linux.git/arch/riscv/kernel/setup.c, branch v5.4.158

riscv: add prototypes for assembly language functions from head.S

2019-10-28T07:46:00+00:00

Add prototypes for assembly language functions defined in head.S,
and include these prototypes into C source files that call those
functions.

This patch resolves the following warnings from sparse:

arch/riscv/kernel/setup.c:39:10: warning: symbol 'hart_lottery' was not declared. Should it be static?
arch/riscv/kernel/setup.c:42:13: warning: symbol 'parse_dtb' was not declared. Should it be static?
arch/riscv/kernel/smpboot.c:33:6: warning: symbol '__cpu_up_stack_pointer' was not declared. Should it be static?
arch/riscv/kernel/smpboot.c:34:6: warning: symbol '__cpu_up_task_pointer' was not declared. Should it be static?
arch/riscv/mm/fault.c:25:17: warning: symbol 'do_page_fault' was not declared. Should it be static?

This change should have no functional impact.

Signed-off-by: Paul Walmsley

RISC-V: Setup initial page tables in two stages

2019-07-09T16:08:04+00:00

Currently, the setup_vm() does initial page table setup in one-shot
very early before enabling MMU. Due to this, the setup_vm() has to map
all possible kernel virtual addresses since it does not know size and
location of RAM. This means we have kernel mappings for non-existent
RAM and any buggy driver (or kernel) code doing out-of-bound access
to RAM will not fault and cause underterministic behaviour.

Further, the setup_vm() creates PMD mappings (i.e. 2M mappings) for
RV64 systems. This means for PAGE_OFFSET=0xffffffe000000000 (i.e.
MAXPHYSMEM_128GB=y), the setup_vm() will require 129 pages (i.e.
516 KB) of memory for initial page tables which is never freed. The
memory required for initial page tables will further increase if
we chose a lower value of PAGE_OFFSET (e.g. 0xffffff0000000000)

This patch implements two-staged initial page table setup, as follows:
1. Early (i.e. setup_vm()): This stage maps kernel image and DTB in
a early page table (i.e. early_pg_dir). The early_pg_dir will be used
only by boot HART so it can be freed as-part of init memory free-up.
2. Final (i.e. setup_vm_final()): This stage maps all possible RAM
banks in the final page table (i.e. swapper_pg_dir). The boot HART
will start using swapper_pg_dir at the end of setup_vm_final(). All
non-boot HARTs directly use the swapper_pg_dir created by boot HART.

We have following advantages with this new approach:
1. Kernel mappings for non-existent RAM don't exists anymore.
2. Memory consumed by initial page tables is now indpendent of the
chosen PAGE_OFFSET.
3. Memory consumed by initial page tables on RV64 system is 2 pages
(i.e. 8 KB) which has significantly reduced and these pages will be
freed as-part of the init memory free-up.

The patch also provides a foundation for implementing strict kernel
mappings where we protect kernel text and rodata using PTE permissions.

Suggested-by: Mike Rapoport 
Signed-off-by: Anup Patel 
[paul.walmsley@sifive.com: updated to apply; fixed a checkpatch warning]
Signed-off-by: Paul Walmsley

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 120

2019-05-24T15:39:02+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 either version 2 of the license or at
  your option any later version 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 you
  should have received a copy of the gnu general public license along
  with this program if not see the file copying or write to the free
  software foundation inc

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 12 file(s).

Signed-off-by: Thomas Gleixner 
Reviewed-by: Richard Fontana 
Reviewed-by: Allison Randal 
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190523091651.231300438@linutronix.de
Signed-off-by: Greg Kroah-Hartman

riscv: cleanup the parse_dtb calling conventions

2019-04-25T21:51:11+00:00

No need to pass the hartid, and the dtb address passed is a physical
address, so don't pretend it is a kernel pointer.

Signed-off-by: Christoph Hellwig 
Signed-off-by: Palmer Dabbelt

RISC-V: Always compile mm/init.c with cmodel=medany and notrace

2019-03-27T01:25:06+00:00

The Linux RISC-V 32bit kernel is broken after we moved setup_vm() from
kernel/setup.c to mm/init.c because Linux RISC-V 32bit kernel by default
uses cmodel=medlow which results in a non-position-independent setup_vm().

This patch fixes Linux RISC-V 32bit kernel booting by:
1. Forcing cmodel=medany for mm/init.c
2. Moving remaing MM-related stuff va_pa_offset, pfn_base and
   empty_zero_page from kernel/setup.c to mm/init.c

Further, the setup_vm() cannot handle GCC instrumentation for FTRACE so
we disable it for mm/init.c by not using "-pg" compiler flag.

Fixes: 6f1e9e946f0b ("RISC-V: Move setup_vm() to mm/init.c")
Suggested-by: Christoph Hellwig 
Suggested-by: Mike Rapoport 
Signed-off-by: Anup Patel 
Reviewed-by: Mike Rapoport 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Palmer Dabbelt

RISC-V: Fixmap support and MM cleanups

2019-03-04T19:47:04+00:00

This patchset does:
1. Moves MM related code from kernel/setup.c to mm/init.c
2. Implements compile-time fixed mappings

Using fixed mappings, we get earlyprints even without SBI calls.

For example, we can now use kernel parameter
"earlycon=uart8250,mmio,0x10000000"
to get early prints on QEMU virt machine without using SBI calls.

The patchset is tested on QEMU virt machine.

Palmer: It looks like some of the code movement here conflicted with the
patches to move hartid handling around.  As far as I can tell the only
changed code was in smp_setup_processor_id(), and I've kept the one in
smp.c.

arch: riscv: fix logic error in parse_dtb

2019-03-04T19:32:14+00:00

The function early_init_dt_scan returns true if a DTB was detected.

Fixes: 8fd6e05c7463 ("arch: riscv: support kernel command line forcing when no DTB passed")
Signed-off-by: Andreas Schwab 
Reviewed-by: Atish Patra 
Reviewed-by: Paul Walmsley 
Tested-by: Paul Walmsley  # FU540 HiFive-U BBL
Signed-off-by: Palmer Dabbelt

RISC-V: Move cpuid to hartid mapping to SMP.

2019-03-04T18:40:38+00:00

Currently, logical CPU id to physical hartid mapping is defined for both
smp and non-smp configurations. This is not required as we need this
only for smp configuration.  The mapping function can define directly
boot_cpu_hartid for non-smp use case.

The reverse mapping function i.e. hartid to cpuid can be called for any
valid but not booted harts. So it should return default cpu 0 only if it
is a boot hartid.

Signed-off-by: Atish Patra 
Reviewed-by: Anup Patel 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Palmer Dabbelt

RISC-V: Move setup_vm() to mm/init.c

2019-02-21T05:56:31+00:00

The setup_vm() is responsible for setting up initial page table hence
should be placed in mm/init.c.

Signed-off-by: Anup Patel 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Palmer Dabbelt

RISC-V: Move setup_bootmem() to mm/init.c

2019-02-21T05:55:49+00:00

The setup_bootmem() mainly populates memblocks and does early memory
reservations. The right location for this function is mm/init.c. It
calls setup_initrd() so we move that as well.

Signed-off-by: Anup Patel 
Reviewed-by: Christoph Hellwig 
Reviewed-by: Palmer Dabbelt 
Reviewed-by: Mike Rapoport