[PATCH 0/5] add portable version of __builtin_add_overflow

[PATCH 0/5] add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

Andre Muezerie (5):
  maintainers: add portable version of __builtin_add_overflow
  lib/eal: add portable version of __builtin_add_overflow
  doc/api: add portable version of __builtin_add_overflow
  drivers/net: use portable version of __builtin_add_overflow
  app/test: add tests for portable versions of __builtin_add_overflow

 MAINTAINERS                    |   1 +
 app/test/meson.build           |   1 +
 app/test/test_math.c           | 125 +++++++++++++++++++++++++++++++++
 doc/api/doxy-api-index.md      |   1 +
 drivers/net/ice/base/ice_nvm.c |   9 ++-
 lib/eal/include/meson.build    |   1 +
 lib/eal/include/rte_math.h     |  42 +++++++++++
 7 files changed, 175 insertions(+), 5 deletions(-)
 create mode 100644 app/test/test_math.c
 create mode 100644 lib/eal/include/rte_math.h

--
2.47.0.vfs.0.3

[PATCH 1/5] maintainers: add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 60bdcce543..4b03b6752e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -180,6 +180,7 @@ F: app/test/test_devargs.c
 F: app/test/test_eal*
 F: app/test/test_errno.c
 F: app/test/test_lcores.c
+F: app/test/test_math.c
 F: app/test/test_memcpy*
 F: app/test/test_per_lcore.c
 F: app/test/test_pflock.c
-- 
2.47.0.vfs.0.3

[PATCH 2/5] lib/eal: add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

This patch introduces __rte_add_overflow_u8, __rte_add_overflow_u16
and __rte_add_overflow_u32.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 lib/eal/include/meson.build |  1 +
 lib/eal/include/rte_math.h  | 42 +++++++++++++++++++++++++++++++++++++
 2 files changed, 43 insertions(+)
 create mode 100644 lib/eal/include/rte_math.h

diff --git a/lib/eal/include/meson.build b/lib/eal/include/meson.build
index d903577caa..041a4105b5 100644
--- a/lib/eal/include/meson.build
+++ b/lib/eal/include/meson.build
@@ -31,6 +31,7 @@ headers += files(
         'rte_lcore_var.h',
         'rte_lock_annotations.h',
         'rte_malloc.h',
+        'rte_math.h',
         'rte_mcslock.h',
         'rte_memory.h',
         'rte_memzone.h',
diff --git a/lib/eal/include/rte_math.h b/lib/eal/include/rte_math.h
new file mode 100644
index 0000000000..df2f3d4d34
--- /dev/null
+++ b/lib/eal/include/rte_math.h
@@ -0,0 +1,42 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2025 Microsoft Corporation
+ */
+
+#ifndef _RTE_MATH_H_
+#define _RTE_MATH_H_
+
+/**
+ * @file
+ *
+ * Math function definitions for DPDK.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Functions that allow performing simple arithmetic operations together with
+ * checking whether the operations overflowed.
+ * Example of usage:
+ *     uint8_t overflow;
+ *     uint16_t a, b, result;
+ *     a = 1;
+ *     b = 2;
+ *     overflow = __rte_add_overflow_u16(a, b, &result);
+ */
+#ifdef RTE_TOOLCHAIN_MSVC
+#define __rte_add_overflow_u8(a, b, res) _addcarry_u8(0, a, b, res)
+#define __rte_add_overflow_u16(a, b, res) _addcarry_u16(0, a, b, res)
+#define __rte_add_overflow_u32(a, b, res) _addcarry_u32(0, a, b, res)
+#else
+#define __rte_add_overflow_u8(a, b, res) __builtin_add_overflow(a, b, res)
+#define __rte_add_overflow_u16(a, b, res) __builtin_add_overflow(a, b, res)
+#define __rte_add_overflow_u32(a, b, res) __builtin_add_overflow(a, b, res)
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
-- 
2.47.0.vfs.0.3

[PATCH 3/5] doc/api: add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 doc/api/doxy-api-index.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
index f0193502bc..c95a86448d 100644
--- a/doc/api/doxy-api-index.md
+++ b/doc/api/doxy-api-index.md
@@ -226,6 +226,7 @@ The public API headers are grouped by topics:
   [checksum](@ref rte_cksum.h),
   [config file](@ref rte_cfgfile.h),
   [key/value args](@ref rte_kvargs.h),
+  [math](@ref rte_math.h),
   [argument parsing](@ref rte_argparse.h),
   [ptr_compress](@ref rte_ptr_compress.h),
   [string](@ref rte_string_fns.h),
-- 
2.47.0.vfs.0.3

