* [PATCH v3 1/5] x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
2025-02-13 13:57 ` [PATCH v3 0/5] rust: Add bug/warn abstractions FUJITA Tomonori
@ 2025-02-13 13:57 ` FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 2/5] riscv/bug: " FUJITA Tomonori
` (4 subsequent siblings)
5 siblings, 0 replies; 17+ messages in thread
From: FUJITA Tomonori @ 2025-02-13 13:57 UTC (permalink / raw)
To: linux-kernel, rust-for-linux
Cc: Peter Zijlstra, x86, linux-riscv, linux-arm-kernel, loongarch,
tglx, mingo, bp, dave.hansen, hpa, paul.walmsley, palmer, aou,
catalin.marinas, will, chenhuacai, kernel, tangyouling, hejinyang,
yangtiezhu, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
benno.lossin, a.hindborg, aliceryhl, tmgross
Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
Rust to avoid the duplication.
No functional changes.
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
arch/x86/include/asm/bug.h | 56 +++++++++++++++++++-------------------
1 file changed, 28 insertions(+), 28 deletions(-)
diff --git a/arch/x86/include/asm/bug.h b/arch/x86/include/asm/bug.h
index e85ac0c7c039..61570ec9464c 100644
--- a/arch/x86/include/asm/bug.h
+++ b/arch/x86/include/asm/bug.h
@@ -28,45 +28,42 @@
#ifdef CONFIG_GENERIC_BUG
#ifdef CONFIG_X86_32
-# define __BUG_REL(val) ".long " __stringify(val)
+# define __BUG_REL(val) ".long " val
#else
-# define __BUG_REL(val) ".long " __stringify(val) " - ."
+# define __BUG_REL(val) ".long " val " - ."
#endif
#ifdef CONFIG_DEBUG_BUGVERBOSE
+#define __BUG_ENTRY(file, line, flags) \
+ "2:\t" __BUG_REL("1b") "\t# bug_entry::bug_addr\n" \
+ "\t" __BUG_REL(file) "\t# bug_entry::file\n" \
+ "\t.word " line "\t# bug_entry::line\n" \
+ "\t.word " flags "\t# bug_entry::flags\n"
+#else
+#define __BUG_ENTRY(file, ine, flags) \
+ "2:\t" __BUG_REL("1b") "\t# bug_entry::bug_addr\n" \
+ "\t.word " flags "\t# bug_entry::flags\n"
+#endif
+
+#define _BUG_FLAGS_ASM(ins, file, line, flags, size, extra) \
+ "1:\t" ins "\n" \
+ ".pushsection __bug_table,\"aw\"\n" \
+ __BUG_ENTRY(file, line, flags) \
+ "\t.org 2b + " size "\n" \
+ ".popsection\n" \
+ extra
#define _BUG_FLAGS(ins, flags, extra) \
do { \
- asm_inline volatile("1:\t" ins "\n" \
- ".pushsection __bug_table,\"aw\"\n" \
- "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
- "\t" __BUG_REL(%c0) "\t# bug_entry::file\n" \
- "\t.word %c1" "\t# bug_entry::line\n" \
- "\t.word %c2" "\t# bug_entry::flags\n" \
- "\t.org 2b+%c3\n" \
- ".popsection\n" \
- extra \
+ asm_inline volatile(_BUG_FLAGS_ASM(ins, "%c0", \
+ "%c1", "%c2", "%c3", extra) \
: : "i" (__FILE__), "i" (__LINE__), \
"i" (flags), \
"i" (sizeof(struct bug_entry))); \
} while (0)
-#else /* !CONFIG_DEBUG_BUGVERBOSE */
-
-#define _BUG_FLAGS(ins, flags, extra) \
-do { \
- asm_inline volatile("1:\t" ins "\n" \
- ".pushsection __bug_table,\"aw\"\n" \
- "2:\t" __BUG_REL(1b) "\t# bug_entry::bug_addr\n" \
- "\t.word %c0" "\t# bug_entry::flags\n" \
- "\t.org 2b+%c1\n" \
- ".popsection\n" \
- extra \
- : : "i" (flags), \
- "i" (sizeof(struct bug_entry))); \
-} while (0)
-
-#endif /* CONFIG_DEBUG_BUGVERBOSE */
+#define ARCH_WARN_ASM(file, line, flags, size) \
+ _BUG_FLAGS_ASM(ASM_UD2, file, line, flags, size, "")
#else
@@ -88,11 +85,14 @@ do { \
* were to trigger, we'd rather wreck the machine in an attempt to get the
* message out than not know about it.
*/
+
+#define ARCH_WARN_REACHABLE ANNOTATE_REACHABLE(1b)
+
#define __WARN_FLAGS(flags) \
do { \
__auto_type __flags = BUGFLAG_WARNING|(flags); \
instrumentation_begin(); \
- _BUG_FLAGS(ASM_UD2, __flags, ANNOTATE_REACHABLE(1b)); \
+ _BUG_FLAGS(ASM_UD2, __flags, ARCH_WARN_REACHABLE); \
instrumentation_end(); \
} while (0)
--
2.43.0
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v3 2/5] riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
2025-02-13 13:57 ` [PATCH v3 0/5] rust: Add bug/warn abstractions FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 1/5] x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust FUJITA Tomonori
@ 2025-02-13 13:57 ` FUJITA Tomonori
2025-02-28 10:13 ` Alexandre Ghiti
2025-02-13 13:57 ` [PATCH v3 3/5] arm64/bug: " FUJITA Tomonori
` (3 subsequent siblings)
5 siblings, 1 reply; 17+ messages in thread
From: FUJITA Tomonori @ 2025-02-13 13:57 UTC (permalink / raw)
To: linux-kernel, rust-for-linux
Cc: x86, linux-riscv, linux-arm-kernel, loongarch, tglx, mingo, bp,
dave.hansen, peterz, hpa, paul.walmsley, palmer, aou,
catalin.marinas, will, chenhuacai, kernel, tangyouling, hejinyang,
yangtiezhu, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
benno.lossin, a.hindborg, aliceryhl, tmgross
Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
Rust to avoid the duplication.
No functional changes.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
arch/riscv/include/asm/bug.h | 37 +++++++++++++++++++++---------------
1 file changed, 22 insertions(+), 15 deletions(-)
diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
index 1aaea81fb141..6ab13b56feb0 100644
--- a/arch/riscv/include/asm/bug.h
+++ b/arch/riscv/include/asm/bug.h
@@ -31,40 +31,45 @@ typedef u32 bug_insn_t;
#ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
#define __BUG_ENTRY_ADDR RISCV_INT " 1b - ."
-#define __BUG_ENTRY_FILE RISCV_INT " %0 - ."
+#define __BUG_ENTRY_FILE(file) RISCV_INT " " file " - ."
