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x86/boot/e820: Clean up __e820__update_table() et al

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The __e820__update_table() function has various weirdly named variables,
such as 'pbios', 'biosmap' and 'pnr_map' which are pretty confusing
and actively misleading at times.

This weird naming found its way into other functions as well, such as
__append_e820_table() and append_e820_table().

Standardize the naming to make it all much easier to read:

	biosmap  ->  entries
	pbios    ->  entry
	nr_map   ->  nr_entries
        pnr_map  ->  nr_entries
	...

Also clean up the types used: entry indices routinely mixed u32 and int,
standardize on u32 thoughout.

Update the comments as well, while at it.

No change in functionality.

Cc: Alex Thorlton <athorlton@sgi.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Huang, Ying <ying.huang@intel.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Paul Jackson <pj@sgi.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Tejun Heo <tj@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wei Yang <richard.weiyang@gmail.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Ingo Molnar
2017-01-28 18:35:24 +01:00
parent f9748fa045
commit 9a02fd0f1e
1 changed files with 61 additions and 59 deletions
Download Patch File Download Diff File Expand all files Collapse all files

120
arch/x86/kernel/e820.c
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@@ -175,23 +175,23 @@ void __init e820__print_table(char *who)
} }
/* /*
* Sanitize the BIOS E820 map. * Sanitize an E820 map.
* *
* Some E820 responses include overlapping entries. The following * Some E820 layouts include overlapping entries. The following
* replaces the original E820 map with a new one, removing overlaps, * replaces the original E820 map with a new one, removing overlaps,
* and resolving conflicting memory types in favor of highest * and resolving conflicting memory types in favor of highest
* numbered type. * numbered type.
* *
* The input parameter biosmap points to an array of 'struct * The input parameter 'entries' points to an array of 'struct
* e820_entry' which on entry has elements in the range [0, *pnr_map) * e820_entry' which on entry has elements in the range [0, *nr_entries)
* valid, and which has space for up to max_nr_map entries. * valid, and which has space for up to max_nr_entries entries.
* On return, the resulting sanitized E820 map entries will be in * On return, the resulting sanitized E820 map entries will be in
* overwritten in the same location, starting at biosmap. * overwritten in the same location, starting at 'entries'.
* *
* The integer pointed to by pnr_map must be valid on entry (the * The integer pointed to by nr_entries must be valid on entry (the
* current number of valid entries located at biosmap). If the * current number of valid entries located at 'entries'). If the
* sanitizing succeeds the *pnr_map will be updated with the new * sanitizing succeeds the *nr_entries will be updated with the new
* number of valid entries (something no more than max_nr_map). * number of valid entries (something no more than max_nr_entries).
* *
* The return value from e820__update_table() is zero if it * The return value from e820__update_table() is zero if it
* successfully 'sanitized' the map entries passed in, and is -1 * successfully 'sanitized' the map entries passed in, and is -1
@@ -236,8 +236,8 @@ void __init e820__print_table(char *who)
* ______________________4_ * ______________________4_
*/ */
struct change_member { struct change_member {
/* Pointer to the original BIOS entry: */ /* Pointer to the original entry: */
struct e820_entry *pbios; struct e820_entry *entry;
/* Address for this change point: */ /* Address for this change point: */
unsigned long long addr; unsigned long long addr;
}; };
@@ -256,33 +256,33 @@ static int __init cpcompare(const void *a, const void *b)
if (ap->addr != bp->addr) if (ap->addr != bp->addr)
return ap->addr > bp->addr ? 1 : -1; return ap->addr > bp->addr ? 1 : -1;
return (ap->addr != ap->pbios->addr) - (bp->addr != bp->pbios->addr); return (ap->addr != ap->entry->addr) - (bp->addr != bp->entry->addr);
