[PATCH] powerpc/fadump: fix integer overflow in MIN_RMA size check

[Sayali Patil]

The MIN_RMA size checks in fadump_setup_param_area() use
(MIN_RMA * 1024 * 1024), which is evaluated in int and can
overflow when MIN_RMA is 2048 or larger. This triggers compiler
warnings such as:

warning: integer overflow in expression of type 'int'
results in '0' [-Woverflow]

Promote MIN_RMA to u64 before the multiplication so the expression
is evaluated in 64-bit and matches the surrounding physical address
and memory size calculations.

This fixes both the comparison against ppc64_rma_size and the
assignment to range_start.

Fixes: b7bb46062457 ("powerpc/fadump: fix additional param memory reservation 
for HASH MMU")
Signed-off-by: Sayali Patil <saya...@linux.ibm.com>
---
 arch/powerpc/kernel/fadump.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/arch/powerpc/kernel/fadump.c b/arch/powerpc/kernel/fadump.c
index 501d43bf18f3..dea7f7105e42 100644
--- a/arch/powerpc/kernel/fadump.c
+++ b/arch/powerpc/kernel/fadump.c
@@ -1759,10 +1759,10 @@ void __init fadump_setup_param_area(void)
                 * 2. The range should be between MIN_RMA and RMA size 
(ppc64_rma_size)
                 * 3. It must not overlap with the fadump reserved area.
                 */
-               if (ppc64_rma_size < MIN_RMA*1024*1024)
+               if (ppc64_rma_size < (u64)MIN_RMA * 1024 * 1024)
                        return;
 
-               range_start = MIN_RMA * 1024 * 1024;
+               range_start = (u64)MIN_RMA * 1024 * 1024;
                range_end = min(ppc64_rma_size, fw_dump.boot_mem_top);
        }
 
-- 
2.52.0