linux/arch/parisc/Kconfig
Sven Schnelle 6ca6366220 parisc: add dynamic ftrace
This patch implements dynamic ftrace for PA-RISC. The required mcount
call sequences can get pretty long, so instead of patching the
whole call sequence out of the functions, we are using
-fpatchable-function-entry from gcc. This puts a configurable amount of
NOPS before/at the start of the function. Taking do_sys_open() as example,
which would look like this when the call is patched out:

1036b248:       08 00 02 40     nop
1036b24c:       08 00 02 40     nop
1036b250:       08 00 02 40     nop
1036b254:       08 00 02 40     nop

1036b258 <do_sys_open>:
1036b258:       08 00 02 40     nop
1036b25c:       08 03 02 41     copy r3,r1
1036b260:       6b c2 3f d9     stw rp,-14(sp)
1036b264:       08 1e 02 43     copy sp,r3
1036b268:       6f c1 01 00     stw,ma r1,80(sp)

When ftrace gets enabled for this function the kernel will patch these
NOPs to:

1036b248:       10 19 57 20     <address of ftrace>
1036b24c:       6f c1 00 80     stw,ma r1,40(sp)
1036b250:       48 21 3f d1     ldw -18(r1),r1
1036b254:       e8 20 c0 02     bv,n r0(r1)

1036b258 <do_sys_open>:
1036b258:       e8 3f 1f df     b,l,n .-c,r1
1036b25c:       08 03 02 41     copy r3,r1
1036b260:       6b c2 3f d9     stw rp,-14(sp)
1036b264:       08 1e 02 43     copy sp,r3
1036b268:       6f c1 01 00     stw,ma r1,80(sp)

So the first NOP in do_sys_open() will be patched to jump backwards into
some minimal trampoline code which pushes a stackframe, saves r1 which
holds the return address, loads the address of the real ftrace function,
and branches to that location. For 64 Bit things are getting a bit more
complicated (and longer) because we must make sure that the address of
ftrace location is 8 byte aligned, and the offset passed to ldd for
fetching the address is 8 byte aligned as well.

Note that gcc has a bug which misplaces the function label, and needs a
patch to make dynamic ftrace work. See
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=90751 for details.

Signed-off-by: Sven Schnelle <svens@stackframe.org>
Signed-off-by: Helge Deller <deller@gmx.de>
2019-06-08 12:56:29 +02:00

