Commit Graph

3 Commits

Author SHA1 Message Date
Linus Torvalds a308a71022 generic ioremap support
- clean up various obsolete ioremap and iounmap variants
  - add a new generic ioremap implementation and switch csky, nds32 and
    riscv over to it
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Merge tag 'ioremap-5.5' of git://git.infradead.org/users/hch/ioremap

Pull generic ioremap support from Christoph Hellwig:
 "This adds the remaining bits for an entirely generic ioremap and
  iounmap to lib/ioremap.c. To facilitate that, it cleans up the giant
  mess of weird ioremap variants we had with no users outside the arch
  code.

  For now just the three newest ports use the code, but there is more
  than a handful others that can be converted without too much work.

  Summary:

   - clean up various obsolete ioremap and iounmap variants

   - add a new generic ioremap implementation and switch csky, nds32 and
     riscv over to it"

* tag 'ioremap-5.5' of git://git.infradead.org/users/hch/ioremap: (21 commits)
  nds32: use generic ioremap
  csky: use generic ioremap
  csky: remove ioremap_cache
  riscv: use the generic ioremap code
  lib: provide a simple generic ioremap implementation
  sh: remove __iounmap
  nios2: remove __iounmap
  hexagon: remove __iounmap
  m68k: rename __iounmap and mark it static
  arch: rely on asm-generic/io.h for default ioremap_* definitions
  asm-generic: don't provide ioremap for CONFIG_MMU
  asm-generic: ioremap_uc should behave the same with and without MMU
  xtensa: clean up ioremap
  x86: Clean up ioremap()
  parisc: remove __ioremap
  nios2: remove __ioremap
  alpha: remove the unused __ioremap wrapper
  hexagon: clean up ioremap
  ia64: rename ioremap_nocache to ioremap_uc
  unicore32: remove ioremap_cached
  ...
2019-11-28 10:57:12 -08:00
Christoph Hellwig 6bd33e1ece riscv: add nommu support
The kernel runs in M-mode without using page tables, and thus can't run
bare metal without help from additional firmware.

Most of the patch is just stubbing out code not needed without page
tables, but there is an interesting detail in the signals implementation:

 - The normal RISC-V syscall ABI only implements rt_sigreturn as VDSO
   entry point, but the ELF VDSO is not supported for nommu Linux.
   We instead copy the code to call the syscall onto the stack.

In addition to enabling the nommu code a new defconfig for a small
kernel image that can run in nommu mode on qemu is also provided, to run
a kernel in qemu you can use the following command line:

qemu-system-riscv64 -smp 2 -m 64 -machine virt -nographic \
	-kernel arch/riscv/boot/loader \
	-drive file=rootfs.ext2,format=raw,id=hd0 \
	-device virtio-blk-device,drive=hd0

Contains contributions from Damien Le Moal <Damien.LeMoal@wdc.com>.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Anup Patel <anup@brainfault.org>
[paul.walmsley@sifive.com: updated to apply; add CONFIG_MMU guards
 around PCI_IOBASE definition to fix build issues; fixed checkpatch
 issues; move the PCI_IO_* and VMEMMAP address space macros along
 with the others; resolve sparse warning]
Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-17 15:17:39 -08:00
Paul Walmsley 0c3ac28931 riscv: separate MMIO functions into their own header file
Separate the low-level MMIO static inline functions and macros, such
as {read,write}{b,w,l,q}(), into their own header file under
arch/riscv/include: asm/mmio.h.  This is done to break a header
dependency chain that arises when both asm/pgtable.h and asm/io.h are
included by asm/timex.h.  Since the problem is related to the legacy
I/O port support in asm/io.h, this allows files under arch/riscv that
encounter those issues to simply include asm/mmio.h instead, and
bypass the legacy I/O port functions.  Existing users of asm/io.h
don't need to change anything, since asm/mmio.h is included by
asm/io.h.

While here, clean up some checkpatch.pl-related issues with the
original code.

Signed-off-by: Paul Walmsley <paul.walmsley@sifive.com>
2019-11-05 09:11:18 -08:00