[PATCH v4 0/6] elf: Define note name macros

[PATCH v4 0/6] elf: Define note name macros

[Akihiko Odaki]

elf.h had a comment saying:
> Notes used in ET_CORE. Architectures export some of the arch register
> sets using the corresponding note types via the PTRACE_GETREGSET and
> PTRACE_SETREGSET requests.
> The note name for these types is "LINUX", except NT_PRFPREG that is
> named "CORE".

However, NT_PRSTATUS is also named "CORE". It is also unclear what
"these types" refers to.

To fix these problems, define a name for each note type. The added
definitions are macros so the kernel and userspace can directly refer to
them.

For userspace program developers
---------------------------------------------------
While the main purpose of new macros is documentation, they are also
hoped to be useful for userspace programs. Please check patch
"elf: Define note name macros" and if you have a suggestion to make it
more convenient for you, please share.

I added the Binutils mailing list to the CC as it contains code to parse
dumps. I'm also planning to share this series on LLVM Discourse.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
Changes in v4:
- s/powwerpc/powerpc/
- s/NT_INIT/nt_init/g s/NT_SIZE/nt_size/g
- Removed parentheses that have little value.
- Fixed the code alignment in get_cpu_elf_notes_size().
- Link to v3: https://lore.kernel.org/r/20250107-elf-v3-0-99cb505b1ab2@daynix.com

Changes in v3:
- Added patch "s390/crash: Use note name macros".
- Changed to interleave note name and type macros.
- Described NN_ and NT_ macros.
- Link to v2: https://lore.kernel.org/r/20250104-elf-v2-0-77dc2e06db4e@daynix.com

Changes in v2:
- Added a macro definition for each note type instead of trying to
  describe in a comment.
- Link to v1: https://lore.kernel.org/r/20241225-elf-v1-1-79e940350d50@daynix.com

---
Akihiko Odaki (6):
      elf: Define note name macros
      binfmt_elf: Use note name macros
      powerpc: Use note name macros
      crash: Use note name macros
      s390/crash: Use note name macros
      crash: Remove KEXEC_CORE_NOTE_NAME

 arch/powerpc/kernel/fadump.c               |  2 +-
 arch/powerpc/platforms/powernv/opal-core.c |  8 +--
 arch/s390/kernel/crash_dump.c              | 62 ++++++++-------------
 fs/binfmt_elf.c                            | 21 ++++----
 fs/binfmt_elf_fdpic.c                      |  8 +--
 fs/proc/kcore.c                            | 12 ++---
 include/linux/kexec.h                      |  2 -
 include/linux/vmcore_info.h                |  3 +-
 include/uapi/linux/elf.h                   | 86 ++++++++++++++++++++++++++++--
 kernel/crash_core.c                        |  2 +-
 10 files changed, 133 insertions(+), 73 deletions(-)
---
base-commit: a32e14f8aef69b42826cf0998b068a43d486a9e9
change-id: 20241210-elf-b80ea3949c39

Best regards,
-- 
Akihiko Odaki <akihiko.odaki@daynix.com>

[PATCH v4 1/6] elf: Define note name macros

[Akihiko Odaki]

elf.h had a comment saying:
> Notes used in ET_CORE. Architectures export some of the arch register
> sets using the corresponding note types via the PTRACE_GETREGSET and
> PTRACE_SETREGSET requests.
> The note name for these types is "LINUX", except NT_PRFPREG that is
> named "CORE".

However, NT_PRSTATUS is also named "CORE". It is also unclear what
"these types" refers to.

To fix these problems, define a name for each note type. The added
definitions are macros so the kernel and userspace can directly refer to
them.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Baoquan He <bhe@redhat.com>
---
 include/uapi/linux/elf.h | 86 ++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 83 insertions(+), 3 deletions(-)

diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
index b44069d29cec..343f5c40d03a 100644
--- a/include/uapi/linux/elf.h
+++ b/include/uapi/linux/elf.h
@@ -368,99 +368,179 @@ typedef struct elf64_shdr {
 #define ELF_OSABI ELFOSABI_NONE
 #endif
 
