Handle pages filled with zero that are not stored in the ELF file
directly, but have addresses between p_filesz and p_memsz of a segment.
This allows makedumpfile to dump-dmesg from a previously makedumpfile-ed
vmcore where all 0-page were excluded (dump_level & 1) for example.
Signed-off-by: Ivan Delalande <colona at arista.com>
---
elf_info.c | 22 ++++++++++++++++++++++
elf_info.h | 1 +
makedumpfile.c | 17 +++++++++++++++++
3 files changed, 40 insertions(+)
diff --git a/elf_info.c b/elf_info.c
index 8bce942..d9d1f42 100644
--- a/elf_info.c
+++ b/elf_info.c
@@ -42,6 +42,7 @@ struct pt_load_segment {
unsigned long long phys_end;
unsigned long long virt_start;
unsigned long long virt_end;
+ size_t mem_size;
};
static int nr_cpus; /* number of cpu */
@@ -166,6 +167,7 @@ dump_Elf_load(Elf64_Phdr *prog, int num_load)
pls->virt_start = prog->p_vaddr;
pls->virt_end = pls->virt_start + prog->p_filesz;
pls->file_offset = prog->p_offset;
+ pls->mem_size = prog->p_memsz;
DEBUG_MSG("LOAD (%d)\n", num_load);
DEBUG_MSG(" phys_start : %llx\n", pls->phys_start);
@@ -584,6 +586,26 @@ offset_to_pt_load_end(off_t offset)
}
/*
+ * Return true if a page is in the zone between p_filesz and p_memsz of a
+ * segment, which is a page filled with zero and not stored in the ELF file.
+ */
+int
+paddr_is_null(unsigned long long paddr)
+{
+ int i;
+ struct pt_load_segment *pls;
+
+ for (i = 0; i < num_pt_loads; i++) {
+ pls = &pt_loads[i];
+ if ((paddr >= pls->phys_end)
+ && (paddr + info->page_size
+ <= pls->phys_start + pls->mem_size))
+ return TRUE;
+ }
+ return FALSE;
+}
+
+/*
* Judge whether the page is fractional or not.
*/
int
diff --git a/elf_info.h b/elf_info.h
index e712253..4823311 100644
--- a/elf_info.h
+++ b/elf_info.h
@@ -36,6 +36,7 @@ unsigned long long page_head_to_phys_start(unsigned long long head_paddr);
unsigned long long page_head_to_phys_end(unsigned long long head_paddr);
off_t offset_to_pt_load_start(off_t offset);
off_t offset_to_pt_load_end(off_t offset);
+int paddr_is_null(unsigned long long paddr);
unsigned long long vaddr_to_paddr_general(unsigned long long vaddr);
off_t vaddr_to_offset_slow(int fd, char *filename, unsigned long long vaddr);
unsigned long long get_max_paddr(void);
diff --git a/makedumpfile.c b/makedumpfile.c
index b802446..491f278 100644
--- a/makedumpfile.c
+++ b/makedumpfile.c
@@ -652,11 +652,20 @@ readpage_elf(unsigned long long paddr, void *bufptr)
size_t size1, size2;
unsigned long long phys_start, phys_end, frac_head = 0;
+ /*
+ * Check the 0-filled pages that are not in the ELF file.
+ */
+ if (paddr_is_null(paddr)) {
+ memset(bufptr, 0, info->page_size);
+ return TRUE;
+ }
+
offset1 = paddr_to_offset(paddr);
offset2 = paddr_to_offset(paddr + info->page_size);
phys_start = paddr;
phys_end = paddr + info->page_size;
+
/*
* Check the case phys_start isn't aligned by page size like below:
*
@@ -726,6 +735,14 @@ readpage_elf_parallel(int fd_memory, unsigned long long paddr, void *bufptr)
size_t size1, size2;
unsigned long long phys_start, phys_end, frac_head = 0;
+ /*
+ * Check the 0-filled pages that are not in the ELF file.
+ */
+ if (paddr_is_null(paddr)) {
+ memset(bufptr, 0, info->page_size);
+ return TRUE;
+ }
+
offset1 = paddr_to_offset(paddr);
offset2 = paddr_to_offset(paddr + info->page_size);
phys_start = paddr;
--
2.7.0
--
Ivan "Colona" Delalande
Arista Networks
