new stack frame here to remain ABI-compliant in
- * stashing LR.
- */
-#define bpf_slow_path_common(SIZE) \
- mflr r0; \
- PPC_STL r0, PPC_LR_STKOFF(r1); \
- /* R3 goes in parameter space of caller's frame */ \
- PPC_STL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
- PPC_STL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
- PPC_STL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
- addi r5, r1, BPF_PPC_STACK_BASIC+(2*REG_SZ); \
- PPC_STLU r1, -BPF_PPC_SLOWPATH_FRAME(r1); \
- /* R3 = r_skb, as passed */ \
- mr r4, r_addr; \
- li r6, SIZE; \
- bl skb_copy_bits; \
- nop; \
- /* R3 = 0 on success */ \
- addi r1, r1, BPF_PPC_SLOWPATH_FRAME; \
- PPC_LL r0, PPC_LR_STKOFF(r1); \
- PPC_LL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
- PPC_LL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
- mtlr r0; \
- PPC_LCMPI r3, 0; \
- blt bpf_error; /* cr0 = LT */ \
- PPC_LL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
- /* Great success! */
-
-bpf_slow_path_word:
- bpf_slow_path_common(4)
- /* Data value is on stack, and cr0 != LT */
- lwz r_A, BPF_PPC_STACK_BASIC+(2*REG_SZ)(r1)
- blr
-
-bpf_slow_path_half:
- bpf_slow_path_common(2)
- lhz r_A, BPF_PPC_STACK_BASIC+(2*8)(r1)
- blr
-
-bpf_slow_path_byte:
- bpf_slow_path_common(1)
- lbz r_A, BPF_PPC_STACK_BASIC+(2*8)(r1)
- blr
-
-bpf_slow_path_byte_msh:
- bpf_slow_path_common(1)
- lbz r_X, BPF_PPC_STACK_BASIC+(2*8)(r1)
- rlwinm r_X, r_X, 2, 32-4-2, 31-2
- blr
-
-/* Call out to bpf_internal_load_pointer_neg_helper:
- * We'll need to back up our volatile regs first; we have
- * local variable space at r1+(BPF_PPC_STACK_BASIC).
- * Allocate a new stack frame here to remain ABI-compliant in
- * stashing LR.
- */
-#define sk_negative_common(SIZE) \
- mflr r0; \
- PPC_STL r0, PPC_LR_STKOFF(r1); \
- /* R3 goes in parameter space of caller's frame */ \
- PPC_STL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
- PPC_STL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
- PPC_STL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
- PPC_STLU r1, -BPF_PPC_SLOWPATH_FRAME(r1); \
- /* R3 = r_skb, as passed */ \
- mr r4, r_addr; \
- li r5, SIZE; \
- bl bpf_internal_load_pointer_neg_helper; \
- nop; \
- /* R3 != 0 on success */ \
- addi r1, r1, BPF_PPC_SLOWPATH_FRAME; \
- PPC_LL r0, PPC_LR_STKOFF(r1); \
- PPC_LL r_A, (BPF_PPC_STACK_BASIC+(0*REG_SZ))(r1); \
- PPC_LL r_X, (BPF_PPC_STACK_BASIC+(1*REG_SZ))(r1); \
- mtlr r0; \
- PPC_LCMPLI r3, 0; \
- beq bpf_error_slow; /* cr0 = EQ */ \
- mr r_addr, r3; \
- PPC_LL r_skb, (BPF_PPC_STACKFRAME+BPF_PPC_STACK_R3_OFF)(r1); \
- /* Great success! */
-
-bpf_slow_path_word_neg:
- lis r_scratch1,-32 /* SKF_LL_OFF */
- PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
- blt bpf_error /* cr0 = LT */
- .globl sk_load_word_negative_offset
-sk_load_word_negative_offset:
- sk_negative_common(4)
- lwz r_A, 0(r_addr)
- blr
-
-bpf_slow_path_half_neg:
- lis r_scratch1,-32 /* SKF_LL_OFF */
- PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
- blt bpf_error /* cr0 = LT */
- .globl sk_load_half_negative_offset
