* [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper
@ 2016-06-04 22:00 Zi Shen Lim
2016-06-04 22:00 ` [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL Zi Shen Lim
` (2 more replies)
0 siblings, 3 replies; 11+ messages in thread
From: Zi Shen Lim @ 2016-06-04 22:00 UTC (permalink / raw)
To: David S. Miller, Catalin Marinas, Will Deacon
Cc: Zi Shen Lim, Yang Shi, Alexei Starovoitov, Daniel Borkmann,
netdev, linux-arm-kernel, linux-kernel
Add support for JMP_CALL_X (tail call) introduced by commit 04fd61ab36ec
("bpf: allow bpf programs to tail-call other bpf programs").
bpf_tail_call() arguments:
ctx - context pointer passed to next program
array - pointer to map which type is BPF_MAP_TYPE_PROG_ARRAY
index - index inside array that selects specific program to run
In this implementation arm64 JIT jumps into callee program after prologue,
so callee program reuses the same stack. For tail_call_cnt, we use the
callee-saved R26 (which was already saved/restored but previously unused
by JIT).
With this patch a tail call generates the following code on arm64:
if (index >= array->map.max_entries)
goto out;
34: mov x10, #0x10 // #16
38: ldr w10, [x1,x10]
3c: cmp w2, w10
40: b.ge 0x0000000000000074
if (tail_call_cnt > MAX_TAIL_CALL_CNT)
goto out;
tail_call_cnt++;
44: mov x10, #0x20 // #32
48: cmp x26, x10
4c: b.gt 0x0000000000000074
50: add x26, x26, #0x1
prog = array->ptrs[index];
if (prog == NULL)
goto out;
54: mov x10, #0x68 // #104
58: ldr x10, [x1,x10]
5c: ldr x11, [x10,x2]
60: cbz x11, 0x0000000000000074
goto *(prog->bpf_func + prologue_size);
64: mov x10, #0x20 // #32
68: ldr x10, [x11,x10]
6c: add x10, x10, #0x20
70: br x10
74:
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
---
arch/arm64/net/bpf_jit.h | 3 +-
arch/arm64/net/bpf_jit_comp.c | 105 ++++++++++++++++++++++++++++++++++++++----
2 files changed, 98 insertions(+), 10 deletions(-)
diff --git a/arch/arm64/net/bpf_jit.h b/arch/arm64/net/bpf_jit.h
index aee5637..7c16e54 100644
--- a/arch/arm64/net/bpf_jit.h
+++ b/arch/arm64/net/bpf_jit.h
@@ -1,7 +1,7 @@
/*
* BPF JIT compiler for ARM64
*
- * Copyright (C) 2014-2015 Zi Shen Lim <zlim.lnx@gmail.com>
+ * Copyright (C) 2014-2016 Zi Shen Lim <zlim.lnx@gmail.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
@@ -55,6 +55,7 @@
#define A64_BL(imm26) A64_BRANCH((imm26) << 2, LINK)
/* Unconditional branch (register) */
+#define A64_BR(Rn) aarch64_insn_gen_branch_reg(Rn, AARCH64_INSN_BRANCH_NOLINK)
#define A64_BLR(Rn) aarch64_insn_gen_branch_reg(Rn, AARCH64_INSN_BRANCH_LINK)
#define A64_RET(Rn) aarch64_insn_gen_branch_reg(Rn, AARCH64_INSN_BRANCH_RETURN)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 49ba37e..51abc97 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -18,6 +18,7 @@
#define pr_fmt(fmt) "bpf_jit: " fmt
+#include <linux/bpf.h>
#include <linux/filter.h>
#include <linux/printk.h>
#include <linux/skbuff.h>
@@ -33,6 +34,7 @@ int bpf_jit_enable __read_mostly;
#define TMP_REG_1 (MAX_BPF_JIT_REG + 0)
#define TMP_REG_2 (MAX_BPF_JIT_REG + 1)
+#define TCALL_CNT (MAX_BPF_JIT_REG + 2)
/* Map BPF registers to A64 registers */
static const int bpf2a64[] = {
@@ -54,6 +56,8 @@ static const int bpf2a64[] = {
/* temporary registers for internal BPF JIT */
