[PATCH V17 0/7] Rust Support for powerpc

[PATCH V17 0/7] Rust Support for powerpc

[Mukesh Kumar Chaurasiya (IBM)]

Enable experimental rust support for ppc64le and ppc32be. The patch for
ppc32 has been provided by Link Mauve[1] and ppc64le support[2] has been
merged over it. ppc32 needs some toolchain fixes mentioned in the patch
`rust: Add PowerPC support` and the discussion for that is done here[1].

This has been tested on
- powernv9 hardware
- pseries P11 hardware
- pseries(9, 10) qemu
- powernv(9, 10) qemu
- rustdoc on x86 and powerpc64le
- rusttest on x86 and powerpc64le

We are actively working with our LLVM team to get the target for ppc,
ppc64 and ppc64le in the rust compiler.

[1] https://lore.kernel.org/all/20260204030507.8203-1-linkmauve@linkmauve.fr
[2] https://lore.kernel.org/all/20260204042417.83903-1-mkchauras@gmail.com

Changelog:
V16 -> V17:
- Rebased to latest v7.2-rc2 

V15 -> V16:
- Rebased to latest v7.1-rc4
V15: https://lore.kernel.org/all/20260426105932.2270364-1-mkchauras@gmail.com/

V14 -> V15:
- Fix an issue with rustdoc build on ppc64le
V14: https://lore.kernel.org/all/20260426085725.2090827-1-mkchauras@gmail.com/

V13 -> V14:
- 2nd patch is rewritten (Christian)
- Fixed a small typo in rust/Makefile (Sashiko)
- Fixed commit message in Patch 4 (Sashiko)
V13: https://lore.kernel.org/all/20260424054742.45832-1-mkchauras@gmail.com/

V12 -> V13:
- Added a patch for fixing build issue on ppc32 by Link Mauve
- Added another patch to fix a build issue in dma-buf
- Added another patch to enforce minimum `rustc` version for powerpc
V12: https://lore.kernel.org/all/20260421120958.190430-1-mkchauras@gmail.com/

V11 -> V12:
- Rebased to mainline (rust/Makefile conflict resolved)
V11: https://lore.kernel.org/all/20260417152253.2312961-1-mkchauras@gmail.com/

V10 -> V11:
- Updated `rust/Makefile`
- Not all libraries are move to `rust/host` directory now. Only
  proc_macro2, quote and syn are moved
- Special handling for pin init is added. Details in commit
- Removed mkdir for `rust/host`, this is now handled by toolchain.
V10: https://lore.kernel.org/all/20260406200149.3727922-1-mkchauras@gmail.com/

V9 -> V10:
- rust/Makefile updated with review comments from Miguel
- Patch 1/4 updated with commit message and subject
V9: https://lore.kernel.org/all/20260404121610.1956528-1-mkchauras@gmail.com/

V8 -> V9:
- rust/Makefile updated with a directory instead of abspath
V8: https://lore.kernel.org/all/20260403145308.1042622-1-mkchauras@gmail.com/

V7 -> V8:
- rust/Makefile updated to separate host libraries from target
V7: https://lore.kernel.org/all/20260329160254.2592207-1-mkchauras@gmail.com/

Changelog:
V6 -> V7:
- Documentation removed as powerpc is still under development
- Added a fix for race condition in rust/Makefile
V6: https://lore.kernel.org/all/20260210090023.2587534-1-mkchauras@gmail.com

V5 -> V6:
- Added a missing Tested by from Venkat which got missed since V3
- Support is marked as Maintained instead of experimental
V5: https://lore.kernel.org/all/20260210053756.2088302-1-mkchauras@gmail.com

V4 -> V5:
- Removed a nested ifdef from PPC64 for Little endian toolchain
V4: https://lore.kernel.org/all/20260209105456.1551677-1-mkchauras@gmail.com

V3 -> V4:
- Co-developed-by header added in patch 1
V3: https://lore.kernel.org/all/20260205180429.3280657-1-mkchauras@gmail.com

V2 -> V3:
- Splited HAVE_RUST in 2 lines
- BINDGEN_TARGET_powerpc initialized before assigning the same to
  BINDGEN_TARGET
V2: https://lore.kernel.org/all/20260204210125.613350-1-mkchauras@gmail.com

V1 -> V2:
- jump label fix for rust has been moved to a separate patch
- PPC32 support has been taken
- rust support has been marked experimental
- target.json dependency has been removed
- HAVE_RUST now depends on CPU_LITTLE_ENDIAN for PPC64
V1: https://lore.kernel.org/all/20260204042417.83903-1-mkchauras@gmail.com 

