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

From: Hari Bathini
Date: Tue Jan 24 2017 - 13:12:26 EST



On Tuesday 17 January 2017 10:36 PM, Hari Bathini wrote:


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?


Hello IA64 folks,

Could you please review this patch..?

Thanks
Hari