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linux/arch/sparc/Kconfig
Linus Torvalds 9471f1f2f5 Merge branch 'expand-stack' 
This modifies our user mode stack expansion code to always take the
mmap_lock for writing before modifying the VM layout.

It's actually something we always technically should have done, but
because we didn't strictly need it, we were being lazy ("opportunistic"
sounds so much better, doesn't it?) about things, and had this hack in
place where we would extend the stack vma in-place without doing the
proper locking.

And it worked fine.  We just needed to change vm_start (or, in the case
of grow-up stacks, vm_end) and together with some special ad-hoc locking
using the anon_vma lock and the mm->page_table_lock, it all was fairly
straightforward.

That is, it was all fine until Ruihan Li pointed out that now that the
vma layout uses the maple tree code, we *really* don't just change
vm_start and vm_end any more, and the locking really is broken.  Oops.

It's not actually all _that_ horrible to fix this once and for all, and
do proper locking, but it's a bit painful.  We have basically three
different cases of stack expansion, and they all work just a bit
differently:

 - the common and obvious case is the page fault handling. It's actually
   fairly simple and straightforward, except for the fact that we have
   something like 24 different versions of it, and you end up in a maze
   of twisty little passages, all alike.

 - the simplest case is the execve() code that creates a new stack.
   There are no real locking concerns because it's all in a private new
   VM that hasn't been exposed to anybody, but lockdep still can end up
   unhappy if you get it wrong.

 - and finally, we have GUP and page pinning, which shouldn't really be
   expanding the stack in the first place, but in addition to execve()
   we also use it for ptrace(). And debuggers do want to possibly access
   memory under the stack pointer and thus need to be able to expand the
   stack as a special case.

None of these cases are exactly complicated, but the page fault case in
particular is just repeated slightly differently many many times.  And
ia64 in particular has a fairly complicated situation where you can have
both a regular grow-down stack _and_ a special grow-up stack for the
register backing store.

So to make this slightly more manageable, the bulk of this series is to
first create a helper function for the most common page fault case, and
convert all the straightforward architectures to it.

Thus the new 'lock_mm_and_find_vma()' helper function, which ends up
being used by x86, arm, powerpc, mips, riscv, alpha, arc, csky, hexagon,
loongarch, nios2, sh, sparc32, and xtensa.  So we not only convert more
than half the architectures, we now have more shared code and avoid some
of those twisty little passages.

And largely due to this common helper function, the full diffstat of
this series ends up deleting more lines than it adds.

That still leaves eight architectures (ia64, m68k, microblaze, openrisc,
parisc, s390, sparc64 and um) that end up doing 'expand_stack()'
manually because they are doing something slightly different from the
normal pattern.  Along with the couple of special cases in execve() and
GUP.

So there's a couple of patches that first create 'locked' helper
versions of the stack expansion functions, so that there's a obvious
path forward in the conversion.  The execve() case is then actually
pretty simple, and is a nice cleanup from our old "grow-up stackls are
special, because at execve time even they grow down".

The #ifdef CONFIG_STACK_GROWSUP in that code just goes away, because
it's just more straightforward to write out the stack expansion there
manually, instead od having get_user_pages_remote() do it for us in some
situations but not others and have to worry about locking rules for GUP.

And the final step is then to just convert the remaining odd cases to a
new world order where 'expand_stack()' is called with the mmap_lock held
for reading, but where it might drop it and upgrade it to a write, only
to return with it held for reading (in the success case) or with it
completely dropped (in the failure case).

In the process, we remove all the stack expansion from GUP (where
dropping the lock wouldn't be ok without special rules anyway), and add
it in manually to __access_remote_vm() for ptrace().

Thanks to Adrian Glaubitz and Frank Scheiner who tested the ia64 cases.
Everything else here felt pretty straightforward, but the ia64 rules for
stack expansion are really quite odd and very different from everything
else.  Also thanks to Vegard Nossum who caught me getting one of those
odd conditions entirely the wrong way around.

