Add support for arm32 by luodeb · Pull Request #359 · arceos-org/arceos

luodeb · 2026-03-16T08:30:49Z

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Copilot

Pull request overview

This PR adds initial ARM32 (ARMv7-A) architecture support to the ArceOS operating system, alongside upgrading several dependencies (page_table_multiarch 0.5→0.6, various crate bumps) and adapting the page table API to a new cursor-based interface.

Changes:

Adds ARM32 target (armv7a-none-eabi) across build system, CI, QEMU configuration, platform crate wiring, and architecture-specific code paths (TLS, percpu, paging, C headers, setjmp/longjmp stubs).
Migrates page table operations from direct map/unmap/protect_region calls to a cursor-based API (pt.cursor().map_region(...)) to match page_table_multiarch v0.6.
Fixes potential overflow in network benchmarks by changing counter types from usize to u64 (needed for 32-bit targets where 10 * GB overflows usize).

Reviewed changes

Copilot reviewed 30 out of 31 changed files in this pull request and generated 12 comments.

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File	Description
Cargo.toml	Adds workspace deps and patches for arm32 fork dependencies
Cargo.lock	Dependency version updates and new arm32-related crates
Makefile	Adds arm32 target, changes default MEM to 1G
rust-toolchain.toml	Adds armv7a-none-eabi target
scripts/make/*.mk	Adds arm32 QEMU machine, CFLAGS, platform mappings
modules/axhal/*	Adds arm32 platform crate, page table type, TLS/percpu, paging API migration
modules/axmm/src/backend/*.rs	Migrates to cursor-based page table API
modules/axmm/src/aspace.rs	Cursor-based API + access_flags conversion
modules/axnet/src/smoltcp_impl/bench.rs	Fixes usize overflow on 32-bit by using u64
modules/axdriver/src/drivers.rs	Adds debug log in ramdisk probe
ulib/axlibc/*	Arm32 C header support, stub setjmp/longjmp, build.rs fix
api/arceos_posix_api/src/imp/time.rs	Fixes tv_sec cast for 32-bit
examples/*	Adds arm32 platform support
.github/workflows/*.yml	Adds arm32 to CI matrix

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Copilot

Pull request overview

Adds ARM32 (armv7a) support across the build system, libc shims, HAL, and CI to enable building and running ArceOS on qemu-system-arm (virt).

Changes:

Add ARM32 target support in Makefiles, QEMU runner scripts, Rust toolchain targets, and CI matrices.
Extend axlibc/posix API headers and shims for ARM32 ABI details (TLS, setjmp/longjmp, stdint/float/assert).
Update core dependencies and paging/percpu integrations to newer crate APIs that support ARM32.

Reviewed changes

Copilot reviewed 35 out of 37 changed files in this pull request and generated 7 comments.

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File	Description
ulib/axlibc/src/setjmp.rs	Adds ARM32-specific returns/termination paths for setjmp/longjmp stubs.
ulib/axlibc/src/malloc.rs	Aligns allocator metadata for ARM32 ABI expectations.
ulib/axlibc/include/stdint.h	Defines intptr_t/uintptr_t sizing for `__arm__`.
ulib/axlibc/include/setjmp.h	Introduces ARM32 `__jmp_buf` sizing.
ulib/axlibc/include/float.h	Adds ARM32 long-double/decimal constants.
ulib/axlibc/include/assert.h	Implements standard `NDEBUG` behavior for `assert`.
ulib/axlibc/build.rs	Forces explicit clang `--target` for bindgen to avoid host ABI leakage.
scripts/make/qemu.mk	Adds QEMU machine/cpu settings and args for ARM virt.
scripts/make/platform.mk	Adds ARM platform package selection and updates error message.
scripts/make/build_c.mk	Adds ARM soft-float CFLAGS when `fp-simd` is disabled.
rust-toolchain.toml	Adds `armv7a-none-eabi` target to toolchain targets list.
modules/axtask/Cargo.toml	Bumps `percpu` dependency version for ARM32 support.
modules/axruntime/Cargo.toml	Bumps `axplat`/`percpu` versions for ARM32 support.
modules/axnet/src/smoltcp_impl/bench.rs	Switches bandwidth counters to `u64` to avoid 32-bit overflow.
modules/axmm/src/backend/mod.rs	Updates to new page-table cursor-based protect_region API.
modules/axmm/src/backend/linear.rs	Updates to cursor-based map/unmap region APIs.
modules/axmm/src/backend/alloc.rs	Updates populate/map/unmap/remap to cursor-based APIs.
modules/axmm/src/aspace.rs	Updates copy/protect logic to cursor API and truncates access flags.
modules/axipi/Cargo.toml	Bumps `percpu` dependency version.
modules/axhal/src/tls.rs	Adds ARM32 TLS layout constants and `__aeabi_read_tp` hook.
modules/axhal/src/percpu.rs	Adds ARM32 IRQ-guarded current task access; updates percpu init API.
modules/axhal/src/paging.rs	Adapts paging handler to multi-frame allocation API; adds ARM page table type.
modules/axhal/src/lib.rs	Links ARM platform crate when targeting ARM32.
modules/axhal/linker.lds.S	Changes `.data` alignment to 16K (affects all targets).
modules/axhal/Cargo.toml	Updates feature lists and bumps deps (`percpu`, `axplat`, `page_table_multiarch`); adds ARM platform dep.
examples/shell/Cargo.toml	Formatting-only change (no functional impact).
examples/helloworld-myplat/src/main.rs	Adds ARM platform extern crate selection.
examples/helloworld-myplat/Cargo.toml	Adds `arm-qemu-virt` feature and ARM target dependency.
arceos-apps	Updates the subproject git commit pointer.
api/arceos_posix_api/src/imp/time.rs	Changes `tv_sec` conversion casts (likely for 32-bit compatibility).
api/arceos_posix_api/src/imp/pthread/mutex.rs	Adds alignment static assert for pthread mutex ABI.
api/arceos_posix_api/build.rs	Adds 32-bit variants for pthread mutex initializer and forces 8-byte alignment.
Makefile	Adds `arm` ARCH option and sets Rust target triple for ARM.
Cargo.toml	Adds workspace-level deps and patches crates.io deps to git repos/branches for ARM32.
.github/workflows/test.yml	Adds ARM to test matrix; switches arceos-apps source/commit.
.github/workflows/build.yml	Adds ARM to build matrices and installs ARM target.

