When building ARCH=arm64 allmodconfig with clang, there is a warning
about high stack usage in avs_path_create(), which breaks the build due
to CONFIG_WERROR=y:
sound/soc/intel/avs/path.c:815:18: error: stack frame size (2176) exceeds limit (2048) in 'avs_path_create' [-Werror,-Wframe-larger-than]
struct avs_path *avs_path_create(struct avs_dev *adev, u32 dma_id,
^
1 error generated.
This warning is also visible with allmodconfig on other architectures.
The minimum set of configs that triggers this on top of ARCH=arm64
allnoconfig:
CONFIG_COMPILE_TEST=y
CONFIG_FORTIFY_SOURCE=y
CONFIG_KASAN=y
CONFIG_PCI=y
CONFIG_SOUND=y
CONFIG_SND=y
CONFIG_SND_SOC=y
CONFIG_SND_SOC_INTEL_AVS=y
When CONFIG_FORTIFY_SOURCE is enabled, memcmp() (called from
guid_equal()) becomes a wrapper to do compile time checking, which
interacts poorly with inlining plus CONFIG_KASAN=y.
With ARCH=arm64 allmodconfig + CONFIG_KASAN=n + CONFIG_FRAME_WARN=128,
the stack usage is much better:
sound/soc/intel/avs/path.c:815:18: warning: stack frame size (624) exceeds limit (128) in 'avs_path_create' [-Wframe-larger-than]
struct avs_path *avs_path_create(struct avs_dev *adev, u32 dma_id,
^
sound/soc/intel/avs/path.c:873:5: warning: stack frame size (144) exceeds limit (128) in 'avs_path_bind' [-Wframe-larger-than]
int avs_path_bind(struct avs_path *path)
^
2 warnings generated.
To avoid this warning, mark avs_path_module_type_create() as
noinline_for_stack, which redistributes the stack usage across multiple
functions, regardless of CONFIG_KASAN.
With ARCH=arm64 allmodconfig + CONFIG_FRAME_WARN=128, the warnings show:
avs_path_create(): 192
avs_path_bind(): 272
avs_path_module_type_create(): 416
avs_mux_create(): 160
avs_updown_mix_create(): 160
avs_aec_create(): 176
avs_asrc_create(): 144
With ARCH=arm64 allmodconfig + CONFIG_FRAME_WARN=128 + CONFIG_KASAN=n,
the warnings show:
avs_path_create(): 192
avs_path_bind(): 144
avs_path_module_type_create(): 416
avs_mux_create(): 176
avs_updown_mix_create(): 176
avs_src_create(): 144
avs_aec_create(): 192
avs_asrc_create(): 144
avs_wov_create(): 144
Link: https://github.com/ClangBuiltLinux/linux/issues/1642
Signed-off-by: Nathan Chancellor <[email protected]>
---
sound/soc/intel/avs/path.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/sound/soc/intel/avs/path.c b/sound/soc/intel/avs/path.c
index 3d46dd5e5bc4..ec2aa0001f91 100644
--- a/sound/soc/intel/avs/path.c
+++ b/sound/soc/intel/avs/path.c
@@ -449,7 +449,8 @@ static int avs_modext_create(struct avs_dev *adev, struct avs_path_module *mod)
return ret;
}
-static int avs_path_module_type_create(struct avs_dev *adev, struct avs_path_module *mod)
+static noinline_for_stack int avs_path_module_type_create(struct avs_dev *adev,
+ struct avs_path_module *mod)
{
const guid_t *type = &mod->template->cfg_ext->type;
base-commit: ff6992735ade75aae3e35d16b17da1008d753d28
--
2.37.1
On 7/20/2022 8:52 PM, Nathan Chancellor wrote:
> When building ARCH=arm64 allmodconfig with clang, there is a warning
> about high stack usage in avs_path_create(), which breaks the build due
> to CONFIG_WERROR=y:
>
> sound/soc/intel/avs/path.c:815:18: error: stack frame size (2176) exceeds limit (2048) in 'avs_path_create' [-Werror,-Wframe-larger-than]
> struct avs_path *avs_path_create(struct avs_dev *adev, u32 dma_id,
> ^
> 1 error generated.
