xref: /openbmc/linux/arch/xtensa/Kconfig (revision a89a501c)
1# SPDX-License-Identifier: GPL-2.0
2config XTENSA
3	def_bool y
4	select ARCH_32BIT_OFF_T
5	select ARCH_HAS_BINFMT_FLAT if !MMU
6	select ARCH_HAS_DMA_PREP_COHERENT if MMU
7	select ARCH_HAS_SYNC_DMA_FOR_CPU if MMU
8	select ARCH_HAS_SYNC_DMA_FOR_DEVICE if MMU
9	select ARCH_HAS_DMA_SET_UNCACHED if MMU
10	select ARCH_USE_QUEUED_RWLOCKS
11	select ARCH_USE_QUEUED_SPINLOCKS
12	select ARCH_WANT_FRAME_POINTERS
13	select ARCH_WANT_IPC_PARSE_VERSION
14	select BUILDTIME_TABLE_SORT
15	select CLONE_BACKWARDS
16	select COMMON_CLK
17	select DMA_REMAP if MMU
18	select GENERIC_ATOMIC64
19	select GENERIC_CLOCKEVENTS
20	select GENERIC_IRQ_SHOW
21	select GENERIC_PCI_IOMAP
22	select GENERIC_SCHED_CLOCK
23	select GENERIC_STRNCPY_FROM_USER if KASAN
24	select HAVE_ARCH_AUDITSYSCALL
25	select HAVE_ARCH_JUMP_LABEL if !XIP_KERNEL
26	select HAVE_ARCH_KASAN if MMU && !XIP_KERNEL
27	select HAVE_ARCH_SECCOMP_FILTER
28	select HAVE_ARCH_TRACEHOOK
29	select HAVE_DEBUG_KMEMLEAK
30	select HAVE_DMA_CONTIGUOUS
31	select HAVE_EXIT_THREAD
32	select HAVE_FUNCTION_TRACER
33	select HAVE_FUTEX_CMPXCHG if !MMU
34	select HAVE_HW_BREAKPOINT if PERF_EVENTS
35	select HAVE_IRQ_TIME_ACCOUNTING
36	select HAVE_OPROFILE
37	select HAVE_PCI
38	select HAVE_PERF_EVENTS
39	select HAVE_STACKPROTECTOR
40	select HAVE_SYSCALL_TRACEPOINTS
41	select IRQ_DOMAIN
42	select MODULES_USE_ELF_RELA
43	select PERF_USE_VMALLOC
44	select SET_FS
45	select VIRT_TO_BUS
46	help
47	  Xtensa processors are 32-bit RISC machines designed by Tensilica
48	  primarily for embedded systems.  These processors are both
49	  configurable and extensible.  The Linux port to the Xtensa
50	  architecture supports all processor configurations and extensions,
51	  with reasonable minimum requirements.  The Xtensa Linux project has
52	  a home page at <http://www.linux-xtensa.org/>.
53
54config GENERIC_HWEIGHT
55	def_bool y
56
57config ARCH_HAS_ILOG2_U32
58	def_bool n
59
60config ARCH_HAS_ILOG2_U64
61	def_bool n
62
63config NO_IOPORT_MAP
64	def_bool n
65
66config HZ
67	int
68	default 100
69
70config LOCKDEP_SUPPORT
71	def_bool y
72
73config STACKTRACE_SUPPORT
74	def_bool y
75
76config TRACE_IRQFLAGS_SUPPORT
77	def_bool y
78
79config MMU
80	def_bool n
81
82config HAVE_XTENSA_GPIO32
83	def_bool n
84
85config KASAN_SHADOW_OFFSET
86	hex
87	default 0x6e400000
88
89menu "Processor type and features"
90
91choice
92	prompt "Xtensa Processor Configuration"
93	default XTENSA_VARIANT_FSF
94
95config XTENSA_VARIANT_FSF
96	bool "fsf - default (not generic) configuration"
97	select MMU
98
99config XTENSA_VARIANT_DC232B
100	bool "dc232b - Diamond 232L Standard Core Rev.B (LE)"
101	select MMU
102	select HAVE_XTENSA_GPIO32
103	help
104	  This variant refers to Tensilica's Diamond 232L Standard core Rev.B (LE).
105
106config XTENSA_VARIANT_DC233C
107	bool "dc233c - Diamond 233L Standard Core Rev.C (LE)"