#else
#define __BUG_ENTRY_ADDR RISCV_PTR " 1b"
-#define __BUG_ENTRY_FILE RISCV_PTR " %0"
+#define __BUG_ENTRY_FILE(file) RISCV_PTR " " file
#endif
#ifdef CONFIG_DEBUG_BUGVERBOSE
-#define __BUG_ENTRY \
+#define __BUG_ENTRY(file, line, flags) \
__BUG_ENTRY_ADDR "\n\t" \
- __BUG_ENTRY_FILE "\n\t" \
- RISCV_SHORT " %1\n\t" \
- RISCV_SHORT " %2"
+ __BUG_ENTRY_FILE(file) "\n\t" \
+ RISCV_SHORT " " line "\n\t" \
+ RISCV_SHORT " " flags
#else
-#define __BUG_ENTRY \
- __BUG_ENTRY_ADDR "\n\t" \
- RISCV_SHORT " %2"
+#define __BUG_ENTRY(file, line, flags) \
+ __BUG_ENTRY_ADDR "\n\t" \
+ RISCV_SHORT " " flags
#endif
#ifdef CONFIG_GENERIC_BUG
-#define __BUG_FLAGS(flags) \
-do { \
- __asm__ __volatile__ ( \
+
+#define ARCH_WARN_ASM(file, line, flags, size) \
"1:\n\t" \
"ebreak\n" \
".pushsection __bug_table,\"aw\"\n\t" \
"2:\n\t" \
- __BUG_ENTRY "\n\t" \
- ".org 2b + %3\n\t" \
- ".popsection" \
+ __BUG_ENTRY(file, line, flags) "\n\t" \
+ ".org 2b + " size "\n\t" \
+ ".popsection\n" \
+
+#define __BUG_FLAGS(flags) \
+do { \
+ __asm__ __volatile__ ( \
+ ARCH_WARN_ASM("%0", "%1", "%2", "%3") \
: \
: "i" (__FILE__), "i" (__LINE__), \
"i" (flags), \
"i" (sizeof(struct bug_entry))); \
} while (0)
+
#else /* CONFIG_GENERIC_BUG */
#define __BUG_FLAGS(flags) do { \
__asm__ __volatile__ ("ebreak\n"); \
@@ -78,6 +83,8 @@ do { \
#define __WARN_FLAGS(flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
+#define ARCH_WARN_REACHABLE
+
#define HAVE_ARCH_BUG
#include <asm-generic/bug.h>
--
2.43.0
^ permalink raw reply related [flat|nested] 17+ messages in thread* Re: [PATCH v3 2/5] riscv/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
2025-02-13 13:57 ` [PATCH v3 2/5] riscv/bug: " FUJITA Tomonori
@ 2025-02-28 10:13 ` Alexandre Ghiti
0 siblings, 0 replies; 17+ messages in thread
From: Alexandre Ghiti @ 2025-02-28 10:13 UTC (permalink / raw)
To: FUJITA Tomonori, linux-kernel, rust-for-linux
Cc: x86, linux-riscv, linux-arm-kernel, loongarch, tglx, mingo, bp,
dave.hansen, peterz, hpa, paul.walmsley, palmer, aou,
catalin.marinas, will, chenhuacai, kernel, tangyouling, hejinyang,
yangtiezhu, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
benno.lossin, a.hindborg, aliceryhl, tmgross
Hi FUJITA,
On 13/02/2025 14:57, FUJITA Tomonori wrote:
> Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
> Rust to avoid the duplication.
>
> No functional changes.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> ---
> arch/riscv/include/asm/bug.h | 37 +++++++++++++++++++++---------------
> 1 file changed, 22 insertions(+), 15 deletions(-)
>
> diff --git a/arch/riscv/include/asm/bug.h b/arch/riscv/include/asm/bug.h
> index 1aaea81fb141..6ab13b56feb0 100644
> --- a/arch/riscv/include/asm/bug.h
> +++ b/arch/riscv/include/asm/bug.h
> @@ -31,40 +31,45 @@ typedef u32 bug_insn_t;
>
> #ifdef CONFIG_GENERIC_BUG_RELATIVE_POINTERS
> #define __BUG_ENTRY_ADDR RISCV_INT " 1b - ."
> -#define __BUG_ENTRY_FILE RISCV_INT " %0 - ."
> +#define __BUG_ENTRY_FILE(file) RISCV_INT " " file " - ."
> #else
> #define __BUG_ENTRY_ADDR RISCV_PTR " 1b"
> -#define __BUG_ENTRY_FILE RISCV_PTR " %0"
> +#define __BUG_ENTRY_FILE(file) RISCV_PTR " " file
> #endif
>
> #ifdef CONFIG_DEBUG_BUGVERBOSE
> -#define __BUG_ENTRY \
> +#define __BUG_ENTRY(file, line, flags) \
> __BUG_ENTRY_ADDR "\n\t" \
> - __BUG_ENTRY_FILE "\n\t" \
> - RISCV_SHORT " %1\n\t" \
> - RISCV_SHORT " %2"
> + __BUG_ENTRY_FILE(file) "\n\t" \
> + RISCV_SHORT " " line "\n\t" \
> + RISCV_SHORT " " flags
> #else
> -#define __BUG_ENTRY \
> - __BUG_ENTRY_ADDR "\n\t" \
> - RISCV_SHORT " %2"
> +#define __BUG_ENTRY(file, line, flags) \
> + __BUG_ENTRY_ADDR "\n\t" \
> + RISCV_SHORT " " flags
> #endif
>
> #ifdef CONFIG_GENERIC_BUG
> -#define __BUG_FLAGS(flags) \
> -do { \
> - __asm__ __volatile__ ( \
> +
> +#define ARCH_WARN_ASM(file, line, flags, size) \
> "1:\n\t" \
> "ebreak\n" \
> ".pushsection __bug_table,\"aw\"\n\t" \
> "2:\n\t" \
> - __BUG_ENTRY "\n\t" \
> - ".org 2b + %3\n\t" \
> - ".popsection" \
> + __BUG_ENTRY(file, line, flags) "\n\t" \
> + ".org 2b + " size "\n\t" \
> + ".popsection\n" \
> +
> +#define __BUG_FLAGS(flags) \
> +do { \
> + __asm__ __volatile__ ( \
> + ARCH_WARN_ASM("%0", "%1", "%2", "%3") \
> : \
> : "i" (__FILE__), "i" (__LINE__), \
> "i" (flags), \
> "i" (sizeof(struct bug_entry))); \
> } while (0)
> +
> #else /* CONFIG_GENERIC_BUG */
> #define __BUG_FLAGS(flags) do { \
> __asm__ __volatile__ ("ebreak\n"); \
> @@ -78,6 +83,8 @@ do { \
>
> #define __WARN_FLAGS(flags) __BUG_FLAGS(BUGFLAG_WARNING|(flags))
>
> +#define ARCH_WARN_REACHABLE
> +
> #define HAVE_ARCH_BUG
>
> #include <asm-generic/bug.h>
This looks good to me so:
Acked-by: Alexandre Ghiti <alexghiti@rivosinc.com>
Thanks,
Alex
^ permalink raw reply [flat|nested] 17+ messages in thread
* [PATCH v3 3/5] arm64/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
2025-02-13 13:57 ` [PATCH v3 0/5] rust: Add bug/warn abstractions FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 1/5] x86/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 2/5] riscv/bug: " FUJITA Tomonori
@ 2025-02-13 13:57 ` FUJITA Tomonori
2025-02-26 19:27 ` Catalin Marinas
2025-02-13 13:57 ` [PATCH v3 4/5] loongarch/bug: " FUJITA Tomonori
` (2 subsequent siblings)
5 siblings, 1 reply; 17+ messages in thread
From: FUJITA Tomonori @ 2025-02-13 13:57 UTC (permalink / raw)
To: linux-kernel, rust-for-linux
Cc: x86, linux-riscv, linux-arm-kernel, loongarch, tglx, mingo, bp,
dave.hansen, peterz, hpa, paul.walmsley, palmer, aou,
catalin.marinas, will, chenhuacai, kernel, tangyouling, hejinyang,
yangtiezhu, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
benno.lossin, a.hindborg, aliceryhl, tmgross
Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
Rust to avoid the duplication.
No functional changes.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
arch/arm64/include/asm/asm-bug.h | 33 ++++++++++++++++++++++++++++----
1 file changed, 29 insertions(+), 4 deletions(-)
diff --git a/arch/arm64/include/asm/asm-bug.h b/arch/arm64/include/asm/asm-bug.h
index 6e73809f6492..a5f13801b784 100644
--- a/arch/arm64/include/asm/asm-bug.h
+++ b/arch/arm64/include/asm/asm-bug.h
@@ -21,16 +21,21 @@
#endif
#ifdef CONFIG_GENERIC_BUG
-
-#define __BUG_ENTRY(flags) \
+#define __BUG_ENTRY_START \
.pushsection __bug_table,"aw"; \
.align 2; \
14470: .long 14471f - .; \
-_BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
- .short flags; \
+
+#define __BUG_ENTRY_END \
.align 2; \
.popsection; \
14471:
+
+#define __BUG_ENTRY(flags) \
+ __BUG_ENTRY_START \
+_BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
+ .short flags; \
+ __BUG_ENTRY_END
#else
#define __BUG_ENTRY(flags)
#endif
@@ -41,4 +46,24 @@ _BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
#define ASM_BUG() ASM_BUG_FLAGS(0)
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+#define __BUG_LOCATION_STRING(file, line) \
+ ".long " file "- .;" \
+ ".short " line ";"
+#else
+#define __BUG_LOCATION_STRING(file, line)
+#endif
+
+#define __BUG_ENTRY_STRING(file, line, flags) \
+ __stringify(__BUG_ENTRY_START) \
+ __BUG_LOCATION_STRING(file, line) \
+ ".short " flags ";" \
+ __stringify(__BUG_ENTRY_END)
+
+#define ARCH_WARN_ASM(file, line, flags, size) \
+ __BUG_ENTRY_STRING(file, line, flags) \
+ __stringify(brk BUG_BRK_IMM)
+
+#define ARCH_WARN_REACHABLE
+
#endif /* __ASM_ASM_BUG_H */
--
2.43.0
^ permalink raw reply related [flat|nested] 17+ messages in thread* Re: [PATCH v3 3/5] arm64/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
2025-02-13 13:57 ` [PATCH v3 3/5] arm64/bug: " FUJITA Tomonori
@ 2025-02-26 19:27 ` Catalin Marinas
2025-02-27 7:01 ` FUJITA Tomonori
0 siblings, 1 reply; 17+ messages in thread
From: Catalin Marinas @ 2025-02-26 19:27 UTC (permalink / raw)
To: FUJITA Tomonori
Cc: linux-kernel, rust-for-linux, x86, linux-riscv, linux-arm-kernel,
loongarch, tglx, mingo, bp, dave.hansen, peterz, hpa,
paul.walmsley, palmer, aou, will, chenhuacai, kernel, tangyouling,
hejinyang, yangtiezhu, ojeda, alex.gaynor, boqun.feng, gary,
bjorn3_gh, benno.lossin, a.hindborg, aliceryhl, tmgross
On Thu, Feb 13, 2025 at 10:57:57PM +0900, FUJITA Tomonori wrote:
> Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
> Rust to avoid the duplication.
