| Message ID | E1b9xsO-0003sa-Sr@e0050434b2927.dyn.armlinux.org.uk (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 06/06/2016:05:59:44 PM, Russell King wrote: > Add a helper to exclude a region from a set of memory ranges. > > Signed-off-by: Russell King <rmk@arm.linux.org.uk> Reviewed-by: Pratyush Anand <panand@redhat.com> > --- > kexec/mem_regions.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++ > kexec/mem_regions.h | 4 +++ > 2 files changed, 75 insertions(+) > > diff --git a/kexec/mem_regions.c b/kexec/mem_regions.c > index 804984a..b01a5c8 100644 > --- a/kexec/mem_regions.c > +++ b/kexec/mem_regions.c > @@ -55,3 +55,74 @@ int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, > 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 > + * > + * Exclude a memory region from a set of memory ranges. We assume that > + * the region to be excluded is either wholely located within one of the > + * memory ranges, or not at all. > + */ > +int mem_regions_exclude(struct memory_ranges *ranges, > + const struct memory_range *range) > +{ > + int i, ret; > + > + 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) { > + 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 { > + /* > + * Split this area into 2 smaller ones and > + * remove excluded range from between. First > + * create new entry for the remaining area. > + */ > + ret = mem_regions_add(ranges, range->end + 1, > + r->end - range->end, 0); > + if (ret < 0) > + return ret; > + > + /* > + * Update this area to end before excluded > + * range. > + */ > + r->end = range->start - 1; > + break; > + } > + } > + } > + return 0; > +} > diff --git a/kexec/mem_regions.h b/kexec/mem_regions.h > index da7b5e8..ae9e972 100644 > --- a/kexec/mem_regions.h > +++ b/kexec/mem_regions.h > @@ -2,9 +2,13 @@ > #define MEM_REGIONS_H > > struct memory_ranges; > +struct memory_range; > > void mem_regions_sort(struct memory_ranges *ranges); > > +int mem_regions_exclude(struct memory_ranges *ranges, > + const struct memory_range *range); > + > int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, > unsigned long long length, int type); > > -- > 1.9.1
diff --git a/kexec/mem_regions.c b/kexec/mem_regions.c index 804984a..b01a5c8 100644 --- a/kexec/mem_regions.c +++ b/kexec/mem_regions.c @@ -55,3 +55,74 @@ int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, 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 + * + * Exclude a memory region from a set of memory ranges. We assume that + * the region to be excluded is either wholely located within one of the + * memory ranges, or not at all. + */ +int mem_regions_exclude(struct memory_ranges *ranges, + const struct memory_range *range) +{ + int i, ret; + + 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) { + 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 { + /* + * Split this area into 2 smaller ones and + * remove excluded range from between. First + * create new entry for the remaining area. + */ + ret = mem_regions_add(ranges, range->end + 1, + r->end - range->end, 0); + if (ret < 0) + return ret; + + /* + * Update this area to end before excluded + * range. + */ + r->end = range->start - 1; + break; + } + } + } + return 0; +} diff --git a/kexec/mem_regions.h b/kexec/mem_regions.h index da7b5e8..ae9e972 100644 --- a/kexec/mem_regions.h +++ b/kexec/mem_regions.h @@ -2,9 +2,13 @@ #define MEM_REGIONS_H struct memory_ranges; +struct memory_range; void mem_regions_sort(struct memory_ranges *ranges); +int mem_regions_exclude(struct memory_ranges *ranges, + const struct memory_range *range); + int mem_regions_add(struct memory_ranges *ranges, unsigned long long base, unsigned long long length, int type);
Add a helper to exclude a region from a set of memory ranges. Signed-off-by: Russell King <rmk@arm.linux.org.uk> --- kexec/mem_regions.c | 71 +++++++++++++++++++++++++++++++++++++++++++++++++++++ kexec/mem_regions.h | 4 +++ 2 files changed, 75 insertions(+)