[PATCH V7 0/4] Rust support for powerpc

[PATCH V7 0/4] 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 and power10 pseries qemu.

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:
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

Link Mauve (1):
  rust: Add PowerPC support

Mukesh Kumar Chaurasiya (IBM) (3):
  rust: Fix a race condition in Makefile
  powerpc/jump_label: adjust inline asm to be consistent
  powerpc: Enable Rust for ppc64le

 arch/powerpc/Kconfig                  |  2 ++
 arch/powerpc/Makefile                 |  7 +++++++
 arch/powerpc/include/asm/jump_label.h | 23 +++++++++++++----------
 rust/Makefile                         | 13 +++++++++++--
 4 files changed, 33 insertions(+), 12 deletions(-)

-- 
2.53.0

[PATCH V7 1/4] rust: Fix a race condition in Makefile

[Mukesh Kumar Chaurasiya (IBM)]

When compiling with -j1 flag in powerpc, the libproc_macro finds the
libcore.rmeta both in toolchain and local rust directory. libproc_macro
should use the toolchain provided libcore.rmeta.

So for this, make libproc_macro2 libquote and libsyn dependent on core.o
so that libcore.rmeta is generated after these 3 files are done
compiling.

Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>
---
 rust/Makefile | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/rust/Makefile b/rust/Makefile
index 9801af2e1e02..8e62f6fcf94f 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -650,7 +650,8 @@ $(obj)/core.o: private skip_flags = $(core-skip_flags)
 $(obj)/core.o: private rustc_objcopy = $(foreach sym,$(redirect-intrinsics),--redefine-sym $(sym)=__rust$(sym))
 $(obj)/core.o: private rustc_target_flags = $(core-flags)
 $(obj)/core.o: $(RUST_LIB_SRC)/core/src/lib.rs \
-    $(wildcard $(objtree)/include/config/RUSTC_VERSION_TEXT) FORCE
+    $(wildcard $(objtree)/include/config/RUSTC_VERSION_TEXT) FORCE \
+    | $(obj)/libproc_macro2.rlib $(obj)/libquote.rlib $(obj)/libsyn.rlib FORCE
 	+$(call if_changed_rule,rustc_library)
 ifneq ($(or $(CONFIG_X86_64),$(CONFIG_X86_32)),)
 $(obj)/core.o: scripts/target.json
-- 
2.53.0

[PATCH V7 2/4] 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>
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..a6b211502bfe 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;
-- 
2.53.0

[PATCH V7 3/4] 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>
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 10240cb80904..1246b3add8ff 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -284,6 +284,7 @@ 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 8e62f6fcf94f..7ea7570e3f17 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -402,13 +402,15 @@ 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
 BINDGEN_TARGET_arm64	:= aarch64-linux-gnu
 BINDGEN_TARGET_arm	:= arm-linux-gnueabi
 BINDGEN_TARGET_loongarch	:= loongarch64-linux-gnusf
+BINDGEN_TARGET_powerpc	:= powerpc-linux-gnu
 BINDGEN_TARGET_um	:= $(BINDGEN_TARGET_$(SUBARCH))
 BINDGEN_TARGET		:= $(BINDGEN_TARGET_$(SRCARCH))
 
-- 
2.53.0

[PATCH V7 4/4] powerpc: Enable Rust for ppc64le

[Mukesh Kumar Chaurasiya (IBM)]

Enabling rust support for ppc64le only.

Tested on powernv9:

$ uname -rm
6.19.0-rc8+ ppc64le

$ sudo modprobe rust_minimal
[  632.890850] rust_minimal: Rust minimal sample (init)
[  632.890881] rust_minimal: Am I built-in? false
[  632.890898] rust_minimal: test_parameter: 1

$ sudo rmmod rust_minimal
[  648.272832] rust_minimal: My numbers are [72, 108, 200]
[  648.272873] rust_minimal: Rust minimal sample (exit)

$ sudo modprobe rust_print
[  843.410391] rust_print: Rust printing macros sample (init)
[  843.410424] rust_print: Emergency message (level 0) without args
[  843.410451] rust_print: Alert message (level 1) without args
[  843.410477] rust_print: Critical message (level 2) without args
[  843.410503] rust_print: Error message (level 3) without args
[  843.410530] rust_print: Warning message (level 4) without args
[  843.410557] rust_print: Notice message (level 5) without args
[  843.410594] rust_print: Info message (level 6) without args
[  843.410617] rust_print: A line that is continued without args
[  843.410646] rust_print: Emergency message (level 0) with args
[  843.410675] rust_print: Alert message (level 1) with args
[  843.410691] rust_print: Critical message (level 2) with args
[  843.410727] rust_print: Error message (level 3) with args
[  843.410761] rust_print: Warning message (level 4) with args
[  843.410796] rust_print: Notice message (level 5) with args
[  843.410821] rust_print: Info message (level 6) with args
[  843.410854] rust_print: A line that is continued with args
[  843.410892] rust_print: 1
[  843.410895] rust_print: "hello, world"
[  843.410924] rust_print: [samples/rust/rust_print_main.rs:35:5] c = "hello, world"
[  843.410977] rust_print: Arc<dyn Display> says 42
[  843.410979] rust_print: Arc<dyn Display> says hello, world