[PATCH 4/5] drivers/net: use portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. It should be replaced with
a portable version that can also be used with other compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 drivers/net/ice/base/ice_nvm.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ice/base/ice_nvm.c b/drivers/net/ice/base/ice_nvm.c
index 56c6c96a95..1fc64b502c 100644
--- a/drivers/net/ice/base/ice_nvm.c
+++ b/drivers/net/ice/base/ice_nvm.c
@@ -3,6 +3,7 @@
  */
 
 #include "ice_common.h"
+#include <rte_math.h>
 
 #define GL_MNG_DEF_DEVID 0x000B611C
 
@@ -469,8 +470,6 @@ int ice_read_sr_word(struct ice_hw *hw, u16 offset, u16 *data)
 	return status;
 }
 
-#define check_add_overflow __builtin_add_overflow
-
 /**
  * ice_get_pfa_module_tlv - Reads sub module TLV from NVM PFA
  * @hw: pointer to hardware structure
@@ -500,7 +499,7 @@ ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, u16 *module_tlv_len,
 		return status;
 	}
 
-	if (check_add_overflow(pfa_ptr, (u16)(pfa_len - 1), &max_tlv)) {
+	if (__rte_add_overflow_u16(pfa_ptr, (u16)(pfa_len - 1), &max_tlv)) {
 		ice_debug(hw, ICE_DBG_INIT, "PFA starts at offset %u. PFA length of %u caused 16-bit arithmetic overflow.\n",
 				  pfa_ptr, pfa_len);
 		return ICE_ERR_INVAL_SIZE;
@@ -541,8 +540,8 @@ ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, u16 *module_tlv_len,
 			return ICE_ERR_INVAL_SIZE;
 		}
 
-		if (check_add_overflow(next_tlv, (u16)2, &next_tlv) ||
-		    check_add_overflow(next_tlv, tlv_len, &next_tlv)) {
+		if (__rte_add_overflow_u16(next_tlv, (u16)2, &next_tlv) ||
+		    __rte_add_overflow_u16(next_tlv, tlv_len, &next_tlv)) {
 			ice_debug(hw, ICE_DBG_INIT, "TLV of type %u and length 0x%04x caused 16-bit arithmetic overflow. The PFA starts at 0x%04x and has length of 0x%04x\n",
 					  tlv_sub_module_type, tlv_len, pfa_ptr, pfa_len);
 			return ICE_ERR_INVAL_SIZE;
-- 
2.47.0.vfs.0.3

[PATCH 5/5] app/test: add tests for portable versions of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

This patch adds tests for these new portable functions, to confirm
they behave the same way across different compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 app/test/meson.build |   1 +
 app/test/test_math.c | 125 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 126 insertions(+)
 create mode 100644 app/test/test_math.c