>
> This warning is also visible with allmodconfig on other architectures.
> The minimum set of configs that triggers this on top of ARCH=arm64
> allnoconfig:
>
> CONFIG_COMPILE_TEST=y
> CONFIG_FORTIFY_SOURCE=y
> CONFIG_KASAN=y
> CONFIG_PCI=y
> CONFIG_SOUND=y
> CONFIG_SND=y
> CONFIG_SND_SOC=y
> CONFIG_SND_SOC_INTEL_AVS=y
>
> When CONFIG_FORTIFY_SOURCE is enabled, memcmp() (called from
> guid_equal()) becomes a wrapper to do compile time checking, which
> interacts poorly with inlining plus CONFIG_KASAN=y.
>
> With ARCH=arm64 allmodconfig + CONFIG_KASAN=n + CONFIG_FRAME_WARN=128,
> the stack usage is much better:
>
> sound/soc/intel/avs/path.c:815:18: warning: stack frame size (624) exceeds limit (128) in 'avs_path_create' [-Wframe-larger-than]
> struct avs_path *avs_path_create(struct avs_dev *adev, u32 dma_id,
> ^
> sound/soc/intel/avs/path.c:873:5: warning: stack frame size (144) exceeds limit (128) in 'avs_path_bind' [-Wframe-larger-than]
> int avs_path_bind(struct avs_path *path)
> ^
> 2 warnings generated.
>
> To avoid this warning, mark avs_path_module_type_create() as
> noinline_for_stack, which redistributes the stack usage across multiple
> functions, regardless of CONFIG_KASAN.
>
> With ARCH=arm64 allmodconfig + CONFIG_FRAME_WARN=128, the warnings show:
>
> avs_path_create(): 192
> avs_path_bind(): 272
> avs_path_module_type_create(): 416
> avs_mux_create(): 160
> avs_updown_mix_create(): 160
> avs_aec_create(): 176
> avs_asrc_create(): 144
>
> With ARCH=arm64 allmodconfig + CONFIG_FRAME_WARN=128 + CONFIG_KASAN=n,
> the warnings show:
>
> avs_path_create(): 192
> avs_path_bind(): 144
> avs_path_module_type_create(): 416
> avs_mux_create(): 176
> avs_updown_mix_create(): 176
> avs_src_create(): 144
> avs_aec_create(): 192
> avs_asrc_create(): 144
> avs_wov_create(): 144
>
> Link: https://github.com/ClangBuiltLinux/linux/issues/1642
> Signed-off-by: Nathan Chancellor <[email protected]>
> ---
> sound/soc/intel/avs/path.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/sound/soc/intel/avs/path.c b/sound/soc/intel/avs/path.c
> index 3d46dd5e5bc4..ec2aa0001f91 100644
> --- a/sound/soc/intel/avs/path.c
> +++ b/sound/soc/intel/avs/path.c
> @@ -449,7 +449,8 @@ static int avs_modext_create(struct avs_dev *adev, struct avs_path_module *mod)
> return ret;
> }
>
> -static int avs_path_module_type_create(struct avs_dev *adev, struct avs_path_module *mod)
> +static noinline_for_stack int avs_path_module_type_create(struct avs_dev *adev,
> + struct avs_path_module *mod)
> {
> const guid_t *type = &mod->template->cfg_ext->type;
>
>
> base-commit: ff6992735ade75aae3e35d16b17da1008d753d28
Not a fan of this.
My first question would be what clang does differently in this
configuration (ARM) than in all other configurations (x86, etc.) and gcc.
Overall as evidenced by:
> CONFIG_COMPILE_TEST=y
this is test only and this commit doesn't fix anything for x86 this
driver targets.
Based on description in message and in github link:
Looking at avs_path_module_type_create() it uses guid_equal() which is
marked as inline, but is just a wrapper around memcmp(), which in case
of fortify is still marked as inline... memcmp itself has 2 size_t
variables for performing fortify check... no matter how I calculate, it
shouldn't go above stack size, unless clang decides to also inline all
calls to static avs_xxx_create functions. They are not marked as inline
or noinline, so in theory compiler is free to do whatever it wants, but
apparently it goes wrong way? Of course the above may be wrong, because
I just analyzed code, not real output of clang.