+/* Note definitions: NN_ defines names. NT_ defines types. */
+
 /*
  * Notes used in ET_CORE. Architectures export some of the arch register sets
  * using the corresponding note types via the PTRACE_GETREGSET and
  * PTRACE_SETREGSET requests.
- * The note name for these types is "LINUX", except NT_PRFPREG that is named
- * "CORE".
  */
+#define NN_PRSTATUS	"CORE"
 #define NT_PRSTATUS	1
+#define NN_PRFPREG	"CORE"
 #define NT_PRFPREG	2
+#define NN_PRPSINFO	"CORE"
 #define NT_PRPSINFO	3
+#define NN_TASKSTRUCT	"CORE"
 #define NT_TASKSTRUCT	4
+#define NN_AUXV		"CORE"
 #define NT_AUXV		6
 /*
  * Note to userspace developers: size of NT_SIGINFO note may increase
  * in the future to accomodate more fields, don't assume it is fixed!
  */
+#define NN_SIGINFO      "CORE"
 #define NT_SIGINFO      0x53494749
+#define NN_FILE         "CORE"
 #define NT_FILE         0x46494c45
+#define NN_PRXFPREG     "LINUX"
 #define NT_PRXFPREG     0x46e62b7f      /* copied from gdb5.1/include/elf/common.h */
+#define NN_PPC_VMX	"LINUX"
 #define NT_PPC_VMX	0x100		/* PowerPC Altivec/VMX registers */
+#define NN_PPC_SPE	"LINUX"
 #define NT_PPC_SPE	0x101		/* PowerPC SPE/EVR registers */
+#define NN_PPC_VSX	"LINUX"
 #define NT_PPC_VSX	0x102		/* PowerPC VSX registers */
+#define NN_PPC_TAR	"LINUX"
 #define NT_PPC_TAR	0x103		/* Target Address Register */
+#define NN_PPC_PPR	"LINUX"
 #define NT_PPC_PPR	0x104		/* Program Priority Register */
+#define NN_PPC_DSCR	"LINUX"
 #define NT_PPC_DSCR	0x105		/* Data Stream Control Register */
+#define NN_PPC_EBB	"LINUX"
 #define NT_PPC_EBB	0x106		/* Event Based Branch Registers */
+#define NN_PPC_PMU	"LINUX"
 #define NT_PPC_PMU	0x107		/* Performance Monitor Registers */
+#define NN_PPC_TM_CGPR	"LINUX"
 #define NT_PPC_TM_CGPR	0x108		/* TM checkpointed GPR Registers */
+#define NN_PPC_TM_CFPR	"LINUX"
 #define NT_PPC_TM_CFPR	0x109		/* TM checkpointed FPR Registers */
+#define NN_PPC_TM_CVMX	"LINUX"
 #define NT_PPC_TM_CVMX	0x10a		/* TM checkpointed VMX Registers */
+#define NN_PPC_TM_CVSX	"LINUX"
 #define NT_PPC_TM_CVSX	0x10b		/* TM checkpointed VSX Registers */
+#define NN_PPC_TM_SPR	"LINUX"
 #define NT_PPC_TM_SPR	0x10c		/* TM Special Purpose Registers */
+#define NN_PPC_TM_CTAR	"LINUX"
 #define NT_PPC_TM_CTAR	0x10d		/* TM checkpointed Target Address Register */
+#define NN_PPC_TM_CPPR	"LINUX"
 #define NT_PPC_TM_CPPR	0x10e		/* TM checkpointed Program Priority Register */
+#define NN_PPC_TM_CDSCR	"LINUX"
 #define NT_PPC_TM_CDSCR	0x10f		/* TM checkpointed Data Stream Control Register */
+#define NN_PPC_PKEY	"LINUX"
 #define NT_PPC_PKEY	0x110		/* Memory Protection Keys registers */
+#define NN_PPC_DEXCR	"LINUX"
 #define NT_PPC_DEXCR	0x111		/* PowerPC DEXCR registers */
+#define NN_PPC_HASHKEYR	"LINUX"
 #define NT_PPC_HASHKEYR	0x112		/* PowerPC HASHKEYR register */
+#define NN_386_TLS	"LINUX"
 #define NT_386_TLS	0x200		/* i386 TLS slots (struct user_desc) */
+#define NN_386_IOPERM	"LINUX"
 #define NT_386_IOPERM	0x201		/* x86 io permission bitmap (1=deny) */
+#define NN_X86_XSTATE	"LINUX"
 #define NT_X86_XSTATE	0x202		/* x86 extended state using xsave */
 /* Old binutils treats 0x203 as a CET state */
+#define NN_X86_SHSTK	"LINUX"
 #define NT_X86_SHSTK	0x204		/* x86 SHSTK state */
+#define NN_X86_XSAVE_LAYOUT	"LINUX"
 #define NT_X86_XSAVE_LAYOUT	0x205	/* XSAVE layout description */
+#define NN_S390_HIGH_GPRS	"LINUX"
 #define NT_S390_HIGH_GPRS	0x300	/* s390 upper register halves */
+#define NN_S390_TIMER	"LINUX"
 #define NT_S390_TIMER	0x301		/* s390 timer register */
+#define NN_S390_TODCMP	"LINUX"
 #define NT_S390_TODCMP	0x302		/* s390 TOD clock comparator register */
+#define NN_S390_TODPREG	"LINUX"
 #define NT_S390_TODPREG	0x303		/* s390 TOD programmable register */
+#define NN_S390_CTRS	"LINUX"
 #define NT_S390_CTRS	0x304		/* s390 control registers */
+#define NN_S390_PREFIX	"LINUX"
 #define NT_S390_PREFIX	0x305		/* s390 prefix register */
+#define NN_S390_LAST_BREAK	"LINUX"
 #define NT_S390_LAST_BREAK	0x306	/* s390 breaking event address */
+#define NN_S390_SYSTEM_CALL	"LINUX"
 #define NT_S390_SYSTEM_CALL	0x307	/* s390 system call restart data */
+#define NN_S390_TDB	"LINUX"
 #define NT_S390_TDB	0x308		/* s390 transaction diagnostic block */
+#define NN_S390_VXRS_LOW	"LINUX"
 #define NT_S390_VXRS_LOW	0x309	/* s390 vector registers 0-15 upper half */
+#define NN_S390_VXRS_HIGH	"LINUX"
 #define NT_S390_VXRS_HIGH	0x30a	/* s390 vector registers 16-31 */
+#define NN_S390_GS_CB	"LINUX"
 #define NT_S390_GS_CB	0x30b		/* s390 guarded storage registers */
+#define NN_S390_GS_BC	"LINUX"
 #define NT_S390_GS_BC	0x30c		/* s390 guarded storage broadcast control block */
+#define NN_S390_RI_CB	"LINUX"
 #define NT_S390_RI_CB	0x30d		/* s390 runtime instrumentation */
+#define NN_S390_PV_CPU_DATA	"LINUX"
 #define NT_S390_PV_CPU_DATA	0x30e	/* s390 protvirt cpu dump data */
+#define NN_ARM_VFP	"LINUX"
 #define NT_ARM_VFP	0x400		/* ARM VFP/NEON registers */
+#define NN_ARM_TLS	"LINUX"
 #define NT_ARM_TLS	0x401		/* ARM TLS register */
+#define NN_ARM_HW_BREAK	"LINUX"
 #define NT_ARM_HW_BREAK	0x402		/* ARM hardware breakpoint registers */
+#define NN_ARM_HW_WATCH	"LINUX"
 #define NT_ARM_HW_WATCH	0x403		/* ARM hardware watchpoint registers */
+#define NN_ARM_SYSTEM_CALL	"LINUX"
 #define NT_ARM_SYSTEM_CALL	0x404	/* ARM system call number */
+#define NN_ARM_SVE	"LINUX"
 #define NT_ARM_SVE	0x405		/* ARM Scalable Vector Extension registers */
+#define NN_ARM_PAC_MASK		"LINUX"
 #define NT_ARM_PAC_MASK		0x406	/* ARM pointer authentication code masks */
+#define NN_ARM_PACA_KEYS	"LINUX"
 #define NT_ARM_PACA_KEYS	0x407	/* ARM pointer authentication address keys */
+#define NN_ARM_PACG_KEYS	"LINUX"
 #define NT_ARM_PACG_KEYS	0x408	/* ARM pointer authentication generic key */
+#define NN_ARM_TAGGED_ADDR_CTRL	"LINUX"
 #define NT_ARM_TAGGED_ADDR_CTRL	0x409	/* arm64 tagged address control (prctl()) */
+#define NN_ARM_PAC_ENABLED_KEYS	"LINUX"
 #define NT_ARM_PAC_ENABLED_KEYS	0x40a	/* arm64 ptr auth enabled keys (prctl()) */
+#define NN_ARM_SSVE	"LINUX"
 #define NT_ARM_SSVE	0x40b		/* ARM Streaming SVE registers */
+#define NN_ARM_ZA	"LINUX"
 #define NT_ARM_ZA	0x40c		/* ARM SME ZA registers */
+#define NN_ARM_ZT	"LINUX"
 #define NT_ARM_ZT	0x40d		/* ARM SME ZT registers */
+#define NN_ARM_FPMR	"LINUX"
 #define NT_ARM_FPMR	0x40e		/* ARM floating point mode register */
+#define NN_ARM_POE	"LINUX"
 #define NT_ARM_POE	0x40f		/* ARM POE registers */
+#define NN_ARM_GCS	"LINUX"
 #define NT_ARM_GCS	0x410		/* ARM GCS state */
+#define NN_ARC_V2	"LINUX"
 #define NT_ARC_V2	0x600		/* ARCv2 accumulator/extra registers */
+#define NN_VMCOREDD	"LINUX"
 #define NT_VMCOREDD	0x700		/* Vmcore Device Dump Note */
+#define NN_MIPS_DSP	"LINUX"
 #define NT_MIPS_DSP	0x800		/* MIPS DSP ASE registers */
+#define NN_MIPS_FP_MODE	"LINUX"
 #define NT_MIPS_FP_MODE	0x801		/* MIPS floating-point mode */
+#define NN_MIPS_MSA	"LINUX"
 #define NT_MIPS_MSA	0x802		/* MIPS SIMD registers */
+#define NN_RISCV_CSR	"LINUX"
 #define NT_RISCV_CSR	0x900		/* RISC-V Control and Status Registers */
+#define NN_RISCV_VECTOR	"LINUX"
 #define NT_RISCV_VECTOR	0x901		/* RISC-V vector registers */
+#define NN_RISCV_TAGGED_ADDR_CTRL "LINUX"
 #define NT_RISCV_TAGGED_ADDR_CTRL 0x902	/* RISC-V tagged address control (prctl()) */
+#define NN_LOONGARCH_CPUCFG	"LINUX"
 #define NT_LOONGARCH_CPUCFG	0xa00	/* LoongArch CPU config registers */
+#define NN_LOONGARCH_CSR	"LINUX"
 #define NT_LOONGARCH_CSR	0xa01	/* LoongArch control and status registers */
+#define NN_LOONGARCH_LSX	"LINUX"
 #define NT_LOONGARCH_LSX	0xa02	/* LoongArch Loongson SIMD Extension registers */
+#define NN_LOONGARCH_LASX	"LINUX"
 #define NT_LOONGARCH_LASX	0xa03	/* LoongArch Loongson Advanced SIMD Extension registers */
+#define NN_LOONGARCH_LBT	"LINUX"
 #define NT_LOONGARCH_LBT	0xa04	/* LoongArch Loongson Binary Translation registers */
+#define NN_LOONGARCH_HW_BREAK	"LINUX"
 #define NT_LOONGARCH_HW_BREAK	0xa05   /* LoongArch hardware breakpoint registers */
+#define NN_LOONGARCH_HW_WATCH	"LINUX"
 #define NT_LOONGARCH_HW_WATCH	0xa06   /* LoongArch hardware watchpoint registers */
 