108	select MMU
109	select HAVE_XTENSA_GPIO32
110	help
111	  This variant refers to Tensilica's Diamond 233L Standard core Rev.C (LE).
112
113config XTENSA_VARIANT_CUSTOM
114	bool "Custom Xtensa processor configuration"
115	select HAVE_XTENSA_GPIO32
116	help
117	  Select this variant to use a custom Xtensa processor configuration.
118	  You will be prompted for a processor variant CORENAME.
119endchoice
120
121config XTENSA_VARIANT_CUSTOM_NAME
122	string "Xtensa Processor Custom Core Variant Name"
123	depends on XTENSA_VARIANT_CUSTOM
124	help
125	  Provide the name of a custom Xtensa processor variant.
126	  This CORENAME selects arch/xtensa/variant/CORENAME.
127	  Don't forget you have to select MMU if you have one.
128
129config XTENSA_VARIANT_NAME
130	string
131	default "dc232b"			if XTENSA_VARIANT_DC232B
132	default "dc233c"			if XTENSA_VARIANT_DC233C
133	default "fsf"				if XTENSA_VARIANT_FSF
134	default XTENSA_VARIANT_CUSTOM_NAME	if XTENSA_VARIANT_CUSTOM
135
136config XTENSA_VARIANT_MMU
137	bool "Core variant has a Full MMU (TLB, Pages, Protection, etc)"
138	depends on XTENSA_VARIANT_CUSTOM
139	default y
140	select MMU
141	help
142	  Build a Conventional Kernel with full MMU support,
143	  ie: it supports a TLB with auto-loading, page protection.
144
145config XTENSA_VARIANT_HAVE_PERF_EVENTS
146	bool "Core variant has Performance Monitor Module"
147	depends on XTENSA_VARIANT_CUSTOM
148	default n
149	help
150	  Enable if core variant has Performance Monitor Module with
151	  External Registers Interface.
152
153	  If unsure, say N.
154
155config XTENSA_FAKE_NMI
156	bool "Treat PMM IRQ as NMI"
157	depends on XTENSA_VARIANT_HAVE_PERF_EVENTS
158	default n
159	help
160	  If PMM IRQ is the only IRQ at EXCM level it is safe to
161	  treat it as NMI, which improves accuracy of profiling.
162
163	  If there are other interrupts at or above PMM IRQ priority level
164	  but not above the EXCM level, PMM IRQ still may be treated as NMI,
165	  but only if these IRQs are not used. There will be a build warning
166	  saying that this is not safe, and a bugcheck if one of these IRQs
167	  actually fire.
168
169	  If unsure, say N.
170
171config XTENSA_UNALIGNED_USER
172	bool "Unaligned memory access in user space"
173	help
174	  The Xtensa architecture currently does not handle unaligned
175	  memory accesses in hardware but through an exception handler.
176	  Per default, unaligned memory accesses are disabled in user space.
177
178	  Say Y here to enable unaligned memory access in user space.
179
180config HAVE_SMP
181	bool "System Supports SMP (MX)"
182	depends on XTENSA_VARIANT_CUSTOM
183	select XTENSA_MX
184	help
185	  This option is used to indicate that the system-on-a-chip (SOC)
186	  supports Multiprocessing. Multiprocessor support implemented above
187	  the CPU core definition and currently needs to be selected manually.
188
189	  Multiprocessor support is implemented with external cache and
190	  interrupt controllers.
191
192	  The MX interrupt distributer adds Interprocessor Interrupts
193	  and causes the IRQ numbers to be increased by 4 for devices
194	  like the open cores ethernet driver and the serial interface.
195
196	  You still have to select "Enable SMP" to enable SMP on this SOC.
197
198config SMP
199	bool "Enable Symmetric multi-processing support"
200	depends on HAVE_SMP
201	select GENERIC_SMP_IDLE_THREAD
202	help
203	  Enabled SMP Software; allows more than one CPU/CORE
204	  to be activated during startup.
205
206config NR_CPUS
207	depends on SMP
208	int "Maximum number of CPUs (2-32)"
209	range 2 32
210	default "4"
211
212config HOTPLUG_CPU
213	bool "Enable CPU hotplug support"
214	depends on SMP
215	help
216	  Say Y here to allow turning CPUs off and on. CPUs can be
217	  controlled through /sys/devices/system/cpu.
218
219	  Say N if you want to disable CPU hotplug.
220
221config FAST_SYSCALL_XTENSA
222	bool "Enable fast atomic syscalls"
223	default n
224	help
225	  fast_syscall_xtensa is a syscall that can make atomic operations
226	  on UP kernel when processor has no s32c1i support.
