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u-boot/arch/Kconfig
Simon Glass 0b2fa98aa5 linker_lists: Fix alignment issue 
The linker script uses alphabetic sorting to group the different linker
lists together. Each group has its own struct and potentially its own
alignment. But when the linker packs the structs together it cannot ensure
that a linker list starts on the expected alignment boundary.

For example, if the first list has a struct size of 8 and we place 3 of
them in the image, that means that the next struct will start at offset
0x18 from the start of the linker_list section. If the next struct has
a size of 16 then it will start at an 8-byte aligned offset, but not a
16-byte aligned offset.

With sandbox on x86_64, a reference to a linker list item using
ll_entry_get() can force alignment of that particular linker_list item,
if it is in the same file as the linker_list item is declared.

Consider this example, where struct driver is 0x80 bytes:

	ll_entry_declare(struct driver, fred, driver)

...

	void *p = ll_entry_get(struct driver, fred, driver)

If these two lines of code are in the same file, then the entry is forced
to be aligned at the 'struct driver' alignment, which is 16 bytes. If the
second line of code is in a different file, then no action is taken, since
the compiler cannot update the alignment of the linker_list item.

In the first case, an 8-byte 'fill' region is added:

 .u_boot_list_2_driver_2_testbus_drv
                0x0000000000270018       0x80 test/built-in.o
                0x0000000000270018                _u_boot_list_2_driver_2_testbus_drv
 .u_boot_list_2_driver_2_testfdt1_drv
                0x0000000000270098       0x80 test/built-in.o
                0x0000000000270098                _u_boot_list_2_driver_2_testfdt1_drv
 *fill*         0x0000000000270118        0x8
 .u_boot_list_2_driver_2_testfdt_drv
                0x0000000000270120       0x80 test/built-in.o
                0x0000000000270120                _u_boot_list_2_driver_2_testfdt_drv
 .u_boot_list_2_driver_2_testprobe_drv
                0x00000000002701a0       0x80 test/built-in.o
                0x00000000002701a0                _u_boot_list_2_driver_2_testprobe_drv

With this, the linker_list no-longer works since items after testfdt1_drv
are not at the expected address.

Ideally we would have a way to tell gcc not to align structs in this way.
It is not clear how we could do this, and in any case it would require us
to adjust every struct used by the linker_list feature.

One possible fix is to force each separate linker_list to start on the
largest possible boundary that can be required by the compiler. However
that does not seem to work on x86_64, which uses 16-byte alignment in this
case but needs 32-byte alignment.

So add a Kconfig option to handle this. Set the default value to 4 so
as to avoid changing platforms that don't need it.

Update the ll_entry_start() accordingly.