-/* Note types with note name "GNU" */
+/* Note used in other file types. */
+#define NN_GNU_PROPERTY_TYPE_0	"GNU"
 #define NT_GNU_PROPERTY_TYPE_0	5
 
 /* Note header in a PT_NOTE section */

-- 
2.47.1

[PATCH v4 2/6] binfmt_elf: Use note name macros

[Akihiko Odaki]

Use note name macros to match with the userspace's expectation.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Baoquan He <bhe@redhat.com>
---
 fs/binfmt_elf.c       | 21 ++++++++++-----------
 fs/binfmt_elf_fdpic.c |  8 ++++----
 2 files changed, 14 insertions(+), 15 deletions(-)

diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
index 106f0e8af177..5b4a92e5e508 100644
--- a/fs/binfmt_elf.c
+++ b/fs/binfmt_elf.c
@@ -762,8 +762,7 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
 }
 
 #define NOTE_DATA_SZ SZ_1K
-#define GNU_PROPERTY_TYPE_0_NAME "GNU"
-#define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME))
+#define NOTE_NAME_SZ (sizeof(NN_GNU_PROPERTY_TYPE_0))
 
 static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
 				struct arch_elf_state *arch)
@@ -800,7 +799,7 @@ static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
 	if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 ||
 	    note.nhdr.n_namesz != NOTE_NAME_SZ ||
 	    strncmp(note.data + sizeof(note.nhdr),
-		    GNU_PROPERTY_TYPE_0_NAME, n - sizeof(note.nhdr)))
+		    NN_GNU_PROPERTY_TYPE_0, n - sizeof(note.nhdr)))
 		return -ENOEXEC;
 
 	off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ,
@@ -1603,14 +1602,14 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
 	do
 		i += 2;
 	while (auxv[i - 2] != AT_NULL);
-	fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
+	fill_note(note, NN_AUXV, NT_AUXV, i * sizeof(elf_addr_t), auxv);
 }
 
 static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
 		const kernel_siginfo_t *siginfo)
 {
 	copy_siginfo_to_external(csigdata, siginfo);
-	fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
+	fill_note(note, NN_SIGINFO, NT_SIGINFO, sizeof(*csigdata), csigdata);
 }
 
 /*
@@ -1706,7 +1705,7 @@ static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm
 	}
 
 	size = name_curpos - (char *)data;
-	fill_note(note, "CORE", NT_FILE, size, data);
+	fill_note(note, NN_FILE, NT_FILE, size, data);
 	return 0;
 }
 
@@ -1767,7 +1766,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 	regset_get(t->task, &view->regsets[0],
 		   sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
 
-	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
+	fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS,
 		  PRSTATUS_SIZE, &t->prstatus);
 	info->size += notesize(&t->notes[0]);
 
@@ -1801,7 +1800,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 		if (is_fpreg)
 			SET_PR_FPVALID(&t->prstatus);
 
-		fill_note(&t->notes[note_iter], is_fpreg ? "CORE" : "LINUX",
+		fill_note(&t->notes[note_iter], is_fpreg ? NN_PRFPREG : "LINUX",
 			  note_type, ret, data);
 
 		info->size += notesize(&t->notes[note_iter]);
@@ -1821,7 +1820,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 	fill_prstatus(&t->prstatus.common, p, signr);
 	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
 
-	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
+	fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS, sizeof(t->prstatus),
 		  &(t->prstatus));
 	info->size += notesize(&t->notes[0]);
 
@@ -1832,7 +1831,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
 	}
 
 	t->prstatus.pr_fpvalid = 1;
-	fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
+	fill_note(&t->notes[1], NN_PRFPREG, NT_PRFPREG, sizeof(*fpu), fpu);
 	info->size += notesize(&t->notes[1]);
 
 	return 1;
@@ -1852,7 +1851,7 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
 	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
 	if (!psinfo)
 		return 0;
-	fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
+	fill_note(&info->psinfo, NN_PRPSINFO, NT_PRPSINFO, sizeof(*psinfo), psinfo);
 
 #ifdef CORE_DUMP_USE_REGSET
 	view = task_user_regset_view(dump_task);
diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
index f1a7c4875c4a..96bd9d2f23d7 100644
--- a/fs/binfmt_elf_fdpic.c
+++ b/fs/binfmt_elf_fdpic.c
@@ -1397,7 +1397,7 @@ static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_
 	regset_get(p, &view->regsets[0],
 		   sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
 
-	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
+	fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS, sizeof(t->prstatus),
 		  &t->prstatus);
 	t->num_notes++;
 	*sz += notesize(&t->notes[0]);
@@ -1415,7 +1415,7 @@ static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_
 	}
 
 	if (t->prstatus.pr_fpvalid) {
-		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
+		fill_note(&t->notes[1], NN_PRFPREG, NT_PRFPREG, sizeof(t->fpu),
 			  &t->fpu);
 		t->num_notes++;
 		*sz += notesize(&t->notes[1]);
@@ -1530,7 +1530,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 	 */
 
 	fill_psinfo(psinfo, current->group_leader, current->mm);
-	fill_note(&psinfo_note, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
+	fill_note(&psinfo_note, NN_PRPSINFO, NT_PRPSINFO, sizeof(*psinfo), psinfo);
 	thread_status_size += notesize(&psinfo_note);
 
 	auxv = (elf_addr_t *) current->mm->saved_auxv;
@@ -1538,7 +1538,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
 	do
 		i += 2;
 	while (auxv[i - 2] != AT_NULL);
-	fill_note(&auxv_note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
+	fill_note(&auxv_note, NN_AUXV, NT_AUXV, i * sizeof(elf_addr_t), auxv);
 	thread_status_size += notesize(&auxv_note);
 
 	offset = sizeof(*elf);				/* ELF header */

-- 
2.47.1

[PATCH v4 3/6] powerpc: Use note name macros

[Akihiko Odaki]

Use note name macros to match with the userspace's expectation.

Acked-by: Baoquan He <bhe@redhat.com>
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
---
 arch/powerpc/kernel/fadump.c               | 2 +-
 arch/powerpc/platforms/powernv/opal-core.c | 8 ++++----
 2 files changed, 5 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 4b371c738213..d44349fe8e2b 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -751,7 +751,7 @@ u32 *__init fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
 	 * prstatus.pr_pid = ????
 	 */
 	elf_core_copy_regs(&prstatus.pr_reg, regs);
-	buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
+	buf = append_elf_note(buf, NN_PRSTATUS, NT_PRSTATUS,
 			      &prstatus, sizeof(prstatus));
 	return buf;
 }
diff --git a/arch/powerpc/platforms/powernv/opal-core.c b/arch/powerpc/platforms/powernv/opal-core.c
index c9a9b759cc92..a379ff86c120 100644
--- a/arch/powerpc/platforms/powernv/opal-core.c
+++ b/arch/powerpc/platforms/powernv/opal-core.c
@@ -149,7 +149,7 @@ static Elf64_Word *__init auxv_to_elf64_notes(Elf64_Word *buf,
 	/* end of vector */
 	bufp[idx++] = cpu_to_be64(AT_NULL);
 
-	buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_AUXV,
+	buf = append_elf64_note(buf, NN_AUXV, NT_AUXV,
 				oc_conf->auxv_buf, AUXV_DESC_SZ);
 	return buf;
 }
@@ -252,7 +252,7 @@ static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
 	 * crashing CPU's prstatus.
 	 */
 	first_cpu_note = buf;
-	buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
+	buf = append_elf64_note(buf, NN_PRSTATUS, NT_PRSTATUS,
 				&prstatus, sizeof(prstatus));
 
 	for (i = 0; i < oc_conf->num_cpus; i++, bufp += size_per_thread) {
@@ -279,7 +279,7 @@ static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
 		fill_prstatus(&prstatus, thread_pir, &regs);
 
 		if (thread_pir != oc_conf->crashing_cpu) {
-			buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME,
+			buf = append_elf64_note(buf, NN_PRSTATUS,
 						NT_PRSTATUS, &prstatus,
 						sizeof(prstatus));
 		} else {
@@ -287,7 +287,7 @@ static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
 			 * Add crashing CPU as the first NT_PRSTATUS note for
 			 * GDB to process the core file appropriately.
 			 */
-			append_elf64_note(first_cpu_note, CRASH_CORE_NOTE_NAME,
+			append_elf64_note(first_cpu_note, NN_PRSTATUS,
 					  NT_PRSTATUS, &prstatus,
 					  sizeof(prstatus));
 		}