>
> No functional changes.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
Acked-by: Catalin Marinas <catalin.marinas@arm.com>
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v3 3/5] arm64/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
2025-02-26 19:27 ` Catalin Marinas
@ 2025-02-27 7:01 ` FUJITA Tomonori
0 siblings, 0 replies; 17+ messages in thread
From: FUJITA Tomonori @ 2025-02-27 7:01 UTC (permalink / raw)
To: catalin.marinas, chenhuacai, kernel, loongarch, paul.walmsley,
palmer, aou, linux-riscv
Cc: fujita.tomonori, linux-kernel, rust-for-linux, x86,
linux-arm-kernel, tglx, mingo, bp, dave.hansen, peterz, hpa, will,
tangyouling, hejinyang, yangtiezhu, ojeda, alex.gaynor,
boqun.feng, gary, bjorn3_gh, benno.lossin, a.hindborg, aliceryhl,
tmgross
On Wed, 26 Feb 2025 19:27:55 +0000
Catalin Marinas <catalin.marinas@arm.com> wrote:
> On Thu, Feb 13, 2025 at 10:57:57PM +0900, FUJITA Tomonori wrote:
>> Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
>> Rust to avoid the duplication.
>>
>> No functional changes.
>>
>> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
>
> Acked-by: Catalin Marinas <catalin.marinas@arm.com>
Thanks a lot!
RISC-V and LoongArch maintainers,
Can I get an ack? Or you prefer a different approach?
^ permalink raw reply [flat|nested] 17+ messages in thread
* [PATCH v3 4/5] loongarch/bug: Add ARCH_WARN_ASM macro for BUG/WARN asm code sharing with Rust
2025-02-13 13:57 ` [PATCH v3 0/5] rust: Add bug/warn abstractions FUJITA Tomonori
` (2 preceding siblings ...)
2025-02-13 13:57 ` [PATCH v3 3/5] arm64/bug: " FUJITA Tomonori
@ 2025-02-13 13:57 ` FUJITA Tomonori
2025-02-13 13:57 ` [PATCH v3 5/5] rust: Add warn_on and warn_on_once FUJITA Tomonori
2025-02-26 19:39 ` [PATCH v3 0/5] rust: Add bug/warn abstractions Andreas Hindborg
5 siblings, 0 replies; 17+ messages in thread
From: FUJITA Tomonori @ 2025-02-13 13:57 UTC (permalink / raw)
To: linux-kernel, rust-for-linux
Cc: x86, linux-riscv, linux-arm-kernel, loongarch, tglx, mingo, bp,
dave.hansen, peterz, hpa, paul.walmsley, palmer, aou,
catalin.marinas, will, chenhuacai, kernel, tangyouling, hejinyang,
yangtiezhu, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
benno.lossin, a.hindborg, aliceryhl, tmgross
Add new ARCH_WARN_ASM macro for BUG/WARN assembly code sharing with
Rust to avoid the duplication.
No functional changes.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
arch/loongarch/include/asm/bug.h | 35 ++++++++++++++++++++++++++++----
1 file changed, 31 insertions(+), 4 deletions(-)
diff --git a/arch/loongarch/include/asm/bug.h b/arch/loongarch/include/asm/bug.h
index f6f254f2c5db..06903aef1101 100644
--- a/arch/loongarch/include/asm/bug.h
+++ b/arch/loongarch/include/asm/bug.h
@@ -22,14 +22,21 @@
#ifndef CONFIG_GENERIC_BUG
#define __BUG_ENTRY(flags)
#else
-#define __BUG_ENTRY(flags) \
+
+#define __BUG_ENTRY_START \
.pushsection __bug_table, "aw"; \
.align 2; \
10000: .long 10001f - .; \
- _BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
- .short flags; \
+
+#define __BUG_ENTRY_END \
.popsection; \
10001:
+
+#define __BUG_ENTRY(flags) \
+ __BUG_ENTRY_START \
+ _BUGVERBOSE_LOCATION(__FILE__, __LINE__) \
+ .short flags; \
+ __BUG_ENTRY_END
#endif
#define ASM_BUG_FLAGS(flags) \
@@ -42,10 +49,12 @@
asm_inline volatile (__stringify(ASM_BUG_FLAGS(flags)) \
extra);
+#define ARCH_WARN_REACHABLE ANNOTATE_REACHABLE(10001b)
+
#define __WARN_FLAGS(flags) \
do { \
instrumentation_begin(); \
- __BUG_FLAGS(BUGFLAG_WARNING|(flags), ANNOTATE_REACHABLE(10001b));\
+ __BUG_FLAGS(BUGFLAG_WARNING|(flags), ARCH_WARN_REACHABLE);\
instrumentation_end(); \
} while (0)
@@ -56,6 +65,24 @@ do { \
unreachable(); \
} while (0)
+#ifdef CONFIG_DEBUG_BUGVERBOSE
+#define __BUG_LOCATION_STRING(file, line) \
+ ".long " file "- .;" \
+ ".short " line ";"
+#else
+#define __BUG_LOCATION_STRING(file, line)
+#endif
+
+#define __BUG_ENTRY_STRING(file, line, flags) \
+ __stringify(__BUG_ENTRY_START) \
+ __BUG_LOCATION_STRING(file, line) \
+ ".short " flags ";" \
+ __stringify(__BUG_ENTRY_END)
+
+#define ARCH_WARN_ASM(file, line, flags, size) \
+ __BUG_ENTRY_STRING(file, line, flags) \
+ __stringify(break BRK_BUG) ";"
+
#define HAVE_ARCH_BUG
#include <asm-generic/bug.h>
--
2.43.0
^ permalink raw reply related [flat|nested] 17+ messages in thread* [PATCH v3 5/5] rust: Add warn_on and warn_on_once
2025-02-13 13:57 ` [PATCH v3 0/5] rust: Add bug/warn abstractions FUJITA Tomonori
` (3 preceding siblings ...)
2025-02-13 13:57 ` [PATCH v3 4/5] loongarch/bug: " FUJITA Tomonori
@ 2025-02-13 13:57 ` FUJITA Tomonori
2025-03-03 13:33 ` Alice Ryhl
2025-03-05 8:42 ` Alice Ryhl
2025-02-26 19:39 ` [PATCH v3 0/5] rust: Add bug/warn abstractions Andreas Hindborg
5 siblings, 2 replies; 17+ messages in thread
From: FUJITA Tomonori @ 2025-02-13 13:57 UTC (permalink / raw)
To: linux-kernel, rust-for-linux
Cc: x86, linux-riscv, linux-arm-kernel, loongarch, tglx, mingo, bp,
dave.hansen, peterz, hpa, paul.walmsley, palmer, aou,
catalin.marinas, will, chenhuacai, kernel, tangyouling, hejinyang,
yangtiezhu, ojeda, alex.gaynor, boqun.feng, gary, bjorn3_gh,
benno.lossin, a.hindborg, aliceryhl, tmgross
Add warn_on and warn_on_once macros. Wrapping the C's WARN_* and BUG_*
macros doesn't work so this uses the assembly code exported by the C
side via ARCH_WARN_ASM macro. Like the static branch code, this
generates the assembly code for rust at compile time by using the C
preprocessor.
file()! macro doesn't work for the Rust inline assembly in the same
way as __FILE__ for the C inline assembly. So the code to handle a
file name is different from the C assembly code (similar to the
arm64/loongarch assembly).