Signed-off-by: Simon Glass <sjg@chromium.org>
2020-12-18 20:32:21 -07:00

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config CREATE_ARCH_SYMLINK
bool
config HAVE_ARCH_IOREMAP
bool
config NEEDS_MANUAL_RELOC
bool
config LINKER_LIST_ALIGN
int
default 32 if SANDBOX
default 8 if ARM64 || X86
default 4
help
Force the each linker list to be aligned to this boundary. This
is required if ll_entry_get() is used, since otherwise the linker
may add padding into the table, thus breaking it.
See linker_lists.rst for full details.
choice
prompt "Architecture select"
default SANDBOX
config ARC
bool "ARC architecture"
select ARC_TIMER
select CLK
select DM
select HAVE_PRIVATE_LIBGCC
select SUPPORT_OF_CONTROL
select TIMER
config ARM
bool "ARM architecture"
select CREATE_ARCH_SYMLINK
select HAVE_PRIVATE_LIBGCC if !ARM64
select SUPPORT_OF_CONTROL
config M68K
bool "M68000 architecture"
select HAVE_PRIVATE_LIBGCC
select NEEDS_MANUAL_RELOC
select SYS_BOOT_GET_CMDLINE
select SYS_BOOT_GET_KBD
select SUPPORT_OF_CONTROL
config MICROBLAZE
bool "MicroBlaze architecture"
select NEEDS_MANUAL_RELOC
select SUPPORT_OF_CONTROL
imply CMD_IRQ
config MIPS
bool "MIPS architecture"
select HAVE_ARCH_IOREMAP
select HAVE_PRIVATE_LIBGCC
select SUPPORT_OF_CONTROL
config NDS32
bool "NDS32 architecture"
select SUPPORT_OF_CONTROL
config NIOS2
bool "Nios II architecture"
select CPU
select DM
select OF_CONTROL
select SUPPORT_OF_CONTROL
imply CMD_DM
config PPC
bool "PowerPC architecture"
select HAVE_PRIVATE_LIBGCC
select SUPPORT_OF_CONTROL
select SYS_BOOT_GET_CMDLINE
select SYS_BOOT_GET_KBD
config RISCV
bool "RISC-V architecture"
select CREATE_ARCH_SYMLINK
select SUPPORT_OF_CONTROL
select OF_CONTROL
select DM
imply DM_SERIAL
imply DM_ETH
imply DM_MMC
imply DM_SPI
imply DM_SPI_FLASH
imply BLK
imply CLK
imply MTD
imply TIMER
imply CMD_DM
imply SPL_DM
imply SPL_OF_CONTROL
imply SPL_LIBCOMMON_SUPPORT
imply SPL_LIBGENERIC_SUPPORT
imply SPL_SERIAL_SUPPORT
imply SPL_TIMER
config SANDBOX
bool "Sandbox"
select BOARD_LATE_INIT
select BZIP2
select CMD_POWEROFF
select DM
select DM_GPIO
select DM_I2C
select DM_KEYBOARD
select DM_MMC
select DM_SERIAL
select DM_SPI
select DM_SPI_FLASH
select GZIP_COMPRESSED
select HAVE_BLOCK_DEVICE
select LZO
select OF_BOARD_SETUP
select PCI_ENDPOINT
select SPI
select SUPPORT_OF_CONTROL
select SYSRESET_CMD_POWEROFF
imply BITREVERSE
select BLOBLIST
imply CMD_DM
imply CMD_EXCEPTION
imply CMD_GETTIME
imply CMD_HASH
imply CMD_IO
imply CMD_IOTRACE
imply CMD_LZMADEC
imply CMD_SATA
imply CMD_SF
imply CMD_SF_TEST
imply CRC32_VERIFY
imply FAT_WRITE
imply FIRMWARE
imply HASH_VERIFY
imply LZMA
imply SCSI
imply TEE
imply AVB_VERIFY
imply LIBAVB
imply CMD_AVB
imply UDP_FUNCTION_FASTBOOT
imply VIRTIO_MMIO
imply VIRTIO_PCI
imply VIRTIO_SANDBOX
imply VIRTIO_BLK
imply VIRTIO_NET
imply DM_SOUND
imply PCI_SANDBOX_EP
imply PCH
imply PHYLIB
imply DM_MDIO
imply DM_MDIO_MUX
imply ACPI_PMC
imply ACPI_PMC_SANDBOX
imply CMD_PMC
imply CMD_CLONE
imply SILENT_CONSOLE
imply BOOTARGS_SUBST
config SH
bool "SuperH architecture"
select HAVE_PRIVATE_LIBGCC
select SUPPORT_OF_CONTROL
config X86
bool "x86 architecture"
select SUPPORT_SPL
select SUPPORT_TPL
select CREATE_ARCH_SYMLINK
select DM
select DM_PCI
select HAVE_ARCH_IOMAP
select HAVE_PRIVATE_LIBGCC
select OF_CONTROL
select PCI
select SUPPORT_OF_CONTROL
select TIMER
select USE_PRIVATE_LIBGCC
select X86_TSC_TIMER
imply HAS_ROM if X86_RESET_VECTOR
imply BLK
imply CMD_DM
imply CMD_FPGA_LOADMK
imply CMD_GETTIME
imply CMD_IO
imply CMD_IRQ
imply CMD_PCI
imply CMD_SF
