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powerpc/bpf: use bpf_jit_binary_pack_[alloc|finalize|free]
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commit 90d862f370b6e9de1b5d607843c5a2f9823990f3 upstream.

Use bpf_jit_binary_pack_alloc in powerpc jit. The jit engine first
writes the program to the rw buffer. When the jit is done, the program
is copied to the final location with bpf_jit_binary_pack_finalize.
With multiple jit_subprogs, bpf_jit_free is called on some subprograms
that haven't got bpf_jit_binary_pack_finalize() yet. Implement custom
bpf_jit_free() like in commit 1d5f82d ("bpf, x86: fix freeing of
not-finalized bpf_prog_pack") to call bpf_jit_binary_pack_finalize(),
if necessary. As bpf_flush_icache() is not needed anymore, remove it.

Signed-off-by: Hari Bathini <[email protected]>
Acked-by: Song Liu <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://msgid.link/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>
Signed-off-by: August <[email protected]>
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@hbathini @Dangku
hbathini authored and Dangku committed Aug 7, 2024
1 parent 7d68c05 commit d0877bd
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Showing 4 changed files with 96 additions and 51 deletions.
18 changes: 5 additions & 13 deletions arch/powerpc/net/bpf_jit.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -36,9 +36,6 @@
EMIT(PPC_RAW_BRANCH(offset)); \
} while (0)

/* bl (unconditional 'branch' with link) */
#define PPC_BL(dest) EMIT(PPC_RAW_BL((dest) - (unsigned long)(image + ctx->idx)))

/* "cond" here covers BO:BI fields. */
#define PPC_BCC_SHORT(cond, dest) \
do { \
Expand Down Expand Up @@ -147,12 +144,6 @@ struct codegen_context {
#define BPF_FIXUP_LEN 2 /* Two instructions => 8 bytes */
#endif

static inline void bpf_flush_icache(void *start, void *end)
{
smp_wmb(); /* smp write barrier */
flush_icache_range((unsigned long)start, (unsigned long)end);
}

static inline bool bpf_is_seen_register(struct codegen_context *ctx, int i)
{
return ctx->seen & (1 << (31 - i));
Expand All @@ -169,16 +160,17 @@ static inline void bpf_clear_seen_register(struct codegen_context *ctx, int i)
}

void bpf_jit_init_reg_mapping(struct codegen_context *ctx);
int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func);
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func);
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
u32 *addrs, int pass, bool extra_pass);
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);
int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg, long exit_addr);

int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct codegen_context *ctx,
int insn_idx, int jmp_off, int dst_reg);
int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, u32 *fimage, int pass,
struct codegen_context *ctx, int insn_idx,
int jmp_off, int dst_reg);

#endif

Expand Down
106 changes: 79 additions & 27 deletions arch/powerpc/net/bpf_jit_comp.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -40,9 +40,12 @@ int bpf_jit_emit_exit_insn(u32 *image, struct codegen_context *ctx, int tmp_reg,
}

struct powerpc_jit_data {
struct bpf_binary_header *header;
/* address of rw header */
struct bpf_binary_header *hdr;
/* address of ro final header */
struct bpf_binary_header *fhdr;
u32 *addrs;
u8 *image;
u8 *fimage;
u32 proglen;
struct codegen_context ctx;
};
Expand All @@ -63,11 +66,14 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
struct codegen_context cgctx;
int pass;
int flen;
struct bpf_binary_header *bpf_hdr;
struct bpf_binary_header *fhdr = NULL;
struct bpf_binary_header *hdr = NULL;
struct bpf_prog *org_fp = fp;
struct bpf_prog *tmp_fp;
bool bpf_blinded = false;
bool extra_pass = false;
u8 *fimage = NULL;
u32 *fcode_base;
u32 extable_len;
u32 fixup_len;

Expand Down Expand Up @@ -97,9 +103,16 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
addrs = jit_data->addrs;
if (addrs) {
cgctx = jit_data->ctx;
image = jit_data->image;
bpf_hdr = jit_data->header;
/*
* JIT compiled to a writable location (image/code_base) first.
* It is then moved to the readonly final location (fimage/fcode_base)
* using instruction patching.
*/
fimage = jit_data->fimage;
fhdr = jit_data->fhdr;
proglen = jit_data->proglen;
hdr = jit_data->hdr;
image = (void *)hdr + ((void *)fimage - (void *)fhdr);
extra_pass = true;
/* During extra pass, ensure index is reset before repopulating extable entries */
cgctx.exentry_idx = 0;
Expand All @@ -119,7 +132,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
cgctx.stack_size = round_up(fp->aux->stack_depth, 16);

