[PATCH 4.19 208/421] of: Fix truncation of memory sizes on 32-bit platforms

Greg Kroah-Hartman
2021-07-19T16:26:29Z

From: Geert Uytterhoeven <geert+renesas@glider.be>

[ Upstream commit 2892d8a00d23d511a0591ac4b2ff3f050ae1f004 ]

Variable "size" has type "phys_addr_t", which can be either 32-bit or
64-bit on 32-bit systems, while "unsigned long" is always 32-bit on
32-bit systems. Hence the cast in

(unsigned long)size / SZ_1M

may truncate a 64-bit size to 32-bit, as casts have a higher operator
precedence than divisions.

Fix this by inverting the order of the cast and division, which should
be safe for memory blocks smaller than 4 PiB. Note that the division is
actually a shift, as SZ_1M is a power-of-two constant, hence there is no
need to use div_u64().

While at it, use "%lu" to format "unsigned long".

Fixes: e8d9d1f5485b52ec ("drivers: of: add initialization code for static reserved memory")
Fixes: 3f0c8206644836e4 ("drivers: of: add initialization code for dynamic reserved memory")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/4a1117e72d13d26126f57be034c20dac02f1e915.1623835273.git.geert+renesas@glider.be
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/of/fdt.c | 8 ++++----
drivers/of/of_reserved_mem.c | 8 ++++----
2 files changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 800ad252cf9c..1eb6af6439ad 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c
@@ -576,11 +576,11 @@ static int __init __reserved_mem_reserve_reg(unsigned long node,

if (size &&
early_init_dt_reserve_memory_arch(base, size, nomap) == 0)
- pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %ld MiB\n",
- uname, &base, (unsigned long)size / SZ_1M);
+ pr_debug("Reserved memory: reserved region for node '%s': base %pa, size %lu MiB\n",
+ uname, &base, (unsigned long)(size / SZ_1M));
else
- pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %ld MiB\n",
- uname, &base, (unsigned long)size / SZ_1M);
+ pr_info("Reserved memory: failed to reserve memory for node '%s': base %pa, size %lu MiB\n",
+ uname, &base, (unsigned long)(size / SZ_1M));

len -= t_len;
if (first) {
diff --git a/drivers/of/of_reserved_mem.c b/drivers/of/of_reserved_mem.c
index 19f95552da4d..ff230ee2423f 100644
--- a/drivers/of/of_reserved_mem.c
+++ b/drivers/of/of_reserved_mem.c
@@ -154,9 +154,9 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
ret = early_init_dt_alloc_reserved_memory_arch(size,
align, start, end, nomap, &base);
if (ret == 0) {
- pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
+ pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
uname, &base,
- (unsigned long)size / SZ_1M);
+ (unsigned long)(size / SZ_1M));
break;
}
len -= t_len;
@@ -166,8 +166,8 @@ static int __init __reserved_mem_alloc_size(unsigned long node,
ret = early_init_dt_alloc_reserved_memory_arch(size, align,
0, 0, nomap, &base);
if (ret == 0)
- pr_debug("allocated memory for '%s' node: base %pa, size %ld MiB\n",
- uname, &base, (unsigned long)size / SZ_1M);
+ pr_debug("allocated memory for '%s' node: base %pa, size %lu MiB\n",
+ uname, &base, (unsigned long)(size / SZ_1M));
}

if (base == 0) {
--
2.30.2