diff --git a/app/test/meson.build b/app/test/meson.build
index 22b3291fa6..ab23f8dc79 100644
--- a/app/test/meson.build
+++ b/app/test/meson.build
@@ -118,6 +118,7 @@ source_file_deps = {
     'test_lpm_perf.c': ['net', 'lpm'],
     'test_malloc.c': [],
     'test_malloc_perf.c': [],
+    'test_math.c': [],
     'test_mbuf.c': ['net'],
     'test_mcslock.c': [],
     'test_member.c': ['member', 'net'],
diff --git a/app/test/test_math.c b/app/test/test_math.c
new file mode 100644
index 0000000000..55fb11f22c
--- /dev/null
+++ b/app/test/test_math.c
@@ -0,0 +1,125 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (C) 2025 Microsoft Corporation
+ */
+
+#include <rte_math.h>
+#include <rte_debug.h>
+
+#include "test.h"
+
+/* Check condition and return if true. */
+#define TEST_MATH_RETURN_IF_ERROR(X) \
+do { \
+	if (X) { \
+		return -1; \
+	} \
+} while (0)
+
+RTE_LOG_REGISTER(math_logtype_test, test.math, INFO);
+
+static int
+verify_add_overflow_u8(uint8_t a, uint8_t b,
+		uint8_t expected_res, uint8_t expected_overflow)
+{
+	uint8_t res;
+	uint8_t overflow = __rte_add_overflow_u8(a, b, &res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: __rte_add_overflow_u8(0x%x, 0x%x) returned result 0x%x,"
+			" but 0x%x was expected.", a, b, res, expected_res);
+	RTE_TEST_ASSERT_EQUAL(overflow, expected_overflow,
+			"ERROR: __rte_add_overflow_u8(0x%x, 0x%x) returned overflow 0x%x,"
+			" but 0x%x was expected.", a, b, overflow, expected_overflow);
+
+	return 0;
+}
+
+static int
+verify_add_overflow_u16(uint16_t a, uint16_t b,
+		uint16_t expected_res, uint16_t expected_overflow)
+{
+	uint16_t res;
+	uint8_t overflow = __rte_add_overflow_u16(a, b, &res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: __rte_add_overflow_u16(0x%x, 0x%x) returned result 0x%x,"
+			" but 0x%x was expected.", a, b, res, expected_res);
+	RTE_TEST_ASSERT_EQUAL(overflow, expected_overflow,
+			"ERROR: __rte_add_overflow_u16(0x%x, 0x%x) returned overflow 0x%x,"
+			" but 0x%x was expected.", a, b, overflow, expected_overflow);
+
+	return 0;
+}
+
+static int
+verify_add_overflow_u32(uint32_t a, uint32_t b,
+		uint32_t expected_res, uint32_t expected_overflow)
+{
+	uint32_t res;
+	uint8_t overflow = __rte_add_overflow_u32(a, b, &res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: __rte_add_overflow_u32(0x%x, 0x%x) returned result 0x%x,"
+			" but 0x%x was expected.", a, b, res, expected_res);
+	RTE_TEST_ASSERT_EQUAL(overflow, expected_overflow,
+			"ERROR: __rte_add_overflow_u32(0x%x, 0x%x) returned overflow 0x%x,"
+			" but 0x%x was expected.", a, b, overflow, expected_overflow);
+
+	return 0;
+}
+
+static int
+test_add_overflow_u8(void)
+{
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u8(0, 0, 0, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u8(0, 1, 1, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u8(0, 0xFF, 0xFF, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u8(1, 0xFF, 0, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u8(2, 0xFF, 1, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u8(4, 0xFE, 2, 1));
+
+	return 0;
+}
+
+static int
+test_add_overflow_u16(void)
+{
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u16(0, 0, 0, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u16(0, 1, 1, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u16(0, 0xFFFF, 0xFFFF, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u16(1, 0xFFFF, 0, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u16(2, 0xFFFF, 1, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u16(4, 0xFFFE, 2, 1));
+
+	return 0;
+}
+
+static int
+test_add_overflow_u32(void)
+{
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u32(0, 0, 0, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u32(0, 1, 1, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u32(0, 0xFFFFFFFF, 0xFFFFFFFF, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u32(1, 0xFFFFFFFF, 0, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u32(2, 0xFFFFFFFF, 1, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow_u32(4, 0xFFFFFFFE, 2, 1));
+
+	return 0;
+}
+
+static struct unit_test_suite math_test_suite = {
+	.suite_name = "math autotest",
+	.setup = NULL,
+	.teardown = NULL,
+	.unit_test_cases = {
+		TEST_CASE(test_add_overflow_u8),
+		TEST_CASE(test_add_overflow_u16),
+		TEST_CASE(test_add_overflow_u32),
+		TEST_CASES_END()
+	}
+};
+
+static int
+test_math(void)
+{
+	return unit_test_suite_runner(&math_test_suite);
+}
+
+REGISTER_FAST_TEST(math_autotest, true, true, test_math);
-- 
2.47.0.vfs.0.3

Re: [PATCH 0/5] add portable version of __builtin_add_overflow

[Stephen Hemminger]

On Thu,  2 Jan 2025 14:32:43 -0800
Andre Muezerie <andremue@linux.microsoft.com> wrote:

> __builtin_add_overflow is gcc specific. There's a need for a portable
> version that can also be used with other compilers.
> 
> Andre Muezerie (5):
>   maintainers: add portable version of __builtin_add_overflow
>   lib/eal: add portable version of __builtin_add_overflow
>   doc/api: add portable version of __builtin_add_overflow
>   drivers/net: use portable version of __builtin_add_overflow
>   app/test: add tests for portable versions of __builtin_add_overflow
> 
>  MAINTAINERS                    |   1 +
>  app/test/meson.build           |   1 +
>  app/test/test_math.c           | 125 +++++++++++++++++++++++++++++++++
>  doc/api/doxy-api-index.md      |   1 +
>  drivers/net/ice/base/ice_nvm.c |   9 ++-
>  lib/eal/include/meson.build    |   1 +
>  lib/eal/include/rte_math.h     |  42 +++++++++++
>  7 files changed, 175 insertions(+), 5 deletions(-)
>  create mode 100644 app/test/test_math.c
>  create mode 100644 lib/eal/include/rte_math.h
> 
> --
> 2.47.0.vfs.0.3
> 

You should add _builtin_add_overflow into the checkpatch naughty list.
Or maybe all the _builtin_XXX functions?

