[v2] eal/arm: replace RTE_BUILD_BUG on non-constant
Checks
Commit Message
The ARM implementation of rte_pause uses RTE_BUILD_BUG_ON to check
memorder, which is not constant. This causes compile errors when it is
enabled with RTE_ARM_USE_WFE. eg.
../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
../lib/eal/include/rte_common.h:530:56: error: expression in static assertion is not constant
530 | #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
| ^~~~~~~~~~~~
../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
156 | RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
| ^~~~~~~~~~~~~~~~
Fix the compile errors by replacing the check with an assert, like in
the generic implementation (lib/eal/include/generic/rte_pause.h).
Fixes: 875f350924b8 ("eal: add a new helper for wait until scheme")
Signed-off-by: Daniel Gregory <daniel.gregory@bytedance.com>
---
Cc: feifei.wang2@arm.com
---
lib/eal/arm/include/rte_pause_64.h | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
Comments
Apologies, mis-sent this before attaching a changelog:
v2:
* replaced RTE_ASSERT with assert
* added Fixes: tag
On Fri, 3 May 2024 19:27:30 +0100
Daniel Gregory <daniel.gregory@bytedance.com> wrote:
> The ARM implementation of rte_pause uses RTE_BUILD_BUG_ON to check
> memorder, which is not constant. This causes compile errors when it is
> enabled with RTE_ARM_USE_WFE. eg.
>
> ../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
> ../lib/eal/include/rte_common.h:530:56: error: expression in static assertion is not constant
> 530 | #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
> | ^~~~~~~~~~~~
> ../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
> 156 | RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
> | ^~~~~~~~~~~~~~~~
>
> Fix the compile errors by replacing the check with an assert, like in
> the generic implementation (lib/eal/include/generic/rte_pause.h).
No, don't hide the problem.
What code is calling these. Looks like a real bug. Could be behind layers of wrappers.
+ Arm team to the loop.
Removed invalid email address.
From: Daniel Gregory <daniel.gregory@bytedance.com>
Date: Saturday, May 4, 2024 at 2:27 AM
To: Ruifeng Wang <Ruifeng.Wang@arm.com>
Cc: dev@dpdk.org <dev@dpdk.org>, Punit Agrawal <punit.agrawal@bytedance.com>, Liang Ma <liangma@bytedance.com>, Daniel Gregory <daniel.gregory@bytedance.com>, Feifei Wang <Feifei.Wang2@arm.com>
Subject: [PATCH v2] eal/arm: replace RTE_BUILD_BUG on non-constant
The ARM implementation of rte_pause uses RTE_BUILD_BUG_ON to check
memorder, which is not constant. This causes compile errors when it is
enabled with RTE_ARM_USE_WFE. eg.
../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
../lib/eal/include/rte_common.h:530:56: error: expression in static assertion is not constant
530 | #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
| ^~~~~~~~~~~~
../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
156 | RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
| ^~~~~~~~~~~~~~~~
Fix the compile errors by replacing the check with an assert, like in
the generic implementation (lib/eal/include/generic/rte_pause.h).
Fixes: 875f350924b8 ("eal: add a new helper for wait until scheme")
Signed-off-by: Daniel Gregory <daniel.gregory@bytedance.com>
---
Cc: feifei.wang2@arm.com
---
lib/eal/arm/include/rte_pause_64.h | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
> ../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
> ../lib/eal/include/rte_common.h:530:56: error: expression in static assertion
> is not constant
> 530 | #define RTE_BUILD_BUG_ON(condition) do {
> static_assert(!(condition), #condition); } while (0)
> | ^~~~~~~~~~~~
> ../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro
> ‘RTE_BUILD_BUG_ON’
> 156 | RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
> | ^~~~~~~~~~~~~~~~
>
> Fix the compile errors by replacing the check with an assert, like in the generic
> implementation (lib/eal/include/generic/rte_pause.h).
>
> Fixes: 875f350924b8 ("eal: add a new helper for wait until scheme")
>
> Signed-off-by: Daniel Gregory <daniel.gregory@bytedance.com>
Acked-by: Wathsala Vithanage <wathsala.vithanage@arm.com>
04/05/2024 02:59, Stephen Hemminger:
> On Fri, 3 May 2024 19:27:30 +0100
> Daniel Gregory <daniel.gregory@bytedance.com> wrote:
>
> > The ARM implementation of rte_pause uses RTE_BUILD_BUG_ON to check
> > memorder, which is not constant. This causes compile errors when it is
> > enabled with RTE_ARM_USE_WFE. eg.