Anyway, I think I want to actually move all the stack expansion code to
a whole new file of its own, rather than have it split up between
mm/mmap.c and mm/memory.c, but since this will have to be backported to
the initial maple tree vma introduction anyway, I tried to keep the
patches _fairly_ minimal.

Also, while I don't think it's valid to expand the stack from GUP, the
final patch in here is a "warn if some crazy GUP user wants to try to
expand the stack" patch.  That one will be reverted before the final
release, but it's left to catch any odd cases during the merge window
and release candidates.

Reported-by: Ruihan Li <lrh2000@pku.edu.cn>

* branch 'expand-stack':
  gup: add warning if some caller would seem to want stack expansion
  mm: always expand the stack with the mmap write lock held
  execve: expand new process stack manually ahead of time
  mm: make find_extend_vma() fail if write lock not held
  powerpc/mm: convert coprocessor fault to lock_mm_and_find_vma()
  mm/fault: convert remaining simple cases to lock_mm_and_find_vma()
  arm/mm: Convert to using lock_mm_and_find_vma()
  riscv/mm: Convert to using lock_mm_and_find_vma()
  mips/mm: Convert to using lock_mm_and_find_vma()
  powerpc/mm: Convert to using lock_mm_and_find_vma()
  arm64/mm: Convert to using lock_mm_and_find_vma()
  mm: make the page fault mmap locking killable
  mm: introduce new 'lock_mm_and_find_vma()' page fault helper
2023-06-28 20:35:21 -07:00