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# SPDX-License-Identifier: GPL-2.0
config PARISC
def_bool y
select ARCH_32BIT_OFF_T if !64BIT
select ARCH_MIGHT_HAVE_PC_PARPORT
select HAVE_IDE
select HAVE_OPROFILE
select HAVE_FUNCTION_TRACER
select HAVE_FUNCTION_GRAPH_TRACER
select HAVE_SYSCALL_TRACEPOINTS
select ARCH_WANT_FRAME_POINTERS
select ARCH_HAS_ELF_RANDOMIZE
select ARCH_HAS_STRICT_KERNEL_RWX
select ARCH_HAS_UBSAN_SANITIZE_ALL
select ARCH_NO_SG_CHAIN
select ARCH_SUPPORTS_MEMORY_FAILURE
select RTC_CLASS
select RTC_DRV_GENERIC
select INIT_ALL_POSSIBLE
select BUG
select BUILDTIME_EXTABLE_SORT
select HAVE_PCI
select HAVE_PERF_EVENTS
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZ4
select HAVE_KERNEL_LZMA
select HAVE_KERNEL_LZO
select HAVE_KERNEL_XZ
select GENERIC_ATOMIC64 if !64BIT
select GENERIC_IRQ_PROBE
select GENERIC_PCI_IOMAP
select ARCH_HAVE_NMI_SAFE_CMPXCHG
select GENERIC_SMP_IDLE_THREAD
select GENERIC_CPU_DEVICES
select GENERIC_STRNCPY_FROM_USER
select SYSCTL_ARCH_UNALIGN_ALLOW
select SYSCTL_EXCEPTION_TRACE
select HAVE_MOD_ARCH_SPECIFIC
select VIRT_TO_BUS
select MODULES_USE_ELF_RELA
select CLONE_BACKWARDS
select TTY # Needed for pdc_cons.c
select HAVE_DEBUG_STACKOVERFLOW
select HAVE_ARCH_AUDITSYSCALL
select HAVE_ARCH_HASH
select HAVE_ARCH_JUMP_LABEL
select HAVE_ARCH_JUMP_LABEL_RELATIVE
select HAVE_ARCH_SECCOMP_FILTER
select HAVE_ARCH_TRACEHOOK
select HAVE_REGS_AND_STACK_ACCESS_API
select GENERIC_SCHED_CLOCK
select HAVE_UNSTABLE_SCHED_CLOCK if SMP
select GENERIC_CLOCKEVENTS
select ARCH_NO_COHERENT_DMA_MMAP
select CPU_NO_EFFICIENT_FFS
select NEED_DMA_MAP_STATE
select NEED_SG_DMA_LENGTH
select HAVE_ARCH_KGDB
select HAVE_KPROBES
select HAVE_KRETPROBES
select HAVE_DYNAMIC_FTRACE if $(cc-option,-fpatchable-function-entry=1,1)
select HAVE_FTRACE_MCOUNT_RECORD if HAVE_DYNAMIC_FTRACE
help
The PA-RISC microprocessor is designed by Hewlett-Packard and used
in many of their workstations & servers (HP9000 700 and 800 series,
and later HP3000 series). The PA-RISC Linux project home page is
at <http://www.parisc-linux.org/>.
config CPU_BIG_ENDIAN
def_bool y
config MMU
def_bool y
config STACK_GROWSUP
def_bool y
config GENERIC_LOCKBREAK
bool
default y
depends on SMP && PREEMPT
config ARCH_HAS_ILOG2_U32
bool
default n
config ARCH_HAS_ILOG2_U64
bool
default n
config GENERIC_BUG
bool
default y
depends on BUG
config GENERIC_HWEIGHT
bool
default y
config GENERIC_CALIBRATE_DELAY
bool
default y
config TIME_LOW_RES
bool
depends on SMP
default y
# unless you want to implement ACPI on PA-RISC ... ;-)
config PM
bool
config STACKTRACE_SUPPORT
def_bool y
config ISA_DMA_API
bool
config ARCH_MAY_HAVE_PC_FDC
bool
depends on BROKEN
default y
config PGTABLE_LEVELS
int
default 3 if 64BIT && PARISC_PAGE_SIZE_4KB
default 2
config SYS_SUPPORTS_HUGETLBFS
def_bool y if PA20
menu "Processor type and features"
choice
prompt "Processor type"
default PA7000
config PA7000
bool "PA7000/PA7100"
---help---
This is the processor type of your CPU. This information is
used for optimizing purposes. In order to compile a kernel
that can run on all 32-bit PA CPUs (albeit not optimally fast),
you can specify "PA7000" here.
Specifying "PA8000" here will allow you to select a 64-bit kernel
which is required on some machines.
config PA7100LC
bool "PA7100LC"
help
Select this option for the PCX-L processor, as used in the
712, 715/64, 715/80, 715/100, 715/100XC, 725/100, 743, 748,
D200, D210, D300, D310 and E-class
config PA7200
bool "PA7200"
help
Select this option for the PCX-T' processor, as used in the
C100, C110, J100, J110, J210XC, D250, D260, D350, D360,
K100, K200, K210, K220, K400, K410 and K420
config PA7300LC
bool "PA7300LC"
help
Select this option for the PCX-L2 processor, as used in the
744, A180, B132L, B160L, B180L, C132L, C160L, C180L,
D220, D230, D320 and D330.
config PA8X00
bool "PA8000 and up"
help
Select this option for PCX-U to PCX-W2 processors.
endchoice
# Define implied options from the CPU selection here
config PA20
def_bool y
depends on PA8X00
config PA11
def_bool y
depends on PA7000 || PA7100LC || PA7200 || PA7300LC
select ARCH_HAS_SYNC_DMA_FOR_CPU
select ARCH_HAS_SYNC_DMA_FOR_DEVICE
select DMA_NONCOHERENT_CACHE_SYNC
config PREFETCH
def_bool y
depends on PA8X00 || PA7200
config MLONGCALLS
