Alexandre Ghiti bbf94b0421 riscv: Move early dtb mapping into the fixmap region ...

commit ef69d2559fe91f23d27a3d6fd640b5641787d22e upstream.

riscv establishes 2 virtual mappings:

- early_pg_dir maps the kernel which allows to discover the system
  memory
- swapper_pg_dir installs the final mapping (linear mapping included)

We used to map the dtb in early_pg_dir using DTB_EARLY_BASE_VA, and this
mapping was not carried over in swapper_pg_dir. It happens that
early_init_fdt_scan_reserved_mem() must be called before swapper_pg_dir is
setup otherwise we could allocate reserved memory defined in the dtb.
And this function initializes reserved_mem variable with addresses that
lie in the early_pg_dir dtb mapping: when those addresses are reused
with swapper_pg_dir, this mapping does not exist and then we trap.

The previous "fix" was incorrect as early_init_fdt_scan_reserved_mem()
must be called before swapper_pg_dir is set up otherwise we could
allocate in reserved memory defined in the dtb.

So move the dtb mapping in the fixmap region which is established in
early_pg_dir and handed over to swapper_pg_dir.

This patch had to be backported because:
- the documentation for sv57 is not present here (as sv48/57 are not
  present)
- handling of sv48/57 is not needed (as not present)

Fixes: 922b0375fc93 ("riscv: Fix memblock reservation for device tree blob")
Fixes: 8f3a2b4a96dc ("RISC-V: Move DT mapping outof fixmap")
Fixes: 50e63dd8ed92 ("riscv: fix reserved memory setup")
Reported-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/all/f8e67f82-103d-156c-deb0-d6d6e2756f5e@microchip.com/
Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Reviewed-by: Conor Dooley <conor.dooley@microchip.com>
Tested-by: Conor Dooley <conor.dooley@microchip.com>
Link: https://lore.kernel.org/r/20230329081932.79831-2-alexghiti@rivosinc.com
Cc: stable@vger.kernel.org # 5.15.x
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

2023-05-01 08:23:24 +09:00

..

boot-image-header.rst

RISC-V: Typo fixes in image header and documentation.

2019-12-19 09:32:45 -07:00

features.rst

docs: archis: add a per-architecture features list

2020-12-03 15:10:15 -07:00

index.rst

Documentation: riscv: Add documentation that describes the VM layout

2021-04-26 08:25:05 -07:00

patch-acceptance.rst

Documentation: riscv: add patch acceptance guidelines

2020-01-04 21:49:01 -08:00

pmu.rst

docs: riscv: convert docs to ReST and rename to *.rst

2019-06-14 14:31:32 -06:00

vm-layout.rst

riscv: Move early dtb mapping into the fixmap region

2023-05-01 08:23:24 +09:00