[TMP_REG_1] = A64_R(10),
[TMP_REG_2] = A64_R(11),
+ /* tail_call_cnt */
+ [TCALL_CNT] = A64_R(26),
/* temporary register for blinding constants */
[BPF_REG_AX] = A64_R(9),
};
@@ -146,13 +150,18 @@ static inline int epilogue_offset(const struct jit_ctx *ctx)
#define STACK_SIZE STACK_ALIGN(_STACK_SIZE)
-static void build_prologue(struct jit_ctx *ctx)
+#define PROLOGUE_OFFSET 8
+
+static int build_prologue(struct jit_ctx *ctx)
{
const u8 r6 = bpf2a64[BPF_REG_6];
const u8 r7 = bpf2a64[BPF_REG_7];
const u8 r8 = bpf2a64[BPF_REG_8];
const u8 r9 = bpf2a64[BPF_REG_9];
const u8 fp = bpf2a64[BPF_REG_FP];
+ const u8 tcc = bpf2a64[TCALL_CNT];
+ const int idx0 = ctx->idx;
+ int cur_offset;
/*
* BPF prog stack layout
@@ -162,8 +171,6 @@ static void build_prologue(struct jit_ctx *ctx)
* |FP/LR|
* current A64_FP => -16:+-----+
* | ... | callee saved registers
- * +-----+
- * | | x25/x26
* BPF fp register => -64:+-----+ <= (BPF_FP)
* | |
* | ... | BPF prog stack
@@ -183,18 +190,90 @@ static void build_prologue(struct jit_ctx *ctx)
emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
emit(A64_MOV(1, A64_FP, A64_SP), ctx);
- /* Save callee-saved register */
+ /* Save callee-saved registers */
emit(A64_PUSH(r6, r7, A64_SP), ctx);
emit(A64_PUSH(r8, r9, A64_SP), ctx);
+ emit(A64_PUSH(fp, tcc, A64_SP), ctx);
- /* Save fp (x25) and x26. SP requires 16 bytes alignment */
- emit(A64_PUSH(fp, A64_R(26), A64_SP), ctx);
-
- /* Set up BPF prog stack base register (x25) */
+ /* Set up BPF prog stack base register */
emit(A64_MOV(1, fp, A64_SP), ctx);
+ /* Initialize tail_call_cnt */
+ emit(A64_MOVZ(1, tcc, 0, 0), ctx);
+
/* Set up function call stack */
emit(A64_SUB_I(1, A64_SP, A64_SP, STACK_SIZE), ctx);
+
+ cur_offset = ctx->idx - idx0;
+ if (cur_offset != PROLOGUE_OFFSET) {
+ pr_err_once("PROLOGUE_OFFSET = %d, expected %d!\n",
+ cur_offset, PROLOGUE_OFFSET);
+ return -1;
+ }
+ return 0;
+}
+
+static int out_offset = -1; /* initialized on the first pass of build_body() */
+static int emit_bpf_tail_call(struct jit_ctx *ctx)
+{
+ /* bpf_tail_call(void *prog_ctx, struct bpf_array *array, u64 index) */
+ const u8 r2 = bpf2a64[BPF_REG_2];
+ const u8 r3 = bpf2a64[BPF_REG_3];
+
+ const u8 tmp = bpf2a64[TMP_REG_1];
+ const u8 prg = bpf2a64[TMP_REG_2];
+ const u8 tcc = bpf2a64[TCALL_CNT];
+ const int idx0 = ctx->idx;
+#define cur_offset (ctx->idx - idx0)
+#define jmp_offset (out_offset - (cur_offset))
+ size_t off;
+
+ /* if (index >= array->map.max_entries)
+ * goto out;
+ */
+ off = offsetof(struct bpf_array, map.max_entries);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR32(tmp, r2, tmp), ctx);
+ emit(A64_CMP(0, r3, tmp), ctx);
+ emit(A64_B_(A64_COND_GE, jmp_offset), ctx);
+
+ /* if (tail_call_cnt > MAX_TAIL_CALL_CNT)
+ * goto out;
+ * tail_call_cnt++;
+ */
+ emit_a64_mov_i64(tmp, MAX_TAIL_CALL_CNT, ctx);
+ emit(A64_CMP(1, tcc, tmp), ctx);
+ emit(A64_B_(A64_COND_GT, jmp_offset), ctx);
+ emit(A64_ADD_I(1, tcc, tcc, 1), ctx);
+
+ /* prog = array->ptrs[index];
+ * if (prog == NULL)
+ * goto out;
+ */
+ off = offsetof(struct bpf_array, ptrs);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR64(tmp, r2, tmp), ctx);
+ emit(A64_LDR64(prg, tmp, r3), ctx);