bool "Enable the -mlong-calls compiler option for big kernels"
default y if !MODULES || UBSAN || FTRACE
default n
depends on PA8X00
help
If you configure the kernel to include many drivers built-in instead
as modules, the kernel executable may become too big, so that the
linker will not be able to resolve some long branches and fails to link
your vmlinux kernel. In that case enabling this option will help you
to overcome this limit by using the -mlong-calls compiler option.
Usually you want to say N here, unless you e.g. want to build
a kernel which includes all necessary drivers built-in and which can
be used for TFTP booting without the need to have an initrd ramdisk.
Enabling this option will probably slow down your kernel.
config 64BIT
bool "64-bit kernel"
depends on PA8X00
help
Enable this if you want to support 64bit kernel on PA-RISC platform.
At the moment, only people willing to use more than 2GB of RAM,
or having a 64bit-only capable PA-RISC machine should say Y here.
Since there is no 64bit userland on PA-RISC, there is no point to
enable this option otherwise. The 64bit kernel is significantly bigger
and slower than the 32bit one.
choice
prompt "Kernel page size"
default PARISC_PAGE_SIZE_4KB
config PARISC_PAGE_SIZE_4KB
bool "4KB"
help
This lets you select the page size of the kernel. For best
performance, a page size of 16KB is recommended. For best
compatibility with 32bit applications, a page size of 4KB should be
selected (the vast majority of 32bit binaries work perfectly fine
with a larger page size).
4KB For best 32bit compatibility
16KB For best performance
64KB For best performance, might give more overhead.
If you don't know what to do, choose 4KB.
config PARISC_PAGE_SIZE_16KB
bool "16KB"
depends on PA8X00 && BROKEN
config PARISC_PAGE_SIZE_64KB
bool "64KB"
depends on PA8X00 && BROKEN
endchoice
config PARISC_SELF_EXTRACT
bool "Build kernel as self-extracting executable"
default y
help
Say Y if you want to build the parisc kernel as a kind of
self-extracting executable.
If you say N here, the kernel will be compressed with gzip
which can be loaded by the palo bootloader directly too.
If you don't know what to do here, say Y.
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.
On a uniprocessor machine, the kernel will run faster if you say N.
See also <file:Documentation/lockup-watchdogs.txt> and the SMP-HOWTO
available at <http://www.tldp.org/docs.html#howto>.
If you don't know what to do here, say N.
config PARISC_CPU_TOPOLOGY
bool "Support cpu topology definition"
depends on SMP
default y
help
Support PARISC cpu topology definition.
config SCHED_MC
bool "Multi-core scheduler support"
depends on PARISC_CPU_TOPOLOGY && PA8X00
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 IRQSTACKS
bool "Use separate kernel stacks when processing interrupts"
default y
help
If you say Y here the kernel will use separate kernel stacks
for handling hard and soft interrupts. This can help avoid
overflowing the process kernel stacks.
config HOTPLUG_CPU
bool
default y if SMP
config ARCH_SELECT_MEMORY_MODEL
def_bool y
depends on 64BIT
config ARCH_SPARSEMEM_ENABLE
def_bool y
depends on 64BIT
config ARCH_FLATMEM_ENABLE
def_bool y
config ARCH_SPARSEMEM_DEFAULT
def_bool y
depends on ARCH_SPARSEMEM_ENABLE
source "kernel/Kconfig.hz"
config COMPAT
def_bool y
depends on 64BIT
select COMPAT_BINFMT_ELF if BINFMT_ELF
config SYSVIPC_COMPAT
def_bool y
depends on COMPAT && SYSVIPC
config AUDIT_ARCH
def_bool y
config NR_CPUS
int "Maximum number of CPUs (2-32)"
range 2 32
depends on SMP
default "4"
endmenu
source "drivers/parisc/Kconfig"
config SECCOMP
def_bool y
prompt "Enable seccomp to safely compute untrusted bytecode"
---help---
This kernel feature is useful for number crunching applications
that may need to compute untrusted bytecode during their
execution. By using pipes or other transports made available to
the process as file descriptors supporting the read/write
syscalls, it's possible to isolate those applications in
their own address space using seccomp. Once seccomp is
enabled via prctl(PR_SET_SECCOMP), it cannot be disabled
and the task is only allowed to execute a few safe syscalls
defined by each seccomp mode.
If unsure, say Y. Only embedded should say N here.