kbuild: rust: keep Rust objects out of Clang LTO with inline helpersgrafted

Under `CONFIG_LTO_CLANG` + `CONFIG_RUST_INLINE_HELPERS`, one may hit
`objtool` errors such as:

    vmlinux.o: error: objtool: _R..._3Gsp4boot+0xd6a:
    can't find jump dest instruction at .text._R..._3Gsp4boot+0x1dfd

The reason is that in such builds, the Clang invocation that compiles
the combined Rust plus helpers bitcode emits LLVM bitcode (again) --
the final code generation happens in the linker's LTO step, which the
`-mllvm` trap options passed to Clang do not reach.

This, in turn, means that unreachable traps are missing, and the
impossible paths do not merely fallthrough to the next symbol, but past
the end of their own section, since LTO builds place each function in
its own section.

Thus filter `CC_FLAGS_LTO` out of the Clang invocation, so that it always
emits machine code directly, with the traps in place.

Assisted-by: LLM
Cc: Gary Guo <gary@garyguo.net>
Cc: Boqun Feng <boqun@kernel.org>
Cc: Alice Ryhl <aliceryhl@google.com>
Cc: Matthew Maurer <mmaurer@google.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: stable@vger.kernel.org
Fixes: 3a2486cc1da5 ("kbuild: rust: provide an option to inline C helpers into Rust")
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://patch.msgid.link/20260816133233.197500-2-ojeda@kernel.org
Signed-off-by: Miguel Ojeda <ojeda@kernel.org>