-sk_load_half_negative_offset:
- sk_negative_common(2)
- lhz r_A, 0(r_addr)
- blr
-
-bpf_slow_path_byte_neg:
- lis r_scratch1,-32 /* SKF_LL_OFF */
- PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
- blt bpf_error /* cr0 = LT */
- .globl sk_load_byte_negative_offset
-sk_load_byte_negative_offset:
- sk_negative_common(1)
- lbz r_A, 0(r_addr)
- blr
-
-bpf_slow_path_byte_msh_neg:
- lis r_scratch1,-32 /* SKF_LL_OFF */
- PPC_LCMP r_addr, r_scratch1 /* addr < SKF_* */
- blt bpf_error /* cr0 = LT */
- .globl sk_load_byte_msh_negative_offset
-sk_load_byte_msh_negative_offset:
- sk_negative_common(1)
- lbz r_X, 0(r_addr)
- rlwinm r_X, r_X, 2, 32-4-2, 31-2
- blr
-
-bpf_error_slow:
- /* fabricate a cr0 = lt */
- li r_scratch1, -1
- PPC_LCMPI r_scratch1, 0
-bpf_error:
- /* Entered with cr0 = lt */
- li r3, 0
- /* Generated code will 'blt epilogue', returning 0. */
- blr
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c
deleted file mode 100644
index e809cb5a1631..000000000000
--- a/arch/powerpc/net/bpf_jit_comp.c
+++ /dev/null
@@ -1,683 +0,0 @@
-// SPDX-License-Identifier: GPL-2.0-only
-/* bpf_jit_comp.c: BPF JIT compiler
- *
- * Copyright 2011 Matt Evans <matt@xxxxxxxxxx>, IBM Corporation
- *
- * Based on the x86 BPF compiler, by Eric Dumazet (eric.dumazet@xxxxxxxxx)
- * Ported to ppc32 by Denis Kirjanov <kda@xxxxxxxxxxxxxxxxx>
- */
-#include <linux/moduleloader.h>
-#include <asm/cacheflush.h>
-#include <asm/asm-compat.h>
-#include <linux/netdevice.h>
-#include <linux/filter.h>
-#include <linux/if_vlan.h>
-
-#include "bpf_jit32.h"
-
-static inline void bpf_flush_icache(void *start, void *end)
-{
- smp_wmb();
- flush_icache_range((unsigned long)start, (unsigned long)end);
-}
-
-static void bpf_jit_build_prologue(struct bpf_prog *fp, u32 *image,
- struct codegen_context *ctx)
-{
- int i;
- const struct sock_filter *filter = fp->insns;
-
- if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) {
- /* Make stackframe */
- if (ctx->seen & SEEN_DATAREF) {
- /* If we call any helpers (for loads), save LR */
- EMIT(PPC_INST_MFLR | __PPC_RT(R0));
- PPC_BPF_STL(0, 1, PPC_LR_STKOFF);
-
- /* Back up non-volatile regs. */
- PPC_BPF_STL(r_D, 1, -(REG_SZ*(32-r_D)));
- PPC_BPF_STL(r_HL, 1, -(REG_SZ*(32-r_HL)));
- }
- if (ctx->seen & SEEN_MEM) {
- /*
- * Conditionally save regs r15-r31 as some will be used
- * for M[] data.
- */
- for (i = r_M; i < (r_M+16); i++) {
- if (ctx->seen & (1 << (i-r_M)))
- PPC_BPF_STL(i, 1, -(REG_SZ*(32-i)));
- }
- }
- PPC_BPF_STLU(1, 1, -BPF_PPC_STACKFRAME);
- }
-
- if (ctx->seen & SEEN_DATAREF) {
- /*
- * If this filter needs to access skb data,
- * prepare r_D and r_HL:
- * r_HL = skb->len - skb->data_len
- * r_D = skb->data
- */
- PPC_LWZ_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,
- data_len));
- PPC_LWZ_OFFS(r_HL, r_skb, offsetof(struct sk_buff, len));
- EMIT(PPC_RAW_SUB(r_HL, r_HL, r_scratch1));
- PPC_LL_OFFS(r_D, r_skb, offsetof(struct sk_buff, data));
- }
-
- if (ctx->seen & SEEN_XREG) {
- /*
- * TODO: Could also detect whether first instr. sets X and
- * avoid this (as below, with A).
