[PATCH 1/4] lmb: check if a region can be reserved by lmb_reserve()
Sughosh Ganu
sughosh.ganu at linaro.org
Thu Feb 13 14:11:01 CET 2025
The logic used in lmb_alloc() takes into consideration the existing
reserved regions, and ensures that the allocated region does not
overlap with any existing allocated regions. The lmb_reserve()
function is not doing any such checks -- the requested region might
overlap with an existing region. This also shows up with
lmb_alloc_addr() as this function ends up calling lmb_reserve().
Add a function which checks if the region requested is overlapping
with an existing reserved region, and allow for the reservation to
happen only if both the regions have LMB_NONE flag, which allows
re-requesting of the region. In any other scenario of an overlap, have
lmb_reserve() return -EEXIST, implying that the requested region is
already reserved.
Also add corresponding test cases which checks for overlapping
reservation requests made through lmb_reserve() and lmb_alloc_addr().
Signed-off-by: Sughosh Ganu <sughosh.ganu at linaro.org>
---
lib/lmb.c | 23 ++++++++++++
test/lib/lmb.c | 100 ++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 122 insertions(+), 1 deletion(-)
diff --git a/lib/lmb.c b/lib/lmb.c
index 7ca44591e1d..aeaf120f57d 100644
--- a/lib/lmb.c
+++ b/lib/lmb.c
@@ -595,6 +595,26 @@ static __maybe_unused void lmb_reserve_common_spl(void)
}
}
+static bool lmb_can_reserve_region(phys_addr_t base, phys_size_t size,
+ u32 flags)
+{
+ uint i;
+ struct lmb_region *lmb_reserved = lmb.used_mem.data;
+
+ for (i = 0; i < lmb.used_mem.count; i++) {
+ u32 rgnflags = lmb_reserved[i].flags;
+ phys_addr_t rgnbase = lmb_reserved[i].base;
+ phys_size_t rgnsize = lmb_reserved[i].size;
+
+ if (lmb_addrs_overlap(base, size, rgnbase, rgnsize)) {
+ if (flags != LMB_NONE || flags != rgnflags)
+ return false;
+ }
+ }
+
+ return true;
+}
+
void lmb_add_memory(void)
{
int i;
@@ -667,6 +687,9 @@ long lmb_reserve(phys_addr_t base, phys_size_t size, u32 flags)
long ret = 0;
struct alist *lmb_rgn_lst = &lmb.used_mem;
+ if (!lmb_can_reserve_region(base, size, flags))
+ return -EEXIST;
+
ret = lmb_add_region_flags(lmb_rgn_lst, base, size, flags);
if (ret)
return ret;
diff --git a/test/lib/lmb.c b/test/lib/lmb.c
index fcb5f1af532..6b995c976dd 100644
--- a/test/lib/lmb.c
+++ b/test/lib/lmb.c
@@ -499,6 +499,32 @@ static int lib_test_lmb_overlapping_reserve(struct unit_test_state *uts)
ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, 0x40000000, 0x40000,
0, 0, 0, 0);
+ /* try to allocate overlapping region with a different flag, should fail */
+ ret = lmb_reserve(0x40008000, 0x1000, LMB_NOOVERWRITE);
+ ut_asserteq(ret, -EEXIST);
+
+ /* allocate another region at 0x40050000 with a different flag */
+ ret = lmb_reserve(0x40050000, 0x10000, LMB_NOOVERWRITE);
+ ut_asserteq(ret, 0);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, 0x40000000, 0x40000,
+ 0x40050000, 0x10000, 0, 0);
+
+ /*
+ * try to allocate a region adjacent to region 1 overlapping the 2nd region,
+ * should fail
+ */
+ ret = lmb_reserve(0x40040000, 0x20000, LMB_NONE);
+ ut_asserteq(ret, -EEXIST);
+
+ /*
+ * try to allocate a region between the two regions, but without an overlap,
+ * should succeed. this added region coalesces with the region 1
+ */
+ ret = lmb_reserve(0x40040000, 0x10000, LMB_NONE);
+ ut_asserteq(ret, 0);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, 0x40000000, 0x50000,
+ 0x40050000, 0x10000, 0, 0);
+
lmb_pop(&store);
return 0;
@@ -549,6 +575,78 @@ static int test_alloc_addr(struct unit_test_state *uts, const phys_addr_t ram)
ret = lmb_free(alloc_addr_a, 0x1000);
ut_asserteq(ret, 0);
+ /*
+ * Add two regions with different flags, region1 and region2 with
+ * a gap between them.