227
228	  This syscall is deprecated. It may have issues when called with
229	  invalid arguments. It is provided only for backwards compatibility.
230	  Only enable it if your userspace software requires it.
231
232	  If unsure, say N.
233
234config FAST_SYSCALL_SPILL_REGISTERS
235	bool "Enable spill registers syscall"
236	default n
237	help
238	  fast_syscall_spill_registers is a syscall that spills all active
239	  register windows of a calling userspace task onto its stack.
240
241	  This syscall is deprecated. It may have issues when called with
242	  invalid arguments. It is provided only for backwards compatibility.
243	  Only enable it if your userspace software requires it.
244
245	  If unsure, say N.
246
247config USER_ABI_CALL0
248	bool
249
250choice
251	prompt "Userspace ABI"
252	default USER_ABI_DEFAULT
253	help
254	  Select supported userspace ABI.
255
256	  If unsure, choose the default ABI.
257
258config USER_ABI_DEFAULT
259	bool "Default ABI only"
260	help
261	  Assume default userspace ABI. For XEA2 cores it is windowed ABI.
262	  call0 ABI binaries may be run on such kernel, but signal delivery
263	  will not work correctly for them.
264
265config USER_ABI_CALL0_ONLY
266	bool "Call0 ABI only"
267	select USER_ABI_CALL0
268	help
269	  Select this option to support only call0 ABI in userspace.
270	  Windowed ABI binaries will crash with a segfault caused by
271	  an illegal instruction exception on the first 'entry' opcode.
272
273	  Choose this option if you're planning to run only user code
274	  built with call0 ABI.
275
276config USER_ABI_CALL0_PROBE
277	bool "Support both windowed and call0 ABI by probing"
278	select USER_ABI_CALL0
279	help
280	  Select this option to support both windowed and call0 userspace
281	  ABIs. When enabled all processes are started with PS.WOE disabled
282	  and a fast user exception handler for an illegal instruction is
283	  used to turn on PS.WOE bit on the first 'entry' opcode executed by
284	  the userspace.
285
286	  This option should be enabled for the kernel that must support
287	  both call0 and windowed ABIs in userspace at the same time.
288
289	  Note that Xtensa ISA does not guarantee that entry opcode will
290	  raise an illegal instruction exception on cores with XEA2 when
291	  PS.WOE is disabled, check whether the target core supports it.
292
293endchoice
294
295endmenu
296
297config XTENSA_CALIBRATE_CCOUNT
298	def_bool n
299	help
300	  On some platforms (XT2000, for example), the CPU clock rate can
301	  vary.  The frequency can be determined, however, by measuring
302	  against a well known, fixed frequency, such as an UART oscillator.
303
304config SERIAL_CONSOLE
305	def_bool n
306
307config PLATFORM_HAVE_XIP
308	def_bool n
309
310menu "Platform options"
311
312choice
313	prompt "Xtensa System Type"
314	default XTENSA_PLATFORM_ISS
315
316config XTENSA_PLATFORM_ISS
317	bool "ISS"
318	select XTENSA_CALIBRATE_CCOUNT
319	select SERIAL_CONSOLE
320	help
321	  ISS is an acronym for Tensilica's Instruction Set Simulator.
322
323config XTENSA_PLATFORM_XT2000
324	bool "XT2000"
325	select HAVE_IDE
326	help
327	  XT2000 is the name of Tensilica's feature-rich emulation platform.
328	  This hardware is capable of running a full Linux distribution.
329
330config XTENSA_PLATFORM_XTFPGA
331	bool "XTFPGA"
332	select ETHOC if ETHERNET
333	select PLATFORM_WANT_DEFAULT_MEM if !MMU
334	select SERIAL_CONSOLE
335	select XTENSA_CALIBRATE_CCOUNT
336	select PLATFORM_HAVE_XIP
337	help
338	  XTFPGA is the name of Tensilica board family (LX60, LX110, LX200, ML605).
339	  This hardware is capable of running a full Linux distribution.
340
341endchoice
342
343config PLATFORM_NR_IRQS
344	int
345	default 3 if XTENSA_PLATFORM_XT2000
346	default 0
347
348config XTENSA_CPU_CLOCK
349	int "CPU clock rate [MHz]"
350	depends on !XTENSA_CALIBRATE_CCOUNT
351	default 16
352
353config GENERIC_CALIBRATE_DELAY
354	bool "Auto calibration of the BogoMIPS value"
355	help
356	  The BogoMIPS value can easily be derived from the CPU frequency.
357
358config CMDLINE_BOOL
359	bool "Default bootloader kernel arguments"
360
361config CMDLINE
362	string "Initial kernel command string"
363	depends on CMDLINE_BOOL
364	default "console=ttyS0,38400 root=/dev/ram"
365	help
366	  On some architectures (EBSA110 and CATS), there is currently no way
367	  for the boot loader to pass arguments to the kernel. For these
368	  architectures, you should supply some command-line options at build
369	  time by entering them here. As a minimum, you should specify the
370	  memory size and the root device (e.g., mem=64M root=/dev/nfs).