Link Mauve (2):
  rust: Make __udivdi3() and __umoddi3() panic
  rust: Add PowerPC support

Mukesh Kumar Chaurasiya (IBM) (5):
  rust: Fix "multiple candidates for rmeta dependency core" error
  dma-resv: Fix undefined symbol when CONFIG_DMA_SHARED_BUFFER is
    disabled
  powerpc/jump_label: adjust inline asm to be consistent
  rust/powerpc: Set min rustc version for powerpc
  powerpc: Enable Rust for ppc64le

 arch/powerpc/Kconfig                  |  2 +
 arch/powerpc/Makefile                 |  7 ++++
 arch/powerpc/include/asm/jump_label.h | 23 ++++++-----
 rust/Makefile                         | 56 +++++++++++++++++----------
 rust/compiler_builtins.rs             |  6 +++
 rust/helpers/helpers.c                |  2 +
 scripts/min-tool-version.sh           |  2 +
 7 files changed, 68 insertions(+), 30 deletions(-)

-- 
2.55.0

[PATCH V17 1/7] rust: Fix "multiple candidates for rmeta dependency core" error

[Mukesh Kumar Chaurasiya (IBM)]

When building Rust code for powerpc64le with LLVM=1 and -j1, rustc
encounters an error: "multiple candidates for `rmeta` dependency `core`
found", with two candidates:
1. The host's standard library from the rustup toolchain
2. The kernel's custom libcore.rmeta in the rust/ directory

This occurs because the build system uses `-L$(objtree)/rust` for host
library builds (proc_macro2, quote, syn), which causes rustc to search
the rust/ directory. During this search, rustc finds both the kernel's
custom libcore.rmeta and gains access to the host's standard library,
creating a conflict.

The solution is to separate host libraries into a dedicated rust/host/
subdirectory and use `-L$(objtree)/rust/host` for host builds instead
of `-L$(objtree)/rust`. This ensures that:

1. Host library builds (proc_macro2, quote, syn) only search rust/host/
   and never encounter the kernel's libcore.rmeta
2. Proc macro builds use `-L$(objtree)/rust/host` to find their
   dependencies

Special handling is added for rustdoc-pin_init, which is a host build
(to access the alloc crate) but depends on proc macros from the main
rust/ directory. It uses explicit `--extern` paths to reference the
proc macros without adding `-L$(objtree)/rust`, which would reintroduce
the conflict.

The rust/host/ directory is added to clean-files to ensure it's removed
during `make clean`.

Link: https://github.com/Rust-for-Linux/linux/issues/105
Link: https://github.com/linuxppc/issues/issues/451
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 rust/Makefile | 42 +++++++++++++++++++++++-------------------
 1 file changed, 23 insertions(+), 19 deletions(-)

diff --git a/rust/Makefile b/rust/Makefile
index a870d1616c71..17b2f329c13d 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -3,6 +3,9 @@
 # Where to place rustdoc generated documentation
 rustdoc_output := $(objtree)/Documentation/output/rust/rustdoc
 
+# Clean generated host directory
+clean-files := host/
+
 obj-$(CONFIG_RUST) += core.o compiler_builtins.o ffi.o
 always-$(CONFIG_RUST) += exports_core_generated.h
 
@@ -33,7 +36,7 @@ endif
 
 obj-$(CONFIG_RUST) += exports.o
 
-always-$(CONFIG_RUST) += libproc_macro2.rlib libquote.rlib libsyn.rlib
+always-$(CONFIG_RUST) += host/libproc_macro2.rlib host/libquote.rlib host/libsyn.rlib
 
 always-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated.rs
 always-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.c
@@ -163,7 +166,7 @@ quiet_cmd_rustdoc = RUSTDOC $(if $(rustdoc_host),H, ) $<
 	$(rustc_target_envs) \
 	OBJTREE=$(abspath $(objtree)) \
 	$(RUSTDOC) $(filter-out $(skip_flags) --remap-path-scope=%,$(if $(rustdoc_host),$(rust_common_flags),$(rust_flags))) \
-		$(rustc_target_flags) -L$(objtree)/$(obj) \
+		$(rustc_target_flags) -L$(objtree)/$(obj)$(if $(rustdoc_host),/host) \
 		-Zunstable-options --generate-link-to-definition \
 		--output $(rustdoc_output) \
 		--crate-name $(subst rustdoc-,,$@) \
@@ -261,6 +264,7 @@ rustdoc-pin_init_internal: $(src)/pin-init/internal/src/lib.rs \
 