> >
> > ../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
> > ../lib/eal/include/rte_common.h:530:56: error: expression in static assertion is not constant
> > 530 | #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
> > | ^~~~~~~~~~~~
> > ../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
> > 156 | RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
> > | ^~~~~~~~~~~~~~~~
> >
> > Fix the compile errors by replacing the check with an assert, like in
> > the generic implementation (lib/eal/include/generic/rte_pause.h).
>
> No, don't hide the problem.
>
> What code is calling these. Looks like a real bug. Could be behind layers of wrappers.
I support Stephen's opinion.
Please look for the real issue.
On Thu, Jun 27, 2024 at 05:08:51PM +0200, Thomas Monjalon wrote:
> 04/05/2024 02:59, Stephen Hemminger:
> > On Fri, 3 May 2024 19:27:30 +0100
> > Daniel Gregory <daniel.gregory@bytedance.com> wrote:
> >
> > > The ARM implementation of rte_pause uses RTE_BUILD_BUG_ON to check
> > > memorder, which is not constant. This causes compile errors when it is
> > > enabled with RTE_ARM_USE_WFE. eg.
> > >
> > > ../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
> > > ../lib/eal/include/rte_common.h:530:56: error: expression in static assertion is not constant
> > > 530 | #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
> > > | ^~~~~~~~~~~~
> > > ../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
> > > 156 | RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
> > > | ^~~~~~~~~~~~~~~~
> > >
> > > Fix the compile errors by replacing the check with an assert, like in
> > > the generic implementation (lib/eal/include/generic/rte_pause.h).
> >
> > No, don't hide the problem.
> >
> > What code is calling these. Looks like a real bug. Could be behind layers of wrappers.
>
> I support Stephen's opinion.
> Please look for the real issue.
In DPDK, I have found 26 calls of rte_wait_until_equal_16, largely split
between app/test-bbdev/test_bbdev_perf.c and app/test/test_timer.c, with
a couple calls in lib/eal/include/rte_pflock.h and
lib/eal/include/rte_ticketlock.h as well. 16 calls of
rte_wait_until_equal_32, spread amongst various test cases
(test_func_reentrancy.c test_mcslock.c, test_mempool_perf.c, ...), two
drivers (drivers/event/opdl/opdl_ring.c and
drivers/net/thunderx/nicvf_rxrx.c), lib/eal/common/eal_common_mcfg.c,
lib/eal/include/generic/rte_spinlock.h, lib/ring/rte_ring_c11_pvt.h,
lib/ring/rte_ring_generic_pvt.h and lib/eal/include/rte_mcslock.h. There
is a single call to rte_wait_until_equal_64 in app/test/test_pmd_perf.c
They all correctly use the primitives from rte_stdatomic.h
As I discussed on another chain
https://lore.kernel.org/dpdk-dev/20240509110251.GA3795959@ste-uk-lab-gw/
from what I've seen, it seems that neither Clang nor GCC allow for
static checks on the parameters of inline functions. For instance, the
following does not compile:
static inline __attribute__((always_inline)) int
fn(int val)
{
_Static_assert(val == 0, "val nonzero");
return 0;
}
int main(void) {
return fn(0);
}
( https://godbolt.org/z/TrfWqYoGo )
With the same "expression in static assertion is not constant" error
that I get when cross-compiling DPDK for ARM with WFE enabled on main:
diff --git a/config/arm/meson.build b/config/arm/meson.build
index a45aa9e466..661c735977 100644
--- a/config/arm/meson.build
+++ b/config/arm/meson.build
@@ -18,7 +18,7 @@ flags_common = [
# ['RTE_ARM64_MEMCPY_STRICT_ALIGN', false],
# Enable use of ARM wait for event instruction.
- # ['RTE_ARM_USE_WFE', false],
+ ['RTE_ARM_USE_WFE', true],
['RTE_ARCH_ARM64', true],
['RTE_CACHE_LINE_SIZE', 128]
On Fri, 28 Jun 2024 11:05:20 +0100
Daniel Gregory <daniel.gregory@bytedance.com> wrote:
> > > > The ARM implementation of rte_pause uses RTE_BUILD_BUG_ON to check
> > > > memorder, which is not constant. This causes compile errors when it is
> > > > enabled with RTE_ARM_USE_WFE. eg.
