Every in-kernel use of this function defined it to KERNEL_DS (either as
an actual define, or as an inline function). It's an entirely
historical artifact, and long long long ago used to actually read the
segment selector valueof '%ds' on x86.
Which in the kernel is always KERNEL_DS.
Inspired by a patch from Jann Horn that just did this for a very small
subset of users (the ones in fs/), along with Al who suggested a script.
I then just took it to the logical extreme and removed all the remaining
gunk.
Roughly scripted with
git grep -l '(get_ds())' -- :^tools/ | xargs sed -i 's/(get_ds())/(KERNEL_DS)/'
git grep -lw 'get_ds' -- :^tools/ | xargs sed -i '/^#define get_ds()/d'
plus manual fixups to remove a few unusual usage patterns, the couple of
inline function cases and to fix up a comment that had become stale.
The 'get_ds()' function remains in an x86 kvm selftest, since in user
space it actually does something relevant.
Inspired-by: Jann Horn <jannh@google.com>
Inspired-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch adds files related to memory management and here is our
memory-layout:
Fixmap : 0xffc02000 – 0xfffff000 (4 MB - 12KB)
Pkmap : 0xff800000 – 0xffc00000 (4 MB)
Vmalloc : 0xf0200000 – 0xff000000 (238 MB)
Lowmem : 0x80000000 – 0xc0000000 (1GB)
abiv1 CPU (CK610) is VIPT cache and it doesn't support highmem.
abiv2 CPUs are all PIPT cache and they could support highmem.
Lowmem is directly mapped by msa0 & msa1 reg, and we needn't setup
memory page table for it.
Link:https://lore.kernel.org/lkml/20180518215548.GH17671@n2100.armlinux.org.uk/
Signed-off-by: Guo Ren <ren_guo@c-sky.com>
Cc: Christoph Hellwig <hch@infradead.org>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