 rustdoc-pin_init: private rustdoc_host = yes
 rustdoc-pin_init: private rustc_target_flags = $(pin_init-flags) \
+    --extern pin_init_internal=$(objtree)/$(obj)/$(libpin_init_internal_name) \
     --extern alloc --cfg feature=\"alloc\"
 rustdoc-pin_init: $(src)/pin-init/src/lib.rs rustdoc-pin_init_internal \
     rustdoc-macros FORCE
@@ -572,23 +576,23 @@ quiet_cmd_rustc_procmacrolibrary = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_Q
 	$(if $(skip_clippy),$(RUSTC),$(RUSTC_OR_CLIPPY)) \
 		$(filter-out $(skip_flags),$(rust_common_flags) $(rustc_target_flags)) \
 		--emit=dep-info=$(depfile) --emit=link=$@ --crate-type rlib -O \
-		--out-dir $(objtree)/$(obj) -L$(objtree)/$(obj) \
+		--out-dir $(objtree)/$(obj)/host -L$(objtree)/$(obj)/host \
 		--crate-name $(patsubst lib%.rlib,%,$(notdir $@)) $<
 
-$(obj)/libproc_macro2.rlib: private skip_clippy = 1
-$(obj)/libproc_macro2.rlib: private rustc_target_flags = $(proc_macro2-flags)
-$(obj)/libproc_macro2.rlib: $(src)/proc-macro2/lib.rs FORCE
+$(obj)/host/libproc_macro2.rlib: private skip_clippy = 1
+$(obj)/host/libproc_macro2.rlib: private rustc_target_flags = $(proc_macro2-flags)
+$(obj)/host/libproc_macro2.rlib: $(src)/proc-macro2/lib.rs FORCE
 	+$(call if_changed_dep,rustc_procmacrolibrary)
 
-$(obj)/libquote.rlib: private skip_clippy = 1
-$(obj)/libquote.rlib: private skip_flags = $(quote-skip_flags)
-$(obj)/libquote.rlib: private rustc_target_flags = $(quote-flags)
-$(obj)/libquote.rlib: $(src)/quote/lib.rs $(obj)/libproc_macro2.rlib FORCE
+$(obj)/host/libquote.rlib: private skip_clippy = 1
+$(obj)/host/libquote.rlib: private skip_flags = $(quote-skip_flags)
+$(obj)/host/libquote.rlib: private rustc_target_flags = $(quote-flags)
+$(obj)/host/libquote.rlib: $(src)/quote/lib.rs $(obj)/host/libproc_macro2.rlib FORCE
 	+$(call if_changed_dep,rustc_procmacrolibrary)
 
-$(obj)/libsyn.rlib: private skip_clippy = 1
-$(obj)/libsyn.rlib: private rustc_target_flags = $(syn-flags)
-$(obj)/libsyn.rlib: $(src)/syn/lib.rs $(obj)/libquote.rlib FORCE
+$(obj)/host/libsyn.rlib: private skip_clippy = 1
+$(obj)/host/libsyn.rlib: private rustc_target_flags = $(syn-flags)
+$(obj)/host/libsyn.rlib: $(src)/syn/lib.rs $(obj)/host/libquote.rlib FORCE
 	+$(call if_changed_dep,rustc_procmacrolibrary)
 
 quiet_cmd_rustc_procmacro = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET)) P $@
@@ -598,26 +602,26 @@ quiet_cmd_rustc_procmacro = $(if $(skip_clippy),RUSTC,$(RUSTC_OR_CLIPPY_QUIET))
 		-Clinker-flavor=gcc -Clinker=$(HOSTCC) \
 		-Clink-args='$(call escsq,$(KBUILD_PROCMACROLDFLAGS))' \
 		--emit=dep-info=$(depfile) --emit=link=$@ --extern proc_macro \
-		--crate-type proc-macro -L$(objtree)/$(obj) \
+		--crate-type proc-macro -L$(objtree)/$(obj)/host \
 		--crate-name $(patsubst lib%.$(procmacro-extension),%,$(notdir $@)) \
 		@$(objtree)/include/generated/rustc_cfg $<
 