-- 
2.47.1

[PATCH v4 4/6] crash: Use note name macros

[Akihiko Odaki]

Use note name macros to match with the userspace's expectation.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Baoquan He <bhe@redhat.com>
---
 fs/proc/kcore.c             | 12 ++++++------
 include/linux/vmcore_info.h |  2 +-
 kernel/crash_core.c         |  2 +-
 3 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
index e376f48c4b8b..e5612313b8b4 100644
--- a/fs/proc/kcore.c
+++ b/fs/proc/kcore.c
@@ -34,8 +34,6 @@
 #include <asm/sections.h>
 #include "internal.h"
 
-#define CORE_STR "CORE"
-
 #ifndef ELF_CORE_EFLAGS
 #define ELF_CORE_EFLAGS	0
 #endif
@@ -119,7 +117,9 @@ static size_t get_kcore_size(int *nphdr, size_t *phdrs_len, size_t *notes_len,
 
 	*phdrs_len = *nphdr * sizeof(struct elf_phdr);
 	*notes_len = (4 * sizeof(struct elf_note) +
-		      3 * ALIGN(sizeof(CORE_STR), 4) +
+		      ALIGN(sizeof(NN_PRSTATUS), 4) +
+		      ALIGN(sizeof(NN_PRPSINFO), 4) +
+		      ALIGN(sizeof(NN_TASKSTRUCT), 4) +
 		      VMCOREINFO_NOTE_NAME_BYTES +
 		      ALIGN(sizeof(struct elf_prstatus), 4) +
 		      ALIGN(sizeof(struct elf_prpsinfo), 4) +
@@ -444,11 +444,11 @@ static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
 			goto out;
 		}
 
-		append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,
+		append_kcore_note(notes, &i, NN_PRSTATUS, NT_PRSTATUS, &prstatus,
 				  sizeof(prstatus));
-		append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,
+		append_kcore_note(notes, &i, NN_PRPSINFO, NT_PRPSINFO, &prpsinfo,
 				  sizeof(prpsinfo));
-		append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,
+		append_kcore_note(notes, &i, NN_TASKSTRUCT, NT_TASKSTRUCT, current,
 				  arch_task_struct_size);
 		/*
 		 * vmcoreinfo_size is mostly constant after init time, but it
diff --git a/include/linux/vmcore_info.h b/include/linux/vmcore_info.h
index e1dec1a6a749..1672801fd98c 100644
--- a/include/linux/vmcore_info.h
+++ b/include/linux/vmcore_info.h
@@ -8,7 +8,7 @@
 
 #define CRASH_CORE_NOTE_NAME	   "CORE"
 #define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
-#define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(CRASH_CORE_NOTE_NAME), 4)
+#define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(NN_PRSTATUS), 4)
 #define CRASH_CORE_NOTE_DESC_BYTES ALIGN(sizeof(struct elf_prstatus), 4)
 
 /*
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 078fe5bc5a74..335b8425dd4b 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -436,7 +436,7 @@ void crash_save_cpu(struct pt_regs *regs, int cpu)
 	memset(&prstatus, 0, sizeof(prstatus));
 	prstatus.common.pr_pid = current->pid;
 	elf_core_copy_regs(&prstatus.pr_reg, regs);
-	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
+	buf = append_elf_note(buf, NN_PRSTATUS, NT_PRSTATUS,
 			      &prstatus, sizeof(prstatus));
 	final_note(buf);
 }

-- 
2.47.1

[PATCH v4 5/6] s390/crash: Use note name macros

[Akihiko Odaki]

Use note name macros to match with the userspace's expectation.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Heiko Carstens <hca@linux.ibm.com>
---
 arch/s390/kernel/crash_dump.c | 62 ++++++++++++++++---------------------------
 1 file changed, 23 insertions(+), 39 deletions(-)

diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
index cd0c93a8fb8b..022f4f198edf 100644
--- a/arch/s390/kernel/crash_dump.c
+++ b/arch/s390/kernel/crash_dump.c
@@ -248,15 +248,6 @@ bool is_kdump_kernel(void)
 }
 EXPORT_SYMBOL_GPL(is_kdump_kernel);
 
-static const char *nt_name(Elf64_Word type)
-{
-	const char *name = "LINUX";
-
-	if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
-		name = KEXEC_CORE_NOTE_NAME;
-	return name;
-}
-
 /*
  * Initialize ELF note
  */
@@ -281,10 +272,8 @@ static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
 	return PTR_ADD(buf, len);
 }
 
-static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
-{
-	return nt_init_name(buf, type, desc, d_len, nt_name(type));
-}
+#define nt_init(buf, type, desc) \
+	nt_init_name(buf, NT_ ## type, &(desc), sizeof(desc), NN_ ## type)
 
 /*
  * Calculate the size of ELF note
@@ -300,10 +289,7 @@ static size_t nt_size_name(int d_len, const char *name)
 	return size;
 }
 
-static inline size_t nt_size(Elf64_Word type, int d_len)
-{
-	return nt_size_name(d_len, nt_name(type));
-}
+#define nt_size(type, desc) nt_size_name(sizeof(desc), NN_ ## type)
 
 /*
  * Fill ELF notes for one CPU with save area registers
@@ -324,18 +310,16 @@ static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
 	memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
 	memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
 	/* Create ELF notes for the CPU */
-	ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
-	ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
-	ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
-	ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
-	ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
-	ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
-	ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
+	ptr = nt_init(ptr, PRSTATUS, nt_prstatus);
+	ptr = nt_init(ptr, PRFPREG, nt_fpregset);
+	ptr = nt_init(ptr, S390_TIMER, sa->timer);
+	ptr = nt_init(ptr, S390_TODCMP, sa->todcmp);
+	ptr = nt_init(ptr, S390_TODPREG, sa->todpreg);
+	ptr = nt_init(ptr, S390_CTRS, sa->ctrs);
+	ptr = nt_init(ptr, S390_PREFIX, sa->prefix);
 	if (cpu_has_vx()) {
-		ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
-			      &sa->vxrs_high, sizeof(sa->vxrs_high));
-		ptr = nt_init(ptr, NT_S390_VXRS_LOW,
-			      &sa->vxrs_low, sizeof(sa->vxrs_low));
+		ptr = nt_init(ptr, S390_VXRS_HIGH, sa->vxrs_high);
+		ptr = nt_init(ptr, S390_VXRS_LOW, sa->vxrs_low);
 	}
 	return ptr;
 }
@@ -348,16 +332,16 @@ static size_t get_cpu_elf_notes_size(void)
 	struct save_area *sa = NULL;
 	size_t size;
 
-	size =	nt_size(NT_PRSTATUS, sizeof(struct elf_prstatus));
-	size +=  nt_size(NT_PRFPREG, sizeof(elf_fpregset_t));
-	size +=  nt_size(NT_S390_TIMER, sizeof(sa->timer));
-	size +=  nt_size(NT_S390_TODCMP, sizeof(sa->todcmp));
-	size +=  nt_size(NT_S390_TODPREG, sizeof(sa->todpreg));
-	size +=  nt_size(NT_S390_CTRS, sizeof(sa->ctrs));
-	size +=  nt_size(NT_S390_PREFIX, sizeof(sa->prefix));
+	size =	nt_size(PRSTATUS, struct elf_prstatus);
+	size += nt_size(PRFPREG, elf_fpregset_t);
+	size += nt_size(S390_TIMER, sa->timer);
+	size += nt_size(S390_TODCMP, sa->todcmp);
+	size += nt_size(S390_TODPREG, sa->todpreg);
+	size += nt_size(S390_CTRS, sa->ctrs);
+	size += nt_size(S390_PREFIX, sa->prefix);
 	if (cpu_has_vx()) {
-		size += nt_size(NT_S390_VXRS_HIGH, sizeof(sa->vxrs_high));
-		size += nt_size(NT_S390_VXRS_LOW, sizeof(sa->vxrs_low));
+		size += nt_size(S390_VXRS_HIGH, sa->vxrs_high);
+		size += nt_size(S390_VXRS_LOW, sa->vxrs_low);
 	}
 
 	return size;
@@ -373,7 +357,7 @@ static void *nt_prpsinfo(void *ptr)
 	memset(&prpsinfo, 0, sizeof(prpsinfo));
 	prpsinfo.pr_sname = 'R';
 	strcpy(prpsinfo.pr_fname, "vmlinux");
-	return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
+	return nt_init(ptr, PRPSINFO, prpsinfo);
 }
 