Similarly, ARCH_WARN_REACHABLE is also used at compile time to
generate the assembly code; objtool's reachable anotation code. Only
architectures that use objtool (x86 and loongarch) need it.
Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
---
rust/Makefile | 8 ++
rust/kernel/.gitignore | 2 +
rust/kernel/bug.rs | 100 ++++++++++++++++++
rust/kernel/generated_arch_reachable_asm.rs.S | 7 ++
rust/kernel/generated_arch_warn_asm.rs.S | 7 ++
rust/kernel/lib.rs | 1 +
6 files changed, 125 insertions(+)
create mode 100644 rust/kernel/bug.rs
create mode 100644 rust/kernel/generated_arch_reachable_asm.rs.S
create mode 100644 rust/kernel/generated_arch_warn_asm.rs.S
diff --git a/rust/Makefile b/rust/Makefile
index 8fcfd60447bc..a295b65c43f3 100644
--- a/rust/Makefile
+++ b/rust/Makefile
@@ -34,6 +34,9 @@ obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated.o
obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.o
always-$(subst y,$(CONFIG_RUST),$(CONFIG_JUMP_LABEL)) += kernel/generated_arch_static_branch_asm.rs
+ifndef CONFIG_UML
+always-$(subst y,$(CONFIG_RUST),$(CONFIG_BUG)) += kernel/generated_arch_warn_asm.rs kernel/generated_arch_reachable_asm.rs
+endif
# Avoids running `$(RUSTC)` when it may not be available.
ifdef CONFIG_RUST
@@ -481,5 +484,10 @@ $(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/build_error.o \
ifdef CONFIG_JUMP_LABEL
$(obj)/kernel.o: $(obj)/kernel/generated_arch_static_branch_asm.rs
endif
+ifndef CONFIG_UML
+ifdef CONFIG_BUG
+$(obj)/kernel.o: $(obj)/kernel/generated_arch_warn_asm.rs $(obj)/kernel/generated_arch_reachable_asm.rs
+endif
+endif
endif # CONFIG_RUST
diff --git a/rust/kernel/.gitignore b/rust/kernel/.gitignore
index 6ba39a178f30..f1d7f4225332 100644
--- a/rust/kernel/.gitignore
+++ b/rust/kernel/.gitignore
@@ -1,3 +1,5 @@
# SPDX-License-Identifier: GPL-2.0
/generated_arch_static_branch_asm.rs
+/generated_arch_warn_asm.rs
+/generated_arch_reachable_asm.rs
\ No newline at end of file
diff --git a/rust/kernel/bug.rs b/rust/kernel/bug.rs
new file mode 100644
index 000000000000..7ffd9cb1ad75
--- /dev/null
+++ b/rust/kernel/bug.rs
@@ -0,0 +1,100 @@
+// SPDX-License-Identifier: GPL-2.0
+
+// Copyright (C) 2024 FUJITA Tomonori
+
+//! Support for BUG_* and WARN_* functionality.
+//!
+//! C header: [`include/asm-generic/bug.h`](srctree/include/asm-generic/bug.h)
+
+#[macro_export]
+#[doc(hidden)]
+#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
+macro_rules! warn_flags {
+ ($flags:expr) => {
+ const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
+ // SAFETY: Just an FFI call.
+ #[cfg(CONFIG_DEBUG_BUGVERBOSE)]
+ unsafe {
+ $crate::asm!(concat!(
+ "/* {size} */",
+ ".pushsection .rodata.str1.1, \"aMS\",@progbits, 1\n",
+ "111:\t .string ", "\"", file!(), "\"\n",
+ ".popsection\n",
+ include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
+ include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
+ line = const line!(),
+ flags = const FLAGS,
+ size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
+ );
+ }
+ // SAFETY: Just an FFI call.
+ #[cfg(not(CONFIG_DEBUG_BUGVERBOSE))]
+ unsafe {
+ $crate::asm!(
+ concat!(
+ "/* {size} */",
+ include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
+ include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
+ flags = const FLAGS,
+ size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
+ );
+ }
+ }
+}
+
+#[macro_export]
+#[doc(hidden)]
+#[cfg(all(CONFIG_BUG, CONFIG_UML))]
+macro_rules! warn_flags {
+ ($flags:expr) => {
+ // SAFETY: Just an FFI call.
+ unsafe {
+ $crate::bindings::warn_slowpath_fmt(
+ $crate::c_str!(::core::file!()).as_ptr() as *const ::core::ffi::c_char,
+ line!() as i32,
+ $flags as u32,
+ ::core::ptr::null() as *const ::core::ffi::c_char,
+ );
+ }
+ };
+}
+
+#[macro_export]
+#[doc(hidden)]
+#[cfg(not(CONFIG_BUG))]
+macro_rules! warn_flags {
+ ($flags:expr) => {};
+}
+
+#[doc(hidden)]
+#[macro_export]
+macro_rules! bugflag_taint {
+ ($taint:expr) => {
+ $taint << 8
+ };
+}
+
+/// Report a warning only once.
+#[macro_export]
+macro_rules! warn_on_once {
+ ($cond:expr) => {
+ if $cond {
+ $crate::warn_flags!(
+ $crate::bindings::BUGFLAG_ONCE
+ | $crate::bugflag_taint!($crate::bindings::TAINT_WARN)
+ );
+ }
+ $cond
+ };
+}
+
+/// Report a warning.
+#[macro_export]
+macro_rules! warn_on {
+ ($cond:expr) => {
+ if $cond {
+ $crate::warn_flags!($crate::bugflag_taint!($crate::bindings::TAINT_WARN));
+ }
+ $cond
+ };
+}
diff --git a/rust/kernel/generated_arch_reachable_asm.rs.S b/rust/kernel/generated_arch_reachable_asm.rs.S
new file mode 100644
index 000000000000..3886a9ad3a99
--- /dev/null
+++ b/rust/kernel/generated_arch_reachable_asm.rs.S
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/bug.h>
+
+// Cut here.
+
+::kernel::concat_literals!(ARCH_WARN_REACHABLE)
diff --git a/rust/kernel/generated_arch_warn_asm.rs.S b/rust/kernel/generated_arch_warn_asm.rs.S
new file mode 100644
index 000000000000..8f239b431aa4
--- /dev/null
+++ b/rust/kernel/generated_arch_warn_asm.rs.S
@@ -0,0 +1,7 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+
+#include <linux/bug.h>
+
+// Cut here.
+
+::kernel::concat_literals!(ARCH_WARN_ASM("111b", "{line}", "{flags}", "{size}"))
diff --git a/rust/kernel/lib.rs b/rust/kernel/lib.rs
index 496ed32b0911..c0720846b249 100644
--- a/rust/kernel/lib.rs
+++ b/rust/kernel/lib.rs
@@ -38,6 +38,7 @@
pub mod alloc;
#[cfg(CONFIG_BLOCK)]
pub mod block;
+pub mod bug;
#[doc(hidden)]
pub mod build_assert;
pub mod cred;
--
2.43.0
^ permalink raw reply related [flat|nested] 17+ messages in thread* Re: [PATCH v3 5/5] rust: Add warn_on and warn_on_once
2025-02-13 13:57 ` [PATCH v3 5/5] rust: Add warn_on and warn_on_once FUJITA Tomonori
@ 2025-03-03 13:33 ` Alice Ryhl
2025-03-05 5:13 ` FUJITA Tomonori
2025-03-05 8:42 ` Alice Ryhl
1 sibling, 1 reply; 17+ messages in thread
From: Alice Ryhl @ 2025-03-03 13:33 UTC (permalink / raw)
To: FUJITA Tomonori
Cc: linux-kernel, rust-for-linux, x86, linux-riscv, linux-arm-kernel,
loongarch, tglx, mingo, bp, dave.hansen, peterz, hpa,
paul.walmsley, palmer, aou, catalin.marinas, will, chenhuacai,
kernel, tangyouling, hejinyang, yangtiezhu, ojeda, alex.gaynor,
boqun.feng, gary, bjorn3_gh, benno.lossin, a.hindborg, tmgross
On Thu, Feb 13, 2025 at 3:01 PM FUJITA Tomonori
<fujita.tomonori@gmail.com> wrote:
>
> Add warn_on and warn_on_once macros. Wrapping the C's WARN_* and BUG_*
> macros doesn't work so this uses the assembly code exported by the C
> side via ARCH_WARN_ASM macro. Like the static branch code, this
> generates the assembly code for rust at compile time by using the C
> preprocessor.