371
372config USE_OF
373	bool "Flattened Device Tree support"
374	select OF
375	select OF_EARLY_FLATTREE
376	help
377	  Include support for flattened device tree machine descriptions.
378
379config BUILTIN_DTB_SOURCE
380	string "DTB to build into the kernel image"
381	depends on OF
382
383config PARSE_BOOTPARAM
384	bool "Parse bootparam block"
385	default y
386	help
387	  Parse parameters passed to the kernel from the bootloader. It may
388	  be disabled if the kernel is known to run without the bootloader.
389
390	  If unsure, say Y.
391
392config BLK_DEV_SIMDISK
393	tristate "Host file-based simulated block device support"
394	default n
395	depends on XTENSA_PLATFORM_ISS && BLOCK
396	help
397	  Create block devices that map to files in the host file system.
398	  Device binding to host file may be changed at runtime via proc
399	  interface provided the device is not in use.
400
401config BLK_DEV_SIMDISK_COUNT
402	int "Number of host file-based simulated block devices"
403	range 1 10
404	depends on BLK_DEV_SIMDISK
405	default 2
406	help
407	  This is the default minimal number of created block devices.
408	  Kernel/module parameter 'simdisk_count' may be used to change this
409	  value at runtime. More file names (but no more than 10) may be
410	  specified as parameters, simdisk_count grows accordingly.
411
412config SIMDISK0_FILENAME
413	string "Host filename for the first simulated device"
414	depends on BLK_DEV_SIMDISK = y
415	default ""
416	help
417	  Attach a first simdisk to a host file. Conventionally, this file
418	  contains a root file system.
419
420config SIMDISK1_FILENAME
421	string "Host filename for the second simulated device"
422	depends on BLK_DEV_SIMDISK = y && BLK_DEV_SIMDISK_COUNT != 1
423	default ""
424	help
425	  Another simulated disk in a host file for a buildroot-independent
426	  storage.
427
428config XTFPGA_LCD
429	bool "Enable XTFPGA LCD driver"
430	depends on XTENSA_PLATFORM_XTFPGA
431	default n
432	help
433	  There's a 2x16 LCD on most of XTFPGA boards, kernel may output
434	  progress messages there during bootup/shutdown. It may be useful
435	  during board bringup.
436
437	  If unsure, say N.
438
439config XTFPGA_LCD_BASE_ADDR
440	hex "XTFPGA LCD base address"
441	depends on XTFPGA_LCD
442	default "0x0d0c0000"
443	help
444	  Base address of the LCD controller inside KIO region.
445	  Different boards from XTFPGA family have LCD controller at different
446	  addresses. Please consult prototyping user guide for your board for
447	  the correct address. Wrong address here may lead to hardware lockup.
448
449config XTFPGA_LCD_8BIT_ACCESS
450	bool "Use 8-bit access to XTFPGA LCD"
451	depends on XTFPGA_LCD
452	default n
453	help
454	  LCD may be connected with 4- or 8-bit interface, 8-bit access may
455	  only be used with 8-bit interface. Please consult prototyping user
456	  guide for your board for the correct interface width.
457
458comment "Kernel memory layout"
459
460config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
461	bool "Initialize Xtensa MMU inside the Linux kernel code"
462	depends on !XTENSA_VARIANT_FSF && !XTENSA_VARIANT_DC232B
463	default y if XTENSA_VARIANT_DC233C || XTENSA_VARIANT_CUSTOM
464	help
465	  Earlier version initialized the MMU in the exception vector
466	  before jumping to _startup in head.S and had an advantage that
467	  it was possible to place a software breakpoint at 'reset' and
468	  then enter your normal kernel breakpoints once the MMU was mapped
469	  to the kernel mappings (0XC0000000).
