[PATCH v4 06/27] lmb: allow for resizing lmb regions
Sughosh Ganu
sughosh.ganu at linaro.org
Mon Aug 26 13:59:19 CEST 2024
Allow for resizing of LMB regions if the region attributes match. The
current code returns a failure status on detecting an overlapping
address. This worked up until now since the LMB calls were not
persistent and global -- the LMB memory map was specific and private
to a given caller of the LMB API's.
With the change in the LMB code to make the LMB reservations
persistent, there needs to be a check on whether the memory region can
be resized, and then do it if so. To distinguish between memory that
cannot be resized, add a new flag, LMB_NOOVERWRITE. Reserving a region
of memory with this attribute would indicate that the region cannot be
resized.
Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
---
Changes since V3:
* Do away with multiple assignments in lmb_resize_regions() as
suggested by checkpatch.
include/lmb.h | 1 +
lib/lmb.c | 99 ++++++++++++++++++++++++++++++++++++++++++---------
2 files changed, 84 insertions(+), 16 deletions(-)
diff --git a/include/lmb.h b/include/lmb.h
index 0979dcebc0..cc2c426c13 100644
--- a/include/lmb.h
+++ b/include/lmb.h
@@ -22,6 +22,7 @@
enum lmb_flags {
LMB_NONE = 0,
LMB_NOMAP = BIT(1),
+ LMB_NOOVERWRITE = BIT(2),
};
/**
diff --git a/lib/lmb.c b/lib/lmb.c
index 0aa2d8bd3b..8be0c1a583 100644
--- a/lib/lmb.c
+++ b/lib/lmb.c
@@ -246,6 +246,57 @@ void lmb_init_and_reserve_range(phys_addr_t base, phys_size_t size,
lmb_reserve_common(fdt_blob);
}
+static long lmb_resize_regions(struct alist *lmb_rgn_lst,
+ unsigned long idx_start,
+ phys_addr_t base, phys_size_t size)
+{
+ phys_size_t rgnsize;
+ unsigned long rgn_cnt, idx, idx_end;
+ phys_addr_t rgnbase, rgnend;
+ phys_addr_t mergebase, mergeend;
+ struct lmb_region *rgn = lmb_rgn_lst->data;
+
+ rgn_cnt = 0;
+ idx = idx_start;
+ idx_end = idx_start;
+
+ /*
+ * First thing to do is to identify how many regions
+ * the requested region overlaps.
+ * If the flags match, combine all these overlapping
+ * regions into a single region, and remove the merged
+ * regions.
+ */
+ while (idx <= lmb_rgn_lst->count - 1) {
+ rgnbase = rgn[idx].base;
+ rgnsize = rgn[idx].size;
+
+ if (lmb_addrs_overlap(base, size, rgnbase,
+ rgnsize)) {
+ if (rgn[idx].flags != LMB_NONE)
+ return -1;
+ rgn_cnt++;
+ idx_end = idx;
+ }
+ idx++;
+ }
+
+ /* The merged region's base and size */
+ rgnbase = rgn[idx_start].base;
+ mergebase = min(base, rgnbase);
+ rgnend = rgn[idx_end].base + rgn[idx_end].size;
+ mergeend = max(rgnend, (base + size));
+
+ rgn[idx_start].base = mergebase;
+ rgn[idx_start].size = mergeend - mergebase;
+
+ /* Now remove the merged regions */
+ while (--rgn_cnt)
+ lmb_remove_region(lmb_rgn_lst, idx_start + 1);
+
+ return 0;
+}
+
/**
* lmb_add_region_flags() - Add an lmb region to the given list
* @lmb_rgn_lst: LMB list to which region is to be added(free/used)
@@ -265,7 +316,7 @@ static long lmb_add_region_flags(struct alist *lmb_rgn_lst, phys_addr_t base,