$ sudo rmmod rust_print
[  843.411003] rust_print: "hello, world"
[  888.499935] rust_print: Rust printing macros sample (exit)

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>
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 1246b3add8ff..a5f50434daf3 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -285,6 +285,7 @@ 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 7ea7570e3f17..7fe4cbbd176e 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -410,7 +410,13 @@ BINDGEN_TARGET_x86	:= x86_64-linux-gnu
 BINDGEN_TARGET_arm64	:= aarch64-linux-gnu
 BINDGEN_TARGET_arm	:= arm-linux-gnueabi
 BINDGEN_TARGET_loongarch	:= loongarch64-linux-gnusf
+
+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))
 
-- 
2.53.0

Re: [PATCH V7 0/4] Rust support for powerpc

[Miguel Ojeda]

On Sun, Mar 29, 2026 at 6:03 PM Mukesh Kumar Chaurasiya (IBM)
<mkchauras@gmail.com> wrote:
>
> We are actively working with our LLVM team to get the target for ppc,
> ppc64 and ppc64le in the rust compiler.

That sounds great -- I imagine you refer to a `-none` target? Are
there any links to e.g. upstream Rust issues or PRs that could be nice
to add for context, if any?

It may be good to put this in the commit message. Also, other links
that we should add:

Link: https://github.com/Rust-for-Linux/linux/issues/105
Link: https://github.com/linuxppc/issues/issues/451

Thanks!

Cheers,
Miguel

Re: [PATCH V7 1/4] rust: Fix a race condition in Makefile

[Miguel Ojeda]

On Sun, Mar 29, 2026 at 6:03 PM Mukesh Kumar Chaurasiya (IBM)
<mkchauras@gmail.com> wrote:
>
> When compiling with -j1 flag in powerpc, the libproc_macro finds the
> libcore.rmeta both in toolchain and local rust directory. libproc_macro
> should use the toolchain provided libcore.rmeta.

By toolchain, do you mean the sysroot one or something else?

We should make it such that `rustc` does not try to use them to begin
with, e.g. we added `--sysroot=/dev/null` to prevent that in the past,
please see:

  71479eee9da8 ("rust: Suppress searching builtin sysroot")

In other words, we should try to avoid adding dependencies (even if
order-only) to workaround the issue, but instead we should get rid of
the root issue.

Otherwise, after a build, if we rebuild only one of them, wouldn't it
find again both? i.e. this is not really a "race condition".

From the original message, I see this was happening when building the
host libraries, because the targets happen to match, i.e. you are
doing a native build on powerpc, right?

Perhaps we could put the host `.rmeta`s separately, or something like that.

Thanks!

Cheers,
Miguel

Re: [PATCH V7 1/4] rust: Fix a race condition in Makefile

[Gary Guo]

On Sun Mar 29, 2026 at 6:25 PM BST, Miguel Ojeda wrote:
> On Sun, Mar 29, 2026 at 6:03 PM Mukesh Kumar Chaurasiya (IBM)
> <mkchauras@gmail.com> wrote:
>>
>> When compiling with -j1 flag in powerpc, the libproc_macro finds the
>> libcore.rmeta both in toolchain and local rust directory. libproc_macro
>> should use the toolchain provided libcore.rmeta.
>
> By toolchain, do you mean the sysroot one or something else?
>
> We should make it such that `rustc` does not try to use them to begin
> with, e.g. we added `--sysroot=/dev/null` to prevent that in the past,
> please see:
>
>   71479eee9da8 ("rust: Suppress searching builtin sysroot")
>
> In other words, we should try to avoid adding dependencies (even if
> order-only) to workaround the issue, but instead we should get rid of
> the root issue.
>
> Otherwise, after a build, if we rebuild only one of them, wouldn't it
> find again both? i.e. this is not really a "race condition".
>
> From the original message, I see this was happening when building the
> host libraries, because the targets happen to match, i.e. you are
> doing a native build on powerpc, right?
>
> Perhaps we could put the host `.rmeta`s separately, or something like that.

