Re: [PATCH v4 2/5] ia64: reuse append_elf_note() and final_note() functions

From: Hari Bathini
Date: Tue Jan 17 2017 - 12:07:12 EST



On Friday 06 January 2017 07:33 AM, Dave Young wrote:
On 01/05/17 at 11:01pm, Hari Bathini wrote:
Get rid of multiple definitions of append_elf_note() & final_note()
functions. Reuse these functions compiled under CONFIG_CRASH_CORE
Also, define Elf_Word and use it instead of generic u32 or the more
specific Elf64_Word.

Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx>
---

Changes from v3:
* Dropped hard-coded values and used DIV_ROUND_UP().

Changes from v2:
* Added a definition for Elf_Word.
* Used IA64 version of append_elf_note() and final_note() functions.


arch/ia64/kernel/crash.c | 22 ----------------------
include/linux/crash_core.h | 4 ++++
include/linux/elf.h | 2 ++
kernel/crash_core.c | 34 ++++++++++++++--------------------
kernel/kexec_core.c | 28 ----------------------------
5 files changed, 20 insertions(+), 70 deletions(-)

diff --git a/arch/ia64/kernel/crash.c b/arch/ia64/kernel/crash.c
index 2955f35..75859a0 100644
--- a/arch/ia64/kernel/crash.c
+++ b/arch/ia64/kernel/crash.c
@@ -27,28 +27,6 @@ static int kdump_freeze_monarch;
static int kdump_on_init = 1;
static int kdump_on_fatal_mca = 1;
-static inline Elf64_Word
-*append_elf_note(Elf64_Word *buf, char *name, unsigned type, void *data,
- size_t data_len)
-{
- struct elf_note *note = (struct elf_note *)buf;
- note->n_namesz = strlen(name) + 1;
- note->n_descsz = data_len;
- note->n_type = type;
- buf += (sizeof(*note) + 3)/4;
- memcpy(buf, name, note->n_namesz);
- buf += (note->n_namesz + 3)/4;
- memcpy(buf, data, data_len);
- buf += (data_len + 3)/4;
- return buf;
-}
-
-static void
-final_note(void *buf)
-{
- memset(buf, 0, sizeof(struct elf_note));
-}
-
extern void ia64_dump_cpu_regs(void *);
static DEFINE_PER_CPU(struct elf_prstatus, elf_prstatus);
diff --git a/include/linux/crash_core.h b/include/linux/crash_core.h
index 18d0f94..541a197 100644
--- a/include/linux/crash_core.h
+++ b/include/linux/crash_core.h
@@ -55,6 +55,10 @@ extern u32 vmcoreinfo_note[VMCOREINFO_NOTE_SIZE/4];
extern size_t vmcoreinfo_size;
extern size_t vmcoreinfo_max_size;
+Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
+ void *data, size_t data_len);
+void final_note(Elf_Word *buf);
+
int __init parse_crashkernel(char *cmdline, unsigned long long system_ram,
unsigned long long *crash_size, unsigned long long *crash_base);
int parse_crashkernel_high(char *cmdline, unsigned long long system_ram,
diff --git a/include/linux/elf.h b/include/linux/elf.h
index 20fa8d8..ba069e8 100644
--- a/include/linux/elf.h
+++ b/include/linux/elf.h
@@ -29,6 +29,7 @@ extern Elf32_Dyn _DYNAMIC [];
#define elf_note elf32_note
#define elf_addr_t Elf32_Off
#define Elf_Half Elf32_Half
+#define Elf_Word Elf32_Word
#else
@@ -39,6 +40,7 @@ extern Elf64_Dyn _DYNAMIC [];
#define elf_note elf64_note
#define elf_addr_t Elf64_Off
#define Elf_Half Elf64_Half
+#define Elf_Word Elf64_Word
#endif
diff --git a/kernel/crash_core.c b/kernel/crash_core.c
index 80b441d..362dace 100644
--- a/kernel/crash_core.c
+++ b/kernel/crash_core.c
@@ -291,32 +291,26 @@ int __init parse_crashkernel_low(char *cmdline,
"crashkernel=", suffix_tbl[SUFFIX_LOW]);
}
-static u32 *append_elf_note(u32 *buf, char *name, unsigned int type,
- void *data, size_t data_len)
+Elf_Word *append_elf_note(Elf_Word *buf, char *name, unsigned int type,
+ void *data, size_t data_len)
{
- struct elf_note note;
-
- note.n_namesz = strlen(name) + 1;
- note.n_descsz = data_len;
- note.n_type = type;
- memcpy(buf, &note, sizeof(note));
- buf += (sizeof(note) + 3)/4;
- memcpy(buf, name, note.n_namesz);
- buf += (note.n_namesz + 3)/4;
- memcpy(buf, data, note.n_descsz);
- buf += (note.n_descsz + 3)/4;
+ struct elf_note *note = (struct elf_note *)buf;
+
+ note->n_namesz = strlen(name) + 1;
+ note->n_descsz = data_len;
+ note->n_type = type;
+ buf += DIV_ROUND_UP(sizeof(*note), sizeof(Elf_Word));
+ memcpy(buf, name, note->n_namesz);
+ buf += DIV_ROUND_UP(note->n_namesz, sizeof(Elf_Word));
+ memcpy(buf, data, data_len);
+ buf += DIV_ROUND_UP(data_len, sizeof(Elf_Word));
return buf;
}
-static void final_note(u32 *buf)
+void final_note(Elf_Word *buf)
{
- struct elf_note note;
-
- note.n_namesz = 0;
- note.n_descsz = 0;
- note.n_type = 0;
- memcpy(buf, &note, sizeof(note));
+ memset(buf, 0, sizeof(struct elf_note));
}
static void update_vmcoreinfo_note(void)
diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c
index 2179a16..263d764 100644
--- a/kernel/kexec_core.c
+++ b/kernel/kexec_core.c
@@ -990,34 +990,6 @@ int crash_shrink_memory(unsigned long new_size)
return ret;
}
-static u32 *append_elf_note(u32 *buf, char *name, unsigned type, void *data,
- size_t data_len)
-{
- struct elf_note note;
-
- note.n_namesz = strlen(name) + 1;
- note.n_descsz = data_len;
- note.n_type = type;
- memcpy(buf, &note, sizeof(note));
- buf += (sizeof(note) + 3)/4;
- memcpy(buf, name, note.n_namesz);
- buf += (note.n_namesz + 3)/4;
- memcpy(buf, data, note.n_descsz);
- buf += (note.n_descsz + 3)/4;
-
- return buf;
-}
-
-static void final_note(u32 *buf)
-{
- struct elf_note note;
-
- note.n_namesz = 0;
- note.n_descsz = 0;
- note.n_type = 0;
- memcpy(buf, &note, sizeof(note));
-}
-
void crash_save_cpu(struct pt_regs *regs, int cpu)
{
struct elf_prstatus prstatus;

It looks good to me. But better to have words from IA64 people as well.



Can someone from IA64 arch review this please?

Thanks
Hari