 # Procedural macros can only be used with the `rustc` that compiled it.
 $(obj)/$(libzerocopy_derive_name): private skip_clippy = 1
 $(obj)/$(libzerocopy_derive_name): private rustc_target_flags = $(zerocopy_derive-flags)
-$(obj)/$(libzerocopy_derive_name): $(src)/zerocopy-derive/lib.rs $(obj)/libproc_macro2.rlib \
-    $(obj)/libquote.rlib $(obj)/libsyn.rlib FORCE
+$(obj)/$(libzerocopy_derive_name): $(src)/zerocopy-derive/lib.rs $(obj)/host/libproc_macro2.rlib \
+    $(obj)/host/libquote.rlib $(obj)/host/libsyn.rlib FORCE
 	+$(call if_changed_dep,rustc_procmacro)
 
 $(obj)/$(libmacros_name): private rustc_target_flags = \
     --extern proc_macro2 --extern quote --extern syn
-$(obj)/$(libmacros_name): $(src)/macros/lib.rs $(obj)/libproc_macro2.rlib \
-    $(obj)/libquote.rlib $(obj)/libsyn.rlib FORCE
+$(obj)/$(libmacros_name): $(src)/macros/lib.rs $(obj)/host/libproc_macro2.rlib \
+    $(obj)/host/libquote.rlib $(obj)/host/libsyn.rlib FORCE
 	+$(call if_changed_dep,rustc_procmacro)
 
 $(obj)/$(libpin_init_internal_name): private rustc_target_flags = $(pin_init_internal-flags)
 $(obj)/$(libpin_init_internal_name): $(src)/pin-init/internal/src/lib.rs \
-    $(obj)/libproc_macro2.rlib $(obj)/libquote.rlib $(obj)/libsyn.rlib FORCE
+    $(obj)/host/libproc_macro2.rlib $(obj)/host/libquote.rlib $(obj)/host/libsyn.rlib FORCE
 	+$(call if_changed_dep,rustc_procmacro)
 
 # `rustc` requires `-Zunstable-options` to use custom target specifications
-- 
2.55.0

[PATCH V17 2/7] dma-resv: Fix undefined symbol when CONFIG_DMA_SHARED_BUFFER is disabled

[Mukesh Kumar Chaurasiya (IBM)]

When building with LLVM=1 for architectures like powerpc where
CONFIG_DMA_SHARED_BUFFER is not enabled, the build fails with:

  ld.lld: error: undefined symbol: dma_resv_reset_max_fences
  >>> referenced by helpers.c
  >>>               rust/helpers/helpers.o:(rust_helper_dma_resv_unlock)

The issue occurs because:
1. CONFIG_DEBUG_MUTEXES=y is enabled
2. CONFIG_DMA_SHARED_BUFFER is not enabled
3. dma_resv_reset_max_fences() is declared in the header when
   CONFIG_DEBUG_MUTEXES is set
4. But the function is only compiled in drivers/dma-buf/dma-resv.c,
   which is only built when CONFIG_DMA_SHARED_BUFFER is enabled
5. Rust helpers call dma_resv_unlock() which calls
   dma_resv_reset_max_fences(), causing an undefined symbol

Fix this by compiling `dma-resv.c` file only when CONFIG_DMA_SHARED_BUFFER
is enabled.

Fixes: 9b836641d3bf ("rust: helpers: Add bindings/wrappers for dma_resv_lock")
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Gary Guo <gary@garyguo.net>
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 rust/helpers/helpers.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/rust/helpers/helpers.c b/rust/helpers/helpers.c
index 998e31052e66..4b90a1390ad5 100644
--- a/rust/helpers/helpers.c
+++ b/rust/helpers/helpers.c
@@ -58,7 +58,9 @@
 #include "cred.c"
 #include "device.c"
 #include "dma.c"
+#ifdef CONFIG_DMA_SHARED_BUFFER
 #include "dma-resv.c"
+#endif
 #include "drm.c"
 #include "drm_gpuvm.c"
 #include "err.c"
-- 
2.55.0

[PATCH V17 3/7] powerpc/jump_label: adjust inline asm to be consistent

[Mukesh Kumar Chaurasiya (IBM)]

Added support for a new macro ARCH_STATIC_BRANCH_ASM in powerpc
to avoid duplication of inline asm between C and Rust. This is
inline with 'commit aecaf181651c ("jump_label: adjust inline asm to be consistent")'

