Add support for SPARSEMEM_EXTREME mem_section as a pointer.

Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@debian.org>

3 files changed, 246 insertions, 0 deletions

diff --git a/debian/changelog b/debian/changelog
index f1da216..5a2d846 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,9 @@
+makedumpfile (1:1.6.3-2) UNRELEASED; urgency=medium
+
+  * Add support for SPARSEMEM_EXTREME mem_section as a pointer. (LP: #1750021)
+
+ -- Thadeu Lima de Souza Cascardo <cascardo@debian.org>  Mon, 05 Mar 2018 09:28:55 -0300
+
 makedumpfile (1:1.6.3-1) unstable; urgency=medium
 
   * New upstream release. Main new feature:
diff --git a/debian/patches/0003-sparsemem_extreme.patch b/debian/patches/0003-sparsemem_extreme.patch
new file mode 100644
index 0000000..3345728
--- /dev/null
+++ b/debian/patches/0003-sparsemem_extreme.patch
@@ -0,0 +1,239 @@
+diff --git a/makedumpfile.c b/makedumpfile.c
+index ed138d3..cd3fa4d 100644
+--- a/makedumpfile.c
++++ b/makedumpfile.c
+@@ -3297,7 +3297,7 @@ get_mm_discontigmem(void)
+ 	return TRUE;
+ }
+ 
+-unsigned long
++static unsigned long
+ nr_to_section(unsigned long nr, unsigned long *mem_sec)
+ {
+ 	unsigned long addr;
+@@ -3311,17 +3311,17 @@ nr_to_section(unsigned long nr, unsigned long *mem_sec)
+ 		addr = SYMBOL(mem_section) + (nr * SIZE(mem_section));
+ 	}
+ 
+-	if (!is_kvaddr(addr))
+-		return NOT_KV_ADDR;
+-
+ 	return addr;
+ }
+ 
+-unsigned long
+-section_mem_map_addr(unsigned long addr)
++static unsigned long
++section_mem_map_addr(unsigned long addr, unsigned long *map_mask)
+ {
+ 	char *mem_section;
+ 	unsigned long map;
++	unsigned long mask;
++
++	*map_mask = 0;
+ 
+ 	if (!is_kvaddr(addr))
+ 		return NOT_KV_ADDR;
+@@ -3338,15 +3338,19 @@ section_mem_map_addr(unsigned long addr)
+ 	}
+ 	map = ULONG(mem_section + OFFSET(mem_section.section_mem_map));
+ 	if (info->kernel_version < KERNEL_VERSION(4, 13, 0))
+-		map &= SECTION_MAP_MASK_4_12;
++		mask = SECTION_MAP_MASK_4_12;
+ 	else
+-		map &= SECTION_MAP_MASK;
++		mask = SECTION_MAP_MASK;
++	*map_mask = map & ~mask;
++	if (map == 0x0)
++		*map_mask |= SECTION_MARKED_PRESENT;
++	map &= mask;
+ 	free(mem_section);
+ 
+ 	return map;
+ }
+ 
+-unsigned long
++static unsigned long
+ sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long section_nr)
+ {
+ 	unsigned long mem_map;
+@@ -3354,17 +3358,110 @@ sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long section_nr)
+ 	mem_map =  coded_mem_map +
+ 	    (SECTION_NR_TO_PFN(section_nr) * SIZE(page));
+ 
+-	if (!is_kvaddr(mem_map))
+-		return NOT_KV_ADDR;
+ 	return mem_map;
+ }
++
++/*
++ * On some kernels, mem_section may be a pointer or an array, when
++ * SPARSEMEM_EXTREME is on.
++ *
++ * We assume that section_mem_map is either 0 or has the present bit set.
++ *
++ */
++
++static int
++validate_mem_section(unsigned long *mem_sec,
++		     unsigned long mem_section_ptr, unsigned int mem_section_size,
++		     unsigned long *mem_maps, unsigned int num_section)
++{
++	unsigned int section_nr;
++	unsigned long map_mask;
++	unsigned long section, mem_map;
++	if (!readmem(VADDR, mem_section_ptr, mem_sec, mem_section_size)) {
++		ERRMSG("Can't read mem_section array.\n");
++		return FALSE;
++	}
++	for (section_nr = 0; section_nr < num_section; section_nr++) {
++		section = nr_to_section(section_nr, mem_sec);
++		if (section == NOT_KV_ADDR) {
++			mem_map = NOT_MEMMAP_ADDR;
++		} else {
++			mem_map = section_mem_map_addr(section, &map_mask);
++			if (!(map_mask & SECTION_MARKED_PRESENT)) {
++				return FALSE;
++			}
++			if (mem_map == 0) {
++				mem_map = NOT_MEMMAP_ADDR;
++			} else {
++				mem_map = sparse_decode_mem_map(mem_map,
++								section_nr);
++				if (!is_kvaddr(mem_map)) {
++					return FALSE;
++				}
++			}
++		}
++		mem_maps[section_nr] = mem_map;
++	}
++	return TRUE;
++}
++
++static int
++get_mem_section(unsigned int mem_section_size, unsigned long *mem_maps,
++		unsigned int num_section)
++{
++	unsigned long mem_section_ptr;
++	int ret = FALSE;