470
471	  This unfortunately won't work for U-Boot and likely also wont
472	  work for using KEXEC to have a hot kernel ready for doing a
473	  KDUMP.
474
475	  So now the MMU is initialized in head.S but it's necessary to
476	  use hardware breakpoints (gdb 'hbreak' cmd) to break at _startup.
477	  xt-gdb can't place a Software Breakpoint in the  0XD region prior
478	  to mapping the MMU and after mapping even if the area of low memory
479	  was mapped gdb wouldn't remove the breakpoint on hitting it as the
480	  PC wouldn't match. Since Hardware Breakpoints are recommended for
481	  Linux configurations it seems reasonable to just assume they exist
482	  and leave this older mechanism for unfortunate souls that choose
483	  not to follow Tensilica's recommendation.
484
485	  Selecting this will cause U-Boot to set the KERNEL Load and Entry
486	  address at 0x00003000 instead of the mapped std of 0xD0003000.
487
488	  If in doubt, say Y.
489
490config XIP_KERNEL
491	bool "Kernel Execute-In-Place from ROM"
492	depends on PLATFORM_HAVE_XIP
493	help
494	  Execute-In-Place allows the kernel to run from non-volatile storage
495	  directly addressable by the CPU, such as NOR flash. This saves RAM
496	  space since the text section of the kernel is not loaded from flash
497	  to RAM. Read-write sections, such as the data section and stack,
498	  are still copied to RAM. The XIP kernel is not compressed since
499	  it has to run directly from flash, so it will take more space to
500	  store it. The flash address used to link the kernel object files,
501	  and for storing it, is configuration dependent. Therefore, if you
502	  say Y here, you must know the proper physical address where to
503	  store the kernel image depending on your own flash memory usage.
504
505	  Also note that the make target becomes "make xipImage" rather than
506	  "make Image" or "make uImage". The final kernel binary to put in
507	  ROM memory will be arch/xtensa/boot/xipImage.
508
509	  If unsure, say N.
510
511config MEMMAP_CACHEATTR
512	hex "Cache attributes for the memory address space"
513	depends on !MMU
514	default 0x22222222
515	help
516	  These cache attributes are set up for noMMU systems. Each hex digit
517	  specifies cache attributes for the corresponding 512MB memory
518	  region: bits 0..3 -- for addresses 0x00000000..0x1fffffff,
519	  bits 4..7 -- for addresses 0x20000000..0x3fffffff, and so on.
520
521	  Cache attribute values are specific for the MMU type.
522	  For region protection MMUs:
523	    1: WT cached,
524	    2: cache bypass,
525	    4: WB cached,
526	    f: illegal.
527	  For full MMU:
528	    bit 0: executable,
529	    bit 1: writable,
530	    bits 2..3:
531	      0: cache bypass,
532	      1: WB cache,
533	      2: WT cache,
534	      3: special (c and e are illegal, f is reserved).
535	  For MPU:
536	    0: illegal,
537	    1: WB cache,
538	    2: WB, no-write-allocate cache,
539	    3: WT cache,
540	    4: cache bypass.
541
542config KSEG_PADDR
543	hex "Physical address of the KSEG mapping"
544	depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX && MMU
545	default 0x00000000
546	help
547	  This is the physical address where KSEG is mapped. Please refer to
548	  the chosen KSEG layout help for the required address alignment.
549	  Unpacked kernel image (including vectors) must be located completely
550	  within KSEG.
551	  Physical memory below this address is not available to linux.
552
553	  If unsure, leave the default value here.
554
555config KERNEL_VIRTUAL_ADDRESS
556	hex "Kernel virtual address"
557	depends on MMU && XIP_KERNEL
558	default 0xd0003000
559	help
560	  This is the virtual address where the XIP kernel is mapped.
561	  XIP kernel may be mapped into KSEG or KIO region, virtual address
562	  provided here must match kernel load address provided in
563	  KERNEL_LOAD_ADDRESS.
564
565config KERNEL_LOAD_ADDRESS
566	hex "Kernel load address"
567	default 0x60003000 if !MMU
568	default 0x00003000 if MMU && INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
569	default 0xd0003000 if MMU && !INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
570	help
571	  This is the address where the kernel is loaded.
572	  It is virtual address for MMUv2 configurations and physical address
573	  for all other configurations.
574
575	  If unsure, leave the default value here.
576
577choice
578	prompt "Relocatable vectors location"
579	default XTENSA_VECTORS_IN_TEXT
580	help
581	  Choose whether relocatable vectors are merged into the kernel .text
582	  or placed separately at runtime. This option does not affect
583	  configurations without VECBASE register where vectors are always
584	  placed at their hardware-defined locations.
