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authorChristophe Leroy <christophe.leroy@csgroup.eu>2021-03-22 16:37:46 +0000
committerMichael Ellerman <mpe@ellerman.id.au>2021-04-03 21:22:20 +1100
commit6944caad78fc4de4ecd0364bbc9715b62b020965 (patch)
treeb02e4bc830b0778067a8710e71911bf3495035f2 /arch/powerpc/net/bpf_jit_comp.c
parentpowerpc/signal32: Simplify logging in sigreturn() (diff)
downloadlinux-dev-6944caad78fc4de4ecd0364bbc9715b62b020965.tar.xz
linux-dev-6944caad78fc4de4ecd0364bbc9715b62b020965.zip
powerpc/bpf: Remove classical BPF support for PPC32
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@csgroup.eu> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/fbc3e4fcc9c8f6131d6c705212530b2aa50149ee.1616430991.git.christophe.leroy@csgroup.eu
Diffstat (limited to 'arch/powerpc/net/bpf_jit_comp.c')
-rw-r--r--arch/powerpc/net/bpf_jit_comp.c683
1 files changed, 0 insertions, 683 deletions
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@ozlabs.org>, IBM Corporation
- *
- * Based on the x86 BPF compiler, by Eric Dumazet (eric.dumazet@gmail.com)
- * Ported to ppc32 by Denis Kirjanov <kda@linux-powerpc.org>
- */
-#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);
-}