++	unsigned long *mem_sec = NULL;
++
++	if ((mem_sec = malloc(mem_section_size)) == NULL) {
++		ERRMSG("Can't allocate memory for the mem_section. %s\n",
++		    strerror(errno));
++		return FALSE;
++	}
++	ret = validate_mem_section(mem_sec, SYMBOL(mem_section),
++				   mem_section_size, mem_maps, num_section);
++
++	if (is_sparsemem_extreme()) {
++		int symbol_valid = ret;
++		int pointer_valid;
++		int mem_maps_size = sizeof(*mem_maps) * num_section;
++		unsigned long *mem_maps_ex = NULL;
++		if (!readmem(VADDR, SYMBOL(mem_section), &mem_section_ptr,
++			     sizeof(mem_section_ptr)))
++			goto out;
++
++		if ((mem_maps_ex = malloc(mem_maps_size)) == NULL) {
++			ERRMSG("Can't allocate memory for the mem_maps. %s\n",
++			    strerror(errno));
++			goto out;
++		}
++
++		pointer_valid = validate_mem_section(mem_sec,
++						     mem_section_ptr,
++						     mem_section_size,
++						     mem_maps_ex,
++						     num_section);
++		if (pointer_valid)
++			memcpy(mem_maps, mem_maps_ex, mem_maps_size);
++		if (mem_maps_ex)
++			free(mem_maps_ex);
++		ret = symbol_valid ^ pointer_valid;
++		if (!ret) {
++			ERRMSG("Could not validate mem_section.\n");
++		}
++	}
++out:
++	if (mem_sec != NULL)
++		free(mem_sec);
++	return ret;
++}
++
+ int
+ get_mm_sparsemem(void)
+ {
+ 	unsigned int section_nr, mem_section_size, num_section;
+ 	mdf_pfn_t pfn_start, pfn_end;
+-	unsigned long section, mem_map;
+-	unsigned long *mem_sec = NULL;
++	unsigned long *mem_maps = NULL;
+ 
+ 	int ret = FALSE;
+ 
+@@ -3379,13 +3476,12 @@ get_mm_sparsemem(void)
+ 		info->sections_per_root = _SECTIONS_PER_ROOT();
+ 		mem_section_size = SIZE(mem_section) * NR_SECTION_ROOTS();
+ 	}
+-	if ((mem_sec = malloc(mem_section_size)) == NULL) {
+-		ERRMSG("Can't allocate memory for the mem_section. %s\n",
+-		    strerror(errno));
++	if ((mem_maps = malloc(sizeof(*mem_maps) * num_section)) == NULL) {
++		ERRMSG("Can't allocate memory for the mem_maps. %s\n",
++			strerror(errno));
+ 		return FALSE;
+ 	}
+-	if (!readmem(VADDR, SYMBOL(mem_section), mem_sec,
+-	    mem_section_size)) {
++	if (!get_mem_section(mem_section_size, mem_maps, num_section)) {
+ 		ERRMSG("Can't get the address of mem_section.\n");
+ 		goto out;
+ 	}
+@@ -3397,31 +3493,16 @@ get_mm_sparsemem(void)
+ 		goto out;
+ 	}
+ 	for (section_nr = 0; section_nr < num_section; section_nr++) {
+-		section = nr_to_section(section_nr, mem_sec);
+-		if (section == NOT_KV_ADDR) {
+-			mem_map = NOT_MEMMAP_ADDR;
+-		} else {
+-			mem_map = section_mem_map_addr(section);
+-			if (mem_map == 0) {
+-				mem_map = NOT_MEMMAP_ADDR;
+-			} else {
+-				mem_map = sparse_decode_mem_map(mem_map,
+-								section_nr);
+-				if (!is_kvaddr(mem_map))
+-					mem_map = NOT_MEMMAP_ADDR;
+-			}
+-		}
+ 		pfn_start = section_nr * PAGES_PER_SECTION();
+ 		pfn_end   = pfn_start + PAGES_PER_SECTION();
+ 		if (info->max_mapnr < pfn_end)
+ 			pfn_end = info->max_mapnr;
+-		dump_mem_map(pfn_start, pfn_end, mem_map, section_nr);
++		dump_mem_map(pfn_start, pfn_end, mem_maps[section_nr], section_nr);
+ 	}
+ 	ret = TRUE;
+ out:
+-	if (mem_sec != NULL)
+-		free(mem_sec);
+-
++	if (mem_maps != NULL)
++		free(mem_maps);
+ 	return ret;
+ }
+ 
+diff --git a/makedumpfile.h b/makedumpfile.h
+index 01eece2..58e1aaa 100644
+--- a/makedumpfile.h
++++ b/makedumpfile.h
+@@ -184,6 +184,7 @@ isAnon(unsigned long mapping)
+ #define SECTIONS_PER_ROOT()	(info->sections_per_root)
+ #define SECTION_ROOT_MASK()	(SECTIONS_PER_ROOT() - 1)
+ #define SECTION_NR_TO_ROOT(sec)	((sec) / SECTIONS_PER_ROOT())
++#define SECTION_MARKED_PRESENT  (1UL<<0)
+ #define SECTION_IS_ONLINE	(1UL<<2)
+ #define SECTION_MAP_LAST_BIT	(1UL<<3)
+ #define SECTION_MAP_MASK_4_12	(~(SECTION_IS_ONLINE-1))
diff --git a/debian/patches/series b/debian/patches/series
index 8d0f986..042bad4 100644
--- a/debian/patches/series
+++ b/debian/patches/series
@@ -1,2 +1,3 @@
 0001-Remove-libebl-linkage.patch
 0002-adapt-makefile-to-debian.patch
+0003-sparsemem_extreme.patch