} }
static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_map, u32 *pnr_map) static int __init __e820__update_table(struct e820_entry *entries, u32 max_nr_entries, u32 *nr_entries)
{ {
static struct change_member change_point_list[2*E820_MAX_ENTRIES] __initdata; static struct change_member change_point_list[2*E820_MAX_ENTRIES] __initdata;
static struct change_member *change_point[2*E820_MAX_ENTRIES] __initdata; static struct change_member *change_point[2*E820_MAX_ENTRIES] __initdata;
static struct e820_entry *overlap_list[E820_MAX_ENTRIES] __initdata; static struct e820_entry *overlap_list[E820_MAX_ENTRIES] __initdata;
static struct e820_entry new_bios[E820_MAX_ENTRIES] __initdata; static struct e820_entry new_entries[E820_MAX_ENTRIES] __initdata;
enum e820_type current_type, last_type; enum e820_type current_type, last_type;
unsigned long long last_addr; unsigned long long last_addr;
int chgidx; u32 chgidx;
int overlap_entries; u32 overlap_entries;
int new_bios_entry; u32 new_nr_entries;
int old_nr, new_nr, chg_nr; u32 old_nr, new_nr, chg_nr;
int i; u32 i;
/* If there's only one memory region, don't bother: */ /* If there's only one memory region, don't bother: */
if (*pnr_map < 2) if (*nr_entries < 2)
return -1; return -1;
old_nr = *pnr_map; old_nr = *nr_entries;
BUG_ON(old_nr > max_nr_map); BUG_ON(old_nr > max_nr_entries);
/* Bail out if we find any unreasonable addresses in the BIOS map: */ /* Bail out if we find any unreasonable addresses in the map: */
for (i = 0; i < old_nr; i++) { for (i = 0; i < old_nr; i++) {
if (biosmap[i].addr + biosmap[i].size < biosmap[i].addr) if (entries[i].addr + entries[i].size < entries[i].addr)
return -1; return -1;
} }
@@ -296,11 +296,11 @@ static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_ma
*/ */
chgidx = 0; chgidx = 0;
for (i = 0; i < old_nr; i++) { for (i = 0; i < old_nr; i++) {
if (biosmap[i].size != 0) { if (entries[i].size != 0) {
change_point[chgidx]->addr = biosmap[i].addr; change_point[chgidx]->addr = entries[i].addr;
change_point[chgidx++]->pbios = &biosmap[i]; change_point[chgidx++]->entry = &entries[i];
change_point[chgidx]->addr = biosmap[i].addr + biosmap[i].size; change_point[chgidx]->addr = entries[i].addr + entries[i].size;
change_point[chgidx++]->pbios = &biosmap[i]; change_point[chgidx++]->entry = &entries[i];
} }
} }
chg_nr = chgidx; chg_nr = chgidx;
@@ -308,22 +308,22 @@ static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_ma
/* Sort change-point list by memory addresses (low -> high): */ /* Sort change-point list by memory addresses (low -> high): */
sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL); sort(change_point, chg_nr, sizeof(*change_point), cpcompare, NULL);
/* Create a new BIOS memory map, removing overlaps: */ /* Create a new memory map, removing overlaps: */
overlap_entries = 0; /* Number of entries in the overlap table */ overlap_entries = 0; /* Number of entries in the overlap table */
new_bios_entry = 0; /* Index for creating new bios map entries */ new_nr_entries = 0; /* Index for creating new map entries */
last_type = 0; /* Start with undefined memory type */ last_type = 0; /* Start with undefined memory type */
last_addr = 0; /* Start with 0 as last starting address */ last_addr = 0; /* Start with 0 as last starting address */
/* Loop through change-points, determining effect on the new BIOS map: */ /* Loop through change-points, determining effect on the new map: */
for (chgidx = 0; chgidx < chg_nr; chgidx++) { for (chgidx = 0; chgidx < chg_nr; chgidx++) {
/* Keep track of all overlapping BIOS entries */ /* Keep track of all overlapping entries */
if (change_point[chgidx]->addr == change_point[chgidx]->pbios->addr) { if (change_point[chgidx]->addr == change_point[chgidx]->entry->addr) {
/* Add map entry to overlap list (> 1 entry implies an overlap) */ /* Add map entry to overlap list (> 1 entry implies an overlap) */
overlap_list[overlap_entries++] = change_point[chgidx]->pbios; overlap_list[overlap_entries++] = change_point[chgidx]->entry;
} else { } else {