Anyway it is probably ok, to do this, as while it needs to be fast
module creation is not really time critical, and some time will be spend
to communicate with DSP instead of calculating things, but still wonder
if there isn't something that can be done on compiler side...
On Thu, Jul 21, 2022 at 02:25:20PM +0200, Amadeusz Sławiński wrote:
> On 7/20/2022 8:52 PM, Nathan Chancellor wrote:
> > This warning is also visible with allmodconfig on other architectures.
> My first question would be what clang does differently in this configuration
> (ARM) than in all other configurations (x86, etc.) and gcc.
See above from Nathan's commit message...
On 7/21/2022 4:42 PM, Mark Brown wrote:
> On Thu, Jul 21, 2022 at 02:25:20PM +0200, Amadeusz Sławiński wrote:
>> On 7/20/2022 8:52 PM, Nathan Chancellor wrote:
>
>>> This warning is also visible with allmodconfig on other architectures.
>
>> My first question would be what clang does differently in this configuration
>> (ARM) than in all other configurations (x86, etc.) and gcc.
>
> See above from Nathan's commit message...
Ah, missed that. Anyway, what about if we replace multiple calls to
guid_equal with lookup table and one call in loop?
Do let me know if something like the following works and I will send it
as a proper patch:
diff --git a/sound/soc/intel/avs/path.c b/sound/soc/intel/avs/path.c
index 3d46dd5e5bc4..ce157a8d6552 100644
--- a/sound/soc/intel/avs/path.c
+++ b/sound/soc/intel/avs/path.c
@@ -449,35 +449,39 @@ static int avs_modext_create(struct avs_dev *adev,
struct avs_path_module *mod)
return ret;
}
+static int avs_probe_create(struct avs_dev *adev, struct
avs_path_module *mod)
+{
+ dev_err(adev->dev, "Probe module can't be instantiated by
topology");
+ return -EINVAL;
+}
+
+struct avs_module_create {
+ guid_t *guid;
+ int (*create)(struct avs_dev *adev, struct avs_path_module *mod);
+};
+
+static struct avs_module_create avs_module_create[] = {
+ { &AVS_MIXIN_MOD_UUID, avs_modbase_create },
+ { &AVS_MIXOUT_MOD_UUID, avs_modbase_create },
+ { &AVS_KPBUFF_MOD_UUID, avs_modbase_create },
+ { &AVS_COPIER_MOD_UUID, avs_copier_create },
+ { &AVS_MICSEL_MOD_UUID, avs_micsel_create },
+ { &AVS_MUX_MOD_UUID, avs_mux_create },
+ { &AVS_UPDWMIX_MOD_UUID, avs_updown_mix_create },
+ { &AVS_SRCINTC_MOD_UUID, avs_src_create },
+ { &AVS_AEC_MOD_UUID, avs_aec_create },
+ { &AVS_ASRC_MOD_UUID, avs_asrc_create },
+ { &AVS_INTELWOV_MOD_UUID, avs_wov_create },
+ { &AVS_PROBE_MOD_UUID, avs_probe_create },
+};
+
static int avs_path_module_type_create(struct avs_dev *adev, struct
avs_path_module *mod)
{
const guid_t *type = &mod->template->cfg_ext->type;
- if (guid_equal(type, &AVS_MIXIN_MOD_UUID) ||
- guid_equal(type, &AVS_MIXOUT_MOD_UUID) ||
- guid_equal(type, &AVS_KPBUFF_MOD_UUID))
- return avs_modbase_create(adev, mod);
- if (guid_equal(type, &AVS_COPIER_MOD_UUID))
- return avs_copier_create(adev, mod);
- if (guid_equal(type, &AVS_MICSEL_MOD_UUID))
- return avs_micsel_create(adev, mod);
- if (guid_equal(type, &AVS_MUX_MOD_UUID))
- return avs_mux_create(adev, mod);
- if (guid_equal(type, &AVS_UPDWMIX_MOD_UUID))
- return avs_updown_mix_create(adev, mod);
- if (guid_equal(type, &AVS_SRCINTC_MOD_UUID))
