diff mbox series

[v3,bpf-next,4/6] bpf: Add BTF_KIND_FLOAT support

Message ID 20210220034959.27006-5-iii@linux.ibm.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series Add BTF_KIND_FLOAT support | expand

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netdev/tree_selection success Clearly marked for bpf-next
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netdev/cc_maintainers warning 4 maintainers not CCed: songliubraving@fb.com kpsingh@kernel.org netdev@vger.kernel.org kafai@fb.com
netdev/source_inline success Was 0 now: 0
netdev/verify_signedoff success Link
netdev/module_param success Was 0 now: 0
netdev/build_32bit fail Errors and warnings before: 9 this patch: 10
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/verify_fixes success Link
netdev/checkpatch success total: 0 errors, 0 warnings, 0 checks, 119 lines checked
netdev/build_allmodconfig_warn success Errors and warnings before: 9 this patch: 9
netdev/header_inline success Link
netdev/stable success Stable not CCed

Commit Message

Ilya Leoshkevich Feb. 20, 2021, 3:49 a.m. UTC 
On the kernel side, introduce a new btf_kind_operations. It is
similar to that of BTF_KIND_INT, however, it does not need to
handle encodings and bit offsets. Do not implement printing, since
the kernel does not know how to format floating-point values.

Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
---
 kernel/bpf/btf.c | 77 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 75 insertions(+), 2 deletions(-)

Comments

kernel test robot Feb. 20, 2021, 6:13 a.m. UTC | #1 
Hi Ilya,

I love your patch! Yet something to improve:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/0day-ci/linux/commits/Ilya-Leoshkevich/Add-BTF_KIND_FLOAT-support/20210220-115658
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: nds32-randconfig-r024-20210220 (attached as .config)
compiler: nds32le-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/91b04e9599495806c46c36ba275df4e653a6f112
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Ilya-Leoshkevich/Add-BTF_KIND_FLOAT-support/20210220-115658
        git checkout 91b04e9599495806c46c36ba275df4e653a6f112
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=nds32 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   nds32le-linux-ld: kernel/bpf/btf.o: in function `btf_float_check_member':
>> btf.c:(.text+0x1be6): undefined reference to `__umoddi3'
>> nds32le-linux-ld: btf.c:(.text+0x1bea): undefined reference to `__umoddi3'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
kernel test robot Feb. 20, 2021, 6:24 a.m. UTC | #2 
Hi Ilya,

I love your patch! Yet something to improve:

[auto build test ERROR on bpf-next/master]

url:    https://github.com/0day-ci/linux/commits/Ilya-Leoshkevich/Add-BTF_KIND_FLOAT-support/20210220-115658
base:   https://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf-next.git master
config: microblaze-randconfig-r016-20210219 (attached as .config)
compiler: microblaze-linux-gcc (GCC) 9.3.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/0day-ci/linux/commit/91b04e9599495806c46c36ba275df4e653a6f112
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Ilya-Leoshkevich/Add-BTF_KIND_FLOAT-support/20210220-115658
        git checkout 91b04e9599495806c46c36ba275df4e653a6f112
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-9.3.0 make.cross ARCH=microblaze 

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@intel.com>

All errors (new ones prefixed by >>):

   microblaze-linux-ld: kernel/bpf/btf.o: in function `btf_float_check_member':
>> (.text+0x3bdc): undefined reference to `__umoddi3'

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org
Ilya Leoshkevich Feb. 21, 2021, 4:37 p.m. UTC | #3 
On Sat, 2021-02-20 at 04:49 +0100, Ilya Leoshkevich wrote:
> On the kernel side, introduce a new btf_kind_operations. It is
> similar to that of BTF_KIND_INT, however, it does not need to
> handle encodings and bit offsets. Do not implement printing, since
> the kernel does not know how to format floating-point values.
> 
> Signed-off-by: Ilya Leoshkevich <iii@linux.ibm.com>
> ---
>  kernel/bpf/btf.c | 77
> ++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 75 insertions(+), 2 deletions(-)
> 
> diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
> index 2efeb5f4b343..813c2bfe284f 100644
> --- a/kernel/bpf/btf.c
> +++ b/kernel/bpf/btf.c

[...]

> +static int btf_float_check_member(struct btf_verifier_env *env,
> +                                 const struct btf_type *struct_type,
> +                                 const struct btf_member *member,
> +                                 const struct btf_type *member_type)
> +{
> +       u64 start_offset_bytes;
> +       u64 end_offset_bytes;
> +       u64 align_bytes;
> +       u64 align_bits;
> +
> +       align_bytes = min_t(u64, sizeof(void *), member_type->size);
> +       align_bits = align_bytes * BITS_PER_BYTE;
> +       if (member->offset % align_bits) {

The kernel test robot's link error is most likely due to this line.
I should be using do_div here.