- */
- EMIT(PPC_RAW_LI(r_X, 0));
- }
-
- /* make sure we dont leak kernel information to user */
- if (bpf_needs_clear_a(&filter[0]))
- EMIT(PPC_RAW_LI(r_A, 0));
-}
-
-static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
-{
- int i;
-
- if (ctx->seen & (SEEN_MEM | SEEN_DATAREF)) {
- EMIT(PPC_RAW_ADDI(1, 1, BPF_PPC_STACKFRAME));
- if (ctx->seen & SEEN_DATAREF) {
- PPC_BPF_LL(0, 1, PPC_LR_STKOFF);
- EMIT(PPC_RAW_MTLR(0));
- PPC_BPF_LL(r_D, 1, -(REG_SZ*(32-r_D)));
- PPC_BPF_LL(r_HL, 1, -(REG_SZ*(32-r_HL)));
- }
- if (ctx->seen & SEEN_MEM) {
- /* Restore any saved non-vol registers */
- for (i = r_M; i < (r_M+16); i++) {
- if (ctx->seen & (1 << (i-r_M)))
- PPC_BPF_LL(i, 1, -(REG_SZ*(32-i)));
- }
- }
- }
- /* The RETs have left a return value in R3. */
-
- EMIT(PPC_RAW_BLR());
-}
-
-#define CHOOSE_LOAD_FUNC(K, func) \
- ((int)K < 0 ? ((int)K >= SKF_LL_OFF ? func##_negative_offset : func) : func##_positive_offset)
-
-/* Assemble the body code between the prologue & epilogue. */
-static int bpf_jit_build_body(struct bpf_prog *fp, u32 *image,
- struct codegen_context *ctx,
- unsigned int *addrs)
-{
- const struct sock_filter *filter = fp->insns;
- int flen = fp->len;
- u8 *func;
- unsigned int true_cond;
- int i;
-
- /* Start of epilogue code */
- unsigned int exit_addr = addrs[flen];
-
- for (i = 0; i < flen; i++) {
- unsigned int K = filter[i].k;
- u16 code = bpf_anc_helper(&filter[i]);
-
- /*
- * addrs[] maps a BPF bytecode address into a real offset from
- * the start of the body code.
- */
- addrs[i] = ctx->idx * 4;
-
- switch (code) {
- /*** ALU ops ***/
- case BPF_ALU | BPF_ADD | BPF_X: /* A += X; */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_ADD(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_ADD | BPF_K: /* A += K; */
- if (!K)
- break;
- EMIT(PPC_RAW_ADDI(r_A, r_A, IMM_L(K)));
- if (K >= 32768)
- EMIT(PPC_RAW_ADDIS(r_A, r_A, IMM_HA(K)));
- break;
- case BPF_ALU | BPF_SUB | BPF_X: /* A -= X; */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_SUB(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_SUB | BPF_K: /* A -= K */
- if (!K)
- break;
- EMIT(PPC_RAW_ADDI(r_A, r_A, IMM_L(-K)));
- if (K >= 32768)
- EMIT(PPC_RAW_ADDIS(r_A, r_A, IMM_HA(-K)));
- break;
- case BPF_ALU | BPF_MUL | BPF_X: /* A *= X; */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_MULW(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_MUL | BPF_K: /* A *= K */
- if (K < 32768)
- EMIT(PPC_RAW_MULI(r_A, r_A, K));
- else {
- PPC_LI32(r_scratch1, K);
- EMIT(PPC_RAW_MULW(r_A, r_A, r_scratch1));
- }
- break;
- case BPF_ALU | BPF_MOD | BPF_X: /* A %= X; */
- case BPF_ALU | BPF_DIV | BPF_X: /* A /= X; */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_CMPWI(r_X, 0));
- if (ctx->pc_ret0 != -1) {
- PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
- } else {
