Hi Stephen,
> -----Original Message-----
> From: Stephen Hemminger <step...@networkplumber.org>
> Sent: Monday, July 1, 2019 4:28 AM
> To: Gavin Hu (Arm Technology China) <gavin...@arm.com>
> Cc: dev@dpdk.org; tho...@monjalon.net; jer...@marvell.com;
> hemant.agra...@nxp.com; bruce.richard...@intel.com;
> chao...@linux.vnet.ibm.com; Honnappa Nagarahalli
> <honnappa.nagaraha...@arm.com>; nd <n...@arm.com>
> Subject: Re: [dpdk-dev] [RFC 1/5] eal: add the APIs to wait until equal
>
> On Mon, 1 Jul 2019 00:21:12 +0800
> Gavin Hu <gavin...@arm.com> wrote:
>
> > +#ifdef RTE_USE_WFE
> > +#define rte_wait_until_equal_relaxed(addr, expected) do {\
> > + typeof(*addr) tmp; \
> > + if (__builtin_constant_p((expected))) \
> > + do { \
> > + if (sizeof(*(addr)) == 16)\
> > + asm volatile( \
> > + "sevl\n" \
> > + "1: wfe\n" \
> > + "ldxrh %w0, %1\n" \
> > + "cmp %w0, %w2\n" \
> > + "bne 1b\n" \
> > + : "=&r"(tmp) \
> > + : "Q"(*addr), "i"(expected) \
> > + : "cc", "memory"); \
> > + else if (sizeof(*(addr)) == 32)\
> > + asm volatile( \
> > + "sevl\n" \
> > + "1: wfe\n" \
> > + "ldxr %w0, %1\n" \
> > + "cmp %w0, %w2\n" \
> > + "bne 1b\n" \
> > + : "=&r"(tmp) \
> > + : "Q"(*addr), "i"(expected) \
> > + : "cc", "memory"); \
> > + else if (sizeof(*(addr)) == 64)\
> > + asm volatile( \
> > + "sevl\n" \
> > + "1: wfe\n" \
> > + "ldxr %x0, %1\n" \
> > + "cmp %x0, %x2\n" \
> > + "bne 1b\n" \
> > + : "=&r" (tmp) \
> > + : "Q"(*addr), "i"(expected) \
> > + : "cc", "memory"); \
> > + } while (0); \
> > + else \
> > + do { \
> > + if (sizeof(*(addr)) == 16)\
> > + asm volatile( \
> > + "sevl\n" \
> > + "1: wfe\n" \
> > + "ldxrh %w0, %1\n" \
> > + "cmp %w0, %w2\n" \
> > + "bne 1b\n" \
> > + : "=&r"(tmp) \
> > + : "Q"(*addr), "r"(expected) \
> > + : "cc", "memory"); \
> > + else if (sizeof(*(addr)) == 32)\
> > + asm volatile( \
> > + "sevl\n" \
> > + "1: wfe\n" \
> > + "ldxr %w0, %1\n" \
> > + "cmp %w0, %w2\n" \
> > + "bne 1b\n" \
> > + : "=&r"(tmp) \
> > + : "Q"(*addr), "r"(expected) \
> > + : "cc", "memory"); \
> > + else if (sizeof(*(addr)) == 64)\
> > + asm volatile( \
> > + "sevl\n" \
> > + "1: wfe\n" \
> > + "ldxr %x0, %1\n" \
> > + "cmp %x0, %x2\n" \
> > + "bne 1b\n" \
> > + : "=&r" (tmp) \
> > + : "Q"(*addr), "r"(expected) \
> > + : "cc", "memory"); \
> > + } while (0); \
> > +} while (0)
>
> That is a hot mess.
> Macro's are harder to maintain and offer no benefit over inline functions.
During our internal review, I ever used C11 _Generic to generalize the API to
take different types of arguments.
That makes the API look much simpler and better, but it poses a hard
requirement for C11 and gcc 4.9+.
That means, Gaetan's patch, as shown below, has to be reverted, otherwise there
are compiling errors.
https://gcc.gnu.org/wiki/C11Status
$ git show ea7726a6
commit ea7726a6ee4b2b63313c4a198522a8dcea70c13d
Author: Gaetan Rivet <gaetan.ri...@6wind.com>
Date: Thu Jul 20 14:27:53 2017 +0200
net/failsafe: fix build on FreeBSD 10 with GCC 4.8
diff --git a/drivers/net/failsafe/Makefile b/drivers/net/failsafe/Makefile
index 32aaaa2..d516d36 100644
--- a/drivers/net/failsafe/Makefile
+++ b/drivers/net/failsafe/Makefile
@@ -50,7 +50,7 @@ SRCS-$(CONFIG_RTE_LIBRTE_PMD_FAILSAFE) += failsafe_flow.c
# No exported include files
# Basic CFLAGS:
-CFLAGS += -std=c11 -Wextra
+CFLAGS += -std=gnu99 -Wextra
