u-boot/arch/riscv/Kconfig
Lukas Auer 6b20dc165e riscv: increase stack size to avoid a stack overflow during distro boot
This fixes a problem, where booting Linux using distro boot will
sometimes lead to an invalid instruction exception on the main hart. The
secondary harts are not affected and boot Linux successfully. The root
cause of this problem is a stack overflow on the main hart.

With distro boot, the current default stack size of 8KiB on RISC-V is
not sufficient and will cause a stack overflow. The stacks are allocated
sequentially. In the case of a stack overflow the stack of the main hart
can reach into that of another hart and be corrupted.

The stack overflow previously did not cause any problems, because only
stack frames, which are not used anymore since the hart enters Linux,
were corrupted. Starting with GCC 9, the stack usage has decreased. Now,
only the most recent stack frame overflows into the stack of a secondary
hart and is corrupted. The illegal instruction exception is caused by
the secondary hart overwriting the return address in the stack frame of
the main hart with an address that does not include valid code.

Increase the default stack size of each hart to 16KiB to avoid this
problem.

Reported-by: Aurelien Jarno <aurelien@aurel32.net>
Signed-off-by: Lukas Auer <lukas.auer@aisec.fraunhofer.de>
Tested-by: David Abdurachmanov <david.abdurachmanov@sifive.com>
Tested-by: Aurelien Jarno <aurelien@aurel32.net>
Reviewed-by: Rick Chen <rick@andestech.com>
2019-12-10 08:23:10 +08:00

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menu "RISC-V architecture"
depends on RISCV
config SYS_ARCH
default "riscv"
choice
prompt "Target select"
optional
config TARGET_AX25_AE350
bool "Support ax25-ae350"
config TARGET_MICROCHIP_ICICLE
bool "Support Microchip PolarFire-SoC Icicle Board"
config TARGET_QEMU_VIRT
bool "Support QEMU Virt Board"
config TARGET_SIFIVE_FU540
bool "Support SiFive FU540 Board"
endchoice
config SYS_ICACHE_OFF
bool "Do not enable icache"
default n
help
Do not enable instruction cache in U-Boot.
config SPL_SYS_ICACHE_OFF
bool "Do not enable icache in SPL"
depends on SPL
default SYS_ICACHE_OFF
help
Do not enable instruction cache in SPL.
config SYS_DCACHE_OFF
bool "Do not enable dcache"
default n
help
Do not enable data cache in U-Boot.
config SPL_SYS_DCACHE_OFF
bool "Do not enable dcache in SPL"
depends on SPL
default SYS_DCACHE_OFF
help
Do not enable data cache in SPL.
# board-specific options below
source "board/AndesTech/ax25-ae350/Kconfig"
source "board/emulation/qemu-riscv/Kconfig"
source "board/microchip/mpfs_icicle/Kconfig"
source "board/sifive/fu540/Kconfig"
# platform-specific options below
source "arch/riscv/cpu/ax25/Kconfig"
source "arch/riscv/cpu/generic/Kconfig"
# architecture-specific options below
choice
prompt "Base ISA"
default ARCH_RV32I
config ARCH_RV32I
bool "RV32I"
select 32BIT
help
Choose this option to target the RV32I base integer instruction set.
config ARCH_RV64I
bool "RV64I"
select 64BIT
select PHYS_64BIT
help
Choose this option to target the RV64I base integer instruction set.
endchoice
choice
prompt "Code Model"
default CMODEL_MEDLOW
config CMODEL_MEDLOW
bool "medium low code model"
help
U-Boot and its statically defined symbols must lie within a single 2 GiB
address range and must lie between absolute addresses -2 GiB and +2 GiB.
config CMODEL_MEDANY
bool "medium any code model"
help
U-Boot and its statically defined symbols must be within any single 2 GiB
address range.
endchoice
choice
prompt "Run Mode"
default RISCV_MMODE
config RISCV_MMODE
bool "Machine"
help
Choose this option to build U-Boot for RISC-V M-Mode.
config RISCV_SMODE
bool "Supervisor"
help
Choose this option to build U-Boot for RISC-V S-Mode.
endchoice
choice
prompt "SPL Run Mode"
default SPL_RISCV_MMODE
depends on SPL
config SPL_RISCV_MMODE
bool "Machine"
help
Choose this option to build U-Boot SPL for RISC-V M-Mode.
config SPL_RISCV_SMODE
bool "Supervisor"
help
Choose this option to build U-Boot SPL for RISC-V S-Mode.
endchoice
config RISCV_ISA_C
bool "Emit compressed instructions"
default y
help
Adds "C" to the ISA subsets that the toolchain is allowed to emit
when building U-Boot, which results in compressed instructions in the
U-Boot binary.
config RISCV_ISA_A
def_bool y
config 32BIT
bool
config 64BIT
bool
config SIFIVE_CLINT
bool
depends on RISCV_MMODE || SPL_RISCV_MMODE
select REGMAP
select SYSCON
select SPL_REGMAP if SPL
select SPL_SYSCON if SPL
help
The SiFive CLINT block holds memory-mapped control and status registers
associated with software and timer interrupts.
config ANDES_PLIC
bool
depends on RISCV_MMODE || SPL_RISCV_MMODE
select REGMAP
select SYSCON
select SPL_REGMAP if SPL
select SPL_SYSCON if SPL
help
The Andes PLIC block holds memory-mapped claim and pending registers
associated with software interrupt.
config ANDES_PLMT
bool
depends on RISCV_MMODE || SPL_RISCV_MMODE
select REGMAP
select SYSCON
select SPL_REGMAP if SPL
select SPL_SYSCON if SPL
help
The Andes PLMT block holds memory-mapped mtime register
associated with timer tick.
config RISCV_RDTIME
bool
default y if RISCV_SMODE || SPL_RISCV_SMODE
help
The provides the riscv_get_time() API that is implemented using the
standard rdtime instruction. This is the case for S-mode U-Boot, and
is useful for processors that support rdtime in M-mode too.
config SYS_MALLOC_F_LEN
default 0x1000
config SMP
bool "Symmetric Multi-Processing"
help
This enables support for systems with more than one CPU. If
you say N here, U-Boot will run on single and multiprocessor
machines, but will use only one CPU of a multiprocessor
machine. If you say Y here, U-Boot will run on many, but not
all, single processor machines.
config NR_CPUS
int "Maximum number of CPUs (2-32)"
range 2 32
depends on SMP
default 8
help
On multiprocessor machines, U-Boot sets up a stack for each CPU.
Stack memory is pre-allocated. U-Boot must therefore know the
maximum number of CPUs that may be present.
config SBI_IPI
bool
default y if RISCV_SMODE || SPL_RISCV_SMODE
depends on SMP
config XIP
bool "XIP mode"
help
XIP (eXecute In Place) is a method for executing code directly
from a NOR flash memory without copying the code to ram.
Say yes here if U-Boot boots from flash directly.
config STACK_SIZE_SHIFT
int
default 14
config SPL_LDSCRIPT
default "arch/riscv/cpu/u-boot-spl.lds"
endmenu