+ emit(A64_CBZ(1, prg, jmp_offset), ctx);
+
+ /* goto *(prog->bpf_func + prologue_size); */
+ off = offsetof(struct bpf_prog, bpf_func);
+ emit_a64_mov_i64(tmp, off, ctx);
+ emit(A64_LDR64(tmp, prg, tmp), ctx);
+ emit(A64_ADD_I(1, tmp, tmp, sizeof(u32) * PROLOGUE_OFFSET), ctx);
+ emit(A64_BR(tmp), ctx);
+
+ /* out: */
+ if (out_offset == -1)
+ out_offset = cur_offset;
+ if (cur_offset != out_offset) {
+ pr_err_once("tail_call out_offset = %d, expected %d!\n",
+ cur_offset, out_offset);
+ return -1;
+ }
+ return 0;
+#undef cur_offset
+#undef jmp_offset
}
static void build_epilogue(struct jit_ctx *ctx)
@@ -506,6 +585,11 @@ emit_cond_jmp:
emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
break;
}
+ /* tail call */
+ case BPF_JMP | BPF_CALL | BPF_X:
+ if (emit_bpf_tail_call(ctx))
+ return -EFAULT;
+ break;
/* function return */
case BPF_JMP | BPF_EXIT:
/* Optimization: when last instruction is EXIT,
@@ -780,7 +864,10 @@ struct bpf_prog *bpf_int_jit_compile(struct bpf_prog *prog)
goto out_off;
}
- build_prologue(&ctx);
+ if (build_prologue(&ctx)) {
+ prog = orig_prog;
+ goto out_off;
+ }
ctx.epilogue_offset = ctx.idx;
build_epilogue(&ctx);
--
1.9.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL
2016-06-04 22:00 [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper Zi Shen Lim
@ 2016-06-04 22:00 ` Zi Shen Lim
2016-06-06 17:05 ` Will Deacon
2016-06-04 22:00 ` [PATCH net-next 3/3] arm64: bpf: optimize LD_ABS, LD_IND Zi Shen Lim
2016-06-04 23:46 ` [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper kbuild test robot
2 siblings, 1 reply; 11+ messages in thread
From: Zi Shen Lim @ 2016-06-04 22:00 UTC (permalink / raw)
To: David S. Miller, Catalin Marinas, Will Deacon
Cc: Zi Shen Lim, Yang Shi, Alexei Starovoitov, Daniel Borkmann,
netdev, linux-arm-kernel, linux-kernel
Remove superfluous stack frame, saving us 3 instructions for
every JMP_CALL.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
---
arch/arm64/net/bpf_jit_comp.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 51abc97..7ae304e 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -578,11 +578,8 @@ emit_cond_jmp:
const u64 func = (u64)__bpf_call_base + imm;
emit_a64_mov_i64(tmp, func, ctx);
- emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
- emit(A64_MOV(1, A64_FP, A64_SP), ctx);
emit(A64_BLR(tmp), ctx);
emit(A64_MOV(1, r0, A64_R(0)), ctx);
- emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
break;
}
/* tail call */
--
1.9.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* [PATCH net-next 3/3] arm64: bpf: optimize LD_ABS, LD_IND
2016-06-04 22:00 [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper Zi Shen Lim
2016-06-04 22:00 ` [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL Zi Shen Lim
@ 2016-06-04 22:00 ` Zi Shen Lim
2016-06-04 23:46 ` [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper kbuild test robot
2 siblings, 0 replies; 11+ messages in thread
From: Zi Shen Lim @ 2016-06-04 22:00 UTC (permalink / raw)
To: David S. Miller, Catalin Marinas, Will Deacon
Cc: Zi Shen Lim, Yang Shi, Alexei Starovoitov, Daniel Borkmann,
netdev, linux-arm-kernel, linux-kernel
Remove superfluous stack frame, saving us 3 instructions for every
LD_ABS or LD_IND.