Yeah, we can either remove `-L$(objtree)/$(obj)` and specify `--extern
dep=path-to-dep`, or we can store host libraries to something like
`$(objtree)/$(obj)/host` and use that instead.

The latter should be an easier fix. Also, I can see that we're already having
`-L$(objtree)/$(obj)/test`.

Best,
Gary

Re: [PATCH V7 2/4] powerpc/jump_label: adjust inline asm to be consistent

[Gary Guo]

On Sun Mar 29, 2026 at 5:02 PM BST, Mukesh Kumar Chaurasiya (IBM) wrote:
> 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>
> Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com>

Reviewed-by: Gary Guo <gary@garyguo.net>

> ---
>  arch/powerpc/include/asm/jump_label.h | 23 +++++++++++++----------
>  1 file changed, 13 insertions(+), 10 deletions(-)

Re: [PATCH V7 4/4] powerpc: Enable Rust for ppc64le

[Gary Guo]

On Sun Mar 29, 2026 at 5:02 PM BST, Mukesh Kumar Chaurasiya (IBM) wrote:
> Enabling rust support for ppc64le only.

This line looks inaccurate now given previous commit just enabled it for PPC32
too.

>
> Tested on powernv9:
>
> $ uname -rm
> 6.19.0-rc8+ ppc64le
>
> $ sudo modprobe rust_minimal
> [  632.890850] rust_minimal: Rust minimal sample (init)
> [  632.890881] rust_minimal: Am I built-in? false
> [  632.890898] rust_minimal: test_parameter: 1
>
> $ sudo rmmod rust_minimal
> [  648.272832] rust_minimal: My numbers are [72, 108, 200]
> [  648.272873] rust_minimal: Rust minimal sample (exit)
>
> $ sudo modprobe rust_print
> [  843.410391] rust_print: Rust printing macros sample (init)
> [  843.410424] rust_print: Emergency message (level 0) without args
> [  843.410451] rust_print: Alert message (level 1) without args
> [  843.410477] rust_print: Critical message (level 2) without args
> [  843.410503] rust_print: Error message (level 3) without args
> [  843.410530] rust_print: Warning message (level 4) without args
> [  843.410557] rust_print: Notice message (level 5) without args
> [  843.410594] rust_print: Info message (level 6) without args
> [  843.410617] rust_print: A line that is continued without args
> [  843.410646] rust_print: Emergency message (level 0) with args
> [  843.410675] rust_print: Alert message (level 1) with args
> [  843.410691] rust_print: Critical message (level 2) with args
> [  843.410727] rust_print: Error message (level 3) with args
> [  843.410761] rust_print: Warning message (level 4) with args
> [  843.410796] rust_print: Notice message (level 5) with args
> [  843.410821] rust_print: Info message (level 6) with args
> [  843.410854] rust_print: A line that is continued with args
> [  843.410892] rust_print: 1
> [  843.410895] rust_print: "hello, world"
> [  843.410924] rust_print: [samples/rust/rust_print_main.rs:35:5] c = "hello, world"
> [  843.410977] rust_print: Arc<dyn Display> says 42
> [  843.410979] rust_print: Arc<dyn Display> says hello, world
>
> $ sudo rmmod rust_print
> [  843.411003] rust_print: "hello, world"
> [  888.499935] rust_print: Rust printing macros sample (exit)
>
> 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>
> 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 1246b3add8ff..a5f50434daf3 100644
> --- a/arch/powerpc/Kconfig
> +++ b/arch/powerpc/Kconfig
> @@ -285,6 +285,7 @@ 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

It looks like all it takes to enable PPC BE is to have

#ifdef CONFIG_CPU_LITTLE_ENDIAN
KBUILD_RUSTFLAGS	+= --target=powerpc64le-unknown-linux-gnu
#else
KBUILD_RUSTFLAGS	+= --target=powerpc64-unknown-linux-gnu
#endif

(and similarly add bindgen target)?

I think it might worth having PPC32/PPC64/PPC64LE all enabled in a single
commit, and then you can just claim Rust is enabled for PPC and have an
unconditional

    select HAVE_RUST

Thoughts?