1 files changed, 296 insertions, 0 deletions

diff --git a/sound/soc/sof/sof-pci-dev.c b/sound/soc/sof/sof-pci-dev.c
new file mode 100644
index 000000000..c50249aad
--- /dev/null
+++ b/sound/soc/sof/sof-pci-dev.c
@@ -0,0 +1,296 @@
+// SPDX-License-Identifier: (GPL-2.0-only OR BSD-3-Clause)
+//
+// This file is provided under a dual BSD/GPLv2 license.  When using or
+// redistributing this file, you may do so under either license.
+//
+// Copyright(c) 2018 Intel Corporation
+//
+// Author: Liam Girdwood <liam.r.girdwood@linux.intel.com>
+//
+
+#include <linux/firmware.h>
+#include <linux/dmi.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/platform_data/x86/soc.h>
+#include <linux/pm_runtime.h>
+#include <sound/soc-acpi.h>
+#include <sound/soc-acpi-intel-match.h>
+#include <sound/sof.h>
+#include "ops.h"
+#include "sof-pci-dev.h"
+
+static char *fw_path;
+module_param(fw_path, charp, 0444);
+MODULE_PARM_DESC(fw_path, "deprecated - moved to snd-sof module.");
+
+static char *fw_filename;
+module_param(fw_filename, charp, 0444);
+MODULE_PARM_DESC(fw_filename, "deprecated - moved to snd-sof module.");
+
+static char *lib_path;
+module_param(lib_path, charp, 0444);
+MODULE_PARM_DESC(lib_path, "deprecated - moved to snd-sof module.");
+
+static char *tplg_path;
+module_param(tplg_path, charp, 0444);
+MODULE_PARM_DESC(tplg_path, "deprecated - moved to snd-sof module.");
+
+static char *tplg_filename;
+module_param(tplg_filename, charp, 0444);
+MODULE_PARM_DESC(tplg_filename, "deprecated - moved to snd-sof module.");
+
+static int sof_pci_debug;
+module_param_named(sof_pci_debug, sof_pci_debug, int, 0444);
+MODULE_PARM_DESC(sof_pci_debug, "SOF PCI debug options (0x0 all off)");
+
+static int sof_pci_ipc_type = -1;
+module_param_named(ipc_type, sof_pci_ipc_type, int, 0444);
+MODULE_PARM_DESC(ipc_type, "deprecated - moved to snd-sof module.");
+
+static const char *sof_dmi_override_tplg_name;
+static bool sof_dmi_use_community_key;
+
+#define SOF_PCI_DISABLE_PM_RUNTIME BIT(0)
+
+static int sof_tplg_cb(const struct dmi_system_id *id)
+{
+	sof_dmi_override_tplg_name = id->driver_data;
+	return 1;
+}
+
+static const struct dmi_system_id sof_tplg_table[] = {
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Volteer"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-MAX98373_ALC5682I_I2S_UP4"),
+		},
+		.driver_data = "sof-tgl-rt5682-ssp0-max98373-ssp2.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "Intel Corporation"),
+			DMI_MATCH(DMI_PRODUCT_NAME, "Alder Lake Client Platform"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-ADL_MAX98373_ALC5682I_I2S"),
+		},
+		.driver_data = "sof-adl-rt5682-ssp0-max98373-ssp2.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-MAX98390_ALC5682I_I2S"),
+		},
+		.driver_data = "sof-adl-max98390-ssp2-rt5682-ssp0.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO_AMP-MAX98360_ALC5682VS_I2S_2WAY"),
+		},
+		.driver_data = "sof-adl-max98360a-rt5682-2way.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-AUDIO_MAX98357_ALC5682I_I2S_2WAY"),
+		},
+		.driver_data = "sof-adl-max98357a-rt5682-2way.tplg",
+	},
+	{
+		.callback = sof_tplg_cb,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google_Brya"),
+			DMI_MATCH(DMI_OEM_STRING, "AUDIO-MAX98360_ALC5682I_I2S_AMP_SSP2"),
+		},
+		.driver_data = "sof-adl-max98357a-rt5682.tplg",
+	},
+	{}
+};
+
+/* all Up boards use the community key */
+static int up_use_community_key(const struct dmi_system_id *id)
+{
+	sof_dmi_use_community_key = true;
+	return 1;
+}
+
+/*
+ * For ApolloLake Chromebooks we want to force the use of the Intel production key.
+ * All newer platforms use the community key
+ */
+static int chromebook_use_community_key(const struct dmi_system_id *id)
+{
+	if (!soc_intel_is_apl())
+		sof_dmi_use_community_key = true;
+	return 1;
+}
+
+static const struct dmi_system_id community_key_platforms[] = {
+	{
+		.ident = "Up boards",
+		.callback = up_use_community_key,
+		.matches = {
+			DMI_MATCH(DMI_SYS_VENDOR, "AAEON"),
+		}
+	},
+	{
+		.ident = "Google Chromebooks",
+		.callback = chromebook_use_community_key,
+		.matches = {
+			DMI_MATCH(DMI_PRODUCT_FAMILY, "Google"),
+		}
+	},
+	{
+		.ident = "Google firmware",