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
---
arch/arm64/net/bpf_jit_comp.c | 3 ---
1 file changed, 3 deletions(-)
diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
index 7ae304e..b2fc97a 100644
--- a/arch/arm64/net/bpf_jit_comp.c
+++ b/arch/arm64/net/bpf_jit_comp.c
@@ -731,11 +731,8 @@ emit_cond_jmp:
emit_a64_mov_i64(r3, size, ctx);
emit(A64_SUB_I(1, r4, fp, STACK_SIZE), ctx);
emit_a64_mov_i64(r5, (unsigned long)bpf_load_pointer, ctx);
- emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
- emit(A64_MOV(1, A64_FP, A64_SP), ctx);
emit(A64_BLR(r5), ctx);
emit(A64_MOV(1, r0, A64_R(0)), ctx);
- emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
jmp_offset = epilogue_offset(ctx);
check_imm19(jmp_offset);
--
1.9.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper
2016-06-04 22:00 [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper Zi Shen Lim
2016-06-04 22:00 ` [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL Zi Shen Lim
2016-06-04 22:00 ` [PATCH net-next 3/3] arm64: bpf: optimize LD_ABS, LD_IND Zi Shen Lim
@ 2016-06-04 23:46 ` kbuild test robot
2016-06-05 7:53 ` Daniel Borkmann
2 siblings, 1 reply; 11+ messages in thread
From: kbuild test robot @ 2016-06-04 23:46 UTC (permalink / raw)
To: Zi Shen Lim
Cc: kbuild-all, David S. Miller, Catalin Marinas, Will Deacon,
Zi Shen Lim, Yang Shi, Alexei Starovoitov, Daniel Borkmann,
netdev, linux-arm-kernel, linux-kernel
[-- Attachment #1: Type: text/plain, Size: 3013 bytes --]
Hi,
[auto build test ERROR on net-next/master]
url: https://github.com/0day-ci/linux/commits/Zi-Shen-Lim/arm64-bpf-implement-bpf_tail_call-helper/20160605-060435
config: arm64-defconfig (attached as .config)
compiler: aarch64-linux-gnu-gcc (Debian 5.3.1-8) 5.3.1 20160205
reproduce:
wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
chmod +x ~/bin/make.cross
# save the attached .config to linux build tree
make.cross ARCH=arm64
All errors (new ones prefixed by >>):
In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
include/linux/bpf.h: In function 'bpf_prog_get':
>> include/linux/bpf.h:235:9: error: implicit declaration of function 'ERR_PTR' [-Werror=implicit-function-declaration]
return ERR_PTR(-EOPNOTSUPP);
^
include/linux/bpf.h:235:9: warning: return makes pointer from integer without a cast [-Wint-conversion]
In file included from include/linux/rwsem.h:17:0,
from include/linux/mm_types.h:10,
from include/linux/sched.h:27,
from arch/arm64/include/asm/compat.h:25,
from arch/arm64/include/asm/stat.h:23,
from include/linux/stat.h:5,
from include/linux/compat.h:12,
from include/linux/filter.h:10,
from arch/arm64/net/bpf_jit_comp.c:22:
include/linux/err.h: At top level:
>> include/linux/err.h:23:35: error: conflicting types for 'ERR_PTR'
static inline void * __must_check ERR_PTR(long error)
^
In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
include/linux/bpf.h:235:9: note: previous implicit declaration of 'ERR_PTR' was here
return ERR_PTR(-EOPNOTSUPP);
^
cc1: some warnings being treated as errors
vim +/ERR_PTR +235 include/linux/bpf.h
0fc174de Daniel Borkmann 2015-03-01 229 static inline void bpf_register_prog_type(struct bpf_prog_type_list *tl)
0fc174de Daniel Borkmann 2015-03-01 230 {
0fc174de Daniel Borkmann 2015-03-01 231 }
0fc174de Daniel Borkmann 2015-03-01 232
0fc174de Daniel Borkmann 2015-03-01 233 static inline struct bpf_prog *bpf_prog_get(u32 ufd)
0fc174de Daniel Borkmann 2015-03-01 234 {
0fc174de Daniel Borkmann 2015-03-01 @235 return ERR_PTR(-EOPNOTSUPP);
0fc174de Daniel Borkmann 2015-03-01 236 }
0fc174de Daniel Borkmann 2015-03-01 237
0fc174de Daniel Borkmann 2015-03-01 238 static inline void bpf_prog_put(struct bpf_prog *prog)
:::::: The code at line 235 was first introduced by commit
:::::: 0fc174dea54546e2b1146e1197da1b6d4bc48107 ebpf: make internal bpf API independent of CONFIG_BPF_SYSCALL ifdefs
:::::: TO: Daniel Borkmann <daniel@iogearbox.net>
:::::: CC: David S. Miller <davem@davemloft.net>
---
0-DAY kernel test infrastructure Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all Intel Corporation
[-- Attachment #2: .config.gz --]
[-- Type: application/octet-stream, Size: 25972 bytes --]
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper
2016-06-04 23:46 ` [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper kbuild test robot
@ 2016-06-05 7:53 ` Daniel Borkmann
2016-06-06 4:56 ` Z Lim
0 siblings, 1 reply; 11+ messages in thread
From: Daniel Borkmann @ 2016-06-05 7:53 UTC (permalink / raw)
