Re: [dpdk-dev] [PATCH v5 1/1] eal: add internal ABI marking support

[David Marchand <david.marchand@redhat.com>]

On Thu, Apr 23, 2020 at 5:25 AM Haiyue Wang <haiyue.wang@intel.com> wrote:
>
> Introduce __rte_internal tag to mark internal ABI function which is used
> by the drivers or other libraries.
>
> Signed-off-by: Haiyue Wang <haiyue.wang@intel.com>
> ---
>  buildtools/check-internal-syms.sh   | 57 +++++++++++++++++++++++++++++
>  devtools/check-symbol-change.sh     |  7 ++++
>  devtools/checkpatches.sh            | 38 +++++++++++++++++++
>  devtools/libabigail.abignore        |  5 +++
>  drivers/meson.build                 |  2 +-
>  lib/librte_eal/include/rte_compat.h | 13 +++++++
>  lib/meson.build                     |  2 +-
>  mk/internal/rte.compile-pre.mk      |  3 ++
>  mk/target/generic/rte.vars.mk       |  1 +
>  9 files changed, 126 insertions(+), 2 deletions(-)
>  create mode 100755 buildtools/check-internal-syms.sh

We can have a single script (let's say devtools/check-symbols.sh) that
contains both experimental and internal symbols.


> diff --git a/devtools/check-symbol-change.sh b/devtools/check-symbol-change.sh
> index ed2178e36..978979077 100755
> --- a/devtools/check-symbol-change.sh
> +++ b/devtools/check-symbol-change.sh
> @@ -91,6 +91,13 @@ check_for_rule_violations()
>                 if [ "$ar" = "add" ]
>                 then
>
> +                       if [ "$secname" = "INTERNAL" ]
> +                       then
> +                               # these are absolved from any further checking
> +                               echo "Skipping symbol $symname in INTERNAL"
> +                               continue
> +                       fi
> +
>                         if [ "$secname" = "unknown" ]
>                         then
>                                 # Just inform the user of this occurrence, but

This only handles symbol additions to the INTERNAL section.
Other cases like moving or removing a INTERNAL symbol are not handled.


> diff --git a/devtools/checkpatches.sh b/devtools/checkpatches.sh
> index c30ce64cc..2df8d7f2c 100755
> --- a/devtools/checkpatches.sh
> +++ b/devtools/checkpatches.sh
> @@ -111,6 +111,36 @@ check_experimental_tags() { # <patch>
>         return $res
>  }
>
> +check_internal_tags() { # <patch>
> +       res=0
> +
> +       cat "$1" |awk '
> +       BEGIN {
> +               current_file = "";
> +               ret = 0;
> +       }
> +       /^+++ b\// {
> +               current_file = $2;
> +       }
> +       /^+.*__rte_internal/ {
> +               if (current_file ~ ".c$" ) {
> +                       print "Please only put __rte_internal tags in " \
> +                               "headers ("current_file")";
> +                       ret = 1;
> +               }
> +               if ($1 != "+__rte_internal" || $2 != "") {
> +                       print "__rte_internal must appear alone on the line" \
> +                               " immediately preceding the return type of a function."
> +                       ret = 1;
> +               }
> +       }
> +       END {
> +               exit ret;
> +       }' || res=1
> +
> +       return $res
> +}
> +
>  number=0
>  range='origin/master..'
>  quiet=false
> @@ -194,6 +224,14 @@ check () { # <patch> <commit> <title>
>                 ret=1
>         fi
>
> +       ! $verbose || printf '\nChecking __rte_internal tags:\n'
> +       report=$(check_internal_tags "$tmpinput")
> +       if [ $? -ne 0 ] ; then
> +               $headline_printed || print_headline "$3"
> +               printf '%s\n' "$report"
> +               ret=1
> +       fi
> +
>         if [ "$tmpinput" != "$1" ]; then
>                 rm -f "$tmpinput"
>                 trap - INT
> diff --git a/devtools/libabigail.abignore b/devtools/libabigail.abignore
> index cd86d89ca..3e8e2ea74 100644
> --- a/devtools/libabigail.abignore
> +++ b/devtools/libabigail.abignore
> @@ -3,6 +3,11 @@
>  [suppress_variable]
>          symbol_version = EXPERIMENTAL
>
> +[suppress_function]
> +        symbol_version = INTERNAL
> +[suppress_variable]
> +        symbol_version = INTERNAL
> +
>  ; Explicit ignore for driver-only ABI
>  [suppress_type]
>          name = rte_cryptodev_ops
> diff --git a/drivers/meson.build b/drivers/meson.build
> index 4d8f842ab..cac07161f 100644
> --- a/drivers/meson.build
> +++ b/drivers/meson.build
> @@ -20,7 +20,7 @@ dpdk_driver_classes = ['common',
>  disabled_drivers = run_command(list_dir_globs, get_option('disable_drivers'),
>                 ).stdout().split()
>
> -default_cflags = machine_args + ['-DALLOW_EXPERIMENTAL_API']
> +default_cflags = machine_args + ['-DALLOW_EXPERIMENTAL_API'] + ['-DALLOW_INTERNAL_API']

Nit:
default_cflags = machine_args
default_cflags += ['-DALLOW_EXPERIMENTAL_API']
default_cflags += ['-DALLOW_INTERNAL_API']

>  if cc.has_argument('-Wno-format-truncation')
>         default_cflags += '-Wno-format-truncation'
>  endif

More importantly on this file:

- drivers/meson.build is not updated to check for internal symbols, see:
  https://git.dpdk.org/dpdk/tree/drivers/meson.build#n166


- For fully experimental libraries, we have a special so version:
  https://git.dpdk.org/dpdk/tree/drivers/meson.build#n131

  This will apply to common drivers that will be 100% internal.
  Not sure if this is an issue.