> > > >
> > > > ../lib/eal/arm/include/rte_pause_64.h: In function ‘rte_wait_until_equal_16’:
> > > > ../lib/eal/include/rte_common.h:530:56: error: expression in static assertion is not constant
> > > > 530 | #define RTE_BUILD_BUG_ON(condition) do { static_assert(!(condition), #condition); } while (0)
> > > > | ^~~~~~~~~~~~
> > > > ../lib/eal/arm/include/rte_pause_64.h:156:9: note: in expansion of macro ‘RTE_BUILD_BUG_ON’
> > > > 156 | RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
> > > > | ^~~~~~~~~~~~~~~~
> > > >
> > > > Fix the compile errors by replacing the check with an assert, like in
> > > > the generic implementation (lib/eal/include/generic/rte_pause.h).
> > >
> > > No, don't hide the problem.
> > >
> > > What code is calling these. Looks like a real bug. Could be behind layers of wrappers.
> >
> > I support Stephen's opinion.
> > Please look for the real issue.
>
> In DPDK, I have found 26 calls of rte_wait_until_equal_16, largely split
> between app/test-bbdev/test_bbdev_perf.c and app/test/test_timer.c, with
> a couple calls in lib/eal/include/rte_pflock.h and
> lib/eal/include/rte_ticketlock.h as well. 16 calls of
> rte_wait_until_equal_32, spread amongst various test cases
> (test_func_reentrancy.c test_mcslock.c, test_mempool_perf.c, ...), two
> drivers (drivers/event/opdl/opdl_ring.c and
> drivers/net/thunderx/nicvf_rxrx.c), lib/eal/common/eal_common_mcfg.c,
> lib/eal/include/generic/rte_spinlock.h, lib/ring/rte_ring_c11_pvt.h,
> lib/ring/rte_ring_generic_pvt.h and lib/eal/include/rte_mcslock.h. There
> is a single call to rte_wait_until_equal_64 in app/test/test_pmd_perf.c
>
> They all correctly use the primitives from rte_stdatomic.h
>
> As I discussed on another chain
> https://lore.kernel.org/dpdk-dev/20240509110251.GA3795959@ste-uk-lab-gw/
> from what I've seen, it seems that neither Clang nor GCC allow for
> static checks on the parameters of inline functions. For instance, the
> following does not compile:
>
> static inline __attribute__((always_inline)) int
> fn(int val)
> {
> _Static_assert(val == 0, "val nonzero");
> return 0;
> }
>
> int main(void) {
> return fn(0);
> }
>
> ( https://godbolt.org/z/TrfWqYoGo )
>
> With the same "expression in static assertion is not constant" error
> that I get when cross-compiling DPDK for ARM with WFE enabled on main:
This is unexpected, but I can validate that it works that way.
Maybe because of combination of how inlining works and how the
static asserts are evaluated.
It does work if fn() is a macro
#define fn(val) ({ static_assert(val == 0, "val nonzero"); 0; })
@@ -10,6 +10,8 @@
extern "C" {
#endif
+#include <assert.h>
+
#include <rte_common.h>
#ifdef RTE_ARM_USE_WFE
@@ -153,7 +155,7 @@ rte_wait_until_equal_16(volatile uint16_t *addr, uint16_t expected,
{
uint16_t value;
- RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
+ assert(memorder != rte_memory_order_acquire &&
memorder != rte_memory_order_relaxed);
__RTE_ARM_LOAD_EXC_16(addr, value, memorder)
@@ -172,7 +174,7 @@ rte_wait_until_equal_32(volatile uint32_t *addr, uint32_t expected,
{
uint32_t value;
- RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
+ assert(memorder != rte_memory_order_acquire &&
memorder != rte_memory_order_relaxed);
__RTE_ARM_LOAD_EXC_32(addr, value, memorder)
@@ -191,7 +193,7 @@ rte_wait_until_equal_64(volatile uint64_t *addr, uint64_t expected,
{
uint64_t value;
- RTE_BUILD_BUG_ON(memorder != rte_memory_order_acquire &&
+ assert(memorder != rte_memory_order_acquire &&
memorder != rte_memory_order_relaxed);
__RTE_ARM_LOAD_EXC_64(addr, value, memorder)