Co-developed-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com>
Reviewed-by: Alice Ryhl <aliceryhl@google.com>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Reviewed-by: Gary Guo <gary@garyguo.net>
Link: https://github.com/Rust-for-Linux/linux/issues/105
Link: https://github.com/linuxppc/issues/issues/451
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 arch/powerpc/include/asm/jump_label.h | 23 +++++++++++++----------
 1 file changed, 13 insertions(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/jump_label.h b/arch/powerpc/include/asm/jump_label.h
index d4eaba459a0e..3016e9c8d6bc 100644
--- a/arch/powerpc/include/asm/jump_label.h
+++ b/arch/powerpc/include/asm/jump_label.h
@@ -15,14 +15,20 @@
 #define JUMP_ENTRY_TYPE		stringify_in_c(FTR_ENTRY_LONG)
 #define JUMP_LABEL_NOP_SIZE	4
 
+#define JUMP_TABLE_ENTRY(key, label)			\
+	".pushsection __jump_table,  \"aw\"	\n\t"	\
+	".long 1b - ., " label " - .		\n\t"	\
+	JUMP_ENTRY_TYPE key " - .		\n\t"	\
+	".popsection 				\n\t"
+
+#define ARCH_STATIC_BRANCH_ASM(key, label)		\
+	"1:	nop				\n\t"	\
+	JUMP_TABLE_ENTRY(key, label)
+
 static __always_inline bool arch_static_branch(struct static_key *key, bool branch)
 {
-	asm goto("1:\n\t"
-		 "nop # arch_static_branch\n\t"
-		 ".pushsection __jump_table,  \"aw\"\n\t"
-		 ".long 1b - ., %l[l_yes] - .\n\t"
-		 JUMP_ENTRY_TYPE "%c0 - .\n\t"
-		 ".popsection \n\t"
+	asm goto(
+		 ARCH_STATIC_BRANCH_ASM("%c0", "%l[l_yes]")
 		 : :  "i" (&((char *)key)[branch]) : : l_yes);
 
 	return false;
@@ -34,10 +40,7 @@ static __always_inline bool arch_static_branch_jump(struct static_key *key, bool
 {
 	asm goto("1:\n\t"
 		 "b %l[l_yes] # arch_static_branch_jump\n\t"
-		 ".pushsection __jump_table,  \"aw\"\n\t"
-		 ".long 1b - ., %l[l_yes] - .\n\t"
-		 JUMP_ENTRY_TYPE "%c0 - .\n\t"
-		 ".popsection \n\t"
+		 JUMP_TABLE_ENTRY("%c0", "%l[l_yes]")
 		 : :  "i" (&((char *)key)[branch]) : : l_yes);
 
 	return false;
-- 
2.55.0

[PATCH V17 4/7] rust/powerpc: Set min rustc version for powerpc

[Mukesh Kumar Chaurasiya (IBM)]

Minimum `rustc` version required for powerpc is 1.95 as some critical
features required for compiling rust code for kernel are not there.

For example Stable inline asm support which got merged in 1.95.

Link: https://github.com/rust-lang/rust/pull/147996
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 scripts/min-tool-version.sh | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
index 031f2192b390..99bfdcaa3396 100755
--- a/scripts/min-tool-version.sh
+++ b/scripts/min-tool-version.sh
@@ -33,6 +33,8 @@ llvm)
 rustc)
 	if [ "$SRCARCH" = "s390" ]; then
 		echo 1.96.0
+	elif [ "$ARCH" = powerpc ]; then
+		echo 1.95.0
 	else
 		echo 1.85.0
 	fi
-- 
2.55.0

Re: [PATCH V17 4/7] rust/powerpc: Set min rustc version for powerpc

[Link Mauve]

Hi,

On Wed, Jul 08, 2026 at 01:54:51PM +0530, Mukesh Kumar Chaurasiya (IBM) wrote:
> Minimum `rustc` version required for powerpc is 1.95 as some critical
> features required for compiling rust code for kernel are not there.
> 
> For example Stable inline asm support which got merged in 1.95.

Didn’t we decide on 1.85.0 with the asm_experimental_arch feature
instead?  And possibly on 64-bit 1.87.0 if it isn’t possible to disable
altivec correctly there?