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# SPDX-License-Identifier: GPL-2.0-only
config 64BIT
bool "64-bit kernel" if "$(ARCH)" = "sparc"
default "$(ARCH)" = "sparc64"
help
SPARC is a family of RISC microprocessors designed and marketed by
Sun Microsystems, incorporated. They are very widely found in Sun
workstations and clones.
Say yes to build a 64-bit kernel - formerly known as sparc64
Say no to build a 32-bit kernel - formerly known as sparc
config SPARC
bool
default y
select ARCH_MIGHT_HAVE_PC_PARPORT if SPARC64 && PCI
select ARCH_MIGHT_HAVE_PC_SERIO
select DMA_OPS
select OF
select OF_PROMTREE
select HAVE_ASM_MODVERSIONS
select HAVE_ARCH_KGDB if !SMP || SPARC64
select HAVE_ARCH_TRACEHOOK
select HAVE_ARCH_SECCOMP if SPARC64
select HAVE_EXIT_THREAD
select HAVE_PCI
select SYSCTL_EXCEPTION_TRACE
select RTC_CLASS
select RTC_DRV_M48T59
select RTC_SYSTOHC
select HAVE_ARCH_JUMP_LABEL if SPARC64
select GENERIC_IRQ_SHOW
select ARCH_WANT_IPC_PARSE_VERSION
select GENERIC_PCI_IOMAP
select HAS_IOPORT
select HAVE_HARDLOCKUP_DETECTOR_SPARC64 if SPARC64
select HAVE_CBPF_JIT if SPARC32
select HAVE_EBPF_JIT if SPARC64
select HAVE_DEBUG_BUGVERBOSE
select GENERIC_SMP_IDLE_THREAD
select MODULES_USE_ELF_RELA
select PCI_SYSCALL if PCI
select PCI_MSI_ARCH_FALLBACKS if PCI_MSI
select ODD_RT_SIGACTION
select OLD_SIGSUSPEND
select CPU_NO_EFFICIENT_FFS
select LOCKDEP_SMALL if LOCKDEP
select NEED_DMA_MAP_STATE
select NEED_SG_DMA_LENGTH
select TRACE_IRQFLAGS_SUPPORT
config SPARC32
def_bool !64BIT
select ARCH_32BIT_OFF_T
select ARCH_HAS_CPU_FINALIZE_INIT if !SMP
select ARCH_HAS_SYNC_DMA_FOR_CPU
select CLZ_TAB
select DMA_DIRECT_REMAP
select GENERIC_ATOMIC64
select HAVE_UID16
select LOCK_MM_AND_FIND_VMA
select OLD_SIGACTION
select ZONE_DMA
config SPARC64
def_bool 64BIT
select ALTERNATE_USER_ADDRESS_SPACE
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_KRETPROBES
select HAVE_KPROBES
select MMU_GATHER_RCU_TABLE_FREE if SMP
select MMU_GATHER_MERGE_VMAS
select MMU_GATHER_NO_FLUSH_CACHE
select HAVE_ARCH_TRANSPARENT_HUGEPAGE
select HAVE_DYNAMIC_FTRACE
select HAVE_FTRACE_MCOUNT_RECORD
select HAVE_SYSCALL_TRACEPOINTS
select HAVE_CONTEXT_TRACKING_USER
select HAVE_TIF_NOHZ
select HAVE_DEBUG_KMEMLEAK
select IOMMU_HELPER
select SPARSE_IRQ
select RTC_DRV_CMOS
select RTC_DRV_BQ4802
select RTC_DRV_SUN4V
select RTC_DRV_STARFIRE
select HAVE_PERF_EVENTS
select PERF_USE_VMALLOC
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select HAVE_C_RECORDMCOUNT
select HAVE_ARCH_AUDITSYSCALL
select ARCH_SUPPORTS_ATOMIC_RMW
select ARCH_SUPPORTS_DEBUG_PAGEALLOC
select HAVE_NMI
select HAVE_REGS_AND_STACK_ACCESS_API
select ARCH_USE_QUEUED_RWLOCKS
select ARCH_USE_QUEUED_SPINLOCKS
select GENERIC_TIME_VSYSCALL
select ARCH_CLOCKSOURCE_DATA
select ARCH_HAS_PTE_SPECIAL
select PCI_DOMAINS if PCI
select ARCH_HAS_GIGANTIC_PAGE
select HAVE_SOFTIRQ_ON_OWN_STACK
select HAVE_SETUP_PER_CPU_AREA
select NEED_PER_CPU_EMBED_FIRST_CHUNK
select NEED_PER_CPU_PAGE_FIRST_CHUNK
config ARCH_PROC_KCORE_TEXT
def_bool y
config CPU_BIG_ENDIAN
def_bool y
config ARCH_ATU
bool
default y if SPARC64
config STACKTRACE_SUPPORT
bool
default y if SPARC64
config LOCKDEP_SUPPORT
bool
default y if SPARC64
config ARCH_HIBERNATION_POSSIBLE
def_bool y if SPARC64
config AUDIT_ARCH
bool
default y
config MMU
bool
default y
config HIGHMEM
bool
default y if SPARC32
select KMAP_LOCAL
config GENERIC_ISA_DMA
bool
default y if SPARC32
config PGTABLE_LEVELS
default 4 if 64BIT
default 3
config ARCH_SUPPORTS_UPROBES
def_bool y if SPARC64
menu "Processor type and features"
config SMP
bool "Symmetric multi-processing support"
help
This enables support for systems with more than one CPU. If you have
a system with only one CPU, say N. If you have a system with more
than one CPU, say Y.
If you say N here, the kernel will run on uni- and multiprocessor
machines, but will use only one CPU of a multiprocessor machine. If
you say Y here, the kernel will run on many, but not all,
uniprocessor machines. On a uniprocessor machine, the kernel
will run faster if you say N here.
People using multiprocessor machines who say Y here should also say
Y to "Enhanced Real Time Clock Support", below. The "Advanced Power