>
> file()! macro doesn't work for the Rust inline assembly in the same
> way as __FILE__ for the C inline assembly. So the code to handle a
> file name is different from the C assembly code (similar to the
> arm64/loongarch assembly).
>
> Similarly, ARCH_WARN_REACHABLE is also used at compile time to
> generate the assembly code; objtool's reachable anotation code. Only
> architectures that use objtool (x86 and loongarch) need it.
>
> Signed-off-by: FUJITA Tomonori <fujita.tomonori@gmail.com>
> ---
> rust/Makefile | 8 ++
> rust/kernel/.gitignore | 2 +
> rust/kernel/bug.rs | 100 ++++++++++++++++++
> rust/kernel/generated_arch_reachable_asm.rs.S | 7 ++
> rust/kernel/generated_arch_warn_asm.rs.S | 7 ++
> rust/kernel/lib.rs | 1 +
> 6 files changed, 125 insertions(+)
> create mode 100644 rust/kernel/bug.rs
> create mode 100644 rust/kernel/generated_arch_reachable_asm.rs.S
> create mode 100644 rust/kernel/generated_arch_warn_asm.rs.S
>
> diff --git a/rust/Makefile b/rust/Makefile
> index 8fcfd60447bc..a295b65c43f3 100644
> --- a/rust/Makefile
> +++ b/rust/Makefile
> @@ -34,6 +34,9 @@ obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated.o
> obj-$(CONFIG_RUST_KERNEL_DOCTESTS) += doctests_kernel_generated_kunit.o
>
> always-$(subst y,$(CONFIG_RUST),$(CONFIG_JUMP_LABEL)) += kernel/generated_arch_static_branch_asm.rs
> +ifndef CONFIG_UML
> +always-$(subst y,$(CONFIG_RUST),$(CONFIG_BUG)) += kernel/generated_arch_warn_asm.rs kernel/generated_arch_reachable_asm.rs
> +endif
>
> # Avoids running `$(RUSTC)` when it may not be available.
> ifdef CONFIG_RUST
> @@ -481,5 +484,10 @@ $(obj)/kernel.o: $(src)/kernel/lib.rs $(obj)/build_error.o \
> ifdef CONFIG_JUMP_LABEL
> $(obj)/kernel.o: $(obj)/kernel/generated_arch_static_branch_asm.rs
> endif
> +ifndef CONFIG_UML
> +ifdef CONFIG_BUG
> +$(obj)/kernel.o: $(obj)/kernel/generated_arch_warn_asm.rs $(obj)/kernel/generated_arch_reachable_asm.rs
> +endif
> +endif
>
> endif # CONFIG_RUST
> diff --git a/rust/kernel/.gitignore b/rust/kernel/.gitignore
> index 6ba39a178f30..f1d7f4225332 100644
> --- a/rust/kernel/.gitignore
> +++ b/rust/kernel/.gitignore
> @@ -1,3 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0
>
> /generated_arch_static_branch_asm.rs
> +/generated_arch_warn_asm.rs
> +/generated_arch_reachable_asm.rs
> \ No newline at end of file
> diff --git a/rust/kernel/bug.rs b/rust/kernel/bug.rs
> new file mode 100644
> index 000000000000..7ffd9cb1ad75
> --- /dev/null
> +++ b/rust/kernel/bug.rs
> @@ -0,0 +1,100 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +// Copyright (C) 2024 FUJITA Tomonori
> +
> +//! Support for BUG_* and WARN_* functionality.
> +//!
> +//! C header: [`include/asm-generic/bug.h`](srctree/include/asm-generic/bug.h)
> +
> +#[macro_export]
> +#[doc(hidden)]
> +#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
> +macro_rules! warn_flags {
> + ($flags:expr) => {
> + const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
> + // SAFETY: Just an FFI call.
> + #[cfg(CONFIG_DEBUG_BUGVERBOSE)]
> + unsafe {
> + $crate::asm!(concat!(
> + "/* {size} */",
> + ".pushsection .rodata.str1.1, \"aMS\",@progbits, 1\n",
> + "111:\t .string ", "\"", file!(), "\"\n",
> + ".popsection\n",
It looks like you're doing this so that you can reference the filename
with "111b", but could you do this instead:
const _FILE: &[u8] = file!().as_bytes();
// Plus one for nul-terminator.
static FILE: [u8; 1 + _FILE.len()] = {
let mut bytes = [0; 1 + _FILE.len()];
let mut i = 0;
while i < _FILE.len() {
bytes[i] = _FILE[i];
i += 1;
}
bytes
};
and then use
asm!(
concat!(
"/* {size} */",
include!(concat!(env!("OBJTREE"),
"/rust/kernel/generated_arch_warn_asm.rs")),
include!(concat!(env!("OBJTREE"),
"/rust/kernel/generated_arch_reachable_asm.rs")));
file = sym FILE,
line = const line!(),
...
);
with
::kernel::concat_literals!(ARCH_WARN_ASM("{file}", "{line}",
"{flags}", "{size}")),
That would be a lot simpler to understand than what you are doing.
Alice
^ permalink raw reply [flat|nested] 17+ messages in thread* Re: [PATCH v3 5/5] rust: Add warn_on and warn_on_once
2025-03-03 13:33 ` Alice Ryhl
@ 2025-03-05 5:13 ` FUJITA Tomonori
0 siblings, 0 replies; 17+ messages in thread
From: FUJITA Tomonori @ 2025-03-05 5:13 UTC (permalink / raw)
To: aliceryhl
Cc: fujita.tomonori, linux-kernel, rust-for-linux, x86, linux-riscv,
linux-arm-kernel, loongarch, tglx, mingo, bp, dave.hansen, peterz,
hpa, paul.walmsley, palmer, aou, catalin.marinas, will,
chenhuacai, kernel, tangyouling, hejinyang, yangtiezhu, ojeda,
alex.gaynor, boqun.feng, gary, bjorn3_gh, benno.lossin,
a.hindborg, tmgross
On Mon, 3 Mar 2025 14:33:39 +0100
Alice Ryhl <aliceryhl@google.com> wrote:
>> +#[macro_export]
>> +#[doc(hidden)]
>> +#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
>> +macro_rules! warn_flags {
>> + ($flags:expr) => {
>> + const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
>> + // SAFETY: Just an FFI call.
>> + #[cfg(CONFIG_DEBUG_BUGVERBOSE)]
>> + unsafe {
>> + $crate::asm!(concat!(
>> + "/* {size} */",
>> + ".pushsection .rodata.str1.1, \"aMS\",@progbits, 1\n",
>> + "111:\t .string ", "\"", file!(), "\"\n",
>> + ".popsection\n",
>
> It looks like you're doing this so that you can reference the filename
> with "111b", but could you do this instead:
>
> const _FILE: &[u8] = file!().as_bytes();
> // Plus one for nul-terminator.
> static FILE: [u8; 1 + _FILE.len()] = {
> let mut bytes = [0; 1 + _FILE.len()];
> let mut i = 0;
> while i < _FILE.len() {
> bytes[i] = _FILE[i];
> i += 1;
> }
> bytes
> };
Neat! I will use this in the next version.
> and then use
>
> asm!(
> concat!(
> "/* {size} */",
> include!(concat!(env!("OBJTREE"),
> "/rust/kernel/generated_arch_warn_asm.rs")),
> include!(concat!(env!("OBJTREE"),
> "/rust/kernel/generated_arch_reachable_asm.rs")));
> file = sym FILE,
> line = const line!(),
> ...
> );
>
> with
> ::kernel::concat_literals!(ARCH_WARN_ASM("{file}", "{line}",
> "{flags}", "{size}")),
>
> That would be a lot simpler to understand than what you are doing.
Indeed.
Thanks a lot!