> 
> Link: https://github.com/rust-lang/rust/pull/147996
> Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
> ---
>  scripts/min-tool-version.sh | 2 ++
>  1 file changed, 2 insertions(+)
> 
> diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
> index 031f2192b390..99bfdcaa3396 100755
> --- a/scripts/min-tool-version.sh
> +++ b/scripts/min-tool-version.sh
> @@ -33,6 +33,8 @@ llvm)
>  rustc)
>  	if [ "$SRCARCH" = "s390" ]; then
>  		echo 1.96.0
> +	elif [ "$ARCH" = powerpc ]; then
> +		echo 1.95.0
>  	else
>  		echo 1.85.0
>  	fi
> -- 
> 2.55.0
> 
> 

-- 
Link Mauve

Re: [PATCH V17 4/7] rust/powerpc: Set min rustc version for powerpc

[Mukesh Kumar Chaurasiya]

On Wed, Jul 08, 2026 at 10:39:30AM +0200, Link Mauve wrote:
> Hi,
> 
> On Wed, Jul 08, 2026 at 01:54:51PM +0530, Mukesh Kumar Chaurasiya (IBM) wrote:
> > Minimum `rustc` version required for powerpc is 1.95 as some critical
> > features required for compiling rust code for kernel are not there.
> > 
> > For example Stable inline asm support which got merged in 1.95.
> 
> Didn’t we decide on 1.85.0 with the asm_experimental_arch feature
> instead?  And possibly on 64-bit 1.87.0 if it isn’t possible to disable
> altivec correctly there?
> 
1.85.0 or 1.85.1 is not feasible for ppc64le.
PPC maintainer is ok with 1.95 for PPC. It's still experimental for PPC.

Regards,
Mukesh

> > 
> > Link: https://github.com/rust-lang/rust/pull/147996
> > Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
> > ---
> >  scripts/min-tool-version.sh | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> > diff --git a/scripts/min-tool-version.sh b/scripts/min-tool-version.sh
> > index 031f2192b390..99bfdcaa3396 100755
> > --- a/scripts/min-tool-version.sh
> > +++ b/scripts/min-tool-version.sh
> > @@ -33,6 +33,8 @@ llvm)
> >  rustc)
> >  	if [ "$SRCARCH" = "s390" ]; then
> >  		echo 1.96.0
> > +	elif [ "$ARCH" = powerpc ]; then
> > +		echo 1.95.0
> >  	else
> >  		echo 1.85.0
> >  	fi
> > -- 
> > 2.55.0
> > 
> > 
> 
> -- 
> Link Mauve

[PATCH V17 5/7] rust: Make __udivdi3() and __umoddi3() panic

[Mukesh Kumar Chaurasiya (IBM)]

From: Link Mauve <linkmauve@linkmauve.fr>

The core crate currently depends on these two functions for i64/u64/
i128/u128/core::time::Duration formatting, but we shouldn’t use that in
the kernel so let’s panic if they are ever called.

This doesn’t yet fix drm_panic_qr.rs, which also uses __udivdi3 when
CONFIG_CC_OPTIMIZE_FOR_SIZE=y, but at least makes the rest of the kernel
build on PPC32.

Signed-off-by: Link Mauve <linkmauve@linkmauve.fr>
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 rust/Makefile             | 4 ++++
 rust/compiler_builtins.rs | 6 ++++++
 2 files changed, 10 insertions(+)

diff --git a/rust/Makefile b/rust/Makefile
index 17b2f329c13d..7aa8fcad4c43 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -677,6 +677,10 @@ ifneq ($(or $(CONFIG_ARM64),$(and $(CONFIG_RISCV),$(CONFIG_64BIT))),)
 		__ashrti3 \
 		__ashlti3 __lshrti3
 endif
+ifdef CONFIG_PPC32
+	redirect-intrinsics += \
+		__udivdi3 __umoddi3
+endif
 
 ifdef CONFIG_MODVERSIONS
 cmd_gendwarfksyms = $(if $(skip_gendwarfksyms),, \
diff --git a/rust/compiler_builtins.rs b/rust/compiler_builtins.rs
index dd16c1dc899c..fc6b54636dd5 100644
--- a/rust/compiler_builtins.rs
+++ b/rust/compiler_builtins.rs
@@ -97,5 +97,11 @@ pub extern "C" fn $ident() {
     __aeabi_uldivmod,
 });
 
+#[cfg(target_arch = "powerpc")]
+define_panicking_intrinsics!("`u64` division/modulo should not be used", {
+    __udivdi3,
+    __umoddi3,
+});
+
 // NOTE: if you are adding a new intrinsic here, you should also add it to
 // `redirect-intrinsics` in `rust/Makefile`.
-- 
2.55.0

[PATCH V17 6/7] rust: Add PowerPC support

[Mukesh Kumar Chaurasiya (IBM)]

From: Link Mauve <linkmauve@linkmauve.fr>

For now only Big Endian 32-bit PowerPC is supported, as that is the only
hardware I have.  This has been tested on the Nintendo Wii so far, but I
plan on also using it on the GameCube, Wii U and Apple G4.