- PPC_BCC_SHORT(COND_NE, (ctx->idx*4)+12);
- EMIT(PPC_RAW_LI(r_ret, 0));
- PPC_JMP(exit_addr);
- }
- if (code == (BPF_ALU | BPF_MOD | BPF_X)) {
- EMIT(PPC_RAW_DIVWU(r_scratch1, r_A, r_X));
- EMIT(PPC_RAW_MULW(r_scratch1, r_X, r_scratch1));
- EMIT(PPC_RAW_SUB(r_A, r_A, r_scratch1));
- } else {
- EMIT(PPC_RAW_DIVWU(r_A, r_A, r_X));
- }
- break;
- case BPF_ALU | BPF_MOD | BPF_K: /* A %= K; */
- PPC_LI32(r_scratch2, K);
- EMIT(PPC_RAW_DIVWU(r_scratch1, r_A, r_scratch2));
- EMIT(PPC_RAW_MULW(r_scratch1, r_scratch2, r_scratch1));
- EMIT(PPC_RAW_SUB(r_A, r_A, r_scratch1));
- break;
- case BPF_ALU | BPF_DIV | BPF_K: /* A /= K */
- if (K == 1)
- break;
- PPC_LI32(r_scratch1, K);
- EMIT(PPC_RAW_DIVWU(r_A, r_A, r_scratch1));
- break;
- case BPF_ALU | BPF_AND | BPF_X:
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_AND(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_AND | BPF_K:
- if (!IMM_H(K))
- EMIT(PPC_RAW_ANDI(r_A, r_A, K));
- else {
- PPC_LI32(r_scratch1, K);
- EMIT(PPC_RAW_AND(r_A, r_A, r_scratch1));
- }
- break;
- case BPF_ALU | BPF_OR | BPF_X:
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_OR(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_OR | BPF_K:
- if (IMM_L(K))
- EMIT(PPC_RAW_ORI(r_A, r_A, IMM_L(K)));
- if (K >= 65536)
- EMIT(PPC_RAW_ORIS(r_A, r_A, IMM_H(K)));
- break;
- case BPF_ANC | SKF_AD_ALU_XOR_X:
- case BPF_ALU | BPF_XOR | BPF_X: /* A ^= X */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_XOR(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_XOR | BPF_K: /* A ^= K */
- if (IMM_L(K))
- EMIT(PPC_RAW_XORI(r_A, r_A, IMM_L(K)));
- if (K >= 65536)
- EMIT(PPC_RAW_XORIS(r_A, r_A, IMM_H(K)));
- break;
- case BPF_ALU | BPF_LSH | BPF_X: /* A <<= X; */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_SLW(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_LSH | BPF_K:
- if (K == 0)
- break;
- else
- EMIT(PPC_RAW_SLWI(r_A, r_A, K));
- break;
- case BPF_ALU | BPF_RSH | BPF_X: /* A >>= X; */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_SRW(r_A, r_A, r_X));
- break;
- case BPF_ALU | BPF_RSH | BPF_K: /* A >>= K; */
- if (K == 0)
- break;
- else
- EMIT(PPC_RAW_SRWI(r_A, r_A, K));
- break;
- case BPF_ALU | BPF_NEG:
- EMIT(PPC_RAW_NEG(r_A, r_A));
- break;
- case BPF_RET | BPF_K:
- PPC_LI32(r_ret, K);
- if (!K) {
- if (ctx->pc_ret0 == -1)
- ctx->pc_ret0 = i;
- }
- /*
- * If this isn't the very last instruction, branch to
- * the epilogue if we've stuff to clean up. Otherwise,
- * if there's nothing to tidy, just return. If we /are/
- * the last instruction, we're about to fall through to
- * the epilogue to return.
- */
- if (i != flen - 1) {
- /*
- * Note: 'seen' is properly valid only on pass
- * #2. Both parts of this conditional are the
- * same instruction size though, meaning the
- * first pass will still correctly determine the
- * code size/addresses.