Re: [PATCH 0/5] add portable version of __builtin_add_overflow

[Andre Muezerie]

On Thu, Jan 02, 2025 at 03:51:55PM -0800, Stephen Hemminger wrote:
> On Thu,  2 Jan 2025 14:32:43 -0800
> Andre Muezerie <andremue@linux.microsoft.com> wrote:
> 
> > __builtin_add_overflow is gcc specific. There's a need for a portable
> > version that can also be used with other compilers.
> > 
> > Andre Muezerie (5):
> >   maintainers: add portable version of __builtin_add_overflow
> >   lib/eal: add portable version of __builtin_add_overflow
> >   doc/api: add portable version of __builtin_add_overflow
> >   drivers/net: use portable version of __builtin_add_overflow
> >   app/test: add tests for portable versions of __builtin_add_overflow
> > 
> >  MAINTAINERS                    |   1 +
> >  app/test/meson.build           |   1 +
> >  app/test/test_math.c           | 125 +++++++++++++++++++++++++++++++++
> >  doc/api/doxy-api-index.md      |   1 +
> >  drivers/net/ice/base/ice_nvm.c |   9 ++-
> >  lib/eal/include/meson.build    |   1 +
> >  lib/eal/include/rte_math.h     |  42 +++++++++++
> >  7 files changed, 175 insertions(+), 5 deletions(-)
> >  create mode 100644 app/test/test_math.c
> >  create mode 100644 lib/eal/include/rte_math.h
> > 
> > --
> > 2.47.0.vfs.0.3
> > 
> 
> You should add _builtin_add_overflow into the checkpatch naughty list.
> Or maybe all the _builtin_XXX functions?

Absolutely! Let me add that for a v2 series.

Re: [PATCH 0/5] add portable version of __builtin_add_overflow

[Andre Muezerie]

On Thu, Jan 02, 2025 at 04:15:31PM -0800, Andre Muezerie wrote:
> On Thu, Jan 02, 2025 at 03:51:55PM -0800, Stephen Hemminger wrote:
> > On Thu,  2 Jan 2025 14:32:43 -0800
> > Andre Muezerie <andremue@linux.microsoft.com> wrote:
> > 
> > > __builtin_add_overflow is gcc specific. There's a need for a portable
> > > version that can also be used with other compilers.
> > > 
> > > Andre Muezerie (5):
> > >   maintainers: add portable version of __builtin_add_overflow
> > >   lib/eal: add portable version of __builtin_add_overflow
> > >   doc/api: add portable version of __builtin_add_overflow
> > >   drivers/net: use portable version of __builtin_add_overflow
> > >   app/test: add tests for portable versions of __builtin_add_overflow
> > > 
> > >  MAINTAINERS                    |   1 +
> > >  app/test/meson.build           |   1 +
> > >  app/test/test_math.c           | 125 +++++++++++++++++++++++++++++++++
> > >  doc/api/doxy-api-index.md      |   1 +
> > >  drivers/net/ice/base/ice_nvm.c |   9 ++-
> > >  lib/eal/include/meson.build    |   1 +
> > >  lib/eal/include/rte_math.h     |  42 +++++++++++
> > >  7 files changed, 175 insertions(+), 5 deletions(-)
> > >  create mode 100644 app/test/test_math.c
> > >  create mode 100644 lib/eal/include/rte_math.h
> > > 
> > > --
> > > 2.47.0.vfs.0.3
> > > 
> > 
> > You should add _builtin_add_overflow into the checkpatch naughty list.
> > Or maybe all the _builtin_XXX functions?
> 
> Absolutely! Let me add that for a v2 series.

Turns out such check was already added recently
(MESSAGE='Using __builtin helpers, prefer EAL macros'), so further changes
needed at this point.

RE: [PATCH 2/5] lib/eal: add portable version of __builtin_add_overflow

[Morten Brørup]

> From: Andre Muezerie [mailto:andremue@linux.microsoft.com]
> Sent: Thursday, 2 January 2025 23.33
> 
> __builtin_add_overflow is gcc specific. There's a need for a portable
> version that can also be used with other compilers.
> 
> This patch introduces __rte_add_overflow_u8, __rte_add_overflow_u16
> and __rte_add_overflow_u32.

Instead of the proposed three type-specific macros, add one generic rte_add_overflow(a, b, res) macro, like rte_bit_test() [1] using "_Generic".

[1]: https://elixir.bootlin.com/dpdk/v24.11.1/source/lib/eal/include/rte_bitops.h#L130

You may still need the type-specific macros as internal helpers for the MSVC implementation.

Furthermore, a 64 bit variant might be useful.

PS: DPDK naming convention typically uses just "8"/"16"/"32" postfix to the function name, not "_u8"/"_u16"/"_u32".