/* Scouting faux-generate pass 0 */
if (bpf_jit_build_body(fp, 0, &cgctx, addrs, 0, false)) {
if (bpf_jit_build_body(fp, NULL, NULL, &cgctx, addrs, 0, false)) {
/* We hit something illegal or unsupported. */
fp = org_fp;
goto out_addrs;
Expand All @@ -134,7 +147,7 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
*/
if (cgctx.seen & SEEN_TAILCALL || !is_offset_in_branch_range((long)cgctx.idx * 4)) {
cgctx.idx = 0;
if (bpf_jit_build_body(fp, 0, &cgctx, addrs, 0, false)) {
if (bpf_jit_build_body(fp, NULL, NULL, &cgctx, addrs, 0, false)) {
fp = org_fp;
goto out_addrs;
}
Expand All @@ -156,26 +169,30 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
proglen = cgctx.idx * 4;
alloclen = proglen + FUNCTION_DESCR_SIZE + fixup_len + extable_len;

bpf_hdr = bpf_jit_binary_alloc(alloclen, &image, 4, bpf_jit_fill_ill_insns);
if (!bpf_hdr) {
fhdr = bpf_jit_binary_pack_alloc(alloclen, &fimage, 4, &hdr, &image,
bpf_jit_fill_ill_insns);
if (!fhdr) {
fp = org_fp;
goto out_addrs;
}

if (extable_len)
fp->aux->extable = (void *)image + FUNCTION_DESCR_SIZE + proglen + fixup_len;
fp->aux->extable = (void *)fimage + FUNCTION_DESCR_SIZE + proglen + fixup_len;

skip_init_ctx:
code_base = (u32 *)(image + FUNCTION_DESCR_SIZE);
fcode_base = (u32 *)(fimage + FUNCTION_DESCR_SIZE);

/* Code generation passes 1-2 */
for (pass = 1; pass < 3; pass++) {
/* Now build the prologue, body code & epilogue for real. */
cgctx.idx = 0;
cgctx.alt_exit_addr = 0;
bpf_jit_build_prologue(code_base, &cgctx);
if (bpf_jit_build_body(fp, code_base, &cgctx, addrs, pass, extra_pass)) {
bpf_jit_binary_free(bpf_hdr);
if (bpf_jit_build_body(fp, code_base, fcode_base, &cgctx, addrs, pass,
extra_pass)) {
bpf_arch_text_copy(&fhdr->size, &hdr->size, sizeof(hdr->size));
bpf_jit_binary_pack_free(fhdr, hdr);
fp = org_fp;
goto out_addrs;
}
Expand All @@ -195,17 +212,19 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)

#ifdef CONFIG_PPC64_ELF_ABI_V1
/* Function descriptor nastiness: Address + TOC */
((u64 *)image)[0] = (u64)code_base;
((u64 *)image)[0] = (u64)fcode_base;
((u64 *)image)[1] = local_paca->kernel_toc;
#endif

fp->bpf_func = (void *)image;
fp->bpf_func = (void *)fimage;
fp->jited = 1;
fp->jited_len = proglen + FUNCTION_DESCR_SIZE;

bpf_flush_icache(bpf_hdr, (u8 *)bpf_hdr + bpf_hdr->size);
if (!fp->is_func || extra_pass) {
bpf_jit_binary_lock_ro(bpf_hdr);
if (bpf_jit_binary_pack_finalize(fp, fhdr, hdr)) {
fp = org_fp;
goto out_addrs;
}
bpf_prog_fill_jited_linfo(fp, addrs);
out_addrs:
kfree(addrs);
Expand All @@ -215,8 +234,9 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
jit_data->addrs = addrs;
jit_data->ctx = cgctx;
jit_data->proglen = proglen;
jit_data->image = image;
jit_data->header = bpf_hdr;
jit_data->fimage = fimage;
jit_data->fhdr = fhdr;
jit_data->hdr = hdr;
}

out:
Expand All @@ -230,12 +250,13 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *fp)
* The caller should check for (BPF_MODE(code) == BPF_PROBE_MEM) before calling
* this function, as this only applies to BPF_PROBE_MEM, for now.
*/
int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct codegen_context *ctx,
int insn_idx, int jmp_off, int dst_reg)
int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, u32 *fimage, int pass,
struct codegen_context *ctx, int insn_idx, int jmp_off,
int dst_reg)
{
off_t offset;
unsigned long pc;
struct exception_table_entry *ex;
struct exception_table_entry *ex, *ex_entry;
u32 *fixup;

/* Populate extable entries only in the last pass */
Expand All @@ -246,9 +267,16 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct code
WARN_ON_ONCE(ctx->exentry_idx >= fp->aux->num_exentries))
return -EINVAL;

/*
* Program is first written to image before copying to the
* final location (fimage). Accordingly, update in the image first.
* As all offsets used are relative, copying as is to the
* final location should be alright.
*/
pc = (unsigned long)&image[insn_idx];
ex = (void *)fp->aux->extable - (void *)fimage + (void *)image;

fixup = (void *)fp->aux->extable -
fixup = (void *)ex -
(fp->aux->num_exentries * BPF_FIXUP_LEN * 4) +
(ctx->exentry_idx * BPF_FIXUP_LEN * 4);