To: kbuild test robot, Zi Shen Lim
Cc: kbuild-all, David S. Miller, Catalin Marinas, Will Deacon,
Yang Shi, Alexei Starovoitov, netdev, linux-arm-kernel,
linux-kernel
On 06/05/2016 01:46 AM, kbuild test robot wrote:
> Hi,
>
> [auto build test ERROR on net-next/master]
>
> url: https://github.com/0day-ci/linux/commits/Zi-Shen-Lim/arm64-bpf-implement-bpf_tail_call-helper/20160605-060435
> config: arm64-defconfig (attached as .config)
> compiler: aarch64-linux-gnu-gcc (Debian 5.3.1-8) 5.3.1 20160205
> reproduce:
> wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
> chmod +x ~/bin/make.cross
> # save the attached .config to linux build tree
> make.cross ARCH=arm64
>
> All errors (new ones prefixed by >>):
>
> In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
> include/linux/bpf.h: In function 'bpf_prog_get':
>>> include/linux/bpf.h:235:9: error: implicit declaration of function 'ERR_PTR' [-Werror=implicit-function-declaration]
> return ERR_PTR(-EOPNOTSUPP);
> ^
> include/linux/bpf.h:235:9: warning: return makes pointer from integer without a cast [-Wint-conversion]
> In file included from include/linux/rwsem.h:17:0,
> from include/linux/mm_types.h:10,
> from include/linux/sched.h:27,
> from arch/arm64/include/asm/compat.h:25,
> from arch/arm64/include/asm/stat.h:23,
> from include/linux/stat.h:5,
> from include/linux/compat.h:12,
> from include/linux/filter.h:10,
> from arch/arm64/net/bpf_jit_comp.c:22:
> include/linux/err.h: At top level:
>>> include/linux/err.h:23:35: error: conflicting types for 'ERR_PTR'
> static inline void * __must_check ERR_PTR(long error)
> ^
> In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
> include/linux/bpf.h:235:9: note: previous implicit declaration of 'ERR_PTR' was here
> return ERR_PTR(-EOPNOTSUPP);
> ^
> cc1: some warnings being treated as errors
Looks like including linux/bpf.h at the very beginning causes issues when bpf
syscall is disabled. We should probably just include linux/err.h from bpf.h.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper
2016-06-05 7:53 ` Daniel Borkmann
@ 2016-06-06 4:56 ` Z Lim
2016-06-06 8:11 ` Daniel Borkmann
0 siblings, 1 reply; 11+ messages in thread
From: Z Lim @ 2016-06-06 4:56 UTC (permalink / raw)
To: Daniel Borkmann
Cc: kbuild test robot, kbuild-all, David S. Miller, Catalin Marinas,
Will Deacon, Yang Shi, Alexei Starovoitov, Network Development,
linux-arm-kernel, LKML
[-- Attachment #1: Type: text/plain, Size: 2546 bytes --]
Hi Daniel,
On Sun, Jun 5, 2016 at 12:53 AM, Daniel Borkmann <daniel@iogearbox.net> wrote:
> On 06/05/2016 01:46 AM, kbuild test robot wrote:
>>
>> Hi,
>>
>> [auto build test ERROR on net-next/master]
>>
>> url:
>> https://github.com/0day-ci/linux/commits/Zi-Shen-Lim/arm64-bpf-implement-bpf_tail_call-helper/20160605-060435
>> config: arm64-defconfig (attached as .config)
>> compiler: aarch64-linux-gnu-gcc (Debian 5.3.1-8) 5.3.1 20160205
>> reproduce:
>> wget
>> https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross
>> -O ~/bin/make.cross
>> chmod +x ~/bin/make.cross
>> # save the attached .config to linux build tree
>> make.cross ARCH=arm64
>>
>> All errors (new ones prefixed by >>):
>>
>> In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
>> include/linux/bpf.h: In function 'bpf_prog_get':
>>>>
>>>> include/linux/bpf.h:235:9: error: implicit declaration of function
>>>> 'ERR_PTR' [-Werror=implicit-function-declaration]
>>
>> return ERR_PTR(-EOPNOTSUPP);
>> ^
>> include/linux/bpf.h:235:9: warning: return makes pointer from integer
>> without a cast [-Wint-conversion]
>> In file included from include/linux/rwsem.h:17:0,
>> from include/linux/mm_types.h:10,
>> from include/linux/sched.h:27,
>> from arch/arm64/include/asm/compat.h:25,
>> from arch/arm64/include/asm/stat.h:23,
>> from include/linux/stat.h:5,
>> from include/linux/compat.h:12,
>> from include/linux/filter.h:10,
>> from arch/arm64/net/bpf_jit_comp.c:22:
>> include/linux/err.h: At top level:
>>>>
>>>> include/linux/err.h:23:35: error: conflicting types for 'ERR_PTR'
>>
>> static inline void * __must_check ERR_PTR(long error)
>> ^
>> In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
>> include/linux/bpf.h:235:9: note: previous implicit declaration of
>> 'ERR_PTR' was here
>> return ERR_PTR(-EOPNOTSUPP);
>> ^
>> cc1: some warnings being treated as errors
>
>
> Looks like including linux/bpf.h at the very beginning causes issues when
> bpf
> syscall is disabled. We should probably just include linux/err.h from bpf.h.