/* Remove entry from list (order independent, so swap with last): */ /* Remove entry from list (order independent, so swap with last): */
for (i = 0; i < overlap_entries; i++) { for (i = 0; i < overlap_entries; i++) {
if (overlap_list[i] == change_point[chgidx]->pbios) if (overlap_list[i] == change_point[chgidx]->entry)
overlap_list[i] = overlap_list[overlap_entries-1]; overlap_list[i] = overlap_list[overlap_entries-1];
} }
overlap_entries--; overlap_entries--;
@@ -339,31 +339,31 @@ static int __init __e820__update_table(struct e820_entry *biosmap, int max_nr_ma
current_type = overlap_list[i]->type; current_type = overlap_list[i]->type;
} }
/* Continue building up new BIOS map based on this information: */ /* Continue building up new map based on this information: */
if (current_type != last_type || current_type == E820_TYPE_PRAM) { if (current_type != last_type || current_type == E820_TYPE_PRAM) {
if (last_type != 0) { if (last_type != 0) {
new_bios[new_bios_entry].size = change_point[chgidx]->addr - last_addr; new_entries[new_nr_entries].size = change_point[chgidx]->addr - last_addr;
/* Move forward only if the new size was non-zero: */ /* Move forward only if the new size was non-zero: */
if (new_bios[new_bios_entry].size != 0) if (new_entries[new_nr_entries].size != 0)
/* No more space left for new BIOS entries? */ /* No more space left for new entries? */
if (++new_bios_entry >= max_nr_map) if (++new_nr_entries >= max_nr_entries)
break; break;
} }
if (current_type != 0) { if (current_type != 0) {
new_bios[new_bios_entry].addr = change_point[chgidx]->addr; new_entries[new_nr_entries].addr = change_point[chgidx]->addr;
new_bios[new_bios_entry].type = current_type; new_entries[new_nr_entries].type = current_type;
last_addr = change_point[chgidx]->addr; last_addr = change_point[chgidx]->addr;
} }
last_type = current_type; last_type = current_type;
} }
} }
/* Retain count for new BIOS entries: */ /* Retain count for the new entries: */
new_nr = new_bios_entry; new_nr = new_nr_entries;
/* Copy new BIOS mapping into the original location: */ /* Copy the new entries into the original location: */
memcpy(biosmap, new_bios, new_nr*sizeof(*biosmap)); memcpy(entries, new_entries, new_nr*sizeof(*entries));
*pnr_map = new_nr; *nr_entries = new_nr;
return 0; return 0;
} }
@@ -373,13 +373,15 @@ int __init e820__update_table(struct e820_table *table)
return __e820__update_table(table->entries, ARRAY_SIZE(table->entries), &table->nr_entries); return __e820__update_table(table->entries, ARRAY_SIZE(table->entries), &table->nr_entries);
} }
static int __init __append_e820_table(struct e820_entry *biosmap, int nr_map) static int __init __append_e820_table(struct e820_entry *entries, u32 nr_entries)
{ {
while (nr_map) { struct e820_entry *entry = entries;
u64 start = biosmap->addr;
u64 size = biosmap->size; while (nr_entries) {
u64 start = entry->addr;
u64 size = entry->size;
u64 end = start + size - 1; u64 end = start + size - 1;
u32 type = biosmap->type; u32 type = entry->type;
/* Ignore the entry on 64-bit overflow: */ /* Ignore the entry on 64-bit overflow: */
if (start > end && likely(size)) if (start > end && likely(size))
@@ -387,8 +389,8 @@ static int __init __append_e820_table(struct e820_entry *biosmap, int nr_map)
e820__range_add(start, size, type); e820__range_add(start, size, type);
biosmap++; entry++;
nr_map--; nr_entries--;
} }
return 0; return 0;
} }
@@ -402,13 +404,13 @@ static int __init __append_e820_table(struct e820_entry *biosmap, int nr_map)
* will have given us a memory map that we can use to properly * will have given us a memory map that we can use to properly
* set up memory. If we aren't, we'll fake a memory map. * set up memory. If we aren't, we'll fake a memory map.
*/ */
static int __init append_e820_table(struct e820_entry *biosmap, int nr_map) static int __init append_e820_table(struct e820_entry *entries, u32 nr_entries)
{ {
/* Only one memory region (or negative)? Ignore it */ /* Only one memory region (or negative)? Ignore it */
if (nr_map < 2) if (nr_entries < 2)
return -1; return -1;
return __append_e820_table(biosmap, nr_map); return __append_e820_table(entries, nr_entries);
} }
static u64 __init static u64 __init