+		.callback = chromebook_use_community_key,
+		.matches = {
+			DMI_MATCH(DMI_BIOS_VERSION, "Google"),
+		}
+	},
+	{},
+};
+
+EXPORT_NS_DEV_PM_OPS(sof_pci_pm, SND_SOC_SOF_PCI_DEV) = {
+	.prepare = snd_sof_prepare,
+	.complete = snd_sof_complete,
+	SYSTEM_SLEEP_PM_OPS(snd_sof_suspend, snd_sof_resume)
+	RUNTIME_PM_OPS(snd_sof_runtime_suspend, snd_sof_runtime_resume,
+		       snd_sof_runtime_idle)
+};
+
+static void sof_pci_probe_complete(struct device *dev)
+{
+	dev_dbg(dev, "Completing SOF PCI probe");
+
+	if (sof_pci_debug & SOF_PCI_DISABLE_PM_RUNTIME)
+		return;
+
+	/* allow runtime_pm */
+	pm_runtime_set_autosuspend_delay(dev, SND_SOF_SUSPEND_DELAY_MS);
+	pm_runtime_use_autosuspend(dev);
+
+	/*
+	 * runtime pm for pci device is "forbidden" by default.
+	 * so call pm_runtime_allow() to enable it.
+	 */
+	pm_runtime_allow(dev);
+
+	/* mark last_busy for pm_runtime to make sure not suspend immediately */
+	pm_runtime_mark_last_busy(dev);
+
+	/* follow recommendation in pci-driver.c to decrement usage counter */
+	pm_runtime_put_noidle(dev);
+}
+
+int sof_pci_probe(struct pci_dev *pci, const struct pci_device_id *pci_id)
+{
+	struct sof_loadable_file_profile *path_override;
+	struct device *dev = &pci->dev;
+	const struct sof_dev_desc *desc =
+		(const struct sof_dev_desc *)pci_id->driver_data;
+	struct snd_sof_pdata *sof_pdata;
+	int ret;
+
+	dev_dbg(&pci->dev, "PCI DSP detected");
+
+	if (!desc) {
+		dev_err(dev, "error: no matching PCI descriptor\n");
+		return -ENODEV;
+	}
+
+	if (!desc->ops) {
+		dev_err(dev, "error: no matching PCI descriptor ops\n");
+		return -ENODEV;
+	}
+
+	sof_pdata = devm_kzalloc(dev, sizeof(*sof_pdata), GFP_KERNEL);
+	if (!sof_pdata)
+		return -ENOMEM;
+
+	ret = pcim_enable_device(pci);
+	if (ret < 0)
+		return ret;
+
+	ret = pcim_request_all_regions(pci, "Audio DSP");
+	if (ret < 0)
+		return ret;
+
+	sof_pdata->name = pci_name(pci);
+
+	/* PCI defines a vendor ID of 0xFFFF as invalid. */
+	if (pci->subsystem_vendor != 0xFFFF) {
+		sof_pdata->subsystem_vendor = pci->subsystem_vendor;
+		sof_pdata->subsystem_device = pci->subsystem_device;
+		sof_pdata->subsystem_id_set = true;
+	}
+
+	sof_pdata->desc = desc;
+	sof_pdata->dev = dev;
+
+	path_override = &sof_pdata->ipc_file_profile_base;
+
+	if (sof_pci_ipc_type < 0) {
+		path_override->ipc_type = desc->ipc_default;
+	} else if (sof_pci_ipc_type < SOF_IPC_TYPE_COUNT) {
+		path_override->ipc_type = sof_pci_ipc_type;
+	} else {
+		dev_err(dev, "Invalid IPC type requested: %d\n", sof_pci_ipc_type);
+		return -EINVAL;
+	}
+
+	path_override->fw_path = fw_path;
+	path_override->fw_name = fw_filename;
+	path_override->fw_lib_path = lib_path;
+	path_override->tplg_path = tplg_path;
+
+	if (dmi_check_system(community_key_platforms) &&
+	    sof_dmi_use_community_key) {
+		path_override->fw_path_postfix = "community";
+		path_override->fw_lib_path_postfix = "community";
+	}
+
+	/*
+	 * the topology filename will be provided in the machine descriptor, unless
+	 * it is overridden by a module parameter or DMI quirk.
+	 */
+	if (tplg_filename) {
+		path_override->tplg_name = tplg_filename;
+	} else {
+		dmi_check_system(sof_tplg_table);
+		if (sof_dmi_override_tplg_name)
+			path_override->tplg_name = sof_dmi_override_tplg_name;
+	}
+
+	/* set callback to be called on successful device probe to enable runtime_pm */
+	sof_pdata->sof_probe_complete = sof_pci_probe_complete;
+
+	/* call sof helper for DSP hardware probe */
+	return snd_sof_device_probe(dev, sof_pdata);
+}
+EXPORT_SYMBOL_NS(sof_pci_probe, "SND_SOC_SOF_PCI_DEV");
+
+void sof_pci_remove(struct pci_dev *pci)
+{
+	/* call sof helper for DSP hardware remove */
+	snd_sof_device_remove(&pci->dev);
+
+	/* follow recommendation in pci-driver.c to increment usage counter */
+	if (snd_sof_device_probe_completed(&pci->dev) &&
+	    !(sof_pci_debug & SOF_PCI_DISABLE_PM_RUNTIME))
+		pm_runtime_get_noresume(&pci->dev);
+}
+EXPORT_SYMBOL_NS(sof_pci_remove, "SND_SOC_SOF_PCI_DEV");
+
+void sof_pci_shutdown(struct pci_dev *pci)
+{
+	snd_sof_device_shutdown(&pci->dev);
+}
+EXPORT_SYMBOL_NS(sof_pci_shutdown, "SND_SOC_SOF_PCI_DEV");
+
+MODULE_LICENSE("Dual BSD/GPL");
+MODULE_DESCRIPTION("SOF support for PCI platforms");