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xtensa: move kernel memory layout to platform options

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Currently kernel memory layout settings are split between "Processor
type and features" and "Platform options" menus. Consolidate them under
"Platform options".

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
This commit is contained in:
Max Filippov 2019-10-01 00:25:30 -07:00
parent 123b8db839
commit 76743c0e09
1 changed files with 175 additions and 173 deletions
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348
arch/xtensa/Kconfig
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@ -213,151 +213,6 @@ config HOTPLUG_CPU
Say N if you want to disable CPU hotplug.
config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
bool "Initialize Xtensa MMU inside the Linux kernel code"
depends on !XTENSA_VARIANT_FSF && !XTENSA_VARIANT_DC232B
default y if XTENSA_VARIANT_DC233C || XTENSA_VARIANT_CUSTOM
help
Earlier version initialized the MMU in the exception vector
before jumping to _startup in head.S and had an advantage that
it was possible to place a software breakpoint at 'reset' and
then enter your normal kernel breakpoints once the MMU was mapped
to the kernel mappings (0XC0000000).
This unfortunately won't work for U-Boot and likely also wont
work for using KEXEC to have a hot kernel ready for doing a
KDUMP.
So now the MMU is initialized in head.S but it's necessary to
use hardware breakpoints (gdb 'hbreak' cmd) to break at _startup.
xt-gdb can't place a Software Breakpoint in the 0XD region prior
to mapping the MMU and after mapping even if the area of low memory
was mapped gdb wouldn't remove the breakpoint on hitting it as the
PC wouldn't match. Since Hardware Breakpoints are recommended for
Linux configurations it seems reasonable to just assume they exist
and leave this older mechanism for unfortunate souls that choose
not to follow Tensilica's recommendation.
Selecting this will cause U-Boot to set the KERNEL Load and Entry
address at 0x00003000 instead of the mapped std of 0xD0003000.
If in doubt, say Y.
config MEMMAP_CACHEATTR
hex "Cache attributes for the memory address space"
depends on !MMU
default 0x22222222
help
These cache attributes are set up for noMMU systems. Each hex digit
specifies cache attributes for the corresponding 512MB memory
region: bits 0..3 -- for addresses 0x00000000..0x1fffffff,
bits 4..7 -- for addresses 0x20000000..0x3fffffff, and so on.
Cache attribute values are specific for the MMU type.
For region protection MMUs:
1: WT cached,
2: cache bypass,
4: WB cached,
f: illegal.
For ful MMU:
bit 0: executable,
bit 1: writable,
bits 2..3:
0: cache bypass,
1: WB cache,
2: WT cache,
3: special (c and e are illegal, f is reserved).
For MPU:
0: illegal,
1: WB cache,
2: WB, no-write-allocate cache,
3: WT cache,
4: cache bypass.
config KSEG_PADDR
hex "Physical address of the KSEG mapping"
depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX && MMU
default 0x00000000
help
This is the physical address where KSEG is mapped. Please refer to
the chosen KSEG layout help for the required address alignment.
Unpacked kernel image (including vectors) must be located completely
within KSEG.
Physical memory below this address is not available to linux.
If unsure, leave the default value here.
config KERNEL_LOAD_ADDRESS
hex "Kernel load address"
default 0x60003000 if !MMU
default 0x00003000 if MMU && INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
default 0xd0003000 if MMU && !INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
help
This is the address where the kernel is loaded.
It is virtual address for MMUv2 configurations and physical address
for all other configurations.
If unsure, leave the default value here.
config VECTORS_OFFSET
hex "Kernel vectors offset"
default 0x00003000
help
This is the offset of the kernel image from the relocatable vectors
base.
If unsure, leave the default value here.
choice
prompt "KSEG layout"
depends on MMU
default XTENSA_KSEG_MMU_V2
config XTENSA_KSEG_MMU_V2
bool "MMUv2: 128MB cached + 128MB uncached"
help
MMUv2 compatible kernel memory map: TLB way 5 maps 128MB starting
at KSEG_PADDR to 0xd0000000 with cache and to 0xd8000000
without cache.