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v3 5/5] rust: Add warn_on and warn_on_once
2025-02-13 13:57 ` [PATCH v3 5/5] rust: Add warn_on and warn_on_once FUJITA Tomonori
2025-03-03 13:33 ` Alice Ryhl
@ 2025-03-05 8:42 ` Alice Ryhl
2025-03-05 10:24 ` FUJITA Tomonori
1 sibling, 1 reply; 17+ messages in thread
From: Alice Ryhl @ 2025-03-05 8:42 UTC (permalink / raw)
To: FUJITA Tomonori
Cc: linux-kernel, rust-for-linux, x86, linux-riscv, linux-arm-kernel,
loongarch, tglx, mingo, bp, dave.hansen, peterz, hpa,
paul.walmsley, palmer, aou, catalin.marinas, will, chenhuacai,
kernel, tangyouling, hejinyang, yangtiezhu, ojeda, alex.gaynor,
boqun.feng, gary, bjorn3_gh, benno.lossin, a.hindborg, tmgross
On Thu, Feb 13, 2025 at 10:57:59PM +0900, FUJITA Tomonori wrote:
> Add warn_on and warn_on_once macros. Wrapping the C's WARN_* and BUG_*
> macros doesn't work so this uses the assembly code exported by the C
> side via ARCH_WARN_ASM macro. Like the static branch code, this
> generates the assembly code for rust at compile time by using the C
> preprocessor.
>
> file()! macro doesn't work for the Rust inline assembly in the same
> way as __FILE__ for the C inline assembly. So the code to handle a
> file name is different from the C assembly code (similar to the
> arm64/loongarch assembly).
Nit: Should be file!() not file()!.
> diff --git a/rust/kernel/.gitignore b/rust/kernel/.gitignore
> index 6ba39a178f30..f1d7f4225332 100644
> --- a/rust/kernel/.gitignore
> +++ b/rust/kernel/.gitignore
> @@ -1,3 +1,5 @@
> # SPDX-License-Identifier: GPL-2.0
>
> /generated_arch_static_branch_asm.rs
> +/generated_arch_warn_asm.rs
> +/generated_arch_reachable_asm.rs
> \ No newline at end of file
There should be a newline.
> +++ b/rust/kernel/bug.rs
> @@ -0,0 +1,100 @@
> +// SPDX-License-Identifier: GPL-2.0
> +
> +// Copyright (C) 2024 FUJITA Tomonori
2025?
> +#[macro_export]
> +#[doc(hidden)]
> +#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
> +macro_rules! warn_flags {
> + ($flags:expr) => {
> + const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
> + // SAFETY: Just an FFI call.
> + #[cfg(CONFIG_DEBUG_BUGVERBOSE)]
> + unsafe {
> + $crate::asm!(concat!(
> + "/* {size} */",
> + ".pushsection .rodata.str1.1, \"aMS\",@progbits, 1\n",
> + "111:\t .string ", "\"", file!(), "\"\n",
> + ".popsection\n",
> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
> + line = const line!(),
> + flags = const FLAGS,
> + size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
> + );
> + }
> + // SAFETY: Just an FFI call.
> + #[cfg(not(CONFIG_DEBUG_BUGVERBOSE))]
> + unsafe {
> + $crate::asm!(
> + concat!(
> + "/* {size} */",
> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
> + flags = const FLAGS,
> + size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
> + );
> + }
I generally prefer to have the cfgs on the macro rather in its
expansion. That avoids emitting a lot of code that is not actually used.
> +#[doc(hidden)]
> +#[macro_export]
> +macro_rules! bugflag_taint {
> + ($taint:expr) => {
> + $taint << 8
> + };
> +}
This could just be a const fn.
> +/// Report a warning only once.
> +#[macro_export]
> +macro_rules! warn_on_once {
> + ($cond:expr) => {
> + if $cond {
> + $crate::warn_flags!(
> + $crate::bindings::BUGFLAG_ONCE
> + | $crate::bugflag_taint!($crate::bindings::TAINT_WARN)
Or maybe a constant?
const WARN_ON_ONCE_FLAGS: u32 = bindings::BUGFLAG_ONCE | (bindings::TAINT_WARN << 8);
$crate::warn_flags!($crate::bug::WARN_ON_ONCE_FLAGS);
Alice
^ permalink raw reply [flat|nested] 17+ messages in thread* Re: [PATCH v3 5/5] rust: Add warn_on and warn_on_once
2025-03-05 8:42 ` Alice Ryhl
@ 2025-03-05 10:24 ` FUJITA Tomonori
2025-03-05 10:36 ` Alice Ryhl
0 siblings, 1 reply; 17+ messages in thread
From: FUJITA Tomonori @ 2025-03-05 10:24 UTC (permalink / raw)
To: aliceryhl
Cc: fujita.tomonori, linux-kernel, rust-for-linux, x86, linux-riscv,
linux-arm-kernel, loongarch, tglx, mingo, bp, dave.hansen, peterz,
hpa, paul.walmsley, palmer, aou, catalin.marinas, will,
chenhuacai, kernel, tangyouling, hejinyang, yangtiezhu, ojeda,
alex.gaynor, boqun.feng, gary, bjorn3_gh, benno.lossin,
a.hindborg, tmgross
On Wed, 5 Mar 2025 08:42:57 +0000
Alice Ryhl <aliceryhl@google.com> wrote:
> On Thu, Feb 13, 2025 at 10:57:59PM +0900, FUJITA Tomonori wrote:
>> Add warn_on and warn_on_once macros. Wrapping the C's WARN_* and BUG_*
>> macros doesn't work so this uses the assembly code exported by the C
>> side via ARCH_WARN_ASM macro. Like the static branch code, this
>> generates the assembly code for rust at compile time by using the C
>> preprocessor.
>>
>> file()! macro doesn't work for the Rust inline assembly in the same
>> way as __FILE__ for the C inline assembly. So the code to handle a
>> file name is different from the C assembly code (similar to the
>> arm64/loongarch assembly).
>
> Nit: Should be file!() not file()!.
Ops, thanks.
Actually, the above comment is obsolete. With your solution in the
previous mail, I can remove the asm code for the file name. I'll
remove the comment.
>> diff --git a/rust/kernel/.gitignore b/rust/kernel/.gitignore
>> index 6ba39a178f30..f1d7f4225332 100644
>> --- a/rust/kernel/.gitignore
>> +++ b/rust/kernel/.gitignore
>> @@ -1,3 +1,5 @@
>> # SPDX-License-Identifier: GPL-2.0
>>
>> /generated_arch_static_branch_asm.rs
>> +/generated_arch_warn_asm.rs
>> +/generated_arch_reachable_asm.rs
>> \ No newline at end of file
>
> There should be a newline.
Ah, I'll fix.
>> +++ b/rust/kernel/bug.rs
>> @@ -0,0 +1,100 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +
>> +// Copyright (C) 2024 FUJITA Tomonori
>
> 2025?
I'll add.
>> +#[macro_export]
>> +#[doc(hidden)]
>> +#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
>> +macro_rules! warn_flags {
>> + ($flags:expr) => {
>> + const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
>> + // SAFETY: Just an FFI call.
>> + #[cfg(CONFIG_DEBUG_BUGVERBOSE)]
>> + unsafe {
>> + $crate::asm!(concat!(
>> + "/* {size} */",
>> + ".pushsection .rodata.str1.1, \"aMS\",@progbits, 1\n",
>> + "111:\t .string ", "\"", file!(), "\"\n",
>> + ".popsection\n",
>> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
>> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
>> + line = const line!(),
>> + flags = const FLAGS,
>> + size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
>> + );
>> + }
>> + // SAFETY: Just an FFI call.
>> + #[cfg(not(CONFIG_DEBUG_BUGVERBOSE))]
>> + unsafe {
>> + $crate::asm!(
>> + concat!(
>> + "/* {size} */",
>> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
>> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
>> + flags = const FLAGS,
>> + size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
>> + );
>> + }
>
> I generally prefer to have the cfgs on the macro rather in its
> expansion. That avoids emitting a lot of code that is not actually used.
You prefer the following?
#[cfg(all(CONFIG_BUG, CONFIG_DEBUG_BUGVERBOSE, not(CONFIG_UML)))]
macro_rules! warn_flags {
...
}
#[cfg(all(CONFIG_BUG, not(CONFIG_DEBUG_BUGVERBOSE), not(CONFIG_UML)))]
macro_rules! warn_flags {
...