phys_size_t size, enum lmb_flags flags)
{
unsigned long coalesced = 0;
- long adjacent, i;
+ long ret, i;
struct lmb_region *rgn = lmb_rgn_lst->data;
if (alist_err(lmb_rgn_lst))
@@ -286,23 +337,32 @@ static long lmb_add_region_flags(struct alist *lmb_rgn_lst, phys_addr_t base,
return -1; /* regions with new flags */
}
- adjacent = lmb_addrs_adjacent(base, size, rgnbase, rgnsize);
- if (adjacent > 0) {
+ ret = lmb_addrs_adjacent(base, size, rgnbase, rgnsize);
+ if (ret > 0) {
if (flags != rgnflags)
break;
rgn[i].base -= size;
rgn[i].size += size;
coalesced++;
break;
- } else if (adjacent < 0) {
+ } else if (ret < 0) {
if (flags != rgnflags)
break;
rgn[i].size += size;
coalesced++;
break;
} else if (lmb_addrs_overlap(base, size, rgnbase, rgnsize)) {
- /* regions overlap */
- return -1;
+ if (flags == LMB_NONE) {
+ ret = lmb_resize_regions(lmb_rgn_lst, i, base,
+ size);
+ if (ret < 0)
+ return -1;
+
+ coalesced++;
+ break;
+ } else {
+ return -1;
+ }
}
}
@@ -444,7 +504,7 @@ static phys_addr_t lmb_align_down(phys_addr_t addr, phys_size_t size)
}
static phys_addr_t __lmb_alloc_base(phys_size_t size, ulong align,
- phys_addr_t max_addr)
+ phys_addr_t max_addr, enum lmb_flags flags)
{
long i, rgn;
phys_addr_t base = 0;
@@ -473,8 +533,8 @@ static phys_addr_t __lmb_alloc_base(phys_size_t size, ulong align,
rgn = lmb_overlaps_region(&lmb.used_mem, base, size);
if (rgn < 0) {
/* This area isn't reserved, take it */
- if (lmb_add_region(&lmb.used_mem, base,
- size) < 0)
+ if (lmb_add_region_flags(&lmb.used_mem, base,
+ size, flags) < 0)
return 0;
return base;
}
@@ -497,7 +557,7 @@ phys_addr_t lmb_alloc_base(phys_size_t size, ulong align, phys_addr_t max_addr)
{
phys_addr_t alloc;
- alloc = __lmb_alloc_base(size, align, max_addr);
+ alloc = __lmb_alloc_base(size, align, max_addr, LMB_NONE);
if (alloc == 0)
printf("ERROR: Failed to allocate 0x%lx bytes below 0x%lx.\n",
@@ -506,11 +566,8 @@ phys_addr_t lmb_alloc_base(phys_size_t size, ulong align, phys_addr_t max_addr)
return alloc;
}
-/*
- * Try to allocate a specific address range: must be in defined memory but not
- * reserved
- */
-phys_addr_t lmb_alloc_addr(phys_addr_t base, phys_size_t size)
+static phys_addr_t __lmb_alloc_addr(phys_addr_t base, phys_size_t size,
+ enum lmb_flags flags)
{
long rgn;
struct lmb_region *lmb_memory = lmb.free_mem.data;
@@ -526,13 +583,23 @@ phys_addr_t lmb_alloc_addr(phys_addr_t base, phys_size_t size)
lmb_memory[rgn].size,
base + size - 1, 1)) {
/* ok, reserve the memory */
- if (lmb_reserve(base, size) >= 0)
+ if (lmb_reserve_flags(base, size, flags) >= 0)
return base;
}
}
+
return 0;
}
+/*
+ * Try to allocate a specific address range: must be in defined memory but not
+ * reserved
+ */
+phys_addr_t lmb_alloc_addr(phys_addr_t base, phys_size_t size)
+{
+ return __lmb_alloc_addr(base, size, LMB_NONE);
+}
+
/* Return number of bytes from a given address that are free */
phys_size_t lmb_get_free_size(phys_addr_t addr)
{
--
2.34.1
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