linux.git/arch/riscv/lib, branch v5.5

riscv: Less inefficient gcc tishift helpers (and export their symbols)

2020-01-19T03:13:41+00:00

The existing __lshrti3 was really inefficient, and the other two helpers
are also needed to compile some modules.

Add the missing versions, and export all of the symbols like arm64
already does.

This code is based on the assembly generated by libgcc builds.

This fixes a build break triggered by ubsan:

riscv64-unknown-linux-gnu-ld: lib/ubsan.o: in function `.L2':
ubsan.c:(.text.unlikely+0x38): undefined reference to `__ashlti3'
riscv64-unknown-linux-gnu-ld: ubsan.c:(.text.unlikely+0x42): undefined reference to `__ashrti3'

Signed-off-by: Olof Johansson 
[paul.walmsley@sifive.com: use SYM_FUNC_{START,END} instead of
 ENTRY/ENDPROC; note libgcc origin]
Signed-off-by: Paul Walmsley

riscv: fix compile failure with EXPORT_SYMBOL() & !MMU

2019-12-28T05:44:36+00:00

When support for !MMU was added, the declaration of
__asm_copy_to_user() & __asm_copy_from_user() were #ifdefed
out hence their EXPORT_SYMBOL() give an error message like:
  .../riscv_ksyms.c:13:15: error: '__asm_copy_to_user' undeclared here
  .../riscv_ksyms.c:14:15: error: '__asm_copy_from_user' undeclared here

Since these symbols are not defined with !MMU it's wrong to export them.
Same for __clear_user() (even though this one is also declared in
include/asm-generic/uaccess.h and thus doesn't give an error message).

Fix this by doing the EXPORT_SYMBOL() directly where these symbols
are defined: inside lib/uaccess.S itself.

Fixes: 6bd33e1ece52 ("riscv: fix compile failure with EXPORT_SYMBOL() & !MMU")
Reported-by: kbuild test robot 
Cc: Christoph Hellwig 
Cc: Palmer Dabbelt 
Cc: Paul Walmsley 
Signed-off-by: Luc Van Oostenryck 
Signed-off-by: Paul Walmsley

riscv: add nommu support

2019-11-17T23:17:39+00:00

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 .

Signed-off-by: Christoph Hellwig 
Reviewed-by: Anup Patel 
[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

riscv: abstract out CSR names for supervisor vs machine mode

2019-11-05T17:20:42+00:00

Many of the privileged CSRs exist in a supervisor and machine version
that are used very similarly.  Provide versions of the CSR names and
fields that map to either the S-mode or M-mode variant depending on
a new CONFIG_RISCV_M_MODE kconfig symbol.

Contains contributions from Damien Le Moal 
and Paul Walmsley .

Signed-off-by: Christoph Hellwig 
Acked-by: Thomas Gleixner  # for drivers/clocksource, drivers/irqchip
[paul.walmsley@sifive.com: updated to apply]
Signed-off-by: Paul Walmsley

riscv: Using CSR numbers to access CSRs

2019-08-30T18:04:19+00:00

Since commit a3182c91ef4e ("RISC-V: Access CSRs using CSR numbers"),
we should prefer accessing CSRs using their CSR numbers, but there
are several leftovers like sstatus / sptbr we missed.

Signed-off-by: Bin Meng 
Reviewed-by: Anup Patel 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Paul Walmsley

RISC-V: Remove udivdi3

2019-08-08T23:05:38+00:00

This should never have landed in the first place: it was added as part
of 64-bit divide support for 32-bit systems, but the kernel doesn't
allow this sort of division.  I must have forgotten to remove it.

This patch removes the support.  Since this routine only worked on
64-bit platforms but was only built on 32-bit platforms, it's
essentially just nonsense anyway.

Signed-off-by: Palmer Dabbelt 
Acked-by: Nicolas Pitre 
Link: https://lore.kernel.org/linux-riscv/nycvar.YSQ.7.76.1908061413360.19480@knanqh.ubzr/T/#t
Reported-by: Eric Lin 
Signed-off-by: Paul Walmsley

riscv: delay: use do_div() instead of __udivdi3()

2019-08-08T23:05:38+00:00

In preparation for removing __udivdi3() from the RISC-V
architecture-specific files, convert its one user to use do_div().
This avoids breaking the RV32 build after __udivdi3() is removed.

This second version removes the assignment of the remainder to an
unused temporary variable.  Thanks to Nicolas Pitre 
for the suggestion.

Signed-off-by: Paul Walmsley 
Cc: Nicolas Pitre

Merge tag 'riscv-for-v5.2/fixes-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

2019-06-17T17:34:03+00:00

Pull RISC-V fixes from Paul Walmsley:
 "This contains fixes, defconfig, and DT data changes for the v5.2-rc
  series.

  The fixes are relatively straightforward:

   - Addition of a TLB fence in the vmalloc_fault path, so the CPU
     doesn't enter an infinite page fault loop

   - Readdition of the pm_power_off export, so device drivers that
     reassign it can now be built as modules

   - A udelay() fix for RV32, fixing a miscomputation of the delay time

   - Removal of deprecated smp_mb__*() barriers

  This also adds initial DT data infrastructure for arch/riscv, along
  with initial data for the SiFive FU540-C000 SoC and the corresponding
  HiFive Unleashed board.

  We also update the RV64 defconfig to include some core drivers for the
  FU540 in the build"

* tag 'riscv-for-v5.2/fixes-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
  riscv: remove unused barrier defines
  riscv: mm: synchronize MMU after pte change
  riscv: dts: add initial board data for the SiFive HiFive Unleashed
  riscv: dts: add initial support for the SiFive FU540-C000 SoC
  dt-bindings: riscv: convert cpu binding to json-schema
  dt-bindings: riscv: sifive: add YAML documentation for the SiFive FU540
  arch: riscv: add support for building DTB files from DT source data
  riscv: Fix udelay in RV32.
  riscv: export pm_power_off again
  RISC-V: defconfig: enable clocks, serial console

riscv: Fix udelay in RV32.

2019-06-11T15:04:26+00:00

In RV32, udelay would delay the wrong cycle. When it shifts right
"UDELAY_SHIFT" bits, it either delays 0 cycle or 1 cycle. It only works
correctly in RV64. Because the 'ucycles' always needs to be 64 bits
variable.

Signed-off-by: Nick Hu 
Reviewed-by: Palmer Dabbelt 
[paul.walmsley@sifive.com: fixed minor spelling error]
Signed-off-by: Paul Walmsley

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 286

2019-06-05T15:36:37+00:00

Based on 1 normalized pattern(s):

  this program is free software you can redistribute it and or modify
  it under the terms of the gnu general public license as published by
  the free software foundation version 2 this program is distributed
  in the hope that it will be useful but without any warranty without
  even the implied warranty of merchantability or fitness for a
  particular purpose see the gnu general public license for more
  details

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 97 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Allison Randal 
Reviewed-by: Alexios Zavras 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.025053186@linutronix.de
Signed-off-by: Greg Kroah-Hartman