}
>> +#[doc(hidden)]
>> +#[macro_export]
>> +macro_rules! bugflag_taint {
>> + ($taint:expr) => {
>> + $taint << 8
>> + };
>> +}
>
> This could just be a const fn.
Yeah, would a const fn be preferable?
>> +/// Report a warning only once.
>> +#[macro_export]
>> +macro_rules! warn_on_once {
>> + ($cond:expr) => {
>> + if $cond {
>> + $crate::warn_flags!(
>> + $crate::bindings::BUGFLAG_ONCE
>> + | $crate::bugflag_taint!($crate::bindings::TAINT_WARN)
>
> Or maybe a constant?
>
> const WARN_ON_ONCE_FLAGS: u32 = bindings::BUGFLAG_ONCE | (bindings::TAINT_WARN << 8);
Ok, but you prefer "<< 8" than using const fn bugflag_taint()?
> $crate::warn_flags!($crate::bug::WARN_ON_ONCE_FLAGS);
^ permalink raw reply [flat|nested] 17+ messages in thread* Re: [PATCH v3 5/5] rust: Add warn_on and warn_on_once
2025-03-05 10:24 ` FUJITA Tomonori
@ 2025-03-05 10:36 ` Alice Ryhl
0 siblings, 0 replies; 17+ messages in thread
From: Alice Ryhl @ 2025-03-05 10:36 UTC (permalink / raw)
To: FUJITA Tomonori
Cc: linux-kernel, rust-for-linux, x86, linux-riscv, linux-arm-kernel,
loongarch, tglx, mingo, bp, dave.hansen, peterz, hpa,
paul.walmsley, palmer, aou, catalin.marinas, will, chenhuacai,
kernel, tangyouling, hejinyang, yangtiezhu, ojeda, alex.gaynor,
boqun.feng, gary, bjorn3_gh, benno.lossin, a.hindborg, tmgross
On Wed, Mar 05, 2025 at 07:24:03PM +0900, FUJITA Tomonori wrote:
> On Wed, 5 Mar 2025 08:42:57 +0000
> Alice Ryhl <aliceryhl@google.com> wrote:
>
> > On Thu, Feb 13, 2025 at 10:57:59PM +0900, FUJITA Tomonori wrote:
> >> Add warn_on and warn_on_once macros. Wrapping the C's WARN_* and BUG_*
> >> macros doesn't work so this uses the assembly code exported by the C
> >> side via ARCH_WARN_ASM macro. Like the static branch code, this
> >> generates the assembly code for rust at compile time by using the C
> >> preprocessor.
> >>
> >> file()! macro doesn't work for the Rust inline assembly in the same
> >> way as __FILE__ for the C inline assembly. So the code to handle a
> >> file name is different from the C assembly code (similar to the
> >> arm64/loongarch assembly).
> >
> > Nit: Should be file!() not file()!.
>
> Ops, thanks.
>
> Actually, the above comment is obsolete. With your solution in the
> previous mail, I can remove the asm code for the file name. I'll
> remove the comment.
>
>
> >> diff --git a/rust/kernel/.gitignore b/rust/kernel/.gitignore
> >> index 6ba39a178f30..f1d7f4225332 100644
> >> --- a/rust/kernel/.gitignore
> >> +++ b/rust/kernel/.gitignore
> >> @@ -1,3 +1,5 @@
> >> # SPDX-License-Identifier: GPL-2.0
> >>
> >> /generated_arch_static_branch_asm.rs
> >> +/generated_arch_warn_asm.rs
> >> +/generated_arch_reachable_asm.rs
> >> \ No newline at end of file
> >
> > There should be a newline.
>
> Ah, I'll fix.
>
> >> +++ b/rust/kernel/bug.rs
> >> @@ -0,0 +1,100 @@
> >> +// SPDX-License-Identifier: GPL-2.0
> >> +
> >> +// Copyright (C) 2024 FUJITA Tomonori
> >
> > 2025?
>
> I'll add.
>
> >> +#[macro_export]
> >> +#[doc(hidden)]
> >> +#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
> >> +macro_rules! warn_flags {
> >> + ($flags:expr) => {
> >> + const FLAGS: u32 = $crate::bindings::BUGFLAG_WARNING | $flags;
> >> + // SAFETY: Just an FFI call.
> >> + #[cfg(CONFIG_DEBUG_BUGVERBOSE)]
> >> + unsafe {
> >> + $crate::asm!(concat!(
> >> + "/* {size} */",
> >> + ".pushsection .rodata.str1.1, \"aMS\",@progbits, 1\n",
> >> + "111:\t .string ", "\"", file!(), "\"\n",
> >> + ".popsection\n",
> >> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
> >> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
> >> + line = const line!(),
> >> + flags = const FLAGS,
> >> + size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
> >> + );
> >> + }
> >> + // SAFETY: Just an FFI call.
> >> + #[cfg(not(CONFIG_DEBUG_BUGVERBOSE))]
> >> + unsafe {
> >> + $crate::asm!(
> >> + concat!(
> >> + "/* {size} */",
> >> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_warn_asm.rs")),
> >> + include!(concat!(env!("OBJTREE"), "/rust/kernel/generated_arch_reachable_asm.rs")));
> >> + flags = const FLAGS,
> >> + size = const ::core::mem::size_of::<$crate::bindings::bug_entry>(),
> >> + );
> >> + }
> >
> > I generally prefer to have the cfgs on the macro rather in its
> > expansion. That avoids emitting a lot of code that is not actually used.
>
> You prefer the following?
>
> #[cfg(all(CONFIG_BUG, CONFIG_DEBUG_BUGVERBOSE, not(CONFIG_UML)))]
> macro_rules! warn_flags {
> ...
> }
>
> #[cfg(all(CONFIG_BUG, not(CONFIG_DEBUG_BUGVERBOSE), not(CONFIG_UML)))]
> macro_rules! warn_flags {
> ...
> }
In this case it probably reads better as
#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
#[cfg(CONFIG_DEBUG_BUGVERBOSE)]
macro_rules! warn_flags {
...
}
#[cfg(all(CONFIG_BUG, not(CONFIG_UML)))]
#[cfg(not(CONFIG_DEBUG_BUGVERBOSE))]
macro_rules! warn_flags {
...
}
but yes.
> >> +#[doc(hidden)]
> >> +#[macro_export]
> >> +macro_rules! bugflag_taint {
> >> + ($taint:expr) => {
> >> + $taint << 8
> >> + };
> >> +}
> >
> > This could just be a const fn.
>
> Yeah, would a const fn be preferable?
Yes, I think a constant or const fn is preferable over a macro whenever
possible.
> >> +/// Report a warning only once.
> >> +#[macro_export]
> >> +macro_rules! warn_on_once {
> >> + ($cond:expr) => {
> >> + if $cond {
> >> + $crate::warn_flags!(
> >> + $crate::bindings::BUGFLAG_ONCE
> >> + | $crate::bugflag_taint!($crate::bindings::TAINT_WARN)
> >
> > Or maybe a constant?
> >
> > const WARN_ON_ONCE_FLAGS: u32 = bindings::BUGFLAG_ONCE | (bindings::TAINT_WARN << 8);
>
> Ok, but you prefer "<< 8" than using const fn bugflag_taint()?
I'm also happy with
const WARN_ON_ONCE_FLAGS: u32 = bindings::BUGFLAG_ONCE | bugflag_taint(bindings::TAINT_WARN);
Up to you.
Alice
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v3 0/5] rust: Add bug/warn abstractions
2025-02-13 13:57 ` [PATCH v3 0/5] rust: Add bug/warn abstractions FUJITA Tomonori
` (4 preceding siblings ...)
2025-02-13 13:57 ` [PATCH v3 5/5] rust: Add warn_on and warn_on_once FUJITA Tomonori
@ 2025-02-26 19:39 ` Andreas Hindborg
2025-02-27 6:54 ` FUJITA Tomonori
5 siblings, 1 reply; 17+ messages in thread
From: Andreas Hindborg @ 2025-02-26 19:39 UTC (permalink / raw)
To: FUJITA Tomonori
Cc: linux-kernel, rust-for-linux, x86, linux-riscv, linux-arm-kernel,
loongarch, tglx, mingo, bp, dave.hansen, peterz, hpa,
paul.walmsley, palmer, aou, catalin.marinas, will, chenhuacai,
kernel, tangyouling, hejinyang, yangtiezhu, ojeda, alex.gaynor,
boqun.feng, gary, bjorn3_gh, benno.lossin, aliceryhl, tmgross
Hi Fujita,
"FUJITA Tomonori" <fujita.tomonori@gmail.com> writes:
> This patchset adds warn_on and warn_on_once macros with the bug/warn
> abstraction.