 /*
@@ -589,7 +573,7 @@ static size_t get_elfcorehdr_size(int phdr_count)
 	/* PT_NOTES */
 	size += sizeof(Elf64_Phdr);
 	/* nt_prpsinfo */
-	size += nt_size(NT_PRPSINFO, sizeof(struct elf_prpsinfo));
+	size += nt_size(PRPSINFO, struct elf_prpsinfo);
 	/* regsets */
 	size += get_cpu_cnt() * get_cpu_elf_notes_size();
 	/* nt_vmcoreinfo */

-- 
2.47.1

[PATCH v4 6/6] crash: Remove KEXEC_CORE_NOTE_NAME

[Akihiko Odaki]

KEXEC_CORE_NOTE_NAME is no longer used.

Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Acked-by: Baoquan He <bhe@redhat.com>
---
 include/linux/kexec.h       | 2 --
 include/linux/vmcore_info.h | 1 -
 2 files changed, 3 deletions(-)

diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index f0e9f8eda7a3..c840431eadda 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h
@@ -68,8 +68,6 @@ extern note_buf_t __percpu *crash_notes;
 #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
 #endif
 
-#define KEXEC_CORE_NOTE_NAME	CRASH_CORE_NOTE_NAME
-
 /*
  * This structure is used to hold the arguments that are used when loading
  * kernel binaries.
diff --git a/include/linux/vmcore_info.h b/include/linux/vmcore_info.h
index 1672801fd98c..37e003ae5262 100644
--- a/include/linux/vmcore_info.h
+++ b/include/linux/vmcore_info.h
@@ -6,7 +6,6 @@
 #include <linux/elfcore.h>
 #include <linux/elf.h>
 
-#define CRASH_CORE_NOTE_NAME	   "CORE"
 #define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
 #define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(NN_PRSTATUS), 4)
 #define CRASH_CORE_NOTE_DESC_BYTES ALIGN(sizeof(struct elf_prstatus), 4)

-- 
2.47.1

Re: [PATCH v4 1/6] elf: Define note name macros

[Dave Martin]

Hi,

On Sat, Jan 11, 2025 at 02:48:44PM +0900, Akihiko Odaki wrote:
> elf.h had a comment saying:
> > Notes used in ET_CORE. Architectures export some of the arch register
> > sets using the corresponding note types via the PTRACE_GETREGSET and
> > PTRACE_SETREGSET requests.
> > The note name for these types is "LINUX", except NT_PRFPREG that is
> > named "CORE".
> 
> However, NT_PRSTATUS is also named "CORE". It is also unclear what
> "these types" refers to.
> 
> To fix these problems, define a name for each note type. The added
> definitions are macros so the kernel and userspace can directly refer to
> them.

I guess another motivation is to move towards having elf.h as the
single point of definition for the note names, so that obscure and
duplicate logic for determining note names can be removed.

(Could be worth adding a note on this is the patch is respun, but this
would be overkill otherwise...)


> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Acked-by: Baoquan He <bhe@redhat.com>
> ---
>  include/uapi/linux/elf.h | 86 ++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 83 insertions(+), 3 deletions(-)
> 
> diff --git a/include/uapi/linux/elf.h b/include/uapi/linux/elf.h
> index b44069d29cec..343f5c40d03a 100644
> --- a/include/uapi/linux/elf.h
> +++ b/include/uapi/linux/elf.h
> @@ -368,99 +368,179 @@ typedef struct elf64_shdr {
>  #define ELF_OSABI ELFOSABI_NONE
>  #endif
>  
> +/* Note definitions: NN_ defines names. NT_ defines types. */
> +
>  /*
>   * Notes used in ET_CORE. Architectures export some of the arch register sets
>   * using the corresponding note types via the PTRACE_GETREGSET and
>   * PTRACE_SETREGSET requests.
> - * The note name for these types is "LINUX", except NT_PRFPREG that is named
> - * "CORE".
>   */
> +#define NN_PRSTATUS	"CORE"
>  #define NT_PRSTATUS	1
> +#define NN_PRFPREG	"CORE"
>  #define NT_PRFPREG	2
> +#define NN_PRPSINFO	"CORE"
>  #define NT_PRPSINFO	3
> +#define NN_TASKSTRUCT	"CORE"
>  #define NT_TASKSTRUCT	4
> +#define NN_AUXV		"CORE"
>  #define NT_AUXV		6
>  /*
>   * Note to userspace developers: size of NT_SIGINFO note may increase
>   * in the future to accomodate more fields, don't assume it is fixed!
>   */
> +#define NN_SIGINFO      "CORE"
>  #define NT_SIGINFO      0x53494749
> +#define NN_FILE         "CORE"
>  #define NT_FILE         0x46494c45
> +#define NN_PRXFPREG     "LINUX"
>  #define NT_PRXFPREG     0x46e62b7f      /* copied from gdb5.1/include/elf/common.h */

[...]

> +#define NN_LOONGARCH_HW_WATCH	"LINUX"
>  #define NT_LOONGARCH_HW_WATCH	0xa06   /* LoongArch hardware watchpoint registers */
>  
> -/* Note types with note name "GNU" */
> +/* Note used in other file types. */

For this, it may make sense to be vaguer, e.g.

	/* Other notes */

(We don't dump NT_GNU_PROPERTY_TYPE_0 in coredumps, but I don't think
it would be nonsensical to do so.)

> +#define NN_GNU_PROPERTY_TYPE_0	"GNU"
>  #define NT_GNU_PROPERTY_TYPE_0	5

[...]

With or without those changes,

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

Re: [PATCH v4 2/6] binfmt_elf: Use note name macros

[Dave Martin]

On Sat, Jan 11, 2025 at 02:48:45PM +0900, Akihiko Odaki wrote:
> Use note name macros to match with the userspace's expectation.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Acked-by: Baoquan He <bhe@redhat.com>

