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, 141 insertions, 0 deletions

diff --git a/drivers/misc/eeprom/Kconfig b/drivers/misc/eeprom/Kconfig
new file mode 100644
index 000000000..4d0ce47aa
--- /dev/null
+++ b/drivers/misc/eeprom/Kconfig
@@ -0,0 +1,141 @@
+# SPDX-License-Identifier: GPL-2.0-only
+menu "EEPROM support"
+
+config EEPROM_AT24
+	tristate "I2C EEPROMs / RAMs / ROMs from most vendors"
+	depends on I2C && SYSFS
+	select NVMEM
+	select NVMEM_SYSFS
+	select REGMAP
+	select REGMAP_I2C
+	help
+	  Enable this driver to get read/write support to most I2C EEPROMs
+	  and compatible devices like FRAMs, SRAMs, ROMs etc. After you
+	  configure the driver to know about each chip on your target
+	  board.  Use these generic chip names, instead of vendor-specific
+	  ones like at24c64, 24lc02 or fm24c04:
+
+	     24c00, 24c01, 24c02, spd (readonly 24c02), 24c04, 24c08,
+	     24c16, 24c32, 24c64, 24c128, 24c256, 24c512, 24c1024, 24c2048
+
+	  Unless you like data loss puzzles, always be sure that any chip
+	  you configure as a 24c32 (32 kbit) or larger is NOT really a
+	  24c16 (16 kbit) or smaller, and vice versa. Marking the chip
+	  as read-only won't help recover from this. Also, if your chip
+	  has any software write-protect mechanism you may want to review the
+	  code to make sure this driver won't turn it on by accident.
+
+	  If you use this with an SMBus adapter instead of an I2C adapter,
+	  full functionality is not available.  Only smaller devices are
+	  supported (24c16 and below, max 4 kByte).
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called at24.
+
+config EEPROM_AT25
+	tristate "SPI EEPROMs (FRAMs) from most vendors"
+	depends on SPI && SYSFS
+	select NVMEM
+	select NVMEM_SYSFS
+	select SPI_MEM
+	help
+	  Enable this driver to get read/write support to most SPI EEPROMs
+	  and Cypress FRAMs,
+	  after you configure the board init code to know about each eeprom
+	  on your target board.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called at25.
+
+config EEPROM_MAX6875
+	tristate "Maxim MAX6874/5 power supply supervisor"
+	depends on I2C
+	help
+	  If you say yes here you get read-only support for the user EEPROM of
+	  the Maxim MAX6874/5 EEPROM-programmable, quad power-supply
+	  sequencer/supervisor.
+
+	  All other features of this chip should be accessed via i2c-dev.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called max6875.
+
+
+config EEPROM_93CX6
+	tristate "EEPROM 93CX6 support"
+	help
+	  This is a driver for the EEPROM chipsets 93c46 and 93c66.
+	  The driver supports both read as well as write commands.
+
+	  If unsure, say N.
+
+config EEPROM_93XX46
+	tristate "Microwire EEPROM 93XX46 support"
+	depends on SPI && SYSFS
+	select REGMAP
+	select NVMEM
+	select NVMEM_SYSFS
+	help
+	  Driver for the microwire EEPROM chipsets 93xx46x. The driver
+	  supports both read and write commands and also the command to
+	  erase the whole EEPROM.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called eeprom_93xx46.
+
+	  If unsure, say N.
+
+config EEPROM_DIGSY_MTC_CFG
+	bool "DigsyMTC display configuration EEPROMs device"
+	depends on GPIO_MPC5200 && SPI_GPIO
+	help
+	  This option enables access to display configuration EEPROMs
+	  on digsy_mtc board. You have to additionally select Microwire
+	  EEPROM 93XX46 driver. sysfs entries will be created for that
+	  EEPROM allowing to read/write the configuration data or to
+	  erase the whole EEPROM.
+
+	  If unsure, say N.
+
+config EEPROM_IDT_89HPESX
+	tristate "IDT 89HPESx PCIe-switches EEPROM / CSR support"
+	depends on I2C && SYSFS
+	help
+	  Enable this driver to get read/write access to EEPROM / CSRs
+	  over IDT PCIe-switch i2c-slave interface.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called idt_89hpesx.
+
+config EEPROM_EE1004
+	tristate "SPD EEPROMs on DDR4 memory modules"
+	depends on I2C && SYSFS
+	select NVMEM
+	select NVMEM_SYSFS
+	help
+	  Enable this driver to get read support to SPD EEPROMs following
+	  the JEDEC EE1004 standard. These are typically found on DDR4
+	  SDRAM memory modules.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called ee1004.
+
+config EEPROM_M24LR
+	tristate "STMicroelectronics M24LR RFID/NFC EEPROM support"
+	depends on I2C && SYSFS
+	select REGMAP_I2C
+	select NVMEM
+	select NVMEM_SYSFS
+	help
+	  This enables support for STMicroelectronics M24LR RFID/NFC EEPROM
+	  chips. These dual-interface devices expose two I2C addresses:
+	  one for EEPROM memory access and another for control and system
+	  configuration (e.g. UID, password handling).
+
+	  This driver provides a sysfs interface for control functions and
+	  integrates with the nvmem subsystem for EEPROM access.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called m24lr.
+
+endmenu