KSEG_PADDR must be aligned to 128MB.
config XTENSA_KSEG_256M
bool "256MB cached + 256MB uncached"
depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
help
TLB way 6 maps 256MB starting at KSEG_PADDR to 0xb0000000
with cache and to 0xc0000000 without cache.
KSEG_PADDR must be aligned to 256MB.
config XTENSA_KSEG_512M
bool "512MB cached + 512MB uncached"
depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
help
TLB way 6 maps 512MB starting at KSEG_PADDR to 0xa0000000
with cache and to 0xc0000000 without cache.
KSEG_PADDR must be aligned to 256MB.
endchoice
config HIGHMEM
bool "High Memory Support"
depends on MMU
help
Linux can use the full amount of RAM in the system by
default. However, the default MMUv2 setup only maps the
lowermost 128 MB of memory linearly to the areas starting
at 0xd0000000 (cached) and 0xd8000000 (uncached).
When there are more than 128 MB memory in the system not
all of it can be "permanently mapped" by the kernel.
The physical memory that's not permanently mapped is called
"high memory".
If you are compiling a kernel which will never run on a
machine with more than 128 MB total physical RAM, answer
N here.
If unsure, say Y.
config FAST_SYSCALL_XTENSA
bool "Enable fast atomic syscalls"
default n
@ -561,34 +416,6 @@ config SIMDISK1_FILENAME
Another simulated disk in a host file for a buildroot-independent
storage.
config FORCE_MAX_ZONEORDER
int "Maximum zone order"
default "11"
help
The kernel memory allocator divides physically contiguous memory
blocks into "zones", where each zone is a power of two number of
pages. This option selects the largest power of two that the kernel
keeps in the memory allocator. If you need to allocate very large
blocks of physically contiguous memory, then you may need to
increase this value.
This config option is actually maximum order plus one. For example,
a value of 11 means that the largest free memory block is 2^10 pages.
config PLATFORM_WANT_DEFAULT_MEM
def_bool n
config DEFAULT_MEM_START
hex
prompt "PAGE_OFFSET/PHYS_OFFSET" if !MMU && PLATFORM_WANT_DEFAULT_MEM
default 0x60000000 if PLATFORM_WANT_DEFAULT_MEM
default 0x00000000
help
This is the base address used for both PAGE_OFFSET and PHYS_OFFSET
in noMMU configurations.
If unsure, leave the default value here.
config XTFPGA_LCD
bool "Enable XTFPGA LCD driver"
depends on XTENSA_PLATFORM_XTFPGA
@ -619,6 +446,181 @@ config XTFPGA_LCD_8BIT_ACCESS
only be used with 8-bit interface. Please consult prototyping user
guide for your board for the correct interface width.
comment "Kernel memory layout"
config INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
bool "Initialize Xtensa MMU inside the Linux kernel code"
depends on !XTENSA_VARIANT_FSF && !XTENSA_VARIANT_DC232B
default y if XTENSA_VARIANT_DC233C || XTENSA_VARIANT_CUSTOM
help
Earlier version initialized the MMU in the exception vector
before jumping to _startup in head.S and had an advantage that
it was possible to place a software breakpoint at 'reset' and
then enter your normal kernel breakpoints once the MMU was mapped
to the kernel mappings (0XC0000000).
This unfortunately won't work for U-Boot and likely also wont
work for using KEXEC to have a hot kernel ready for doing a
KDUMP.
So now the MMU is initialized in head.S but it's necessary to
use hardware breakpoints (gdb 'hbreak' cmd) to break at _startup.
xt-gdb can't place a Software Breakpoint in the 0XD region prior
to mapping the MMU and after mapping even if the area of low memory
was mapped gdb wouldn't remove the breakpoint on hitting it as the
PC wouldn't match. Since Hardware Breakpoints are recommended for
Linux configurations it seems reasonable to just assume they exist
and leave this older mechanism for unfortunate souls that choose
not to follow Tensilica's recommendation.
Selecting this will cause U-Boot to set the KERNEL Load and Entry
address at 0x00003000 instead of the mapped std of 0xD0003000.
If in doubt, say Y.
config MEMMAP_CACHEATTR
hex "Cache attributes for the memory address space"
depends on !MMU
default 0x22222222
help
These cache attributes are set up for noMMU systems. Each hex digit
specifies cache attributes for the corresponding 512MB memory
region: bits 0..3 -- for addresses 0x00000000..0x1fffffff,
bits 4..7 -- for addresses 0x20000000..0x3fffffff, and so on.