How about the attached patch? Fixes compilation error on build
!CONFIG_BPF_SYSCALL.
Also, should this patch be sent to net or net-next (along with this series)?
Thanks,
z
[-- Attachment #2: 0001-bpf-fix-missing-header-inclusion.patch --]
[-- Type: text/x-patch, Size: 2223 bytes --]
From 0633e3e528e11b09691fbf533ba7fdaf4c52f772 Mon Sep 17 00:00:00 2001
From: Zi Shen Lim <zlim.lnx@gmail.com>
Date: Sun, 5 Jun 2016 21:43:14 -0700
Subject: [PATCH] bpf: fix missing header inclusion
Commit 0fc174dea545 ("ebpf: make internal bpf API independent of
CONFIG_BPF_SYSCALL ifdefs") introduced usage of ERR_PTR() in
bpf_prog_get(), however did not include linux/err.h.
Without this patch, when compiling arm64 BPF without CONFIG_BPF_SYSCALL:
...
In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
include/linux/bpf.h: In function 'bpf_prog_get':
include/linux/bpf.h:235:9: error: implicit declaration of function 'ERR_PTR' [-Werror=implicit-function-declaration]
return ERR_PTR(-EOPNOTSUPP);
^
include/linux/bpf.h:235:9: warning: return makes pointer from integer without a cast [-Wint-conversion]
In file included from include/linux/rwsem.h:17:0,
from include/linux/mm_types.h:10,
from include/linux/sched.h:27,
from arch/arm64/include/asm/compat.h:25,
from arch/arm64/include/asm/stat.h:23,
from include/linux/stat.h:5,
from include/linux/compat.h:12,
from include/linux/filter.h:10,
from arch/arm64/net/bpf_jit_comp.c:22:
include/linux/err.h: At top level:
include/linux/err.h:23:35: error: conflicting types for 'ERR_PTR'
static inline void * __must_check ERR_PTR(long error)
^
In file included from arch/arm64/net/bpf_jit_comp.c:21:0:
include/linux/bpf.h:235:9: note: previous implicit declaration of 'ERR_PTR' was here
return ERR_PTR(-EOPNOTSUPP);
^
...
Fixes: 0fc174dea545 ("ebpf: make internal bpf API independent of CONFIG_BPF_SYSCALL ifdefs")
Suggested-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
---
include/linux/bpf.h | 1 +
1 file changed, 1 insertion(+)
diff --git a/include/linux/bpf.h b/include/linux/bpf.h
index 8ee27b8..1bcae82 100644
--- a/include/linux/bpf.h
+++ b/include/linux/bpf.h
@@ -11,6 +11,7 @@
#include <linux/workqueue.h>
#include <linux/file.h>
#include <linux/percpu.h>
+#include <linux/err.h>
struct bpf_map;
--
1.9.1
^ permalink raw reply related [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper
2016-06-06 4:56 ` Z Lim
@ 2016-06-06 8:11 ` Daniel Borkmann
2016-06-07 2:33 ` Zi Shen Lim
0 siblings, 1 reply; 11+ messages in thread
From: Daniel Borkmann @ 2016-06-06 8:11 UTC (permalink / raw)
To: Z Lim
Cc: kbuild test robot, kbuild-all, David S. Miller, Catalin Marinas,
Will Deacon, Yang Shi, Alexei Starovoitov, Network Development,
linux-arm-kernel, LKML
On 06/06/2016 06:56 AM, Z Lim wrote:
[...]
> How about the attached patch? Fixes compilation error on build
> !CONFIG_BPF_SYSCALL.
