Mailing List Archive

From: Penny Zheng <Penny.Zheng@arm.com>

Putting overlap and overflow checking in the loop is causing repetitive
operation, so this commit extracts both checking outside the loop.

Signed-off-by: Penny Zheng <penny.zheng@arm.com>
Signed-off-by: Luca Fancellu <luca.fancellu@arm.com>
Reviewed-by: Michal Orzel <michal.orzel@amd.com>
---
v2:
- add Michal R-by
v1:
- Rework of https://patchwork.kernel.org/project/xen-devel/patch/20231206090623.1932275-3-Penny.Zheng@arm.com/
- use strncmp to match the branch above
- drop Michal R-by given the change
---
---
xen/arch/arm/static-shmem.c | 39 +++++++++++++++----------------------
1 file changed, 16 insertions(+), 23 deletions(-)

diff --git a/xen/arch/arm/static-shmem.c b/xen/arch/arm/static-shmem.c
index cb268cd2edf1..40a0e860c79d 100644
--- a/xen/arch/arm/static-shmem.c
+++ b/xen/arch/arm/static-shmem.c
@@ -349,7 +349,7 @@ int __init process_shm_node(const void *fdt, int node, uint32_t address_cells,
{
const struct fdt_property *prop, *prop_id, *prop_role;
const __be32 *cell;
- paddr_t paddr, gaddr, size;
+ paddr_t paddr, gaddr, size, end;
struct meminfo *mem = &bootinfo.reserved_mem;
unsigned int i;
int len;
@@ -422,6 +422,13 @@ int __init process_shm_node(const void *fdt, int node, uint32_t address_cells,
return -EINVAL;
}

+ end = paddr + size;
+ if ( end <= paddr )
+ {
+ printk("fdt: static shared memory region %s overflow\n", shm_id);
+ return -EINVAL;
+ }
+
for ( i = 0; i < mem->nr_banks; i++ )
{
/*
@@ -441,30 +448,13 @@ int __init process_shm_node(const void *fdt, int node, uint32_t address_cells,
return -EINVAL;
}
}
+ else if ( strncmp(shm_id, mem->bank[i].shm_id, MAX_SHM_ID_LENGTH) != 0 )
+ continue;
else
{
- paddr_t end = paddr + size;
- paddr_t bank_end = mem->bank[i].start + mem->bank[i].size;
-
- if ( (end <= paddr) || (bank_end <= mem->bank[i].start) )
- {
- printk("fdt: static shared memory region %s overflow\n", shm_id);
- return -EINVAL;
- }
-
- if ( check_reserved_regions_overlap(paddr, size) )
- return -EINVAL;
- else
- {
- if ( strcmp(shm_id, mem->bank[i].shm_id) != 0 )
- continue;
- else
- {
- printk("fdt: different shared memory region could not share the same shm ID %s\n",
- shm_id);
- return -EINVAL;
- }
- }
+ printk("fdt: different shared memory region could not share the same shm ID %s\n",
+ shm_id);
+ return -EINVAL;
}
}

@@ -472,6 +462,9 @@ int __init process_shm_node(const void *fdt, int node, uint32_t address_cells,
{
if ( i < NR_MEM_BANKS )
{
+ if ( check_reserved_regions_overlap(paddr, size) )
+ return -EINVAL;
+
/* Static shared memory shall be reserved from any other use. */
safe_strcpy(mem->bank[mem->nr_banks].shm_id, shm_id);
mem->bank[mem->nr_banks].start = paddr;
--
2.34.1