- return avs_src_create(adev, mod);
- if (guid_equal(type, &AVS_AEC_MOD_UUID))
- return avs_aec_create(adev, mod);
- if (guid_equal(type, &AVS_ASRC_MOD_UUID))
- return avs_asrc_create(adev, mod);
- if (guid_equal(type, &AVS_INTELWOV_MOD_UUID))
- return avs_wov_create(adev, mod);
-
- if (guid_equal(type, &AVS_PROBE_MOD_UUID)) {
- dev_err(adev->dev, "Probe module can't be instantiated
by topology");
- return -EINVAL;
- }
+ for (int i = 0; i < ARRAY_SIZE(avs_module_create); i++)
+ if (guid_equal(type, avs_module_create[i].guid))
+ return avs_module_create[i].create(adev, mod);
return avs_modext_create(adev, mod);
}
On Thu, Jul 21, 2022 at 05:28:09PM +0200, Amadeusz Sławiński wrote:
> On 7/21/2022 4:42 PM, Mark Brown wrote:
> > On Thu, Jul 21, 2022 at 02:25:20PM +0200, Amadeusz Sławiński wrote:
> > > On 7/20/2022 8:52 PM, Nathan Chancellor wrote:
> >
> > > > This warning is also visible with allmodconfig on other architectures.
> >
> > > My first question would be what clang does differently in this configuration
> > > (ARM) than in all other configurations (x86, etc.) and gcc.
> >
> > See above from Nathan's commit message...
>
> Ah, missed that. Anyway, what about if we replace multiple calls to
> guid_equal with lookup table and one call in loop?
>
> Do let me know if something like the following works and I will send it as a
> proper patch:
Yes, that works! With ARCH=arm64 allmodconfig + CONFIG_FRAME_WARN=128,
there is no single large function, they are all far below the default
2048 limit.
sound/soc/intel/avs/path.c:819:18: warning: stack frame size (256) exceeds limit (128) in 'avs_path_create' [-Wframe-larger-than]
struct avs_path *avs_path_create(struct avs_dev *adev, u32 dma_id,
^
sound/soc/intel/avs/path.c:877:5: warning: stack frame size (272) exceeds limit (128) in 'avs_path_bind' [-Wframe-larger-than]
int avs_path_bind(struct avs_path *path)
^
sound/soc/intel/avs/path.c:143:12: warning: stack frame size (144) exceeds limit (128) in 'avs_copier_create' [-Wframe-larger-than]
static int avs_copier_create(struct avs_dev *adev, struct avs_path_module *mod)
^
sound/soc/intel/avs/path.c:379:12: warning: stack frame size (144) exceeds limit (128) in 'avs_micsel_create' [-Wframe-larger-than]
static int avs_micsel_create(struct avs_dev *adev, struct avs_path_module *mod)
^
sound/soc/intel/avs/path.c:344:12: warning: stack frame size (160) exceeds limit (128) in 'avs_mux_create' [-Wframe-larger-than]
static int avs_mux_create(struct avs_dev *adev, struct avs_path_module *mod)
^
sound/soc/intel/avs/path.c:267:12: warning: stack frame size (160) exceeds limit (128) in 'avs_updown_mix_create' [-Wframe-larger-than]
static int avs_updown_mix_create(struct avs_dev *adev, struct avs_path_module *mod)
^
sound/soc/intel/avs/path.c:325:12: warning: stack frame size (176) exceeds limit (128) in 'avs_aec_create' [-Wframe-larger-than]
static int avs_aec_create(struct avs_dev *adev, struct avs_path_module *mod)
^
sound/soc/intel/avs/path.c:306:12: warning: stack frame size (144) exceeds limit (128) in 'avs_asrc_create' [-Wframe-larger-than]
static int avs_asrc_create(struct avs_dev *adev, struct avs_path_module *mod)
^
8 warnings generated.