Expand All @@ -259,18 +287,42 @@ int bpf_add_extable_entry(struct bpf_prog *fp, u32 *image, int pass, struct code
fixup[BPF_FIXUP_LEN - 1] =
PPC_RAW_BRANCH((long)(pc + jmp_off) - (long)&fixup[BPF_FIXUP_LEN - 1]);

ex = &fp->aux->extable[ctx->exentry_idx];
ex_entry = &ex[ctx->exentry_idx];

offset = pc - (long)&ex->insn;
offset = pc - (long)&ex_entry->insn;
if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
return -ERANGE;
ex->insn = offset;
ex_entry->insn = offset;

offset = (long)fixup - (long)&ex->fixup;
offset = (long)fixup - (long)&ex_entry->fixup;
if (WARN_ON_ONCE(offset >= 0 || offset < INT_MIN))
return -ERANGE;
ex->fixup = offset;
ex_entry->fixup = offset;

ctx->exentry_idx++;
return 0;
}

void bpf_jit_free(struct bpf_prog *fp)
{
if (fp->jited) {
struct powerpc_jit_data *jit_data = fp->aux->jit_data;
struct bpf_binary_header *hdr;

/*
* If we fail the final pass of JIT (from jit_subprogs),
* the program may not be finalized yet. Call finalize here
* before freeing it.
*/
if (jit_data) {
bpf_jit_binary_pack_finalize(fp, jit_data->fhdr, jit_data->hdr);
kvfree(jit_data->addrs);
kfree(jit_data);
}
hdr = bpf_jit_binary_pack_hdr(fp);
bpf_jit_binary_pack_free(hdr, NULL);
WARN_ON_ONCE(!bpf_prog_kallsyms_verify_off(fp));
}

bpf_prog_unlock_free(fp);
}
13 changes: 7 additions & 6 deletions arch/powerpc/net/bpf_jit_comp32.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -200,12 +200,13 @@ void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx)
EMIT(PPC_RAW_BLR());
}

int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
/* Relative offset needs to be calculated based on final image location */
int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func)
{
s32 rel = (s32)func - (s32)(image + ctx->idx);
s32 rel = (s32)func - (s32)(fimage + ctx->idx);

if (image && rel < 0x2000000 && rel >= -0x2000000) {
PPC_BL(func);
EMIT(PPC_RAW_BL(rel));
} else {
/* Load function address into r0 */
EMIT(PPC_RAW_LIS(_R0, IMM_H(func)));
Expand Down Expand Up @@ -278,7 +279,7 @@ static int bpf_jit_emit_tail_call(u32 *image, struct codegen_context *ctx, u32 o
}

/* Assemble the body code between the prologue & epilogue */
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
u32 *addrs, int pass, bool extra_pass)
{
const struct bpf_insn *insn = fp->insnsi;
Expand Down Expand Up @@ -1009,7 +1010,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
jmp_off += 4;
}

ret = bpf_add_extable_entry(fp, image, pass, ctx, insn_idx,
ret = bpf_add_extable_entry(fp, image, fimage, pass, ctx, insn_idx,
jmp_off, dst_reg);
if (ret)
return ret;
Expand Down Expand Up @@ -1065,7 +1066,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
EMIT(PPC_RAW_STW(bpf_to_ppc(BPF_REG_5), _R1, 12));
}

ret = bpf_jit_emit_func_call_rel(image, ctx, func_addr);
ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr);
if (ret)
return ret;

Expand Down
10 changes: 5 additions & 5 deletions arch/powerpc/net/bpf_jit_comp64.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -240,7 +240,7 @@ static int bpf_jit_emit_func_call_hlp(u32 *image, struct codegen_context *ctx, u
return 0;
}

int bpf_jit_emit_func_call_rel(u32 *image, struct codegen_context *ctx, u64 func)
int bpf_jit_emit_func_call_rel(u32 *image, u32 *fimage, struct codegen_context *ctx, u64 func)
{
unsigned int i, ctx_idx = ctx->idx;

Expand Down Expand Up @@ -361,7 +361,7 @@ asm (
);

/* Assemble the body code between the prologue & epilogue */
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *ctx,
int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, u32 *fimage, struct codegen_context *ctx,
u32 *addrs, int pass, bool extra_pass)
{
enum stf_barrier_type stf_barrier = stf_barrier_type_get();
Expand Down Expand Up @@ -952,8 +952,8 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
addrs[++i] = ctx->idx * 4;

if (BPF_MODE(code) == BPF_PROBE_MEM) {
ret = bpf_add_extable_entry(fp, image, pass, ctx, ctx->idx - 1,
4, dst_reg);
ret = bpf_add_extable_entry(fp, image, fimage, pass, ctx,
ctx->idx - 1, 4, dst_reg);
if (ret)
return ret;
}
Expand Down Expand Up @@ -1007,7 +1007,7 @@ int bpf_jit_build_body(struct bpf_prog *fp, u32 *image, struct codegen_context *
if (func_addr_fixed)
ret = bpf_jit_emit_func_call_hlp(image, ctx, func_addr);
else
ret = bpf_jit_emit_func_call_rel(image, ctx, func_addr);
ret = bpf_jit_emit_func_call_rel(image, fimage, ctx, func_addr);

if (ret)
return ret;
Expand Down

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