>
> Wrapping C's BUG/WARN macros does not work well for x86, RISC-V,
> ARM64, and LoongArch. Rust code needs to directly execute the same
> assembly code used on the C side. To avoid duplicating the assembly
> code, this approach mirrors what the static branch code does: it
> generates the assembly code for Rust using the C preprocessor at
> compile time.
>
> The 1st to 4th patches export the BUG/WARN assembly code for Rust on
> each architecture, with no functional changes on the C side. The
> changes for x86 and RISC-V are straightforward. However, the ARM64 and
> LoongArch assembly code are designed differently; they are used by
> both C inline assembly and assembly code. As a result, sharing this
> code with Rust is complicated.
>
> The last patch adds the bug abstraction with warn_on and warn_on_once
> implementations.
>
> This has been tested on x86, ARM64, and RISC-V (QEMU), with only a
> compile test performed for LoongArch.
>
> The assembly code can be used for both BUG and WARN, but currently
> only supports warn_on and warn_on_once. I will work on the remaining
> functionality after this abstraction is merged.
>
How does this series compare/overlap with [1] ?
Best regards,
Andreas Hindborg
[1] https://lore.kernel.org/all/20241126-pr_once_macros-v4-0-410b8ca9643e@tuta.io/
^ permalink raw reply [flat|nested] 17+ messages in thread* Re: [PATCH v3 0/5] rust: Add bug/warn abstractions
2025-02-26 19:39 ` [PATCH v3 0/5] rust: Add bug/warn abstractions Andreas Hindborg
@ 2025-02-27 6:54 ` FUJITA Tomonori
2025-02-27 8:28 ` Andreas Hindborg
0 siblings, 1 reply; 17+ messages in thread
From: FUJITA Tomonori @ 2025-02-27 6:54 UTC (permalink / raw)
To: a.hindborg
Cc: fujita.tomonori, linux-kernel, rust-for-linux, x86, linux-riscv,
linux-arm-kernel, loongarch, tglx, mingo, bp, dave.hansen, peterz,
hpa, paul.walmsley, palmer, aou, catalin.marinas, will,
chenhuacai, kernel, tangyouling, hejinyang, yangtiezhu, ojeda,
alex.gaynor, boqun.feng, gary, bjorn3_gh, benno.lossin, aliceryhl,
tmgross
On Wed, 26 Feb 2025 20:39:45 +0100
Andreas Hindborg <a.hindborg@kernel.org> wrote:
> How does this series compare/overlap with [1] ?
>
> [1] https://lore.kernel.org/all/20241126-pr_once_macros-v4-0-410b8ca9643e@tuta.io/
No overlap. Each solves a different problem. Both are necessary.
This patchset enables Rust code to call C's BUG/WARN properly.
Currently, Rust's BUG() is a simple wrapper for C's BUG()
(rust/helpers/bug.c). I added BUG() to rnull's init() and got the
following:
# insmod /root/rnull_mod.ko
rnull_mod: Rust null_blk loaded
------------[ cut here ]------------
kernel BUG at rust/helpers/bug.c:7!
Oops: invalid opcode: 0000 [#1] SMP
CPU: 0 UID: 0 PID: 31 Comm: insmod Not tainted 6.14.0-rc1+ #103
RIP: 0010:rust_helper_BUG+0x8/0x10
(snip)
This is NOT debug information that we expect. The problem is that
BUG/WARN feature (lib/bug.c) can only be used from assembly.
This patchset includes only warn() but with bug() implementation on
top of this patchset, I got:
# insmod /root/rnull_mod.ko
rnull_mod: Rust null_blk loaded
------------[ cut here ]------------
WARNING: CPU: 0 PID: 31 at /home/fujita/git/linux-rust/drivers/block/rnull.rs:46 _RNvXCsafUg3oOYix8_5rnullNtB2_13NullBlkModu]
Modules linked in: rnull_mod(+)
CPU: 0 UID: 0 PID: 31 Comm: insmod Not tainted 6.14.0-rc1+ #104
RIP: 0010:_RNvXCsafUg3oOYix8_5rnullNtB2_13NullBlkModuleNtCsaYBeKL739Xz_6kernel13InPlaceModule4init+0x71/0x4f0 [rnull_mod]
The [1] patchset adds an abstraciton for include/linux/once_lite.h,
'call a function once' feature, with pr_*_once() implementation.
pr_*_once() just calls printk() once. Unlike BUG/WARN, no debug
information (call place, registers, stack trace, etc).
The only connection between two patchset is that WARN_ONCE() can be
built on top of both like the C side.
^ permalink raw reply [flat|nested] 17+ messages in thread
* Re: [PATCH v3 0/5] rust: Add bug/warn abstractions
2025-02-27 6:54 ` FUJITA Tomonori
@ 2025-02-27 8:28 ` Andreas Hindborg
0 siblings, 0 replies; 17+ messages in thread
From: Andreas Hindborg @ 2025-02-27 8:28 UTC (permalink / raw)
To: FUJITA Tomonori
Cc: linux-kernel, rust-for-linux, x86, linux-riscv, linux-arm-kernel,
loongarch, tglx, mingo, bp, dave.hansen, peterz, hpa,
paul.walmsley, palmer, aou, catalin.marinas, will, chenhuacai,
kernel, tangyouling, hejinyang, yangtiezhu, ojeda, alex.gaynor,
boqun.feng, gary, bjorn3_gh, benno.lossin, aliceryhl, tmgross
"FUJITA Tomonori" <fujita.tomonori@gmail.com> writes:
> On Wed, 26 Feb 2025 20:39:45 +0100
> Andreas Hindborg <a.hindborg@kernel.org> wrote:
>
>> How does this series compare/overlap with [1] ?
>>
>> [1] https://lore.kernel.org/all/20241126-pr_once_macros-v4-0-410b8ca9643e@tuta.io/
>
> No overlap. Each solves a different problem. Both are necessary.
>
> This patchset enables Rust code to call C's BUG/WARN properly.
>
> Currently, Rust's BUG() is a simple wrapper for C's BUG()
> (rust/helpers/bug.c). I added BUG() to rnull's init() and got the
> following:
>
> # insmod /root/rnull_mod.ko
> rnull_mod: Rust null_blk loaded
> ------------[ cut here ]------------
> kernel BUG at rust/helpers/bug.c:7!
> Oops: invalid opcode: 0000 [#1] SMP
> CPU: 0 UID: 0 PID: 31 Comm: insmod Not tainted 6.14.0-rc1+ #103
> RIP: 0010:rust_helper_BUG+0x8/0x10
> (snip)
>
> This is NOT debug information that we expect. The problem is that
> BUG/WARN feature (lib/bug.c) can only be used from assembly.
>
> This patchset includes only warn() but with bug() implementation on
> top of this patchset, I got:
>
> # insmod /root/rnull_mod.ko
> rnull_mod: Rust null_blk loaded
> ------------[ cut here ]------------
> WARNING: CPU: 0 PID: 31 at /home/fujita/git/linux-rust/drivers/block/rnull.rs:46 _RNvXCsafUg3oOYix8_5rnullNtB2_13NullBlkModu]
> Modules linked in: rnull_mod(+)
> CPU: 0 UID: 0 PID: 31 Comm: insmod Not tainted 6.14.0-rc1+ #104
> RIP: 0010:_RNvXCsafUg3oOYix8_5rnullNtB2_13NullBlkModuleNtCsaYBeKL739Xz_6kernel13InPlaceModule4init+0x71/0x4f0 [rnull_mod]
>
>
> The [1] patchset adds an abstraciton for include/linux/once_lite.h,
> 'call a function once' feature, with pr_*_once() implementation.
>
> pr_*_once() just calls printk() once. Unlike BUG/WARN, no debug
> information (call place, registers, stack trace, etc).
>
>
> The only connection between two patchset is that WARN_ONCE() can be
> built on top of both like the C side.
Awesome, thanks for explaining 👍
Best regards,
Andreas Hindborg
^ permalink raw reply [flat|nested] 17+ messages in thread