- */
- if (ctx->seen)
- PPC_JMP(exit_addr);
- else
- EMIT(PPC_RAW_BLR());
- }
- break;
- case BPF_RET | BPF_A:
- EMIT(PPC_RAW_MR(r_ret, r_A));
- if (i != flen - 1) {
- if (ctx->seen)
- PPC_JMP(exit_addr);
- else
- EMIT(PPC_RAW_BLR());
- }
- break;
- case BPF_MISC | BPF_TAX: /* X = A */
- EMIT(PPC_RAW_MR(r_X, r_A));
- break;
- case BPF_MISC | BPF_TXA: /* A = X */
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_MR(r_A, r_X));
- break;
-
- /*** Constant loads/M[] access ***/
- case BPF_LD | BPF_IMM: /* A = K */
- PPC_LI32(r_A, K);
- break;
- case BPF_LDX | BPF_IMM: /* X = K */
- PPC_LI32(r_X, K);
- break;
- case BPF_LD | BPF_MEM: /* A = mem[K] */
- EMIT(PPC_RAW_MR(r_A, r_M + (K & 0xf)));
- ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_LDX | BPF_MEM: /* X = mem[K] */
- EMIT(PPC_RAW_MR(r_X, r_M + (K & 0xf)));
- ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_ST: /* mem[K] = A */
- EMIT(PPC_RAW_MR(r_M + (K & 0xf), r_A));
- ctx->seen |= SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_STX: /* mem[K] = X */
- EMIT(PPC_RAW_MR(r_M + (K & 0xf), r_X));
- ctx->seen |= SEEN_XREG | SEEN_MEM | (1<<(K & 0xf));
- break;
- case BPF_LD | BPF_W | BPF_LEN: /* A = skb->len; */
- BUILD_BUG_ON(sizeof_field(struct sk_buff, len) != 4);
- PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff, len));
- break;
- case BPF_LDX | BPF_W | BPF_ABS: /* A = *((u32 *)(seccomp_data + K)); */
- PPC_LWZ_OFFS(r_A, r_skb, K);
- break;
- case BPF_LDX | BPF_W | BPF_LEN: /* X = skb->len; */
- PPC_LWZ_OFFS(r_X, r_skb, offsetof(struct sk_buff, len));
- break;
-
- /*** Ancillary info loads ***/
- case BPF_ANC | SKF_AD_PROTOCOL: /* A = ntohs(skb->protocol); */
- BUILD_BUG_ON(sizeof_field(struct sk_buff,
- protocol) != 2);
- PPC_NTOHS_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- protocol));
- break;
- case BPF_ANC | SKF_AD_IFINDEX:
- case BPF_ANC | SKF_AD_HATYPE:
- BUILD_BUG_ON(sizeof_field(struct net_device,
- ifindex) != 4);
- BUILD_BUG_ON(sizeof_field(struct net_device,
- type) != 2);
- PPC_LL_OFFS(r_scratch1, r_skb, offsetof(struct sk_buff,
- dev));
- EMIT(PPC_RAW_CMPDI(r_scratch1, 0));
- if (ctx->pc_ret0 != -1) {
- PPC_BCC(COND_EQ, addrs[ctx->pc_ret0]);
- } else {
- /* Exit, returning 0; first pass hits here. */
- PPC_BCC_SHORT(COND_NE, ctx->idx * 4 + 12);
- EMIT(PPC_RAW_LI(r_ret, 0));
- PPC_JMP(exit_addr);
- }
- if (code == (BPF_ANC | SKF_AD_IFINDEX)) {