> diff --git a/lib/librte_eal/include/rte_compat.h b/lib/librte_eal/include/rte_compat.h
> index 3eb33784b..4cd8f68d6 100644
> --- a/lib/librte_eal/include/rte_compat.h
> +++ b/lib/librte_eal/include/rte_compat.h
> @@ -19,4 +19,17 @@ __attribute__((section(".text.experimental")))
>
>  #endif
>
> +#ifndef ALLOW_INTERNAL_API
> +
> +#define __rte_internal \
> +__attribute__((error("Symbol is not public ABI"), \
> +section(".text.internal")))
> +
> +#else
> +
> +#define __rte_internal \
> +__attribute__((section(".text.internal")))
> +
> +#endif
> +
>  #endif /* _RTE_COMPAT_H_ */
> diff --git a/lib/meson.build b/lib/meson.build
> index c28b8df83..4d2f90d6a 100644
> --- a/lib/meson.build
> +++ b/lib/meson.build
> @@ -38,7 +38,7 @@ if is_windows
>         libraries = ['kvargs','eal'] # only supported libraries for windows
>  endif
>
> -default_cflags = machine_args + ['-DALLOW_EXPERIMENTAL_API']
> +default_cflags = machine_args + ['-DALLOW_EXPERIMENTAL_API'] + ['-DALLOW_INTERNAL_API']

Same comments as for drivers/meson.build.


> diff --git a/mk/internal/rte.compile-pre.mk b/mk/internal/rte.compile-pre.mk
> index 82fe098f7..0369786a5 100644
> --- a/mk/internal/rte.compile-pre.mk
> +++ b/mk/internal/rte.compile-pre.mk
> @@ -58,6 +58,8 @@ C_TO_O_DISP = $(if $(V),"$(C_TO_O_STR)","  CC $(@)")
>  endif
>  EXPERIMENTAL_CHECK = $(RTE_SDK)/buildtools/check-experimental-syms.sh
>  CHECK_EXPERIMENTAL = $(EXPERIMENTAL_CHECK) $(SRCDIR)/$(EXPORT_MAP) $@
> +INTERNAL_CHECK = $(RTE_SDK)/buildtools/check-internal-syms.sh
> +CHECK_INTERNAL = $(INTERNAL_CHECK) $(SRCDIR)/$(EXPORT_MAP) $@

With a single script, we can go with:
CHECK_SYMBOLS_SCRIPT = $(RTE_SDK)/buildtools/check-symbols.sh
CHECK_SYMBOLS = $(CHECK_SYMBOLS_SCRIPT) $(SRCDIR)/$(EXPORT_MAP) $@

>
>  PMDINFO_GEN = $(RTE_SDK_BIN)/app/dpdk-pmdinfogen $@ $@.pmd.c
>  PMDINFO_CC = $(CC) $(CPPFLAGS) $(CFLAGS) $(EXTRA_CFLAGS) -c -o $@.pmd.o $@.pmd.c
> @@ -76,6 +78,7 @@ C_TO_O_DO = @set -e; \
>         $(C_TO_O) && \
>         $(PMDINFO_TO_O) && \
>         $(CHECK_EXPERIMENTAL) && \
> +       $(CHECK_INTERNAL) && \

+       $(CHECK_SYMBOLS) && \

>         echo $(C_TO_O_CMD) > $(call obj2cmd,$(@)) && \
>         sed 's,'$@':,dep_'$@' =,' $(call obj2dep,$(@)).tmp > $(call obj2dep,$(@)) && \
>         rm -f $(call obj2dep,$(@)).tmp
> diff --git a/mk/target/generic/rte.vars.mk b/mk/target/generic/rte.vars.mk
> index ec2672897..11b0418e5 100644
> --- a/mk/target/generic/rte.vars.mk
> +++ b/mk/target/generic/rte.vars.mk
> @@ -106,6 +106,7 @@ ifeq ($(BUILDING_RTE_SDK),1)
>  # building sdk
>  CFLAGS += -include $(RTE_OUTPUT)/include/rte_config.h
>  CFLAGS += -DALLOW_EXPERIMENTAL_API
> +CFLAGS += -DALLOW_INTERNAL_API
>  else
>  # if we are building an external application, include SDK's lib and
>  # includes too
> --
> 2.26.2
>

We are missing updates on devtools/check-abi-version.sh and
devtools/update_version_map_abi.py.


-- 
David Marchand