Re: [PATCH 2/5] lib/eal: add portable version of __builtin_add_overflow

[Andre Muezerie]

On Fri, Jan 03, 2025 at 09:19:42AM +0100, Morten Brørup wrote:
> > From: Andre Muezerie [mailto:andremue@linux.microsoft.com]
> > Sent: Thursday, 2 January 2025 23.33
> > 
> > __builtin_add_overflow is gcc specific. There's a need for a portable
> > version that can also be used with other compilers.
> > 
> > This patch introduces __rte_add_overflow_u8, __rte_add_overflow_u16
> > and __rte_add_overflow_u32.
> 
> Instead of the proposed three type-specific macros, add one generic rte_add_overflow(a, b, res) macro, like rte_bit_test() [1] using "_Generic".
> 
> [1]: https://elixir.bootlin.com/dpdk/v24.11.1/source/lib/eal/include/rte_bitops.h#L130
> 
> You may still need the type-specific macros as internal helpers for the MSVC implementation.
> 
> Furthermore, a 64 bit variant might be useful.
> 
> PS: DPDK naming convention typically uses just "8"/"16"/"32" postfix to the function name, not "_u8"/"_u16"/"_u32".

These are great suggestions. I'll incorporate them in the v2 of this series.

[PATCH v2 0/5] add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

Andre Muezerie (5):
  maintainers: add portable version of __builtin_add_overflow
  lib/eal: add portable version of __builtin_add_overflow
  doc/api: add portable version of __builtin_add_overflow
  drivers/net: use portable version of __builtin_add_overflow
  app/test: add tests for portable version of __builtin_add_overflow

 MAINTAINERS                    |   1 +
 app/test/meson.build           |   1 +
 app/test/test_math.c           | 170 +++++++++++++++++++++++++++++++++
 doc/api/doxy-api-index.md      |   1 +
 drivers/net/ice/base/ice_nvm.c |   9 +-
 lib/eal/include/meson.build    |   1 +
 lib/eal/include/rte_math.h     |  46 +++++++++
 7 files changed, 224 insertions(+), 5 deletions(-)
 create mode 100644 app/test/test_math.c
 create mode 100644 lib/eal/include/rte_math.h

--
2.47.0.vfs.0.3

[PATCH v2 1/5] maintainers: add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 MAINTAINERS | 1 +
 1 file changed, 1 insertion(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 0f940ad713..fb64ba893b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -179,6 +179,7 @@ F: app/test/test_devargs.c
 F: app/test/test_eal*
 F: app/test/test_errno.c
 F: app/test/test_lcores.c
+F: app/test/test_math.c
 F: app/test/test_memcpy*
 F: app/test/test_per_lcore.c
 F: app/test/test_pflock.c
-- 
2.47.0.vfs.0.3

[PATCH v2 2/5] lib/eal: add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

This patch introduces rte_add_overflow.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 lib/eal/include/meson.build |  1 +
 lib/eal/include/rte_math.h  | 46 +++++++++++++++++++++++++++++++++++++
 2 files changed, 47 insertions(+)
 create mode 100644 lib/eal/include/rte_math.h

diff --git a/lib/eal/include/meson.build b/lib/eal/include/meson.build
index d903577caa..041a4105b5 100644
--- a/lib/eal/include/meson.build
+++ b/lib/eal/include/meson.build
@@ -31,6 +31,7 @@ headers += files(
         'rte_lcore_var.h',
         'rte_lock_annotations.h',
         'rte_malloc.h',
+        'rte_math.h',
         'rte_mcslock.h',
         'rte_memory.h',
         'rte_memzone.h',
diff --git a/lib/eal/include/rte_math.h b/lib/eal/include/rte_math.h
new file mode 100644
index 0000000000..2f4581f81b
--- /dev/null
+++ b/lib/eal/include/rte_math.h
@@ -0,0 +1,46 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2025 Microsoft Corporation
+ */
+
+#ifndef _RTE_MATH_H_
+#define _RTE_MATH_H_
+
+/**
+ * @file
+ *
+ * Math function definitions for DPDK.
+ */
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/*
+ * Function that allows performing simple arithmetic operations together with
+ * checking whether the operation overflowed.
+ * Example of usage:
+ *     uint8_t overflow;
+ *     uint16_t a, b, result;
+ *     a = 1;
+ *     b = 2;
+ *     overflow = rte_add_overflow(a, b, &result);
+ */
+#ifdef RTE_TOOLCHAIN_MSVC
+#define rte_add_overflow(a, b, res) _Generic((a), \
+	uint8_t : _addcarry_u8, \
+	uint16_t : _addcarry_u16, \
+	uint32_t : _addcarry_u32, \
+	uint64_t : _addcarry_u64)(0, a, b, res)
+#else
+#define rte_add_overflow(a, b, res) _Generic((a), \
+	uint8_t : __builtin_add_overflow, \
+	uint16_t : __builtin_add_overflow, \
+	uint32_t : __builtin_add_overflow, \
+	uint64_t : __builtin_add_overflow)(a, b, res)
+#endif
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif
-- 
2.47.0.vfs.0.3