Management" code will be disabled if you say Y here.
See also <file:Documentation/admin-guide/lockup-watchdogs.rst> and the SMP-HOWTO
available at <https://www.tldp.org/docs.html#howto>.
If you don't know what to do here, say N.
config NR_CPUS
int "Maximum number of CPUs"
depends on SMP
range 2 32 if SPARC32
range 2 4096 if SPARC64
default 32 if SPARC32
default 4096 if SPARC64
source "kernel/Kconfig.hz"
config GENERIC_HWEIGHT
bool
default y
config GENERIC_CALIBRATE_DELAY
bool
default y
config ARCH_MAY_HAVE_PC_FDC
bool
default y
config EMULATED_CMPXCHG
bool
default y if SPARC32
help
Sparc32 does not have a CAS instruction like sparc64. cmpxchg()
is emulated, and therefore it is not completely atomic.
# Makefile helpers
config SPARC32_SMP
bool
default y
depends on SPARC32 && SMP
config SPARC64_SMP
bool
default y
depends on SPARC64 && SMP
config EARLYFB
bool "Support for early boot text console"
default y
depends on SPARC64
help
Say Y here to enable a faster early framebuffer boot console.
config HOTPLUG_CPU
bool "Support for hot-pluggable CPUs"
depends on SPARC64 && SMP
help
Say Y here to experiment with turning CPUs off and on. CPUs
can be controlled through /sys/devices/system/cpu/cpu#.
Say N if you want to disable CPU hotplug.
if SPARC64
source "drivers/cpufreq/Kconfig"
endif
config US3_MC
tristate "UltraSPARC-III Memory Controller driver"
depends on SPARC64
default y
help
This adds a driver for the UltraSPARC-III memory controller.
Loading this driver allows exact mnemonic strings to be
printed in the event of a memory error, so that the faulty DIMM
on the motherboard can be matched to the error.
If in doubt, say Y, as this information can be very useful.
# Global things across all Sun machines.
config GENERIC_LOCKBREAK
bool
default y
depends on SPARC64 && SMP && PREEMPTION
config NUMA
bool "NUMA support"
depends on SPARC64 && SMP
config NODES_SHIFT
int "Maximum NUMA Nodes (as a power of 2)"
range 4 5 if SPARC64
default "5"
depends on NUMA
help
Specify the maximum number of NUMA Nodes available on the target
system. Increases memory reserved to accommodate various tables.
config ARCH_SPARSEMEM_ENABLE
def_bool y if SPARC64
select SPARSEMEM_VMEMMAP_ENABLE
config ARCH_SPARSEMEM_DEFAULT
def_bool y if SPARC64
config ARCH_FORCE_MAX_ORDER
int "Order of maximal physically contiguous allocations"
default "12"
help
The kernel page allocator limits the size of maximal physically
contiguous allocations. The limit is called MAX_ORDER and it
defines the maximal power of two of number of pages that can be
allocated as a single contiguous block. This option allows
overriding the default setting when ability to allocate very
large blocks of physically contiguous memory is required.
Don't change if unsure.
if SPARC64 || COMPILE_TEST
source "kernel/power/Kconfig"
endif
config SCHED_SMT
bool "SMT (Hyperthreading) scheduler support"
depends on SPARC64 && SMP
default y
help
SMT scheduler support improves the CPU scheduler's decision making
when dealing with SPARC cpus at a cost of slightly increased overhead
in some places. If unsure say N here.
config SCHED_MC
bool "Multi-core scheduler support"
depends on SPARC64 && SMP
default y
help
Multi-core scheduler support improves the CPU scheduler's decision
making when dealing with multi-core CPU chips at a cost of slightly
increased overhead in some places. If unsure say N here.
config CMDLINE_BOOL
bool "Default bootloader kernel arguments"
depends on SPARC64
config CMDLINE
string "Initial kernel command string"
depends on CMDLINE_BOOL
default "console=ttyS0,9600 root=/dev/sda1"
help
Say Y here if you want to be able to pass default arguments to
the kernel. This will be overridden by the bootloader, if you
use one (such as SILO). This is most useful if you want to boot
a kernel from TFTP, and want default options to be available
with having them passed on the command line.
NOTE: This option WILL override the PROM bootargs setting!
config SUN_PM
bool
default y if SPARC32
help
Enable power management and CPU standby features on supported
SPARC platforms.
config SPARC_LED
tristate "Sun4m LED driver"
depends on SPARC32
help
This driver toggles the front-panel LED on sun4m systems