These changes aren’t the only ones required to get the kernel to compile
and link on PowerPC, libcore will also have to be changed to not use
integer division to format u64, u128 and core::time::Duration, otherwise
__udivdi3() and __umoddi3() will have to be added.  I have tested this
change by replacing the three implementations with unimplemented!() and
it linked just fine.

Signed-off-by: Link Mauve <linkmauve@linkmauve.fr>
Link: https://github.com/Rust-for-Linux/linux/issues/105
Link: https://github.com/linuxppc/issues/issues/451
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://github.com/rust-lang/compiler-team/issues/986
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 arch/powerpc/Kconfig  | 1 +
 arch/powerpc/Makefile | 2 ++
 rust/Makefile         | 4 +++-
 3 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index f7ce5fff81f0..badd7c99b87f 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -285,6 +285,7 @@ config PPC
 	select HAVE_REGS_AND_STACK_ACCESS_API
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
+	select HAVE_RUST			if PPC32
 	select HAVE_SAMPLE_FTRACE_DIRECT	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	select HAVE_SETUP_PER_CPU_AREA		if PPC64
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index a58b1029592c..589613eaa5dc 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -61,6 +61,8 @@ else
 KBUILD_LDFLAGS_MODULE += $(objtree)/arch/powerpc/lib/crtsavres.o
 endif
 
+KBUILD_RUSTFLAGS 	+= --target=powerpc-unknown-linux-gnu
+
 ifdef CONFIG_CPU_LITTLE_ENDIAN
 KBUILD_CPPFLAGS	+= -mlittle-endian
 KBUILD_LDFLAGS	+= -EL
diff --git a/rust/Makefile b/rust/Makefile
index 7aa8fcad4c43..61e7dc496fe4 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -448,7 +448,8 @@ bindgen_skip_c_flags := -mno-fp-ret-in-387 -mpreferred-stack-boundary=% \
 	-fstrict-flex-arrays=% -fmin-function-alignment=% \
 	-fzero-init-padding-bits=% -mno-fdpic \
 	-fdiagnostics-show-context -fdiagnostics-show-context=% \
-	--param=% --param asan-% -fno-isolate-erroneous-paths-dereference
+	--param=% --param asan-% -fno-isolate-erroneous-paths-dereference \
+	-ffixed-r2 -mmultiple -mno-readonly-in-sdata
 
 # Derived from `scripts/Makefile.clang`.
 BINDGEN_TARGET_x86	:= x86_64-linux-gnu
@@ -458,6 +459,7 @@ BINDGEN_TARGET_loongarch	:= loongarch64-linux-gnusf
 BINDGEN_TARGET_s390	:= s390x-linux-gnu
 # This is only for i386 UM builds, which need the 32-bit target not -m32
 BINDGEN_TARGET_i386	:= i386-linux-gnu
+BINDGEN_TARGET_powerpc	:= powerpc-linux-gnu
 BINDGEN_TARGET_um	:= $(BINDGEN_TARGET_$(SUBARCH))
 BINDGEN_TARGET		:= $(BINDGEN_TARGET_$(SRCARCH))
 
-- 
2.55.0

[PATCH V17 7/7] powerpc: Enable Rust for ppc64le

[Mukesh Kumar Chaurasiya (IBM)]

Enabling rust support for ppc64le.