[PATCH v2 3/5] doc/api: add portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 doc/api/doxy-api-index.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/doc/api/doxy-api-index.md b/doc/api/doxy-api-index.md
index f0193502bc..c95a86448d 100644
--- a/doc/api/doxy-api-index.md
+++ b/doc/api/doxy-api-index.md
@@ -226,6 +226,7 @@ The public API headers are grouped by topics:
   [checksum](@ref rte_cksum.h),
   [config file](@ref rte_cfgfile.h),
   [key/value args](@ref rte_kvargs.h),
+  [math](@ref rte_math.h),
   [argument parsing](@ref rte_argparse.h),
   [ptr_compress](@ref rte_ptr_compress.h),
   [string](@ref rte_string_fns.h),
-- 
2.47.0.vfs.0.3

[PATCH v2 4/5] drivers/net: use portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. It should be replaced with
a portable version that can also be used with other compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 drivers/net/ice/base/ice_nvm.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/net/ice/base/ice_nvm.c b/drivers/net/ice/base/ice_nvm.c
index 56c6c96a95..1002a6b59f 100644
--- a/drivers/net/ice/base/ice_nvm.c
+++ b/drivers/net/ice/base/ice_nvm.c
@@ -3,6 +3,7 @@
  */
 
 #include "ice_common.h"
+#include <rte_math.h>
 
 #define GL_MNG_DEF_DEVID 0x000B611C
 
@@ -469,8 +470,6 @@ int ice_read_sr_word(struct ice_hw *hw, u16 offset, u16 *data)
 	return status;
 }
 
-#define check_add_overflow __builtin_add_overflow
-
 /**
  * ice_get_pfa_module_tlv - Reads sub module TLV from NVM PFA
  * @hw: pointer to hardware structure
@@ -500,7 +499,7 @@ ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, u16 *module_tlv_len,
 		return status;
 	}
 
-	if (check_add_overflow(pfa_ptr, (u16)(pfa_len - 1), &max_tlv)) {
+	if (rte_add_overflow(pfa_ptr, (u16)(pfa_len - 1), &max_tlv)) {
 		ice_debug(hw, ICE_DBG_INIT, "PFA starts at offset %u. PFA length of %u caused 16-bit arithmetic overflow.\n",
 				  pfa_ptr, pfa_len);
 		return ICE_ERR_INVAL_SIZE;
@@ -541,8 +540,8 @@ ice_get_pfa_module_tlv(struct ice_hw *hw, u16 *module_tlv, u16 *module_tlv_len,
 			return ICE_ERR_INVAL_SIZE;
 		}
 
-		if (check_add_overflow(next_tlv, (u16)2, &next_tlv) ||
-		    check_add_overflow(next_tlv, tlv_len, &next_tlv)) {
+		if (rte_add_overflow(next_tlv, (u16)2, &next_tlv) ||
+		    rte_add_overflow(next_tlv, tlv_len, &next_tlv)) {
 			ice_debug(hw, ICE_DBG_INIT, "TLV of type %u and length 0x%04x caused 16-bit arithmetic overflow. The PFA starts at 0x%04x and has length of 0x%04x\n",
 					  tlv_sub_module_type, tlv_len, pfa_ptr, pfa_len);
 			return ICE_ERR_INVAL_SIZE;
-- 
2.47.0.vfs.0.3

[PATCH v2 5/5] app/test: add tests for portable version of __builtin_add_overflow

[Andre Muezerie]

__builtin_add_overflow is gcc specific. There's a need for a portable
version that can also be used with other compilers.

This patch adds tests for these new portable functions, to confirm
they behave the same way across different compilers.

Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
---
 app/test/meson.build |   1 +
 app/test/test_math.c | 170 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 171 insertions(+)
 create mode 100644 app/test/test_math.c

diff --git a/app/test/meson.build b/app/test/meson.build
index d5cb6a7f7a..49e13c5505 100644
--- a/app/test/meson.build
+++ b/app/test/meson.build
@@ -118,6 +118,7 @@ source_file_deps = {
     'test_lpm_perf.c': ['net', 'lpm'],
     'test_malloc.c': [],
     'test_malloc_perf.c': [],
+    'test_math.c': [],
     'test_mbuf.c': ['net'],
     'test_mcslock.c': [],
     'test_member.c': ['member', 'net'],
diff --git a/app/test/test_math.c b/app/test/test_math.c
new file mode 100644
index 0000000000..5b53eba71d
--- /dev/null
+++ b/app/test/test_math.c
@@ -0,0 +1,170 @@
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright (C) 2025 Microsoft Corporation
+ */
+
+#include <rte_math.h>
+#include <rte_debug.h>
+
+#include "test.h"
+#include <inttypes.h>
+
+/* Check condition and return if true. */
+#define TEST_MATH_RETURN_IF_ERROR(X) \
+do { \
+	if (X) { \
+		return -1; \
+	} \
+} while (0)
+
+RTE_LOG_REGISTER(math_logtype_test, test.math, INFO);
+
+static int
+verify_add_overflow8(uint8_t a, uint8_t b,
+		uint8_t expected_res, uint8_t expected_overflow)
+{
+	uint8_t res;
+	uint8_t overflow = rte_add_overflow(a, b, &res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: rte_add_overflow(0x%x, 0x%x) returned result 0x%x,"
+			" but 0x%x was expected.", a, b, res, expected_res);
+	RTE_TEST_ASSERT_EQUAL(overflow, expected_overflow,
+			"ERROR: rte_add_overflow(0x%x, 0x%x) returned overflow 0x%x,"
+			" but 0x%x was expected.", a, b, overflow, expected_overflow);
+
+	return 0;
+}
+
+static int
+verify_add_overflow16(uint16_t a, uint16_t b,
+		uint16_t expected_res, uint8_t expected_overflow)
+{
+	uint16_t res;
+	uint8_t overflow = rte_add_overflow(a, b, &res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: rte_add_overflow(0x%x, 0x%x) returned result 0x%x,"
+			" but 0x%x was expected.", a, b, res, expected_res);
+	RTE_TEST_ASSERT_EQUAL(overflow, expected_overflow,
+			"ERROR: rte_add_overflow(0x%x, 0x%x) returned overflow 0x%x,"
+			" but 0x%x was expected.", a, b, overflow, expected_overflow);
+
+	return 0;
+}
+
+static int
+verify_add_overflow32(uint32_t a, uint32_t b,
+		uint32_t expected_res, uint8_t expected_overflow)
+{
+	uint32_t res;
+	uint8_t overflow = rte_add_overflow(a, b, &res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: rte_add_overflow(0x%x, 0x%x) returned result 0x%x,"
+			" but 0x%x was expected.", a, b, res, expected_res);
+	RTE_TEST_ASSERT_EQUAL(overflow, expected_overflow,
+			"ERROR: rte_add_overflow(0x%x, 0x%x) returned overflow 0x%x,"
+			" but 0x%x was expected.", a, b, overflow, expected_overflow);
+
+	return 0;
+}
+
+static int
+verify_add_overflow64(uint64_t a, uint64_t b,
+		uint64_t expected_res, uint8_t expected_overflow)
+{
+	uint64_t res;
+	uint8_t overflow = rte_add_overflow(a, b, &res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: rte_add_overflow(0x%" PRIx64 ", 0x%" PRIx64 ") returned"
+			" result 0x%" PRIx64 ", but 0x%" PRIx64 " was expected.",
+			a, b, res, expected_res);
+	RTE_TEST_ASSERT_EQUAL(res, expected_res,
+			"ERROR: rte_add_overflow(0x%" PRIx64 ", 0x%" PRIx64 ") returned"
+			" overflow 0x%x, but 0x%x was expected.",
+			a, b, overflow, expected_overflow);
+
+	return 0;
+}
+
+static int
+test_add_overflow8(void)
+{
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow8(0, 0, 0, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow8(0, 1, 1, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow8(0, 0xFF, 0xFF, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow8(1, 0xFF, 0, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow8(2, 0xFF, 1, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow8(4, 0xFE, 2, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow8(0xFF, 0xFF, 0xFE, 1));
+
+	return 0;
+}
+
+static int
+test_add_overflow16(void)
+{
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow16(0, 0, 0, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow16(0, 1, 1, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow16(0, 0xFFFF, 0xFFFF, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow16(1, 0xFFFF, 0, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow16(2, 0xFFFF, 1, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow16(4, 0xFFFE, 2, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow16(
+			0xFFFF, 0xFFFF, 0xFFFE, 1));
+
+	return 0;
+}
+
+static int
+test_add_overflow32(void)
+{
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow32(0, 0, 0, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow32(0, 1, 1, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow32(
+			0, 0xFFFFFFFF, 0xFFFFFFFF, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow32(1, 0xFFFFFFFF, 0, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow32(2, 0xFFFFFFFF, 1, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow32(4, 0xFFFFFFFE, 2, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow32(
+			0xFFFFFFFF, 0xFFFFFFFF, 0xFFFFFFFE, 1));
+
+	return 0;
+}
+
+static int
+test_add_overflow64(void)
+{
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow64(0, 0, 0, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow64(0, 1, 1, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow64(
+			0, 0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF, 0));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow64(
+			1, 0xFFFFFFFFFFFFFFFF, 0, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow64(
+			2, 0xFFFFFFFFFFFFFFFF, 1, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow64(
+			4, 0xFFFFFFFFFFFFFFFE, 2, 1));
+	TEST_MATH_RETURN_IF_ERROR(verify_add_overflow64(
+			0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFF, 0xFFFFFFFFFFFFFFFE, 1));
+
+	return 0;
+}
+
+static struct unit_test_suite math_test_suite = {
+	.suite_name = "math autotest",
+	.setup = NULL,
+	.teardown = NULL,
+	.unit_test_cases = {
+		TEST_CASE(test_add_overflow8),
+		TEST_CASE(test_add_overflow16),
+		TEST_CASE(test_add_overflow32),
+		TEST_CASE(test_add_overflow64),
+		TEST_CASES_END()
+	}
+};
+
+static int
+test_math(void)
+{
+	return unit_test_suite_runner(&math_test_suite);
+}
+
+REGISTER_FAST_TEST(math_autotest, true, true, test_math);
-- 
2.47.0.vfs.0.3