Best,
Gary

> +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 7ea7570e3f17..7fe4cbbd176e 100644
> --- a/rust/Makefile
> +++ b/rust/Makefile
> @@ -410,7 +410,13 @@ BINDGEN_TARGET_x86	:= x86_64-linux-gnu
>  BINDGEN_TARGET_arm64	:= aarch64-linux-gnu
>  BINDGEN_TARGET_arm	:= arm-linux-gnueabi
>  BINDGEN_TARGET_loongarch	:= loongarch64-linux-gnusf
> +
> +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))
>  

Re: [PATCH V7 1/4] rust: Fix a race condition in Makefile

[Mukesh Kumar Chaurasiya]

On Sun, Mar 29, 2026 at 07:25:19PM +0200, Miguel Ojeda wrote:
> On Sun, Mar 29, 2026 at 6:03 PM Mukesh Kumar Chaurasiya (IBM)
> <mkchauras@gmail.com> wrote:
> >
> > When compiling with -j1 flag in powerpc, the libproc_macro finds the
> > libcore.rmeta both in toolchain and local rust directory. libproc_macro
> > should use the toolchain provided libcore.rmeta.
> 
> By toolchain, do you mean the sysroot one or something else?
> 
Hey Miguel,

yeah the sysroot one.
> We should make it such that `rustc` does not try to use them to begin
> with, e.g. we added `--sysroot=/dev/null` to prevent that in the past,
> please see:
> 
>   71479eee9da8 ("rust: Suppress searching builtin sysroot")
> 
> In other words, we should try to avoid adding dependencies (even if
> order-only) to workaround the issue, but instead we should get rid of
> the root issue.
> 
> Otherwise, after a build, if we rebuild only one of them, wouldn't it
> find again both? i.e. this is not really a "race condition".
> 
Yeah this makes sense.

> From the original message, I see this was happening when building the
> host libraries, because the targets happen to match, i.e. you are
> doing a native build on powerpc, right?
Yes we are doing a native powerpc build.
> 
> Perhaps we could put the host `.rmeta`s separately, or something like that.
I didn't understand this part, `.rmeta` for host are kept in sysroot
path, are we trying to change the sysroot directory?

Regards,
Mukesh
>
> Thanks!
> 
> Cheers,
> Miguel

Re: [PATCH V7 1/4] rust: Fix a race condition in Makefile

[Mukesh Kumar Chaurasiya]

On Sun, Mar 29, 2026 at 07:26:55PM +0100, Gary Guo wrote:
> On Sun Mar 29, 2026 at 6:25 PM BST, Miguel Ojeda wrote:
> > On Sun, Mar 29, 2026 at 6:03 PM Mukesh Kumar Chaurasiya (IBM)
> > <mkchauras@gmail.com> wrote:
> >>
> >> When compiling with -j1 flag in powerpc, the libproc_macro finds the
> >> libcore.rmeta both in toolchain and local rust directory. libproc_macro
> >> should use the toolchain provided libcore.rmeta.
> >
> > By toolchain, do you mean the sysroot one or something else?
> >
> > We should make it such that `rustc` does not try to use them to begin
> > with, e.g. we added `--sysroot=/dev/null` to prevent that in the past,
> > please see:
> >
> >   71479eee9da8 ("rust: Suppress searching builtin sysroot")
> >
> > In other words, we should try to avoid adding dependencies (even if
> > order-only) to workaround the issue, but instead we should get rid of
> > the root issue.
> >
> > Otherwise, after a build, if we rebuild only one of them, wouldn't it
> > find again both? i.e. this is not really a "race condition".
> >
> > From the original message, I see this was happening when building the
> > host libraries, because the targets happen to match, i.e. you are
> > doing a native build on powerpc, right?
> >
> > Perhaps we could put the host `.rmeta`s separately, or something like that.
> 
> Yeah, we can either remove `-L$(objtree)/$(obj)` and specify `--extern
> dep=path-to-dep`, or we can store host libraries to something like
> `$(objtree)/$(obj)/host` and use that instead.
> 
Oh now i understood what Miguel was trying to say. Thanks for the
explanation. 
> The latter should be an easier fix. Also, I can see that we're already having
> `-L$(objtree)/$(obj)/test`.
> 
I'll try this.

Regards,
Mukesh
> Best,
> Gary
> 

Re: [PATCH V7 4/4] powerpc: Enable Rust for ppc64le

[Mukesh Kumar Chaurasiya]

