[ARCH/RISC-V] Next RISC-V (#10320)

* [libcpu][risc-v] Refactor the RISC-V architecture port

Introduce an opt-in unified RISC-V common layer for RV32 and RV64 while keeping existing BSPs on the legacy implementation during migration.

- use ARCH_RISCV and ARCH_CPU_64BIT for architecture and XLEN selection
- unify context, trap, MMU, cache, timer, SBI, SMP and ISA handling
- add PLIC, CLIC, ACLINT, APLIC and IMSIC support
- map physical hart IDs to contiguous logical CPU IDs
- add T-Head vendor overrides while preserving legacy ports
- migrate qemu-virt64-riscv with RV32 and RV64 support
- update clock_time, MM, LWP, OFW, PCI and Rust integration

Existing BSPs continue using legacy_common or common64 unless they select RT_USING_RISCV_NEW_COMMON.

Signed-off-by: GuEe-GUI <[email protected]>

* [libcpu][risc-v] skip disabled CPU nodes in early FDT walk

Rbb666 noted that rt_hw_fdt_install_early() walked every /cpus child
without checking status, so disabled cores still joined hart registration
and MMU capability probing. Skip nodes that are not okay/ok via
rt_fdt_device_is_available() before reading reg or mmu-type.

Signed-off-by: seteiro <[email protected]>

* [libcpu][risc-v] Fix per-CPU page table mapping

- reuse existing non-leaf page table entries when mapping per-CPU areas
- reject leaf entry conflicts instead of overwriting mappings

Signed-off-by: GuEe-GUI <[email protected]>

---------

Signed-off-by: GuEe-GUI <[email protected]>
Signed-off-by: seteiro <[email protected]>
Co-authored-by: seteiro <[email protected]>

1 files changed, 86 insertions, 8 deletions

diff --git a/libcpu/risc-v/common/SConscript b/libcpu/risc-v/common/SConscript
index 814cfb01d5..fe50f4fa96 100644
--- a/libcpu/risc-v/common/SConscript
+++ b/libcpu/risc-v/common/SConscript
@@ -1,15 +1,93 @@
-# RT-Thread building script for component
+# RT-Thread building script for the unified RISC-V CPU port
 
+import os
 from building import *
 
-cwd     = GetCurrentDir()
-src     = Glob('*.c') + Glob('*.cpp') + Glob('*_gcc.S')
-CPPPATH = [cwd]
-ASFLAGS = ' -I ' + cwd
+Import('rtconfig')
 
-if not GetDepend('RT_USING_HW_ATOMIC'):
-    SrcRemove(src, 'atomic_riscv.c')
+cwd = GetCurrentDir()
+bsp_path = Dir('#').abspath
+CPPPATH = [cwd + '/include', cwd]
 
-group = DefineGroup('CPU', src, depend = [''], CPPPATH = CPPPATH, ASFLAGS = ASFLAGS)
+if GetDepend('ARCH_RISCV_VECTOR'):
+    CPPPATH += [os.path.join(cwd, '..', 'vector', 'rvv-1.0')]
+bsp_startup_obj = []
+builtin_fdt_obj = []
+src = [
+    'backtrace.c',
+    'cpu.c',
+    'cpuport.c',
+    'isa_ext.c',
+    'riscv_timer.c',
+    'stack.c',
+    'trap.c',
+]
+
+if GetDepend('RT_USING_CACHE'):
+    src += ['cache.c']
+
+if rtconfig.PLATFORM in ['gcc']:
+    src += [
+        'context_gcc.S',
+        'cpu_gcc.S',
+        'stack_gcc.S',
+        'startup.c',
+        'vector_gcc.S',
+    ]
+
+    bsp_startup = os.path.join(bsp_path, 'startup_gcc.S')
+    if os.path.isfile(bsp_startup):
+        bsp_startup_obj = Env.Object('startup_gcc.o', '#startup_gcc.S')
+    else:
+        src += ['startup_gcc.S']
+
+    if GetDepend('RT_USING_BUILTIN_FDT'):
+        dtb_path = os.path.join(bsp_path, GetDepend('RT_BUILTIN_FDT_PATH').strip('"'))
+        builtin_fdt_obj = Env.Object('builtin_fdt_gcc.o', 'builtin_fdt_gcc.S')
+        Env.Depends(builtin_fdt_obj, dtb_path)
+
+if GetDepend('ARCH_MM_MMU'):
+    src += ['mmu.c']
+
+if GetDepend('RT_USING_HW_ATOMIC'):
+    src += ['atomic_riscv.c']
+
+if GetDepend('RT_USING_LWP'):
+    src += ['syscall.c']
+
+if not GetDepend('ARCH_RISCV_M_MODE'):
+    src += ['sbi.c']
+
+    if not GetDepend('RT_USING_DM'):
+        src += ['console.c']
+
+if GetDepend('RT_USING_DM'):
+    src += ['setup.c']
+
+    if GetDepend('RT_USING_SMP'):
+        src += ['cpu_spinwait.c']
+
+        if not GetDepend('ARCH_RISCV_M_MODE'):
+            src += ['cpu_sbi.c']
+
+if not GetDepend('RT_USING_DM'):
+    src += ['interrupt.c']
+
+if GetDepend('ARCH_RISCV_USING_IRQ_STACK'):
+    src += ['irq_stack.c']
+
+group = DefineGroup('libcpu', src, depend = [''], CPPPATH = CPPPATH)
+group += bsp_startup_obj
+group += builtin_fdt_obj
+
+# build for sub-directory
+list = os.listdir(cwd)
+objs = []
+
+for d in list:
+    path = os.path.join(cwd, d)
+    if os.path.isfile(os.path.join(path, 'SConscript')):
+        objs = objs + SConscript(os.path.join(d, 'SConscript'))
+group = group + objs
 
 Return('group')