in a user-specifiable manner. Its state can be probed
by reading /proc/led and its blinking mode can be changed
via writes to /proc/led
config SERIAL_CONSOLE
bool
depends on SPARC32
default y
help
If you say Y here, it will be possible to use a serial port as the
system console (the system console is the device which receives all
kernel messages and warnings and which allows logins in single user
mode). This could be useful if some terminal or printer is connected
to that serial port.
Even if you say Y here, the currently visible virtual console
(/dev/tty0) will still be used as the system console by default, but
you can alter that using a kernel command line option such as
"console=ttyS1". (Try "man bootparam" or see the documentation of
your boot loader (silo) about how to pass options to the kernel at
boot time.)
If you don't have a graphics card installed and you say Y here, the
kernel will automatically use the first serial line, /dev/ttyS0, as
system console.
If unsure, say N.
config SPARC_LEON
bool "Sparc Leon processor family"
depends on SPARC32
select USB_EHCI_BIG_ENDIAN_MMIO
select USB_EHCI_BIG_ENDIAN_DESC
select USB_UHCI_BIG_ENDIAN_MMIO
select USB_UHCI_BIG_ENDIAN_DESC
help
If you say Y here if you are running on a SPARC-LEON processor.
The LEON processor is a synthesizable VHDL model of the
SPARC-v8 standard. LEON is part of the GRLIB collection of
IP cores that are distributed under GPL. GRLIB can be downloaded
from www.gaisler.com. You can download a sparc-linux cross-compilation
toolchain at www.gaisler.com.
if SPARC_LEON
menu "U-Boot options"
config UBOOT_LOAD_ADDR
hex "uImage Load Address"
default 0x40004000
help
U-Boot kernel load address, the address in physical address space
where u-boot will place the Linux kernel before booting it.
This address is normally the base address of main memory + 0x4000.
config UBOOT_FLASH_ADDR
hex "uImage.o Load Address"
default 0x00080000
help
Optional setting only affecting the uImage.o ELF-image used to
download the uImage file to the target using a ELF-loader other than
U-Boot. It may for example be used to download an uImage to FLASH with
the GRMON utility before even starting u-boot.
config UBOOT_ENTRY_ADDR
hex "uImage Entry Address"
default 0xf0004000
help
Do not change this unless you know what you're doing. This is
hardcoded by the SPARC32 and LEON port.
This is the virtual address u-boot jumps to when booting the Linux
Kernel.
endmenu
endif
endmenu
menu "Bus options (PCI etc.)"
config SBUS
bool
default y
config SBUSCHAR
bool
default y
config SUN_LDOMS
bool "Sun Logical Domains support"
depends on SPARC64
help
Say Y here is you want to support virtual devices via
Logical Domains.
config PCIC_PCI
bool
depends on PCI && SPARC32 && !SPARC_LEON
default y
config LEON_PCI
bool
depends on PCI && SPARC_LEON
default y
config SPARC_GRPCI1
bool "GRPCI Host Bridge Support"
depends on LEON_PCI
default y
help
Say Y here to include the GRPCI Host Bridge Driver. The GRPCI
PCI host controller is typically found in GRLIB SPARC32/LEON
systems. The driver has one property (all_pci_errors) controlled
from the bootloader that makes the GRPCI to generate interrupts
on detected PCI Parity and System errors.
config SPARC_GRPCI2
bool "GRPCI2 Host Bridge Support"
depends on LEON_PCI
default y
help
Say Y here to include the GRPCI2 Host Bridge Driver.
config SUN_OPENPROMFS
tristate "Openprom tree appears in /proc/openprom"
help
If you say Y, the OpenPROM device tree will be available as a
virtual file system, which you can mount to /proc/openprom by "mount
-t openpromfs none /proc/openprom".
To compile the /proc/openprom support as a module, choose M here: the
module will be called openpromfs.
Only choose N if you know in advance that you will not need to modify
OpenPROM settings on the running system.
# Makefile helpers
config SPARC64_PCI
bool
default y
depends on SPARC64 && PCI
config SPARC64_PCI_MSI
bool
default y
depends on SPARC64_PCI && PCI_MSI
endmenu
config COMPAT
bool
depends on SPARC64
default y
select HAVE_UID16
select ARCH_WANT_OLD_COMPAT_IPC
select COMPAT_OLD_SIGACTION
source "drivers/sbus/char/Kconfig"
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