Tested on pseries Power11:
╰─❯ dmesg | grep rust
[    0.225728] Initialise system trusted keyrings
[    0.270961] rust_minimal: Rust minimal sample (init)
[    0.270968] rust_minimal: Am I built-in? true
[    0.270974] rust_minimal: test_parameter: 1
[    0.270983] rust_misc_device: Initialising Rust Misc Device Sample
[    0.271012] rust_print: Rust printing macros sample (init)
[    0.271019] rust_print: Emergency message (level 0) without args
[    0.271023] rust_print: Alert message (level 1) without args
[    0.271026] rust_print: Critical message (level 2) without args
[    0.271030] rust_print: Error message (level 3) without args
[    0.271033] rust_print: Warning message (level 4) without args
[    0.271037] rust_print: Notice message (level 5) without args
[    0.271040] rust_print: Info message (level 6) without args
[    0.271043] rust_print: A line that is continued without args
[    0.271054] rust_print: Emergency message (level 0) with args
[    0.271064] rust_print: Alert message (level 1) with args
[    0.271072] rust_print: Critical message (level 2) with args
[    0.271077] rust_print: Error message (level 3) with args
[    0.271083] rust_print: Warning message (level 4) with args
[    0.271091] rust_print: Notice message (level 5) with args
[    0.271097] rust_print: Info message (level 6) with args
[    0.271102] rust_print: A line that is continued with args
[    0.271110] rust_print: 1
[    0.271113] rust_print: "hello, world"
[    0.271121] rust_print: [samples/rust/rust_print_main.rs:35:5] c = "hello, world"
[    0.271129] rust_print: Arc<dyn Display> says 42
[    0.271130] rust_print: Arc<dyn Display> says hello, world
[    0.271136] rust_print: "hello, world"
[    0.271198] usbcore: registered new interface driver rust_driver_usb
[    0.271207] rust_faux_driver: Initialising Rust Faux Device Sample
[    0.271227] faux_driver rust-faux-sample-device: Hello from faux device!
[    0.271297] rust_configfs: Rust configfs sample (init)

Reviewed-by: Link Mauve <linkmauve@linkmauve.fr>
Tested-by: Link Mauve <linkmauve@linkmauve.fr>
Reviewed-by: Christophe Leroy (CS GROUP) <chleroy@kernel.org>
Tested-by: Venkat Rao Bagalkote <venkat88@linux.ibm.com>
Link: https://github.com/Rust-for-Linux/linux/issues/105
Link: https://github.com/linuxppc/issues/issues/451
Acked-by: Gary Guo <gary@garyguo.net>
Link: https://github.com/rust-lang/compiler-team/issues/987
Link: https://github.com/rust-lang/compiler-team/issues/988
Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 arch/powerpc/Kconfig  | 1 +
 arch/powerpc/Makefile | 7 ++++++-
 rust/Makefile         | 6 ++++++
 3 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index badd7c99b87f..650283107b92 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -286,6 +286,7 @@ config PPC
 	select HAVE_RELIABLE_STACKTRACE
 	select HAVE_RSEQ
 	select HAVE_RUST			if PPC32
+	select HAVE_RUST			if PPC64 && CPU_LITTLE_ENDIAN
 	select HAVE_SAMPLE_FTRACE_DIRECT	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	select HAVE_SAMPLE_FTRACE_DIRECT_MULTI	if HAVE_DYNAMIC_FTRACE_WITH_DIRECT_CALLS
 	select HAVE_SETUP_PER_CPU_AREA		if PPC64
diff --git a/arch/powerpc/Makefile b/arch/powerpc/Makefile
index 589613eaa5dc..9385db478c59 100644
--- a/arch/powerpc/Makefile
+++ b/arch/powerpc/Makefile
@@ -61,7 +61,12 @@ else
 KBUILD_LDFLAGS_MODULE += $(objtree)/arch/powerpc/lib/crtsavres.o
 endif
 
-KBUILD_RUSTFLAGS 	+= --target=powerpc-unknown-linux-gnu
+ifdef CONFIG_PPC64
+KBUILD_RUSTFLAGS	+= --target=powerpc64le-unknown-linux-gnu
+KBUILD_RUSTFLAGS	+= -Ctarget-feature=-mma,-vsx,-hard-float,-altivec
+else
+KBUILD_RUSTFLAGS	+= --target=powerpc-unknown-linux-gnu
+endif
 
 ifdef CONFIG_CPU_LITTLE_ENDIAN
 KBUILD_CPPFLAGS	+= -mlittle-endian
diff --git a/rust/Makefile b/rust/Makefile
index 61e7dc496fe4..d2f74998d3c1 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -459,7 +459,13 @@ BINDGEN_TARGET_loongarch	:= loongarch64-linux-gnusf
 BINDGEN_TARGET_s390	:= s390x-linux-gnu
 # This is only for i386 UM builds, which need the 32-bit target not -m32
 BINDGEN_TARGET_i386	:= i386-linux-gnu
+
+ifdef CONFIG_PPC64
+BINDGEN_TARGET_powerpc	:= powerpc64le-linux-gnu
+else
 BINDGEN_TARGET_powerpc	:= powerpc-linux-gnu
+endif
+
 BINDGEN_TARGET_um	:= $(BINDGEN_TARGET_$(SUBARCH))
 BINDGEN_TARGET		:= $(BINDGEN_TARGET_$(SRCARCH))
 
-- 
2.55.0