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

> ---
>  fs/binfmt_elf.c       | 21 ++++++++++-----------
>  fs/binfmt_elf_fdpic.c |  8 ++++----
>  2 files changed, 14 insertions(+), 15 deletions(-)
> 
> diff --git a/fs/binfmt_elf.c b/fs/binfmt_elf.c
> index 106f0e8af177..5b4a92e5e508 100644
> --- a/fs/binfmt_elf.c
> +++ b/fs/binfmt_elf.c
> @@ -762,8 +762,7 @@ static int parse_elf_property(const char *data, size_t *off, size_t datasz,
>  }
>  
>  #define NOTE_DATA_SZ SZ_1K
> -#define GNU_PROPERTY_TYPE_0_NAME "GNU"
> -#define NOTE_NAME_SZ (sizeof(GNU_PROPERTY_TYPE_0_NAME))
> +#define NOTE_NAME_SZ (sizeof(NN_GNU_PROPERTY_TYPE_0))
>  
>  static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
>  				struct arch_elf_state *arch)
> @@ -800,7 +799,7 @@ static int parse_elf_properties(struct file *f, const struct elf_phdr *phdr,
>  	if (note.nhdr.n_type != NT_GNU_PROPERTY_TYPE_0 ||
>  	    note.nhdr.n_namesz != NOTE_NAME_SZ ||
>  	    strncmp(note.data + sizeof(note.nhdr),
> -		    GNU_PROPERTY_TYPE_0_NAME, n - sizeof(note.nhdr)))
> +		    NN_GNU_PROPERTY_TYPE_0, n - sizeof(note.nhdr)))
>  		return -ENOEXEC;
>  
>  	off = round_up(sizeof(note.nhdr) + NOTE_NAME_SZ,
> @@ -1603,14 +1602,14 @@ static void fill_auxv_note(struct memelfnote *note, struct mm_struct *mm)
>  	do
>  		i += 2;
>  	while (auxv[i - 2] != AT_NULL);
> -	fill_note(note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
> +	fill_note(note, NN_AUXV, NT_AUXV, i * sizeof(elf_addr_t), auxv);
>  }
>  
>  static void fill_siginfo_note(struct memelfnote *note, user_siginfo_t *csigdata,
>  		const kernel_siginfo_t *siginfo)
>  {
>  	copy_siginfo_to_external(csigdata, siginfo);
> -	fill_note(note, "CORE", NT_SIGINFO, sizeof(*csigdata), csigdata);
> +	fill_note(note, NN_SIGINFO, NT_SIGINFO, sizeof(*csigdata), csigdata);
>  }
>  
>  /*
> @@ -1706,7 +1705,7 @@ static int fill_files_note(struct memelfnote *note, struct coredump_params *cprm
>  	}
>  
>  	size = name_curpos - (char *)data;
> -	fill_note(note, "CORE", NT_FILE, size, data);
> +	fill_note(note, NN_FILE, NT_FILE, size, data);
>  	return 0;
>  }
>  
> @@ -1767,7 +1766,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
>  	regset_get(t->task, &view->regsets[0],
>  		   sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
>  
> -	fill_note(&t->notes[0], "CORE", NT_PRSTATUS,
> +	fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS,
>  		  PRSTATUS_SIZE, &t->prstatus);
>  	info->size += notesize(&t->notes[0]);
>  
> @@ -1801,7 +1800,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
>  		if (is_fpreg)
>  			SET_PR_FPVALID(&t->prstatus);
>  
> -		fill_note(&t->notes[note_iter], is_fpreg ? "CORE" : "LINUX",
> +		fill_note(&t->notes[note_iter], is_fpreg ? NN_PRFPREG : "LINUX",
>  			  note_type, ret, data);
>  
>  		info->size += notesize(&t->notes[note_iter]);
> @@ -1821,7 +1820,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
>  	fill_prstatus(&t->prstatus.common, p, signr);
>  	elf_core_copy_task_regs(p, &t->prstatus.pr_reg);
>  
> -	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
> +	fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS, sizeof(t->prstatus),
>  		  &(t->prstatus));
>  	info->size += notesize(&t->notes[0]);
>  
> @@ -1832,7 +1831,7 @@ static int fill_thread_core_info(struct elf_thread_core_info *t,
>  	}
>  
>  	t->prstatus.pr_fpvalid = 1;
> -	fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(*fpu), fpu);
> +	fill_note(&t->notes[1], NN_PRFPREG, NT_PRFPREG, sizeof(*fpu), fpu);
>  	info->size += notesize(&t->notes[1]);
>  
>  	return 1;
> @@ -1852,7 +1851,7 @@ static int fill_note_info(struct elfhdr *elf, int phdrs,
>  	psinfo = kmalloc(sizeof(*psinfo), GFP_KERNEL);
>  	if (!psinfo)
>  		return 0;
> -	fill_note(&info->psinfo, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
> +	fill_note(&info->psinfo, NN_PRPSINFO, NT_PRPSINFO, sizeof(*psinfo), psinfo);
>  
>  #ifdef CORE_DUMP_USE_REGSET
>  	view = task_user_regset_view(dump_task);
> diff --git a/fs/binfmt_elf_fdpic.c b/fs/binfmt_elf_fdpic.c
> index f1a7c4875c4a..96bd9d2f23d7 100644
> --- a/fs/binfmt_elf_fdpic.c
> +++ b/fs/binfmt_elf_fdpic.c
> @@ -1397,7 +1397,7 @@ static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_
>  	regset_get(p, &view->regsets[0],
>  		   sizeof(t->prstatus.pr_reg), &t->prstatus.pr_reg);
>  
> -	fill_note(&t->notes[0], "CORE", NT_PRSTATUS, sizeof(t->prstatus),
> +	fill_note(&t->notes[0], NN_PRSTATUS, NT_PRSTATUS, sizeof(t->prstatus),
>  		  &t->prstatus);
>  	t->num_notes++;
>  	*sz += notesize(&t->notes[0]);
> @@ -1415,7 +1415,7 @@ static struct elf_thread_status *elf_dump_thread_status(long signr, struct task_
>  	}
>  
>  	if (t->prstatus.pr_fpvalid) {
> -		fill_note(&t->notes[1], "CORE", NT_PRFPREG, sizeof(t->fpu),
> +		fill_note(&t->notes[1], NN_PRFPREG, NT_PRFPREG, sizeof(t->fpu),
>  			  &t->fpu);
>  		t->num_notes++;
>  		*sz += notesize(&t->notes[1]);
> @@ -1530,7 +1530,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
>  	 */
>  
>  	fill_psinfo(psinfo, current->group_leader, current->mm);
> -	fill_note(&psinfo_note, "CORE", NT_PRPSINFO, sizeof(*psinfo), psinfo);
> +	fill_note(&psinfo_note, NN_PRPSINFO, NT_PRPSINFO, sizeof(*psinfo), psinfo);
>  	thread_status_size += notesize(&psinfo_note);
>  
>  	auxv = (elf_addr_t *) current->mm->saved_auxv;
> @@ -1538,7 +1538,7 @@ static int elf_fdpic_core_dump(struct coredump_params *cprm)
>  	do
>  		i += 2;
>  	while (auxv[i - 2] != AT_NULL);
> -	fill_note(&auxv_note, "CORE", NT_AUXV, i * sizeof(elf_addr_t), auxv);
> +	fill_note(&auxv_note, NN_AUXV, NT_AUXV, i * sizeof(elf_addr_t), auxv);
>  	thread_status_size += notesize(&auxv_note);
>  
>  	offset = sizeof(*elf);				/* ELF header */
> 
> -- 
> 2.47.1
> 
> 

Re: [PATCH v4 3/6] powerpc: Use note name macros

[Dave Martin]

Hi,

On Sat, Jan 11, 2025 at 02:48:46PM +0900, Akihiko Odaki wrote:
> Use note name macros to match with the userspace's expectation.

Note, there seems to be some manual encoding of some arch-specific
notes in arch/powerpc/boot/addnote.c, but since this is all hard-coded
and the note types are not taken from elf.h anyway, I think this is
probably out of scope for this series.  I haven't tried to understand
fully what that code is doing.

Anyway:

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

> 
> Acked-by: Baoquan He <bhe@redhat.com>
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> ---
>  arch/powerpc/kernel/fadump.c               | 2 +-
>  arch/powerpc/platforms/powernv/opal-core.c | 8 ++++----
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
> index 4b371c738213..d44349fe8e2b 100644
> --- a/arch/powerpc/kernel/fadump.c
> +++ b/arch/powerpc/kernel/fadump.c
> @@ -751,7 +751,7 @@ u32 *__init fadump_regs_to_elf_notes(u32 *buf, struct pt_regs *regs)
>  	 * prstatus.pr_pid = ????
>  	 */
>  	elf_core_copy_regs(&prstatus.pr_reg, regs);
> -	buf = append_elf_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
> +	buf = append_elf_note(buf, NN_PRSTATUS, NT_PRSTATUS,
>  			      &prstatus, sizeof(prstatus));
>  	return buf;
>  }
> diff --git a/arch/powerpc/platforms/powernv/opal-core.c b/arch/powerpc/platforms/powernv/opal-core.c
> index c9a9b759cc92..a379ff86c120 100644
> --- a/arch/powerpc/platforms/powernv/opal-core.c
> +++ b/arch/powerpc/platforms/powernv/opal-core.c
> @@ -149,7 +149,7 @@ static Elf64_Word *__init auxv_to_elf64_notes(Elf64_Word *buf,
>  	/* end of vector */
>  	bufp[idx++] = cpu_to_be64(AT_NULL);
>  
> -	buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_AUXV,
> +	buf = append_elf64_note(buf, NN_AUXV, NT_AUXV,
>  				oc_conf->auxv_buf, AUXV_DESC_SZ);
>  	return buf;
>  }
> @@ -252,7 +252,7 @@ static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
>  	 * crashing CPU's prstatus.
>  	 */
>  	first_cpu_note = buf;
> -	buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME, NT_PRSTATUS,
> +	buf = append_elf64_note(buf, NN_PRSTATUS, NT_PRSTATUS,
>  				&prstatus, sizeof(prstatus));
>  
>  	for (i = 0; i < oc_conf->num_cpus; i++, bufp += size_per_thread) {
> @@ -279,7 +279,7 @@ static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
>  		fill_prstatus(&prstatus, thread_pir, &regs);
>  
>  		if (thread_pir != oc_conf->crashing_cpu) {
> -			buf = append_elf64_note(buf, CRASH_CORE_NOTE_NAME,
> +			buf = append_elf64_note(buf, NN_PRSTATUS,
>  						NT_PRSTATUS, &prstatus,
>  						sizeof(prstatus));
>  		} else {
> @@ -287,7 +287,7 @@ static Elf64_Word * __init opalcore_append_cpu_notes(Elf64_Word *buf)
>  			 * Add crashing CPU as the first NT_PRSTATUS note for
>  			 * GDB to process the core file appropriately.
>  			 */
> -			append_elf64_note(first_cpu_note, CRASH_CORE_NOTE_NAME,
> +			append_elf64_note(first_cpu_note, NN_PRSTATUS,
>  					  NT_PRSTATUS, &prstatus,
>  					  sizeof(prstatus));
>  		}
> 
> -- 
> 2.47.1
> 
> 

Re: [PATCH v4 4/6] crash: Use note name macros

[Dave Martin]

On Sat, Jan 11, 2025 at 02:48:47PM +0900, Akihiko Odaki wrote:
> Use note name macros to match with the userspace's expectation.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Acked-by: Baoquan He <bhe@redhat.com>

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

> ---
>  fs/proc/kcore.c             | 12 ++++++------
>  include/linux/vmcore_info.h |  2 +-
>  kernel/crash_core.c         |  2 +-
>  3 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/fs/proc/kcore.c b/fs/proc/kcore.c
> index e376f48c4b8b..e5612313b8b4 100644
> --- a/fs/proc/kcore.c
> +++ b/fs/proc/kcore.c
> @@ -34,8 +34,6 @@
>  #include <asm/sections.h>
>  #include "internal.h"
>  
> -#define CORE_STR "CORE"
> -
>  #ifndef ELF_CORE_EFLAGS
>  #define ELF_CORE_EFLAGS	0
>  #endif
> @@ -119,7 +117,9 @@ static size_t get_kcore_size(int *nphdr, size_t *phdrs_len, size_t *notes_len,
>  
>  	*phdrs_len = *nphdr * sizeof(struct elf_phdr);
>  	*notes_len = (4 * sizeof(struct elf_note) +
> -		      3 * ALIGN(sizeof(CORE_STR), 4) +
> +		      ALIGN(sizeof(NN_PRSTATUS), 4) +
> +		      ALIGN(sizeof(NN_PRPSINFO), 4) +
> +		      ALIGN(sizeof(NN_TASKSTRUCT), 4) +
>  		      VMCOREINFO_NOTE_NAME_BYTES +
>  		      ALIGN(sizeof(struct elf_prstatus), 4) +
>  		      ALIGN(sizeof(struct elf_prpsinfo), 4) +
> @@ -444,11 +444,11 @@ static ssize_t read_kcore_iter(struct kiocb *iocb, struct iov_iter *iter)
>  			goto out;
>  		}
>  
> -		append_kcore_note(notes, &i, CORE_STR, NT_PRSTATUS, &prstatus,
> +		append_kcore_note(notes, &i, NN_PRSTATUS, NT_PRSTATUS, &prstatus,
>  				  sizeof(prstatus));
> -		append_kcore_note(notes, &i, CORE_STR, NT_PRPSINFO, &prpsinfo,
> +		append_kcore_note(notes, &i, NN_PRPSINFO, NT_PRPSINFO, &prpsinfo,
>  				  sizeof(prpsinfo));
> -		append_kcore_note(notes, &i, CORE_STR, NT_TASKSTRUCT, current,
> +		append_kcore_note(notes, &i, NN_TASKSTRUCT, NT_TASKSTRUCT, current,
>  				  arch_task_struct_size);
>  		/*
>  		 * vmcoreinfo_size is mostly constant after init time, but it
> diff --git a/include/linux/vmcore_info.h b/include/linux/vmcore_info.h
> index e1dec1a6a749..1672801fd98c 100644
> --- a/include/linux/vmcore_info.h
> +++ b/include/linux/vmcore_info.h
> @@ -8,7 +8,7 @@
>  
>  #define CRASH_CORE_NOTE_NAME	   "CORE"
>  #define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
> -#define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(CRASH_CORE_NOTE_NAME), 4)
> +#define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(NN_PRSTATUS), 4)
>  #define CRASH_CORE_NOTE_DESC_BYTES ALIGN(sizeof(struct elf_prstatus), 4)
>  
>  /*
> diff --git a/kernel/crash_core.c b/kernel/crash_core.c
> index 078fe5bc5a74..335b8425dd4b 100644
> --- a/kernel/crash_core.c
> +++ b/kernel/crash_core.c
> @@ -436,7 +436,7 @@ void crash_save_cpu(struct pt_regs *regs, int cpu)
>  	memset(&prstatus, 0, sizeof(prstatus));
>  	prstatus.common.pr_pid = current->pid;
>  	elf_core_copy_regs(&prstatus.pr_reg, regs);
> -	buf = append_elf_note(buf, KEXEC_CORE_NOTE_NAME, NT_PRSTATUS,
> +	buf = append_elf_note(buf, NN_PRSTATUS, NT_PRSTATUS,
>  			      &prstatus, sizeof(prstatus));
>  	final_note(buf);
>  }
> 
> -- 
> 2.47.1
> 
> 

Re: [PATCH v4 5/6] s390/crash: Use note name macros

[Dave Martin]

Hi,

On Sat, Jan 11, 2025 at 02:48:48PM +0900, Akihiko Odaki wrote:
> Use note name macros to match with the userspace's expectation.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Acked-by: Heiko Carstens <hca@linux.ibm.com>

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

(I'm not in a position to test this, though.)