Cache attribute values are specific for the MMU type.
For region protection MMUs:
1: WT cached,
2: cache bypass,
4: WB cached,
f: illegal.
For ful MMU:
bit 0: executable,
bit 1: writable,
bits 2..3:
0: cache bypass,
1: WB cache,
2: WT cache,
3: special (c and e are illegal, f is reserved).
For MPU:
0: illegal,
1: WB cache,
2: WB, no-write-allocate cache,
3: WT cache,
4: cache bypass.
config KSEG_PADDR
hex "Physical address of the KSEG mapping"
depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX && MMU
default 0x00000000
help
This is the physical address where KSEG is mapped. Please refer to
the chosen KSEG layout help for the required address alignment.
Unpacked kernel image (including vectors) must be located completely
within KSEG.
Physical memory below this address is not available to linux.
If unsure, leave the default value here.
config KERNEL_LOAD_ADDRESS
hex "Kernel load address"
default 0x60003000 if !MMU
default 0x00003000 if MMU && INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
default 0xd0003000 if MMU && !INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
help
This is the address where the kernel is loaded.
It is virtual address for MMUv2 configurations and physical address
for all other configurations.
If unsure, leave the default value here.
config VECTORS_OFFSET
hex "Kernel vectors offset"
default 0x00003000
help
This is the offset of the kernel image from the relocatable vectors
base.
If unsure, leave the default value here.
config PLATFORM_WANT_DEFAULT_MEM
def_bool n
config DEFAULT_MEM_START
hex
prompt "PAGE_OFFSET/PHYS_OFFSET" if !MMU && PLATFORM_WANT_DEFAULT_MEM
default 0x60000000 if PLATFORM_WANT_DEFAULT_MEM
default 0x00000000
help
This is the base address used for both PAGE_OFFSET and PHYS_OFFSET
in noMMU configurations.
If unsure, leave the default value here.
choice
prompt "KSEG layout"
depends on MMU
default XTENSA_KSEG_MMU_V2
config XTENSA_KSEG_MMU_V2
bool "MMUv2: 128MB cached + 128MB uncached"
help
MMUv2 compatible kernel memory map: TLB way 5 maps 128MB starting
at KSEG_PADDR to 0xd0000000 with cache and to 0xd8000000
without cache.
KSEG_PADDR must be aligned to 128MB.
config XTENSA_KSEG_256M
bool "256MB cached + 256MB uncached"
depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
help
TLB way 6 maps 256MB starting at KSEG_PADDR to 0xb0000000
with cache and to 0xc0000000 without cache.
KSEG_PADDR must be aligned to 256MB.
config XTENSA_KSEG_512M
bool "512MB cached + 512MB uncached"
depends on INITIALIZE_XTENSA_MMU_INSIDE_VMLINUX
help
TLB way 6 maps 512MB starting at KSEG_PADDR to 0xa0000000
with cache and to 0xc0000000 without cache.
KSEG_PADDR must be aligned to 256MB.
endchoice
config HIGHMEM
bool "High Memory Support"
depends on MMU
help
Linux can use the full amount of RAM in the system by
default. However, the default MMUv2 setup only maps the
lowermost 128 MB of memory linearly to the areas starting
at 0xd0000000 (cached) and 0xd8000000 (uncached).
When there are more than 128 MB memory in the system not
all of it can be "permanently mapped" by the kernel.
The physical memory that's not permanently mapped is called
"high memory".
If you are compiling a kernel which will never run on a
machine with more than 128 MB total physical RAM, answer
N here.
If unsure, say Y.
config FORCE_MAX_ZONEORDER
int "Maximum zone order"
default "11"
help
The kernel memory allocator divides physically contiguous memory
blocks into "zones", where each zone is a power of two number of
pages. This option selects the largest power of two that the kernel
keeps in the memory allocator. If you need to allocate very large
blocks of physically contiguous memory, then you may need to
increase this value.
This config option is actually maximum order plus one. For example,
a value of 11 means that the largest free memory block is 2^10 pages.
endmenu
menu "Power management options"