[RFC PATCH makedumpfile v3 1/3] elf_info.c: Introduce is_pmem_pt_load_range

From: Li Zhijian
Date: Fri Jun 02 2023 - 06:31:46 EST


It checks BIT(4) of Elf64_Phdr, currently only the former 3 bits are used
by ELF. In kexec-tool, we extend the BIT(4) to indicate pmem or not.

dump_Elf_load: phys_start phys_end virt_start virt_end is_pmem
dump_Elf_load: LOAD[ 0] 6b800000 6e42c000 ffffffffbcc00000 ffffffffbf82c000 false
dump_Elf_load: LOAD[ 1] 1000 9fc00 ffff975980001000 ffff97598009fc00 false
dump_Elf_load: LOAD[ 2] 100000 7f000000 ffff975980100000 ffff9759ff000000 false
dump_Elf_load: LOAD[ 3] bf000000 bffd7000 ffff975a3f000000 ffff975a3ffd7000 false
dump_Elf_load: LOAD[ 4] 100000000 140000000 ffff975a80000000 ffff975ac0000000 false
dump_Elf_load: LOAD[ 5] 140000000 23e200000 ffff975ac0000000 ffff975bbe200000 true

CC: Baoquan He <bhe@xxxxxxxxxx>
CC: Vivek Goyal <vgoyal@xxxxxxxxxx>
CC: Dave Young <dyoung@xxxxxxxxxx>
CC: kexec@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Li Zhijian <lizhijian@xxxxxxxxxxx>
---
elf_info.c | 31 +++++++++++++++++++++++++++----
elf_info.h | 1 +
2 files changed, 28 insertions(+), 4 deletions(-)

diff --git a/elf_info.c b/elf_info.c
index bc24083655d6..41b36b2804d2 100644
--- a/elf_info.c
+++ b/elf_info.c
@@ -43,6 +43,7 @@ struct pt_load_segment {
unsigned long long phys_end;
unsigned long long virt_start;
unsigned long long virt_end;
+ int is_pmem;
};

static int nr_cpus; /* number of cpu */
@@ -153,6 +154,8 @@ check_elf_format(int fd, char *filename, int *phnum, unsigned int *num_load)
return FALSE;
}

+#define PF_DEV (1 << 4)
+
static int
dump_Elf_load(Elf64_Phdr *prog, int num_load)
{
@@ -170,17 +173,37 @@ dump_Elf_load(Elf64_Phdr *prog, int num_load)
pls->virt_end = pls->virt_start + prog->p_memsz;
pls->file_offset = prog->p_offset;
pls->file_size = prog->p_filesz;
+ pls->is_pmem = !!(prog->p_flags & PF_DEV);

if (num_load == 0)
- DEBUG_MSG("%8s %16s %16s %16s %16s\n", "",
- "phys_start", "phys_end", "virt_start", "virt_end");
+ DEBUG_MSG("%8s %16s %16s %16s %16s %8s\n", "",
+ "phys_start", "phys_end", "virt_start", "virt_end",
+ "is_pmem");

- DEBUG_MSG("LOAD[%2d] %16llx %16llx %16llx %16llx\n", num_load,
- pls->phys_start, pls->phys_end, pls->virt_start, pls->virt_end);
+ DEBUG_MSG("LOAD[%2d] %16llx %16llx %16llx %16llx %8s\n", num_load,
+ pls->phys_start, pls->phys_end, pls->virt_start, pls->virt_end,
+ pls->is_pmem ? "true": "false");

return TRUE;
}

+int is_pmem_pt_load_range(unsigned long long start, unsigned long long end)
+{
+ int i;
+ struct pt_load_segment *pls;
+
+ for (i = 0; i < num_pt_loads; i++) {
+ pls = &pt_loads[i];
+ if (pls->is_pmem && pls->phys_start == NOT_PADDR)
+ return TRUE;
+ if (pls->is_pmem && pls->phys_start != NOT_PADDR &&
+ pls->phys_start <= start && pls->phys_end >= end)
+ return TRUE;
+ }
+
+ return FALSE;
+}
+
static off_t
offset_next_note(void *note)
{
diff --git a/elf_info.h b/elf_info.h
index d5416b32cdd7..a08d59a331f6 100644
--- a/elf_info.h
+++ b/elf_info.h
@@ -64,6 +64,7 @@ int get_pt_load_extents(int idx,
off_t *file_offset,
off_t *file_size);
unsigned int get_num_pt_loads(void);
+int is_pmem_pt_load_range(unsigned long long start, unsigned long long end);

void set_nr_cpus(int num);
int get_nr_cpus(void);
--
2.29.2