>
> Also, should this patch be sent to net or net-next (along with this series)?
Looks good, feel free to add:
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
I think net-next along with your series should be fine since the issue
first appeared there. Thanks, Zi!
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL
2016-06-04 22:00 ` [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL Zi Shen Lim
@ 2016-06-06 17:05 ` Will Deacon
2016-06-07 4:36 ` Z Lim
0 siblings, 1 reply; 11+ messages in thread
From: Will Deacon @ 2016-06-06 17:05 UTC (permalink / raw)
To: Zi Shen Lim
Cc: David S. Miller, Catalin Marinas, Yang Shi, Alexei Starovoitov,
Daniel Borkmann, netdev, linux-arm-kernel, linux-kernel
On Sat, Jun 04, 2016 at 03:00:29PM -0700, Zi Shen Lim wrote:
> Remove superfluous stack frame, saving us 3 instructions for
> every JMP_CALL.
>
> Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
> ---
> arch/arm64/net/bpf_jit_comp.c | 3 ---
> 1 file changed, 3 deletions(-)
>
> diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
> index 51abc97..7ae304e 100644
> --- a/arch/arm64/net/bpf_jit_comp.c
> +++ b/arch/arm64/net/bpf_jit_comp.c
> @@ -578,11 +578,8 @@ emit_cond_jmp:
> const u64 func = (u64)__bpf_call_base + imm;
>
> emit_a64_mov_i64(tmp, func, ctx);
> - emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
> - emit(A64_MOV(1, A64_FP, A64_SP), ctx);
> emit(A64_BLR(tmp), ctx);
> emit(A64_MOV(1, r0, A64_R(0)), ctx);
> - emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
> break;
> }
Is the jitted code intended to be unwindable by standard tools?
Will
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper
2016-06-06 8:11 ` Daniel Borkmann
@ 2016-06-07 2:33 ` Zi Shen Lim
0 siblings, 0 replies; 11+ messages in thread
From: Zi Shen Lim @ 2016-06-07 2:33 UTC (permalink / raw)
To: Daniel Borkmann
Cc: kbuild test robot, kbuild-all, David S. Miller, Catalin Marinas,
Will Deacon, Yang Shi, Alexei Starovoitov, Network Development,
linux-arm-kernel, LKML
On Mon, Jun 6, 2016 at 1:11 AM, Daniel Borkmann <daniel@iogearbox.net> wrote:
> On 06/06/2016 06:56 AM, Z Lim wrote:
> [...]
>>
>> How about the attached patch? Fixes compilation error on build
>> !CONFIG_BPF_SYSCALL.
>>
>> Also, should this patch be sent to net or net-next (along with this
>> series)?
>
>
> Looks good, feel free to add:
>
> Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Thanks Daniel!
>
> I think net-next along with your series should be fine since the issue
> first appeared there. Thanks, Zi!
Sounds good. I'll include this as patch 1/4 (so it doesn't trip
kbuildbot) when I send out v2.
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL
2016-06-06 17:05 ` Will Deacon
@ 2016-06-07 4:36 ` Z Lim
2016-06-07 8:10 ` Will Deacon
0 siblings, 1 reply; 11+ messages in thread
From: Z Lim @ 2016-06-07 4:36 UTC (permalink / raw)
To: Will Deacon
Cc: David S. Miller, Catalin Marinas, Yang Shi, Alexei Starovoitov,
Daniel Borkmann, Network Development, linux-arm-kernel, LKML
Hi Will,
On Mon, Jun 6, 2016 at 10:05 AM, Will Deacon <will.deacon@arm.com> wrote:
> On Sat, Jun 04, 2016 at 03:00:29PM -0700, Zi Shen Lim wrote:
>> Remove superfluous stack frame, saving us 3 instructions for
>> every JMP_CALL.
>>
>> Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
>> ---
>> arch/arm64/net/bpf_jit_comp.c | 3 ---
>> 1 file changed, 3 deletions(-)
>>
>> diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
>> index 51abc97..7ae304e 100644
>> --- a/arch/arm64/net/bpf_jit_comp.c
>> +++ b/arch/arm64/net/bpf_jit_comp.c
>> @@ -578,11 +578,8 @@ emit_cond_jmp:
>> const u64 func = (u64)__bpf_call_base + imm;
>>
>> emit_a64_mov_i64(tmp, func, ctx);
>> - emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
>> - emit(A64_MOV(1, A64_FP, A64_SP), ctx);
>> emit(A64_BLR(tmp), ctx);
>> emit(A64_MOV(1, r0, A64_R(0)), ctx);
>> - emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
>> break;
>> }
>
> Is the jitted code intended to be unwindable by standard tools?