[...]
diff mbox series

Patch

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 2efeb5f4b343..813c2bfe284f 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -173,7 +173,7 @@ 
 #define BITS_ROUNDUP_BYTES(bits) \
 	(BITS_ROUNDDOWN_BYTES(bits) + !!BITS_PER_BYTE_MASKED(bits))
 
-#define BTF_INFO_MASK 0x8f00ffff
+#define BTF_INFO_MASK 0x9f00ffff
 #define BTF_INT_MASK 0x0fffffff
 #define BTF_TYPE_ID_VALID(type_id) ((type_id) <= BTF_MAX_TYPE)
 #define BTF_STR_OFFSET_VALID(name_off) ((name_off) <= BTF_MAX_NAME_OFFSET)
@@ -280,6 +280,7 @@  static const char * const btf_kind_str[NR_BTF_KINDS] = {
 	[BTF_KIND_FUNC_PROTO]	= "FUNC_PROTO",
 	[BTF_KIND_VAR]		= "VAR",
 	[BTF_KIND_DATASEC]	= "DATASEC",
+	[BTF_KIND_FLOAT]	= "FLOAT",
 };
 
 static const char *btf_type_str(const struct btf_type *t)
@@ -574,6 +575,7 @@  static bool btf_type_has_size(const struct btf_type *t)
 	case BTF_KIND_UNION:
 	case BTF_KIND_ENUM:
 	case BTF_KIND_DATASEC:
+	case BTF_KIND_FLOAT:
 		return true;
 	}
 
@@ -1704,6 +1706,7 @@  __btf_resolve_size(const struct btf *btf, const struct btf_type *type,
 		case BTF_KIND_STRUCT:
 		case BTF_KIND_UNION:
 		case BTF_KIND_ENUM:
+		case BTF_KIND_FLOAT:
 			size = type->size;
 			goto resolved;
 
@@ -1849,7 +1852,7 @@  static int btf_df_check_kflag_member(struct btf_verifier_env *env,
 	return -EINVAL;
 }
 
-/* Used for ptr, array and struct/union type members.
+/* Used for ptr, array struct/union and float type members.
  * int, enum and modifier types have their specific callback functions.
  */
 static int btf_generic_check_kflag_member(struct btf_verifier_env *env,
@@ -3675,6 +3678,75 @@  static const struct btf_kind_operations datasec_ops = {
 	.show			= btf_datasec_show,
 };
 
+static s32 btf_float_check_meta(struct btf_verifier_env *env,
+				const struct btf_type *t,
+				u32 meta_left)
+{
+	if (btf_type_vlen(t)) {
+		btf_verifier_log_type(env, t, "vlen != 0");
+		return -EINVAL;
+	}
+
+	if (btf_type_kflag(t)) {
+		btf_verifier_log_type(env, t, "Invalid btf_info kind_flag");
+		return -EINVAL;
+	}
+
+	if (t->size != 2 && t->size != 4 && t->size != 8 && t->size != 12 &&
+	    t->size != 16) {
+		btf_verifier_log_type(env, t, "Invalid type_size");
+		return -EINVAL;
+	}
+
+	btf_verifier_log_type(env, t, NULL);
+
+	return 0;
+}
+
+static int btf_float_check_member(struct btf_verifier_env *env,
+				  const struct btf_type *struct_type,
+				  const struct btf_member *member,
+				  const struct btf_type *member_type)
+{
+	u64 start_offset_bytes;
+	u64 end_offset_bytes;
+	u64 align_bytes;
+	u64 align_bits;
+
+	align_bytes = min_t(u64, sizeof(void *), member_type->size);
+	align_bits = align_bytes * BITS_PER_BYTE;
+	if (member->offset % align_bits) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member is not properly aligned");
+		return -EINVAL;
+	}
+
+	start_offset_bytes = member->offset / BITS_PER_BYTE;
+	end_offset_bytes = start_offset_bytes + member_type->size;
+	if (end_offset_bytes > struct_type->size) {
+		btf_verifier_log_member(env, struct_type, member,
+					"Member exceeds struct_size");
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static void btf_float_log(struct btf_verifier_env *env,
+			  const struct btf_type *t)
+{
+	btf_verifier_log(env, "size=%u", t->size);
+}
+
+static const struct btf_kind_operations float_ops = {
+	.check_meta = btf_float_check_meta,
+	.resolve = btf_df_resolve,
+	.check_member = btf_float_check_member,
+	.check_kflag_member = btf_generic_check_kflag_member,
+	.log_details = btf_float_log,
+	.show = btf_df_show,
+};
+
 static int btf_func_proto_check(struct btf_verifier_env *env,
 				const struct btf_type *t)
 {
@@ -3808,6 +3880,7 @@  static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = {
 	[BTF_KIND_FUNC_PROTO] = &func_proto_ops,
 	[BTF_KIND_VAR] = &var_ops,
 	[BTF_KIND_DATASEC] = &datasec_ops,
+	[BTF_KIND_FLOAT] = &float_ops,
 };
 
 static s32 btf_check_meta(struct btf_verifier_env *env,