+ * Try adding another region, adjacent to region 1 and overlapping
+ * region 2. Should fail.
+ */
+ a = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NONE);
+ ut_asserteq(a, alloc_addr_a);
+
+ b = lmb_alloc_addr(alloc_addr_a + 0x4000, 0x1000, LMB_NOOVERWRITE);
+ ut_asserteq(b, alloc_addr_a + 0x4000);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, a, 0x1000,
+ b, 0x1000, 0, 0);
+
+ c = lmb_alloc_addr(alloc_addr_a + 0x1000, 0x5000, LMB_NONE);
+ ut_asserteq(c, 0);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, a, 0x1000,
+ b, 0x1000, 0, 0);
+
+ ret = lmb_free(a, 0x1000);
+ ut_asserteq(ret, 0);
+ ret = lmb_free(b, 0x1000);
+ ut_asserteq(ret, 0);
+
+
+ /*
+ * Add two regions with same flags(LMB_NONE), region1 and region2
+ * with a gap between them.
+ * Try adding another region, adjacent to region 1 and overlapping
+ * region 2. Should succeed. All regions should coalesce into a
+ * single region.
+ */
+ a = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NONE);
+ ut_asserteq(a, alloc_addr_a);
+
+ b = lmb_alloc_addr(alloc_addr_a + 0x4000, 0x1000, LMB_NONE);
+ ut_asserteq(b, alloc_addr_a + 0x4000);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, a, 0x1000,
+ b, 0x1000, 0, 0);
+
+ c = lmb_alloc_addr(alloc_addr_a + 0x1000, 0x5000, LMB_NONE);
+ ut_asserteq(c, alloc_addr_a + 0x1000);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, a, 0x6000,
+ 0, 0, 0, 0);
+
+ ret = lmb_free(a, 0x6000);
+ ut_asserteq(ret, 0);
+
+ /*
+ * Add two regions with same flags(LMB_NOOVERWRITE), region1 and
+ * region2 with a gap between them.
+ * Try adding another region, adjacent to region 1 and overlapping
+ * region 2. Should fail.
+ */
+ a = lmb_alloc_addr(alloc_addr_a, 0x1000, LMB_NOOVERWRITE);
+ ut_asserteq(a, alloc_addr_a);
+
+ b = lmb_alloc_addr(alloc_addr_a + 0x4000, 0x1000, LMB_NOOVERWRITE);
+ ut_asserteq(b, alloc_addr_a + 0x4000);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, a, 0x1000,
+ b, 0x1000, 0, 0);
+
+ c = lmb_alloc_addr(alloc_addr_a + 0x1000, 0x5000, LMB_NOOVERWRITE);
+ ut_asserteq(c, 0);
+ ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 2, a, 0x1000,
+ b, 0x1000, 0, 0);
+
+ ret = lmb_free(a, 0x1000);
+ ut_asserteq(ret, 0);
+ ret = lmb_free(b, 0x1000);
+ ut_asserteq(ret, 0);
+
/* reserve 3 blocks */
ret = lmb_reserve(alloc_addr_a, 0x10000, LMB_NONE);
ut_asserteq(ret, 0);
@@ -760,7 +858,7 @@ static int lib_test_lmb_flags(struct unit_test_state *uts)
/* reserve again, new flag */
ret = lmb_reserve(0x40010000, 0x10000, LMB_NONE);
- ut_asserteq(ret, -1);
+ ut_asserteq(ret, -EEXIST);
ASSERT_LMB(mem_lst, used_lst, ram, ram_size, 1, 0x40010000, 0x10000,
0, 0, 0, 0);
--
2.34.1
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