> ---
>  arch/s390/kernel/crash_dump.c | 62 ++++++++++++++++---------------------------
>  1 file changed, 23 insertions(+), 39 deletions(-)
> 
> diff --git a/arch/s390/kernel/crash_dump.c b/arch/s390/kernel/crash_dump.c
> index cd0c93a8fb8b..022f4f198edf 100644
> --- a/arch/s390/kernel/crash_dump.c
> +++ b/arch/s390/kernel/crash_dump.c
> @@ -248,15 +248,6 @@ bool is_kdump_kernel(void)
>  }
>  EXPORT_SYMBOL_GPL(is_kdump_kernel);
>  
> -static const char *nt_name(Elf64_Word type)
> -{
> -	const char *name = "LINUX";
> -
> -	if (type == NT_PRPSINFO || type == NT_PRSTATUS || type == NT_PRFPREG)
> -		name = KEXEC_CORE_NOTE_NAME;
> -	return name;
> -}
> -
>  /*
>   * Initialize ELF note
>   */
> @@ -281,10 +272,8 @@ static void *nt_init_name(void *buf, Elf64_Word type, void *desc, int d_len,
>  	return PTR_ADD(buf, len);
>  }
>  
> -static inline void *nt_init(void *buf, Elf64_Word type, void *desc, int d_len)
> -{
> -	return nt_init_name(buf, type, desc, d_len, nt_name(type));
> -}
> +#define nt_init(buf, type, desc) \
> +	nt_init_name(buf, NT_ ## type, &(desc), sizeof(desc), NN_ ## type)
>  
>  /*
>   * Calculate the size of ELF note
> @@ -300,10 +289,7 @@ static size_t nt_size_name(int d_len, const char *name)
>  	return size;
>  }
>  
> -static inline size_t nt_size(Elf64_Word type, int d_len)
> -{
> -	return nt_size_name(d_len, nt_name(type));
> -}
> +#define nt_size(type, desc) nt_size_name(sizeof(desc), NN_ ## type)
>  
>  /*
>   * Fill ELF notes for one CPU with save area registers
> @@ -324,18 +310,16 @@ static void *fill_cpu_elf_notes(void *ptr, int cpu, struct save_area *sa)
>  	memcpy(&nt_fpregset.fpc, &sa->fpc, sizeof(sa->fpc));
>  	memcpy(&nt_fpregset.fprs, &sa->fprs, sizeof(sa->fprs));
>  	/* Create ELF notes for the CPU */
> -	ptr = nt_init(ptr, NT_PRSTATUS, &nt_prstatus, sizeof(nt_prstatus));
> -	ptr = nt_init(ptr, NT_PRFPREG, &nt_fpregset, sizeof(nt_fpregset));
> -	ptr = nt_init(ptr, NT_S390_TIMER, &sa->timer, sizeof(sa->timer));
> -	ptr = nt_init(ptr, NT_S390_TODCMP, &sa->todcmp, sizeof(sa->todcmp));
> -	ptr = nt_init(ptr, NT_S390_TODPREG, &sa->todpreg, sizeof(sa->todpreg));
> -	ptr = nt_init(ptr, NT_S390_CTRS, &sa->ctrs, sizeof(sa->ctrs));
> -	ptr = nt_init(ptr, NT_S390_PREFIX, &sa->prefix, sizeof(sa->prefix));
> +	ptr = nt_init(ptr, PRSTATUS, nt_prstatus);
> +	ptr = nt_init(ptr, PRFPREG, nt_fpregset);
> +	ptr = nt_init(ptr, S390_TIMER, sa->timer);
> +	ptr = nt_init(ptr, S390_TODCMP, sa->todcmp);
> +	ptr = nt_init(ptr, S390_TODPREG, sa->todpreg);
> +	ptr = nt_init(ptr, S390_CTRS, sa->ctrs);
> +	ptr = nt_init(ptr, S390_PREFIX, sa->prefix);
>  	if (cpu_has_vx()) {
> -		ptr = nt_init(ptr, NT_S390_VXRS_HIGH,
> -			      &sa->vxrs_high, sizeof(sa->vxrs_high));
> -		ptr = nt_init(ptr, NT_S390_VXRS_LOW,
> -			      &sa->vxrs_low, sizeof(sa->vxrs_low));
> +		ptr = nt_init(ptr, S390_VXRS_HIGH, sa->vxrs_high);
> +		ptr = nt_init(ptr, S390_VXRS_LOW, sa->vxrs_low);
>  	}
>  	return ptr;
>  }
> @@ -348,16 +332,16 @@ static size_t get_cpu_elf_notes_size(void)
>  	struct save_area *sa = NULL;
>  	size_t size;
>  
> -	size =	nt_size(NT_PRSTATUS, sizeof(struct elf_prstatus));
> -	size +=  nt_size(NT_PRFPREG, sizeof(elf_fpregset_t));
> -	size +=  nt_size(NT_S390_TIMER, sizeof(sa->timer));
> -	size +=  nt_size(NT_S390_TODCMP, sizeof(sa->todcmp));
> -	size +=  nt_size(NT_S390_TODPREG, sizeof(sa->todpreg));
> -	size +=  nt_size(NT_S390_CTRS, sizeof(sa->ctrs));
> -	size +=  nt_size(NT_S390_PREFIX, sizeof(sa->prefix));
> +	size =	nt_size(PRSTATUS, struct elf_prstatus);
> +	size += nt_size(PRFPREG, elf_fpregset_t);
> +	size += nt_size(S390_TIMER, sa->timer);
> +	size += nt_size(S390_TODCMP, sa->todcmp);
> +	size += nt_size(S390_TODPREG, sa->todpreg);
> +	size += nt_size(S390_CTRS, sa->ctrs);
> +	size += nt_size(S390_PREFIX, sa->prefix);
>  	if (cpu_has_vx()) {
> -		size += nt_size(NT_S390_VXRS_HIGH, sizeof(sa->vxrs_high));
> -		size += nt_size(NT_S390_VXRS_LOW, sizeof(sa->vxrs_low));
> +		size += nt_size(S390_VXRS_HIGH, sa->vxrs_high);
> +		size += nt_size(S390_VXRS_LOW, sa->vxrs_low);
>  	}
>  
>  	return size;
> @@ -373,7 +357,7 @@ static void *nt_prpsinfo(void *ptr)
>  	memset(&prpsinfo, 0, sizeof(prpsinfo));
>  	prpsinfo.pr_sname = 'R';
>  	strcpy(prpsinfo.pr_fname, "vmlinux");
> -	return nt_init(ptr, NT_PRPSINFO, &prpsinfo, sizeof(prpsinfo));
> +	return nt_init(ptr, PRPSINFO, prpsinfo);
>  }
>  
>  /*
> @@ -589,7 +573,7 @@ static size_t get_elfcorehdr_size(int phdr_count)
>  	/* PT_NOTES */
>  	size += sizeof(Elf64_Phdr);
>  	/* nt_prpsinfo */
> -	size += nt_size(NT_PRPSINFO, sizeof(struct elf_prpsinfo));
> +	size += nt_size(PRPSINFO, struct elf_prpsinfo);
>  	/* regsets */
>  	size += get_cpu_cnt() * get_cpu_elf_notes_size();
>  	/* nt_vmcoreinfo */
> 
> -- 
> 2.47.1
> 
> 

Re: [PATCH v4 6/6] crash: Remove KEXEC_CORE_NOTE_NAME

[Dave Martin]

Hi,

On Sat, Jan 11, 2025 at 02:48:49PM +0900, Akihiko Odaki wrote:
> KEXEC_CORE_NOTE_NAME is no longer used.
> 
> Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
> Acked-by: Baoquan He <bhe@redhat.com>

Reviewed-by: Dave Martin <Dave.Martin@arm.com>

> ---
>  include/linux/kexec.h       | 2 --
>  include/linux/vmcore_info.h | 1 -
>  2 files changed, 3 deletions(-)
> 
> diff --git a/include/linux/kexec.h b/include/linux/kexec.h
> index f0e9f8eda7a3..c840431eadda 100644
> --- a/include/linux/kexec.h
> +++ b/include/linux/kexec.h
> @@ -68,8 +68,6 @@ extern note_buf_t __percpu *crash_notes;
>  #define KEXEC_CRASH_MEM_ALIGN PAGE_SIZE
>  #endif
>  
> -#define KEXEC_CORE_NOTE_NAME	CRASH_CORE_NOTE_NAME
> -
>  /*
>   * This structure is used to hold the arguments that are used when loading
>   * kernel binaries.
> diff --git a/include/linux/vmcore_info.h b/include/linux/vmcore_info.h
> index 1672801fd98c..37e003ae5262 100644
> --- a/include/linux/vmcore_info.h
> +++ b/include/linux/vmcore_info.h
> @@ -6,7 +6,6 @@
>  #include <linux/elfcore.h>
>  #include <linux/elf.h>
>  
> -#define CRASH_CORE_NOTE_NAME	   "CORE"
>  #define CRASH_CORE_NOTE_HEAD_BYTES ALIGN(sizeof(struct elf_note), 4)
>  #define CRASH_CORE_NOTE_NAME_BYTES ALIGN(sizeof(NN_PRSTATUS), 4)
>  #define CRASH_CORE_NOTE_DESC_BYTES ALIGN(sizeof(struct elf_prstatus), 4)
> 
> -- 
> 2.47.1
> 
>