diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-08 00:27:53 +0300 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2019-03-08 00:27:53 +0300 |
commit | dd1c3ed76f26504621b5ce08b894666aafa38e47 (patch) | |
tree | f879aefbbd7871733bc616cb7f73dd5ffca53f44 /Documentation | |
parent | 6c3ac1134371b51c9601171af2c32153ccb11100 (diff) | |
parent | 60deebe6149a3f02fa6a9fa988dda500effda43f (diff) | |
download | linux-dd1c3ed76f26504621b5ce08b894666aafa38e47.tar.xz |
Merge tag 'xtensa-20190307' of git://github.com/jcmvbkbc/linux-xtensa
Pull xtensa updates from Max Filippov:
- use generic spinlock/rwlock implementations
- clean up IPI processing
- document boot parameters passing to the kernel
- fix get_wchan
- various cleanups in time.c, process.c, traps.c and thread_info.h
* tag 'xtensa-20190307' of git://github.com/jcmvbkbc/linux-xtensa:
xtensa: simplify trap_init
xtensa: drop unused definitions
xtensa: fix get_wchan
xtensa: use generic spinlock/rwlock implementation
xtensa: provide xchg for sizes 1 and 2
xtensa: clean up arch/xtensa/kernel/time.c
xtensa: SMP: rework IPI processing
xtensa: document boot parameter passing
Diffstat (limited to 'Documentation')
-rw-r--r-- | Documentation/xtensa/booting.txt | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/xtensa/booting.txt b/Documentation/xtensa/booting.txt new file mode 100644 index 000000000000..402b33a2619f --- /dev/null +++ b/Documentation/xtensa/booting.txt @@ -0,0 +1,19 @@ +Passing boot parameters to the kernel. + +Boot parameters are represented as a TLV list in the memory. Please see +arch/xtensa/include/asm/bootparam.h for definition of the bp_tag structure and +tag value constants. First entry in the list must have type BP_TAG_FIRST, last +entry must have type BP_TAG_LAST. The address of the first list entry is +passed to the kernel in the register a2. The address type depends on MMU type: +- For configurations without MMU, with region protection or with MPU the + address must be the physical address. +- For configurations with region translarion MMU or with MMUv3 and CONFIG_MMU=n + the address must be a valid address in the current mapping. The kernel will + not change the mapping on its own. +- For configurations with MMUv2 the address must be a virtual address in the + default virtual mapping (0xd0000000..0xffffffff). +- For configurations with MMUv3 and CONFIG_MMU=y the address may be either a + virtual or physical address. In either case it must be within the default + virtual mapping. It is considered physical if it is within the range of + physical addresses covered by the default KSEG mapping (XCHAL_KSEG_PADDR.. + XCHAL_KSEG_PADDR + XCHAL_KSEG_SIZE), otherwise it is considered virtual. |