[PATCH kexec-tools 12/32] kexec: add helper to exlude a region from a set of memory ranges
From: Pratyush Anand <hidden>
Date: 2016-05-27 15:07:41
Also in:
kexec
On Thu, May 26, 2016 at 2:26 PM, Russell King - ARM Linux [off-list ref] wrote:
On Wed, May 25, 2016 at 01:30:44PM +0530, Pratyush Anand wrote:quoted
On Tue, May 3, 2016 at 3:52 PM, Russell King [off-list ref] wrote:quoted
+int mem_regions_exclude(struct memory_ranges *ranges, + const struct memory_range *range) +{ + int i; + + for (i = 0; i < ranges->size; i++) { + struct memory_range *r = ranges->ranges + i; + + /* + * We assume that crash area is fully contained in + * some larger memory area. + */ + if (r->start <= range->start && r->end >= range->end) { + if (r->start == range->start) { + /* Shrink the start of this memory range */ + r->start = range->end + 1; + } else if (r->end == range->end) { + /* Shrink the end of this memory range */ + r->end = range->start - 1;What if r->start == range->start) && (r->end == range->end)?I suppose that could happen, so what about this patch on top (untested).
I think, it should be fine, except.....
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This isn't something I'd be able to test on real hardware, it needs a separate test-suite to be written to do modular testing... kexec/mem_regions.c | 94 +++++++++++++++++++++++++++++++---------------------- 1 file changed, 55 insertions(+), 39 deletions(-)diff --git a/kexec/mem_regions.c b/kexec/mem_regions.c index c6ba942..4e7061b 100644 --- a/kexec/mem_regions.c +++ b/kexec/mem_regions.c@@ -29,6 +29,50 @@ void mem_regions_sort(struct memory_ranges *ranges) } /** + * mem_regions_add() - add a memory region to a set of ranges + * @ranges: ranges to add the memory region to + * @max: maximum number of entries in memory region + * @base: base address of memory region + * @length: length of memory region in bytes + * @type: type of memory region + * + * Add the memory region to the set of ranges, and return %0 if successful, + * or %-1 if we ran out of space. + */ +int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, + unsigned long long length, int type) +{ + struct memory_range *range; + + if (ranges->size >= ranges->max_size) + return -1; + + range = ranges->ranges + ranges->size++; + range->start = base; + range->end = base + length - 1; + range->type = type; + + return 0; +} + +static void mem_regions_remove(struct memory_ranges *ranges, int index) +{ + int tail_entries; + + /* we are assured to have at least one entry */ + ranges->size -= 1; + + /* if we have following entries, shuffle them down one place */ + tail_entries = ranges->size - index; + if (tail_entries) + memmove(ranges->ranges + index, ranges->ranges + index + 1, + tail_entries * sizeof(*ranges->ranges)); + + /* zero the new tail entry */ + memset(ranges->ranges + ranges->size, 0, sizeof(*ranges->ranges)); +} + +/** * mem_regions_exclude() - excludes a memory region from a set of memory ranges * @ranges: memory ranges to exclude the region from * @range: memory range to exclude@@ -40,7 +84,7 @@ void mem_regions_sort(struct memory_ranges *ranges) int mem_regions_exclude(struct memory_ranges *ranges, const struct memory_range *range) { - int i; + int i, ret; for (i = 0; i < ranges->size; i++) { struct memory_range *r = ranges->ranges + i;@@ -51,25 +95,25 @@ int mem_regions_exclude(struct memory_ranges *ranges, */ if (r->start <= range->start && r->end >= range->end) { if (r->start == range->start) { - /* Shrink the start of this memory range */ - r->start = range->end + 1; + if (r->end == range->end) + /* Remove this entry */ + mem_regions_remove(ranges, i); + else + /* Shrink the start of this memory range */ + r->start = range->end + 1; } else if (r->end == range->end) { /* Shrink the end of this memory range */ r->end = range->start - 1; } else { - struct memory_range *new; - /* * Split this area into 2 smaller ones and * remove excluded range from between. First * create new entry for the remaining area. */ - if (ranges->size >= ranges->max_size) - return -1; - - new = ranges->ranges + ranges->size++; - new->start = range->end + 1; - new->end = r->end; + ret = mem_regions_add(ranges, range->end + 1, + r->end, 0);
3rd argument should be (r->end - range->end)
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+ if (ret < 0) + return ret; /* * Update this area to end before excluded@@ -82,31 +126,3 @@ int mem_regions_exclude(struct memory_ranges *ranges, } return 0; } - -/** - * mem_regions_add() - add a memory region to a set of ranges - * @ranges: ranges to add the memory region to - * @max: maximum number of entries in memory region - * @base: base address of memory region - * @length: length of memory region in bytes - * @type: type of memory region - * - * Add the memory region to the set of ranges, and return %0 if successful, - * or %-1 if we ran out of space. - */ -int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, - unsigned long long length, int type) -{ - struct memory_range *range; - - if (ranges->size >= ranges->max_size) - return -1; - - range = ranges->ranges + ranges->size++; - range->start = base; - range->end = base + length - 1; - range->type = type; - - return 0; -} - --RMK's Patch system: http://www.armlinux.org.uk/developer/patches/ FTTC broadband for 0.8mile line: currently at 9.6Mbps down 400kbps up according to speedtest.net.
~Pratyush