585
586config XTENSA_VECTORS_IN_TEXT
587	bool "Merge relocatable vectors into kernel text"
588	depends on !MTD_XIP
589	help
590	  This option puts relocatable vectors into the kernel .text section
591	  with proper alignment.
592	  This is a safe choice for most configurations.
593
594config XTENSA_VECTORS_SEPARATE
595	bool "Put relocatable vectors at fixed address"
596	help
597	  This option puts relocatable vectors at specific virtual address.
598	  Vectors are merged with the .init data in the kernel image and
599	  are copied into their designated location during kernel startup.
600	  Use it to put vectors into IRAM or out of FLASH on kernels with
601	  XIP-aware MTD support.
602
603endchoice
604
605config VECTORS_ADDR
606	hex "Kernel vectors virtual address"
607	default 0x00000000
608	depends on XTENSA_VECTORS_SEPARATE
609	help
610	  This is the virtual address of the (relocatable) vectors base.
611	  It must be within KSEG if MMU is used.
612
613config XIP_DATA_ADDR
614	hex "XIP kernel data virtual address"
615	depends on XIP_KERNEL
616	default 0x00000000
617	help
618	  This is the virtual address where XIP kernel data is copied.
619	  It must be within KSEG if MMU is used.
620
621config PLATFORM_WANT_DEFAULT_MEM
622	def_bool n
623
624config DEFAULT_MEM_START
625	hex
626	prompt "PAGE_OFFSET/PHYS_OFFSET" if !MMU && PLATFORM_WANT_DEFAULT_MEM
627	default 0x60000000 if PLATFORM_WANT_DEFAULT_MEM
628	default 0x00000000
629	help
630	  This is the base address used for both PAGE_OFFSET and PHYS_OFFSET
631	  in noMMU configurations.
632
633	  If unsure, leave the default value here.
634
635choice
636	prompt "KSEG layout"
637	depends on MMU
638	default XTENSA_KSEG_MMU_V2
639
640config XTENSA_KSEG_MMU_V2
641	bool "MMUv2: 128MB cached + 128MB uncached"
642	help
643	  MMUv2 compatible kernel memory map: TLB way 5 maps 128MB starting
644	  at KSEG_PADDR to 0xd0000000 with cache and to 0xd8000000
645	  without cache.
646	  KSEG_PADDR must be aligned to 128MB.
647
648config XTENSA_KSEG_256M
649	bool "256MB cached + 256MB uncached"
650	depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
651	help
652	  TLB way 6 maps 256MB starting at KSEG_PADDR to 0xb0000000
653	  with cache and to 0xc0000000 without cache.
654	  KSEG_PADDR must be aligned to 256MB.
655
656config XTENSA_KSEG_512M
657	bool "512MB cached + 512MB uncached"
658	depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
659	help
660	  TLB way 6 maps 512MB starting at KSEG_PADDR to 0xa0000000
661	  with cache and to 0xc0000000 without cache.
662	  KSEG_PADDR must be aligned to 256MB.
663
664endchoice
665
666config HIGHMEM
667	bool "High Memory Support"
668	depends on MMU
669	help
670	  Linux can use the full amount of RAM in the system by
671	  default. However, the default MMUv2 setup only maps the
672	  lowermost 128 MB of memory linearly to the areas starting
673	  at 0xd0000000 (cached) and 0xd8000000 (uncached).
674	  When there are more than 128 MB memory in the system not
675	  all of it can be "permanently mapped" by the kernel.
676	  The physical memory that's not permanently mapped is called
677	  "high memory".
678
679	  If you are compiling a kernel which will never run on a
680	  machine with more than 128 MB total physical RAM, answer
681	  N here.
682
683	  If unsure, say Y.
684
685config FORCE_MAX_ZONEORDER
686	int "Maximum zone order"
687	default "11"
688	help
689	  The kernel memory allocator divides physically contiguous memory
690	  blocks into "zones", where each zone is a power of two number of
691	  pages.  This option selects the largest power of two that the kernel
692	  keeps in the memory allocator.  If you need to allocate very large
693	  blocks of physically contiguous memory, then you may need to
694	  increase this value.
695
696	  This config option is actually maximum order plus one. For example,
697	  a value of 11 means that the largest free memory block is 2^10 pages.
698
699endmenu
700
701menu "Power management options"
702
703source "kernel/power/Kconfig"
704
705endmenu
706