- PPC_LWZ_OFFS(r_A, r_scratch1,
- offsetof(struct net_device, ifindex));
- } else {
- PPC_LHZ_OFFS(r_A, r_scratch1,
- offsetof(struct net_device, type));
- }
-
- break;
- case BPF_ANC | SKF_AD_MARK:
- BUILD_BUG_ON(sizeof_field(struct sk_buff, mark) != 4);
- PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- mark));
- break;
- case BPF_ANC | SKF_AD_RXHASH:
- BUILD_BUG_ON(sizeof_field(struct sk_buff, hash) != 4);
- PPC_LWZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- hash));
- break;
- case BPF_ANC | SKF_AD_VLAN_TAG:
- BUILD_BUG_ON(sizeof_field(struct sk_buff, vlan_tci) != 2);
-
- PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- vlan_tci));
- break;
- case BPF_ANC | SKF_AD_VLAN_TAG_PRESENT:
- PPC_LBZ_OFFS(r_A, r_skb, PKT_VLAN_PRESENT_OFFSET());
- if (PKT_VLAN_PRESENT_BIT)
- EMIT(PPC_RAW_SRWI(r_A, r_A, PKT_VLAN_PRESENT_BIT));
- if (PKT_VLAN_PRESENT_BIT < 7)
- EMIT(PPC_RAW_ANDI(r_A, r_A, 1));
- break;
- case BPF_ANC | SKF_AD_QUEUE:
- BUILD_BUG_ON(sizeof_field(struct sk_buff,
- queue_mapping) != 2);
- PPC_LHZ_OFFS(r_A, r_skb, offsetof(struct sk_buff,
- queue_mapping));
- break;
- case BPF_ANC | SKF_AD_PKTTYPE:
- PPC_LBZ_OFFS(r_A, r_skb, PKT_TYPE_OFFSET());
- EMIT(PPC_RAW_ANDI(r_A, r_A, PKT_TYPE_MAX));
- EMIT(PPC_RAW_SRWI(r_A, r_A, 5));
- break;
- case BPF_ANC | SKF_AD_CPU:
- PPC_BPF_LOAD_CPU(r_A);
- break;
- /*** Absolute loads from packet header/data ***/
- case BPF_LD | BPF_W | BPF_ABS:
- func = CHOOSE_LOAD_FUNC(K, sk_load_word);
- goto common_load;
- case BPF_LD | BPF_H | BPF_ABS:
- func = CHOOSE_LOAD_FUNC(K, sk_load_half);
- goto common_load;
- case BPF_LD | BPF_B | BPF_ABS:
- func = CHOOSE_LOAD_FUNC(K, sk_load_byte);
- common_load:
- /* Load from [K]. */
- ctx->seen |= SEEN_DATAREF;
- PPC_FUNC_ADDR(r_scratch1, func);
- EMIT(PPC_RAW_MTLR(r_scratch1));
- PPC_LI32(r_addr, K);
- EMIT(PPC_RAW_BLRL());
- /*
- * Helper returns 'lt' condition on error, and an
- * appropriate return value in r3
- */
- PPC_BCC(COND_LT, exit_addr);
- break;
-
- /*** Indirect loads from packet header/data ***/
- case BPF_LD | BPF_W | BPF_IND:
- func = sk_load_word;
- goto common_load_ind;
- case BPF_LD | BPF_H | BPF_IND:
- func = sk_load_half;
- goto common_load_ind;
- case BPF_LD | BPF_B | BPF_IND:
- func = sk_load_byte;
- common_load_ind:
- /*
- * Load from [X + K]. Negative offsets are tested for
- * in the helper functions.