Before this patch:
bpf_prologue => push stack frame
...
jmp_call => push stack frame, call bpf_helper*, pop stack frame
...
bpf_epilogue => pop stack frame, ret
Now:
bpf_prologue => push stack frame
...
jmp_call => call bpf_helper*
...
bpf_epilogue => pop stack frame, ret
*Note: bpf_helpers in kernel/bpf/helper.c
So yes, it's still unwindable.
>
> Will
^ permalink raw reply [flat|nested] 11+ messages in thread
* Re: [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL
2016-06-07 4:36 ` Z Lim
@ 2016-06-07 8:10 ` Will Deacon
0 siblings, 0 replies; 11+ messages in thread
From: Will Deacon @ 2016-06-07 8:10 UTC (permalink / raw)
To: Z Lim
Cc: David S. Miller, Catalin Marinas, Yang Shi, Alexei Starovoitov,
Daniel Borkmann, Network Development, linux-arm-kernel, LKML
On Mon, Jun 06, 2016 at 09:36:03PM -0700, Z Lim wrote:
> On Mon, Jun 6, 2016 at 10:05 AM, Will Deacon <will.deacon@arm.com> wrote:
> > On Sat, Jun 04, 2016 at 03:00:29PM -0700, Zi Shen Lim wrote:
> >> Remove superfluous stack frame, saving us 3 instructions for
> >> every JMP_CALL.
> >>
> >> Signed-off-by: Zi Shen Lim <zlim.lnx@gmail.com>
> >> ---
> >> arch/arm64/net/bpf_jit_comp.c | 3 ---
> >> 1 file changed, 3 deletions(-)
> >>
> >> diff --git a/arch/arm64/net/bpf_jit_comp.c b/arch/arm64/net/bpf_jit_comp.c
> >> index 51abc97..7ae304e 100644
> >> --- a/arch/arm64/net/bpf_jit_comp.c
> >> +++ b/arch/arm64/net/bpf_jit_comp.c
> >> @@ -578,11 +578,8 @@ emit_cond_jmp:
> >> const u64 func = (u64)__bpf_call_base + imm;
> >>
> >> emit_a64_mov_i64(tmp, func, ctx);
> >> - emit(A64_PUSH(A64_FP, A64_LR, A64_SP), ctx);
> >> - emit(A64_MOV(1, A64_FP, A64_SP), ctx);
> >> emit(A64_BLR(tmp), ctx);
> >> emit(A64_MOV(1, r0, A64_R(0)), ctx);
> >> - emit(A64_POP(A64_FP, A64_LR, A64_SP), ctx);
> >> break;
> >> }
> >
> > Is the jitted code intended to be unwindable by standard tools?
>
> Before this patch:
> bpf_prologue => push stack frame
> ...
> jmp_call => push stack frame, call bpf_helper*, pop stack frame
> ...
> bpf_epilogue => pop stack frame, ret
>
> Now:
> bpf_prologue => push stack frame
> ...
> jmp_call => call bpf_helper*
> ...
> bpf_epilogue => pop stack frame, ret
>
> *Note: bpf_helpers in kernel/bpf/helper.c
>
> So yes, it's still unwindable.
Sure, I'm not disputing that. I just wondered whether or not it needs to
be unwindable at all...
Will
^ permalink raw reply [flat|nested] 11+ messages in thread
end of thread, other threads:[~2016-06-07 8:10 UTC | newest]
Thread overview: 11+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2016-06-04 22:00 [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper Zi Shen Lim
2016-06-04 22:00 ` [PATCH net-next 2/3] arm64: bpf: optimize JMP_CALL Zi Shen Lim
2016-06-06 17:05 ` Will Deacon
2016-06-07 4:36 ` Z Lim
2016-06-07 8:10 ` Will Deacon
2016-06-04 22:00 ` [PATCH net-next 3/3] arm64: bpf: optimize LD_ABS, LD_IND Zi Shen Lim
2016-06-04 23:46 ` [PATCH net-next 1/3] arm64: bpf: implement bpf_tail_call() helper kbuild test robot
2016-06-05 7:53 ` Daniel Borkmann
2016-06-06 4:56 ` Z Lim
2016-06-06 8:11 ` Daniel Borkmann
2016-06-07 2:33 ` Zi Shen Lim
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