Comments suppressed due to low confidence (2)

ulib/axlibc/src/setjmp.rs:1

For ARM32, longjmp currently becomes an infinite loop (b .). While it does technically make the function non-returning, it will hard-hang the CPU and mask the real failure mode. If ARM32 longjmp isn't implemented yet, prefer an explicit trap/abort path (so failures are diagnosable) or implement the actual register restore/jump sequence consistent with the __jmp_buf ABI used by your headers.
ulib/axlibc/include/setjmp.h:1
__jmp_buf[64] appears inconsistent with the comment (r4-r14 is 11 regs; d8-d15 is 8 double-precision regs = 16 32-bit words under typical AAPCS; total is far below 64 words even after adding SP/LR/PC/flags). A mismatch here will break the C ABI and any Rust asm implementation that assumes a particular buffer layout/size. Please align the buffer size (and ideally document exact saved slots/ordering) to match the actual ARM32 setjmp/longjmp implementation.

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Pull request overview

Copilot reviewed 35 out of 37 changed files in this pull request and generated 7 comments.

Comments suppressed due to low confidence (1)

Cargo.toml:84

The [patch.crates-io] entries point at moving git branches (e.g. branch = "arm32") and unpinned repos, which makes builds non-reproducible and can silently change dependencies without a lockfile update. Please pin to specific rev hashes (or tags) and consider scoping these patches behind an opt-in feature/profile so default builds keep using published crates.

[patch.crates-io]
axcpu = { git = "https://github.com/luodeb/axcpu.git" }
axplat = { git = "https://github.com/luodeb/axplat_crates.git", branch = "arm32" }
axplat-x86-pc = { git = "https://github.com/luodeb/axplat_crates.git",  branch = "arm32" }
axplat-arm-qemu-virt = { git = "https://github.com/luodeb/axplat_crates.git",  branch = "arm32" }

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equation314

Please split this PR into two parts: one for updating dependency versions, and another for adding ARM support.

equation314

In ulib/axlibc/include/limits.h, __LONG_MAX should be 0x7fffffffL for 32-bit platforms. Otherwise, the following warning will appear when compiling the C application:

In file included from ulib/axlibc/c/stdlib.c:3:                                                                                        
ulib/axlibc/c/stdlib.c: In function ‘strtoul’:                                                                                         
/home/jyk/arceos/ulib/axlibc/include/limits.h:17:25: warning: integer overflow in expression of type ‘long long int’ results in ‘-2’ [-
Woverflow]                                                                                                                             
   17 | #define ULONG_MAX  (2UL * LONG_MAX + 1)                                                                                        
      |                         ^                                                                                                      
ulib/axlibc/c/stdlib.c:174:29: note: in expansion of macro ‘ULONG_MAX’                                                                 
  174 |     cutoff = (unsigned long)ULONG_MAX / (unsigned long)base;                                                                   
      |                             ^~~~~~~~~                                                                                          
/home/jyk/arceos/ulib/axlibc/include/limits.h:17:25: warning: integer overflow in expression of type ‘long long int’ results in ‘-2’ [-
Woverflow]                                                                                                                             
   17 | #define ULONG_MAX  (2UL * LONG_MAX + 1)                                                                                        
      |                         ^                                                                                                      
ulib/axlibc/c/stdlib.c:175:29: note: in expansion of macro ‘ULONG_MAX’                                                                 
  175 |     cutlim = (unsigned long)ULONG_MAX % (unsigned long)base;                                                                   
      |                             ^~~~~~~~~                                                                                          
/home/jyk/arceos/ulib/axlibc/include/limits.h:17:25: warning: integer overflow in expression of type ‘long long int’ results in ‘-2’ [-
Woverflow]                                                                                                                             
   17 | #define ULONG_MAX  (2UL * LONG_MAX + 1)                                                                                        
      |                         ^                                                                                                      
ulib/axlibc/c/stdlib.c:197:15: note: in expansion of macro ‘ULONG_MAX’                                                                 
  197 |         acc = ULONG_MAX;                                                                                                       
      |               ^~~~~~~~~
                                                                                                 ```

Copilot

Pull request overview

Copilot reviewed 36 out of 38 changed files in this pull request and generated 5 comments.