- */
- ctx->seen |= SEEN_DATAREF | SEEN_XREG;
- PPC_FUNC_ADDR(r_scratch1, func);
- EMIT(PPC_RAW_MTLR(r_scratch1));
- EMIT(PPC_RAW_ADDI(r_addr, r_X, IMM_L(K)));
- if (K >= 32768)
- EMIT(PPC_RAW_ADDIS(r_addr, r_addr, IMM_HA(K)));
- EMIT(PPC_RAW_BLRL());
- /* If error, cr0.LT set */
- PPC_BCC(COND_LT, exit_addr);
- break;
-
- case BPF_LDX | BPF_B | BPF_MSH:
- func = CHOOSE_LOAD_FUNC(K, sk_load_byte_msh);
- goto common_load;
- break;
-
- /*** Jump and branches ***/
- case BPF_JMP | BPF_JA:
- if (K != 0)
- PPC_JMP(addrs[i + 1 + K]);
- break;
-
- case BPF_JMP | BPF_JGT | BPF_K:
- case BPF_JMP | BPF_JGT | BPF_X:
- true_cond = COND_GT;
- goto cond_branch;
- case BPF_JMP | BPF_JGE | BPF_K:
- case BPF_JMP | BPF_JGE | BPF_X:
- true_cond = COND_GE;
- goto cond_branch;
- case BPF_JMP | BPF_JEQ | BPF_K:
- case BPF_JMP | BPF_JEQ | BPF_X:
- true_cond = COND_EQ;
- goto cond_branch;
- case BPF_JMP | BPF_JSET | BPF_K:
- case BPF_JMP | BPF_JSET | BPF_X:
- true_cond = COND_NE;
- cond_branch:
- /* same targets, can avoid doing the test :) */
- if (filter[i].jt == filter[i].jf) {
- if (filter[i].jt > 0)
- PPC_JMP(addrs[i + 1 + filter[i].jt]);
- break;
- }
-
- switch (code) {
- case BPF_JMP | BPF_JGT | BPF_X:
- case BPF_JMP | BPF_JGE | BPF_X:
- case BPF_JMP | BPF_JEQ | BPF_X:
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_CMPLW(r_A, r_X));
- break;
- case BPF_JMP | BPF_JSET | BPF_X:
- ctx->seen |= SEEN_XREG;
- EMIT(PPC_RAW_AND_DOT(r_scratch1, r_A, r_X));
- break;
- case BPF_JMP | BPF_JEQ | BPF_K:
- case BPF_JMP | BPF_JGT | BPF_K:
- case BPF_JMP | BPF_JGE | BPF_K:
- if (K < 32768)
- EMIT(PPC_RAW_CMPLWI(r_A, K));
- else {
- PPC_LI32(r_scratch1, K);
- EMIT(PPC_RAW_CMPLW(r_A, r_scratch1));
- }
- break;
- case BPF_JMP | BPF_JSET | BPF_K:
- if (K < 32768)
- /* PPC_ANDI is /only/ dot-form */
- EMIT(PPC_RAW_ANDI(r_scratch1, r_A, K));
- else {
- PPC_LI32(r_scratch1, K);
- EMIT(PPC_RAW_AND_DOT(r_scratch1, r_A,
- r_scratch1));
- }
- break;
- }
- /* Sometimes branches are constructed "backward", with
- * the false path being the branch and true path being
- * a fallthrough to the next instruction.
- */
- if (filter[i].jt == 0)
- /* Swap the sense of the branch */
- PPC_BCC(true_cond ^ COND_CMP_TRUE,
- addrs[i + 1 + filter[i].jf]);
- else {
- PPC_BCC(true_cond, addrs[i + 1 + filter[i].jt]);
- if (filter[i].jf != 0)
- PPC_JMP(addrs[i + 1 + filter[i].jf]);
- }
- break;
- default:
- /* The filter contains something cruel & unusual.
- * We don't handle it, but also there shouldn't be
- * anything missing from our list.
- */
- if (printk_ratelimit())
- pr_err("BPF filter opcode %04x (@%d) unsupported\n",
- filter[i].code, i);
- return -ENOTSUPP;
- }
-
- }
- /* Set end-of-body-code address for exit. */
- addrs[i] = ctx->idx * 4;
-
- return 0;
-}
-
-void bpf_jit_compile(struct bpf_prog *fp)
-{
- unsigned int proglen;
- unsigned int alloclen;
- u32 *image = NULL;
- u32 *code_base;
- unsigned int *addrs;
- struct codegen_context cgctx;
- int pass;
- int flen = fp->len;
-
- if (!bpf_jit_enable)
- return;
-
- addrs = kcalloc(flen + 1, sizeof(*addrs), GFP_KERNEL);
- if (addrs == NULL)
- return;
-
- /*
- * There are multiple assembly passes as the generated code will change
- * size as it settles down, figuring out the max branch offsets/exit
- * paths required.
- *
- * The range of standard conditional branches is +/- 32Kbytes. Since
- * BPF_MAXINSNS = 4096, we can only jump from (worst case) start to
- * finish with 8 bytes/instruction. Not feasible, so long jumps are
- * used, distinct from short branches.
