From 56f186a68b35e8b45136fd44b69c554a0bb0ce35 Mon Sep 17 00:00:00 2001 From: Sughosh Ganu Date: Mon, 3 Mar 2025 19:02:26 +0530 Subject: lmb: check if a region can be reserved by lmb_reserve() 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. Add corresponding test cases which check for overlapping reservation requests made through lmb_reserve() and lmb_alloc_addr(). And while here, fix some of the comments in the test function being touched. Signed-off-by: Sughosh Ganu Reviewed-by: Heinrich Schuchardt --- lib/lmb.c | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'lib') diff --git a/lib/lmb.c b/lib/lmb.c index 93fc1bea07c..32c787f8adf 100644 --- a/lib/lmb.c +++ b/lib/lmb.c @@ -561,6 +561,39 @@ static __maybe_unused void lmb_reserve_common_spl(void) } } +/** + * lmb_can_reserve_region() - check if the region can be reserved + * @base: base address of region to be reserved + * @size: size of region to be reserved + * @flags: flag of the region to be reserved + * + * Go through all the reserved regions and ensure that the requested + * region does not overlap with any existing regions. An overlap is + * allowed only when the flag of the request region and the existing + * region is LMB_NONE. + * + * Return: true if region can be reserved, false otherwise + */ +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; @@ -633,6 +666,9 @@ 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; -- cgit v1.2.3