[RFC PATCH v2 0/7] Extend the reserved PMP entries

[Yu-Chien Peter Lin]

This series extends the number of reserved PMP entry.
The capabilities of the reserved PMP entries include:
- Highest priority
- Allow TOR mode for platform-specific use cases
- Can be consistent across domain context switches
- Allow runtime PMP allocation

A potential use case for reserved PMP entries is to enforce
PMA_UNSAFE regions [1] parsed from the device tree. These
regions may not be exactly covered by one or two NAPOT entries,
so reserved entries can be allocated and configured in TOR mode
to optimize PMP usage. In addition, they do not require
reconfiguration across domains and should remain unchanged
until the hart is reset.

[1] https://lore.kernel.org/all/20251009015839.3460231-16-samuel.holland@sifive.com/

Yu-Chien Peter Lin (7):
  lib: utils: fdt_helper: add fdt_has_isa_extension() helper
  include: sbi: sbi_platform: add reserved_pmp_count field
  platform: generic: introduce fw_platform_get_reserved_pmp_count()
  lib: sbi_init: print total and reserved PMP counts
  lib: sbi: riscv_asm: support reserved PMP allocator
  lib: sbi: sbi_hart: extend PMP handling to support multiple reserved
    entries
  docs: opensbi_config: add description for reserved-pmp-count

 docs/opensbi_config.md             |  9 +++
 include/sbi/riscv_asm.h            |  6 ++
 include/sbi/sbi_hart.h             | 15 -----
 include/sbi/sbi_platform.h         | 10 ++--
 include/sbi_utils/fdt/fdt_helper.h |  2 +
 lib/sbi/riscv_asm.c                | 92 ++++++++++++++++++++++++++++++
 lib/sbi/sbi_domain_context.c       |  4 +-
 lib/sbi/sbi_hart.c                 | 56 ++++++++++++------
 lib/sbi/sbi_init.c                 |  6 +-
 lib/utils/fdt/fdt_helper.c         | 62 ++++++++++++++++++++
 platform/generic/platform.c        | 31 ++++++++++
 11 files changed, 254 insertions(+), 39 deletions(-)

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2.39.3