- *
- * Current:
- *
- * For now, both branch types assemble to 2 words (short branches padded
- * with a NOP); this is less efficient, but assembly will always complete
- * after exactly 3 passes:
- *
- * First pass: No code buffer; Program is "faux-generated" -- no code
- * emitted but maximum size of output determined (and addrs[] filled
- * in). Also, we note whether we use M[], whether we use skb data, etc.
- * All generation choices assumed to be 'worst-case', e.g. branches all
- * far (2 instructions), return path code reduction not available, etc.
- *
- * Second pass: Code buffer allocated with size determined previously.
- * Prologue generated to support features we have seen used. Exit paths
- * determined and addrs[] is filled in again, as code may be slightly
- * smaller as a result.
- *
- * Third pass: Code generated 'for real', and branch destinations
- * determined from now-accurate addrs[] map.
- *
- * Ideal:
- *
- * If we optimise this, near branches will be shorter. On the
- * first assembly pass, we should err on the side of caution and
- * generate the biggest code. On subsequent passes, branches will be
- * generated short or long and code size will reduce. With smaller
- * code, more branches may fall into the short category, and code will
- * reduce more.
- *
- * Finally, if we see one pass generate code the same size as the
- * previous pass we have converged and should now generate code for
- * real. Allocating at the end will also save the memory that would
- * otherwise be wasted by the (small) current code shrinkage.
- * Preferably, we should do a small number of passes (e.g. 5) and if we
- * haven't converged by then, get impatient and force code to generate
- * as-is, even if the odd branch would be left long. The chances of a
- * long jump are tiny with all but the most enormous of BPF filter
- * inputs, so we should usually converge on the third pass.
- */
-
- cgctx.idx = 0;
- cgctx.seen = 0;
- cgctx.pc_ret0 = -1;
- /* Scouting faux-generate pass 0 */
- if (bpf_jit_build_body(fp, 0, &cgctx, addrs))
- /* We hit something illegal or unsupported. */
- goto out;
-
- /*
- * Pretend to build prologue, given the features we've seen. This will
- * update ctgtx.idx as it pretends to output instructions, then we can
- * calculate total size from idx.
- */
- bpf_jit_build_prologue(fp, 0, &cgctx);
- bpf_jit_build_epilogue(0, &cgctx);
-
- proglen = cgctx.idx * 4;
- alloclen = proglen + FUNCTION_DESCR_SIZE;
- image = module_alloc(alloclen);
- if (!image)
- goto out;
-
- code_base = image + (FUNCTION_DESCR_SIZE/4);
-
- /* Code generation passes 1-2 */
- for (pass = 1; pass < 3; pass++) {
- /* Now build the prologue, body code & epilogue for real. */
- cgctx.idx = 0;
- bpf_jit_build_prologue(fp, code_base, &cgctx);
- bpf_jit_build_body(fp, code_base, &cgctx, addrs);
- bpf_jit_build_epilogue(code_base, &cgctx);
-
- if (bpf_jit_enable > 1)
- pr_info("Pass %d: shrink = %d, seen = 0x%x\n", pass,
- proglen - (cgctx.idx * 4), cgctx.seen);
- }
-
- if (bpf_jit_enable > 1)
- /* Note that we output the base address of the code_base
- * rather than image, since opcodes are in code_base.
- */
- bpf_jit_dump(flen, proglen, pass, code_base);
-
- bpf_flush_icache(code_base, code_base + (proglen/4));
-
-#ifdef CONFIG_PPC64
- /* Function descriptor nastiness: Address + TOC */
- ((u64 *)image)[0] = (u64)code_base;
- ((u64 *)image)[1] = local_paca->kernel_toc;
-#endif
-
- fp->bpf_func = (void *)image;
- fp->jited = 1;
-
-out:
- kfree(addrs);
- return;
-}
-
-void bpf_jit_free(struct bpf_prog *fp)
-{
- if (fp->jited)
- module_memfree(fp->bpf_func);
-
- bpf_prog_unlock_free(fp);
-}
--
2.25.0