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…MappingFlags directly

…EMU configurations

…t jmp_buf size in setjmp.h

Introduces support for the ARM QEMU Virt platform, enabling both example and shell use. Upgrades and aligns various dependencies and platform crates to newer versions, improving consistency and compatibility. Increases default memory allocation for QEMU runs, improves driver probing diagnostics, and fixes potential integer truncation in time and network benchmarking logic. Enables additional features in the shell and driver modules for better out-of-the-box experience.

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Pull request overview

Copilot reviewed 36 out of 37 changed files in this pull request and generated 3 comments.

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…nment in linker script; refine setjmp/longjmp implementations for ARM architecture

…AL_IMG

Copilot

Pull request overview

Copilot reviewed 35 out of 36 changed files in this pull request and generated 3 comments.

Comments suppressed due to low confidence (1)

scripts/make/qemu.mk:33

qemu_args-x86_64 now passes $(FINAL_IMG) to -kernel, but FINAL_IMG is a stripped binary or uImage (not the ELF). If the x86_64 boot flow expects an ELF (e.g., for multiboot/segment loading), this will regress make run for x86_64. Please confirm QEMU x86_64 can boot the chosen FINAL_IMG format; otherwise keep using $(OUT_ELF) for x86_64 or set FINAL_IMG to an ELF-compatible image for that arch.

qemu_args-x86_64 := \
  -machine $(machine) \
  -kernel $(OUT_ELF)

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…ngjmp for ARM architecture

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…pport in ARM architecture fix: update timeval conversion to use c_longlong for tv_sec in time module fix: change MemoryControlBlock representation to C-compatible in malloc module fix: enhance setjmp/longjmp implementations with architecture checks and error handling

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Pull request overview

Copilot reviewed 35 out of 36 changed files in this pull request and generated 1 comment.

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…jmp implementation

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Copilot reviewed 35 out of 36 changed files in this pull request and generated 1 comment.

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equation314 · 2026-04-24T15:50:36Z

    fn from(d: Duration) -> Self {
        ctypes::timespec {
-            tv_sec: d.as_secs() as c_long,
+            tv_sec: d.as_secs() as i64,


equation314 · 2026-04-24T15:53:44Z

  endif
 endif

+ifeq ($(ARCH), arm)


Merge with the above libgcc :=

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equation314 added this to ARM32 support Mar 27, 2026

github-project-automation Bot moved this to Todo in ARM32 support Mar 27, 2026

equation314 moved this from Todo to In Progress in ARM32 support Mar 31, 2026

luodeb added 10 commits April 15, 2026 10:33

update page_table to 0.6

b40c0d7

refactor: remove inline function page_fault_flags_to_mapping and use …

84b2f6a

…MappingFlags directly

fix: replace cursor variable with direct method call in unmap_alloc

04a0b02

fix: uncomment KVM acceleration for Darwin in qemu.mk

9497f94

feat: add ARM architecture support in Makefile, paging, percpu, and Q…

1aed160

…EMU configurations

fix: update ARM architecture settings in QEMU configuration and adjus…

d5bb9a4

…t jmp_buf size in setjmp.h

add arm32 support

43cc5cb

axplat_crates

b699356

Adds ARM platform support and refines dependencies

726c93b

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Remove unused feature flag doc_auto_cfg

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luodeb added 2 commits April 20, 2026 14:23

fix: update kernel argument in QEMU makefile to use FINAL_IMG

532e0b6

fix: update package versions and checksums in Cargo.lock; adjust alig…

7ca8daa

…nment in linker script; refine setjmp/longjmp implementations for ARM architecture

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fix: update arceos-apps version in CI workflow

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fix: update x86_64 QEMU kernel argument to use OUT_ELF instead of FIN…

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…AL_IMG

fix: update setup-musl action version to v1.0.3 in CI workflow

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luodeb added 2 commits April 21, 2026 10:58

fix: update setup-musl action version to v1.0.3 in CI workflow

8adc8c9

fix: correct __jmp_buf size and adjust register handling in setjmp/lo…

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…ngjmp for ARM architecture

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luodeb added 2 commits April 24, 2026 17:28

fix: add support for atomic runtime symbols in ARM32 build process

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fix: align MemoryControlBlock structure for improved memory management

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luodeb added 2 commits April 24, 2026 18:00

fix: update error message for unsupported target architecture in long…

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…jmp implementation

code fmt

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