Feel free to add either
Tested-by: Nathan Chancellor <[email protected]> # build
or
Build-tested-by: Nathan Chancellor <[email protected]>
when formally sending, thank you a lot for the fix!
Cheers,
Nathan
> diff --git a/sound/soc/intel/avs/path.c b/sound/soc/intel/avs/path.c
> index 3d46dd5e5bc4..ce157a8d6552 100644
> --- a/sound/soc/intel/avs/path.c
> +++ b/sound/soc/intel/avs/path.c
> @@ -449,35 +449,39 @@ static int avs_modext_create(struct avs_dev *adev,
> struct avs_path_module *mod)
> return ret;
> }
>
> +static int avs_probe_create(struct avs_dev *adev, struct avs_path_module
> *mod)
> +{
> + dev_err(adev->dev, "Probe module can't be instantiated by
> topology");
> + return -EINVAL;
> +}
> +
> +struct avs_module_create {
> + guid_t *guid;
> + int (*create)(struct avs_dev *adev, struct avs_path_module *mod);
> +};
> +
> +static struct avs_module_create avs_module_create[] = {
> + { &AVS_MIXIN_MOD_UUID, avs_modbase_create },
> + { &AVS_MIXOUT_MOD_UUID, avs_modbase_create },
> + { &AVS_KPBUFF_MOD_UUID, avs_modbase_create },
> + { &AVS_COPIER_MOD_UUID, avs_copier_create },
> + { &AVS_MICSEL_MOD_UUID, avs_micsel_create },
> + { &AVS_MUX_MOD_UUID, avs_mux_create },
> + { &AVS_UPDWMIX_MOD_UUID, avs_updown_mix_create },
> + { &AVS_SRCINTC_MOD_UUID, avs_src_create },
> + { &AVS_AEC_MOD_UUID, avs_aec_create },
> + { &AVS_ASRC_MOD_UUID, avs_asrc_create },
> + { &AVS_INTELWOV_MOD_UUID, avs_wov_create },
> + { &AVS_PROBE_MOD_UUID, avs_probe_create },
> +};
> +
> static int avs_path_module_type_create(struct avs_dev *adev, struct
> avs_path_module *mod)
> {
> const guid_t *type = &mod->template->cfg_ext->type;
>
> - if (guid_equal(type, &AVS_MIXIN_MOD_UUID) ||
> - guid_equal(type, &AVS_MIXOUT_MOD_UUID) ||
> - guid_equal(type, &AVS_KPBUFF_MOD_UUID))
> - return avs_modbase_create(adev, mod);
> - if (guid_equal(type, &AVS_COPIER_MOD_UUID))
> - return avs_copier_create(adev, mod);
> - if (guid_equal(type, &AVS_MICSEL_MOD_UUID))
> - return avs_micsel_create(adev, mod);
> - if (guid_equal(type, &AVS_MUX_MOD_UUID))
> - return avs_mux_create(adev, mod);
> - if (guid_equal(type, &AVS_UPDWMIX_MOD_UUID))
> - return avs_updown_mix_create(adev, mod);
> - if (guid_equal(type, &AVS_SRCINTC_MOD_UUID))
> - return avs_src_create(adev, mod);
> - if (guid_equal(type, &AVS_AEC_MOD_UUID))
> - return avs_aec_create(adev, mod);
> - if (guid_equal(type, &AVS_ASRC_MOD_UUID))
> - return avs_asrc_create(adev, mod);
> - if (guid_equal(type, &AVS_INTELWOV_MOD_UUID))
> - return avs_wov_create(adev, mod);
> -
> - if (guid_equal(type, &AVS_PROBE_MOD_UUID)) {
> - dev_err(adev->dev, "Probe module can't be instantiated by
> topology");
> - return -EINVAL;
> - }
> + for (int i = 0; i < ARRAY_SIZE(avs_module_create); i++)
> + if (guid_equal(type, avs_module_create[i].guid))
> + return avs_module_create[i].create(adev, mod);
>
> return avs_modext_create(adev, mod);
> }
>