Re: [PATCH v2 2/5] lib/eal: add portable version of __builtin_add_overflow

[Bruce Richardson]

On Fri, Jan 03, 2025 at 12:39:38PM -0800, Andre Muezerie wrote:
> __builtin_add_overflow is gcc specific. There's a need for a portable
> version that can also be used with other compilers.
> 
> This patch introduces rte_add_overflow.
> 
> Signed-off-by: Andre Muezerie <andremue@linux.microsoft.com>
> ---
>  lib/eal/include/meson.build |  1 +
>  lib/eal/include/rte_math.h  | 46 +++++++++++++++++++++++++++++++++++++
>  2 files changed, 47 insertions(+)
>  create mode 100644 lib/eal/include/rte_math.h
> 
> diff --git a/lib/eal/include/meson.build b/lib/eal/include/meson.build
> index d903577caa..041a4105b5 100644
> --- a/lib/eal/include/meson.build
> +++ b/lib/eal/include/meson.build
> @@ -31,6 +31,7 @@ headers += files(
>          'rte_lcore_var.h',
>          'rte_lock_annotations.h',
>          'rte_malloc.h',
> +        'rte_math.h',
>          'rte_mcslock.h',
>          'rte_memory.h',
>          'rte_memzone.h',
> diff --git a/lib/eal/include/rte_math.h b/lib/eal/include/rte_math.h
> new file mode 100644
> index 0000000000..2f4581f81b
> --- /dev/null
> +++ b/lib/eal/include/rte_math.h
> @@ -0,0 +1,46 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright(c) 2025 Microsoft Corporation
> + */
> +
> +#ifndef _RTE_MATH_H_
> +#define _RTE_MATH_H_
> +
> +/**
> + * @file
> + *
> + * Math function definitions for DPDK.
> + */
> +
> +#ifdef __cplusplus
> +extern "C" {
> +#endif
> +
> +/*
> + * Function that allows performing simple arithmetic operations together with
> + * checking whether the operation overflowed.
> + * Example of usage:
> + *     uint8_t overflow;
> + *     uint16_t a, b, result;
> + *     a = 1;
> + *     b = 2;
> + *     overflow = rte_add_overflow(a, b, &result);
> + */
> +#ifdef RTE_TOOLCHAIN_MSVC
> +#define rte_add_overflow(a, b, res) _Generic((a), \
> +	uint8_t : _addcarry_u8, \
> +	uint16_t : _addcarry_u16, \
> +	uint32_t : _addcarry_u32, \
> +	uint64_t : _addcarry_u64)(0, a, b, res)
> +#else
> +#define rte_add_overflow(a, b, res) _Generic((a), \
> +	uint8_t : __builtin_add_overflow, \
> +	uint16_t : __builtin_add_overflow, \
> +	uint32_t : __builtin_add_overflow, \
> +	uint64_t : __builtin_add_overflow)(a, b, res)
> +#endif

For the gcc version, can you just simplify to the one-line below?

#define rte_add_overflow __builtin_add_overflow

/Bruce