imply CMD_SF_TEST
imply CMD_ZBOOT
imply DM_ETH
imply DM_GPIO
imply DM_KEYBOARD
imply DM_MMC
imply DM_RTC
imply DM_SCSI
imply DM_SERIAL
imply DM_SPI
imply DM_SPI_FLASH
imply DM_USB
imply DM_VIDEO
imply SYSRESET
imply SPL_SYSRESET
imply SYSRESET_X86
imply USB_ETHER_ASIX
imply USB_ETHER_SMSC95XX
imply USB_HOST_ETHER
imply PCH
imply RTC_MC146818
imply IRQ
imply ACPIGEN if !QEMU
imply SYSINFO if GENERATE_SMBIOS_TABLE
imply SYSINFO_SMBIOS if GENERATE_SMBIOS_TABLE
# Thing to enable for when SPL/TPL are enabled: SPL
imply SPL_DM
imply SPL_OF_LIBFDT
imply SPL_DRIVERS_MISC_SUPPORT
imply SPL_GPIO_SUPPORT
imply SPL_PINCTRL
imply SPL_LIBCOMMON_SUPPORT
imply SPL_LIBGENERIC_SUPPORT
imply SPL_SERIAL_SUPPORT
imply SPL_SPI_FLASH_SUPPORT
imply SPL_SPI_SUPPORT
imply SPL_OF_CONTROL
imply SPL_TIMER
imply SPL_REGMAP
imply SPL_SYSCON
# TPL
imply TPL_DM
imply TPL_DRIVERS_MISC_SUPPORT
imply TPL_GPIO_SUPPORT
imply TPL_PINCTRL
imply TPL_LIBCOMMON_SUPPORT
imply TPL_LIBGENERIC_SUPPORT
imply TPL_SERIAL_SUPPORT
imply TPL_OF_CONTROL
imply TPL_TIMER
imply TPL_REGMAP
imply TPL_SYSCON
config XTENSA
bool "Xtensa architecture"
select CREATE_ARCH_SYMLINK
select SUPPORT_OF_CONTROL
endchoice
config SYS_ARCH
string
help
This option should contain the architecture name to build the
appropriate arch/<CONFIG_SYS_ARCH> directory.
All the architectures should specify this option correctly.
config SYS_CPU
string
help
This option should contain the CPU name to build the correct
arch/<CONFIG_SYS_ARCH>/cpu/<CONFIG_SYS_CPU> directory.
This is optional. For those targets without the CPU directory,
leave this option empty.
config SYS_SOC
string
help
This option should contain the SoC name to build the directory
arch/<CONFIG_SYS_ARCH>/cpu/<CONFIG_SYS_CPU>/<CONFIG_SYS_SOC>.
This is optional. For those targets without the SoC directory,
leave this option empty.
config SYS_VENDOR
string
help
This option should contain the vendor name of the target board.
If it is set and
board/<CONFIG_SYS_VENDOR>/common/Makefile exists, the vendor common
directory is compiled.
If CONFIG_SYS_BOARD is also set, the sources under
board/<CONFIG_SYS_VENDOR>/<CONFIG_SYS_BOARD> directory are compiled.
This is optional. For those targets without the vendor directory,
leave this option empty.
config SYS_BOARD
string
help
This option should contain the name of the target board.
If it is set, either board/<CONFIG_SYS_VENDOR>/<CONFIG_SYS_BOARD>
or board/<CONFIG_SYS_BOARD> directory is compiled depending on
whether CONFIG_SYS_VENDOR is set or not.
This is optional. For those targets without the board directory,
leave this option empty.
config SYS_CONFIG_NAME
string
help
This option should contain the base name of board header file.
The header file include/configs/<CONFIG_SYS_CONFIG_NAME>.h
should be included from include/config.h.
config SYS_DISABLE_DCACHE_OPS
bool
help
This option disables dcache flush and dcache invalidation
operations. For example, on coherent systems where cache
operatios are not required, enable this option to avoid them.
Note that, its up to the individual architectures to implement
this functionality.
source "arch/arc/Kconfig"
source "arch/arm/Kconfig"
source "arch/m68k/Kconfig"
source "arch/microblaze/Kconfig"
source "arch/mips/Kconfig"
source "arch/nds32/Kconfig"
source "arch/nios2/Kconfig"
source "arch/powerpc/Kconfig"
source "arch/sandbox/Kconfig"
source "arch/sh/Kconfig"
source "arch/x86/Kconfig"
source "arch/xtensa/Kconfig"
source "arch/riscv/Kconfig"
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