On Sun, Mar 29, 2026 at 07:33:43PM +0100, Gary Guo wrote:
> On Sun Mar 29, 2026 at 5:02 PM BST, Mukesh Kumar Chaurasiya (IBM) wrote:
> > Enabling rust support for ppc64le only.
> 
> This line looks inaccurate now given previous commit just enabled it for PPC32
> too.
> 
Oh yeah, will fix this.
> >
> > Tested on powernv9:
> >
> > $ uname -rm
> > 6.19.0-rc8+ ppc64le
> >
> > $ sudo modprobe rust_minimal
> > [  632.890850] rust_minimal: Rust minimal sample (init)
> > [  632.890881] rust_minimal: Am I built-in? false
> > [  632.890898] rust_minimal: test_parameter: 1
> >
> > $ sudo rmmod rust_minimal
> > [  648.272832] rust_minimal: My numbers are [72, 108, 200]
> > [  648.272873] rust_minimal: Rust minimal sample (exit)
> >
> > $ sudo modprobe rust_print
> > [  843.410391] rust_print: Rust printing macros sample (init)
> > [  843.410424] rust_print: Emergency message (level 0) without args
> > [  843.410451] rust_print: Alert message (level 1) without args
> > [  843.410477] rust_print: Critical message (level 2) without args
> > [  843.410503] rust_print: Error message (level 3) without args
> > [  843.410530] rust_print: Warning message (level 4) without args
> > [  843.410557] rust_print: Notice message (level 5) without args
> > [  843.410594] rust_print: Info message (level 6) without args
> > [  843.410617] rust_print: A line that is continued without args
> > [  843.410646] rust_print: Emergency message (level 0) with args
> > [  843.410675] rust_print: Alert message (level 1) with args
> > [  843.410691] rust_print: Critical message (level 2) with args
> > [  843.410727] rust_print: Error message (level 3) with args
> > [  843.410761] rust_print: Warning message (level 4) with args
> > [  843.410796] rust_print: Notice message (level 5) with args
> > [  843.410821] rust_print: Info message (level 6) with args
> > [  843.410854] rust_print: A line that is continued with args
> > [  843.410892] rust_print: 1
> > [  843.410895] rust_print: "hello, world"
> > [  843.410924] rust_print: [samples/rust/rust_print_main.rs:35:5] c = "hello, world"
> > [  843.410977] rust_print: Arc<dyn Display> says 42
> > [  843.410979] rust_print: Arc<dyn Display> says hello, world
> >
> > $ sudo rmmod rust_print
> > [  843.411003] rust_print: "hello, world"
> > [  888.499935] rust_print: Rust printing macros sample (exit)
> >
> > 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>
> > 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 1246b3add8ff..a5f50434daf3 100644
> > --- a/arch/powerpc/Kconfig
> > +++ b/arch/powerpc/Kconfig
> > @@ -285,6 +285,7 @@ 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
> 
> It looks like all it takes to enable PPC BE is to have
> 
> #ifdef CONFIG_CPU_LITTLE_ENDIAN
> KBUILD_RUSTFLAGS	+= --target=powerpc64le-unknown-linux-gnu
> #else
> KBUILD_RUSTFLAGS	+= --target=powerpc64-unknown-linux-gnu
> #endif
> 
> (and similarly add bindgen target)?
> 
> I think it might worth having PPC32/PPC64/PPC64LE all enabled in a single
> commit, and then you can just claim Rust is enabled for PPC and have an
> unconditional
> 
>     select HAVE_RUST
> 
> Thoughts?
> 
BE still has some issues in the compiler. We are working with our LLVM
team to get those fixed. We can still add the support for BE, but that
won't be compilable as of now.

Regards,
Mukesh
> Best,
> Gary
> 
> > +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 7ea7570e3f17..7fe4cbbd176e 100644
> > --- a/rust/Makefile
> > +++ b/rust/Makefile
> > @@ -410,7 +410,13 @@ BINDGEN_TARGET_x86	:= x86_64-linux-gnu
> >  BINDGEN_TARGET_arm64	:= aarch64-linux-gnu
> >  BINDGEN_TARGET_arm	:= arm-linux-gnueabi
> >  BINDGEN_TARGET_loongarch	:= loongarch64-linux-gnusf
> > +
> > +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))
> >  
> 

Re: [PATCH V7 0/4] Rust support for powerpc

[Mukesh Kumar Chaurasiya]

On Sun, Mar 29, 2026 at 06:20:58PM +0200, Miguel Ojeda wrote:
> On Sun, Mar 29, 2026 at 6:03 PM Mukesh Kumar Chaurasiya (IBM)
> <mkchauras@gmail.com> wrote:
> >
> > We are actively working with our LLVM team to get the target for ppc,
> > ppc64 and ppc64le in the rust compiler.
> 
> That sounds great -- I imagine you refer to a `-none` target? Are
> there any links to e.g. upstream Rust issues or PRs that could be nice
> to add for context, if any?
> 
I couldn't find any as of now. I'll try to fetch em and update
accordingly.
> It may be good to put this in the commit message. Also, other links
> that we should add:
> 
> Link: https://github.com/Rust-for-Linux/linux/issues/105
> Link: https://github.com/linuxppc/issues/issues/451
> 
That sounds great.

> Thanks!
> 
> Cheers,
> Miguel

Regards,
Mukesh