[v3,2/3] config/arm: add support for fallback march
Checks
Commit Message
From: Pavan Nikhilesh <pbhagavatula@marvell.com>
Some ARM CPUs have specific march requirements and
are not compatible with the supported march list.
Add fallback march in case the mcpu and the march
advertised in the part_number_config are not supported
by the compiler.
Example
mcpu = neoverse-n2
march = armv9-a
fallback_march = armv8.5-a
mcpu, march not supported
machine_args = ['-march=armv8.5-a']
mcpu, march, fallback_march not supported
least march supported = armv8-a
machine_args = ['-march=armv8-a']
Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
---
config/arm/meson.build | 10 ++++++++++
1 file changed, 10 insertions(+)
Comments
>
> From: Pavan Nikhilesh <pbhagavatula@marvell.com>
>
> Some ARM CPUs have specific march requirements and are not compatible
> with the supported march list.
> Add fallback march in case the mcpu and the march advertised in the
> part_number_config are not supported by the compiler.
>
> Example
> mcpu = neoverse-n2
> march = armv9-a
> fallback_march = armv8.5-a
>
> mcpu, march not supported
> machine_args = ['-march=armv8.5-a']
>
> mcpu, march, fallback_march not supported
> least march supported = armv8-a
>
> machine_args = ['-march=armv8-a']
>
Similar to "[v3,1/3] config/arm: avoid mcpu and march conflicts" here
also we can avoid selecting march if it's not supported by the compiler.
Ideally, we should exit the build with an error saying march/mcpu is not
supported and suggest further actions (like trying again with
-Dmarch -Dmcpu or -Dplatform=generic-armv9 as discussed in [v3,1/3])
> Signed-off-by: Pavan Nikhilesh <pbhagavatula@marvell.com>
> ---
> config/arm/meson.build | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/config/arm/meson.build b/config/arm/meson.build index
> ba859bd060b5..4e44d1850bae 100644
> --- a/config/arm/meson.build
> +++ b/config/arm/meson.build
> @@ -94,6 +94,7 @@ part_number_config_arm = {
> '0xd49': {
> 'march': 'armv9-a',
> 'march_features': ['sve2'],
> + 'fallback_march': 'armv8.5-a',
> 'mcpu': 'neoverse-n2',
> 'flags': [
> ['RTE_MACHINE', '"neoverse-n2"'], @@ -708,6 +709,7 @@ if
> update_flags
>
> # probe supported archs and their features
> candidate_march = ''
> + fallback_march = ''
> if part_number_config.has_key('march')
> if part_number_config.get('force_march', false) or candidate_mcpu != ''
> if cc.has_argument('-march=' + part_number_config['march']) @@ -
> 728,10 +730,18 @@ if update_flags
> # highest supported march version found
> break
> endif
> + if (part_number_config.has_key('fallback_march') and
> + supported_march == part_number_config['fallback_march'] and
> + cc.has_argument('-march=' + supported_march))
> + fallback_march = supported_march
> + endif
> endforeach
> endif
>
> if candidate_march != part_number_config['march']
> + if fallback_march != ''
> + candidate_march = fallback_march
> + endif
> warning('Configuration march version is @0@, not supported.'
> .format(part_number_config['march']))
> if candidate_march != ''
> --
> 2.43.0
@@ -94,6 +94,7 @@ part_number_config_arm = {
'0xd49': {
'march': 'armv9-a',
'march_features': ['sve2'],
+ 'fallback_march': 'armv8.5-a',
'mcpu': 'neoverse-n2',
'flags': [
['RTE_MACHINE', '"neoverse-n2"'],
@@ -708,6 +709,7 @@ if update_flags
# probe supported archs and their features
candidate_march = ''
+ fallback_march = ''
if part_number_config.has_key('march')
if part_number_config.get('force_march', false) or candidate_mcpu != ''
if cc.has_argument('-march=' + part_number_config['march'])
@@ -728,10 +730,18 @@ if update_flags
# highest supported march version found
break
endif
+ if (part_number_config.has_key('fallback_march') and
+ supported_march == part_number_config['fallback_march'] and
+ cc.has_argument('-march=' + supported_march))
+ fallback_march = supported_march
+ endif
endforeach
endif
if candidate_march != part_number_config['march']
+ if fallback_march != ''
+ candidate_march = fallback_march
+ endif
warning('Configuration march version is @0@, not supported.'
.format(part_number_config['march']))
if candidate_march != ''