[PATCH v2] hw/misc/allwinner-h3-dramc: enforce 64-bit multiply when calculating row mirror address

[PATCH v2] hw/misc/allwinner-h3-dramc: enforce 64-bit multiply when calculating row mirror address

[Niek Linnenbank]

The allwinner_h3_dramc_map_rows function simulates row addressing behavior
when bootloader software attempts to detect the amount of available SDRAM.

Currently the line that calculates the 64-bit address of the mirrored row
uses a signed 32-bit multiply operation that in theory could result in the
upper 32-bit be all 1s. This commit ensures that the row mirror address
is calculated using only 64-bit operations.

Reported-by: Peter Maydell <peter.maydell@linaro.org>
Signed-off-by: Niek Linnenbank <nieklinnenbank@gmail.com>
---
 hw/misc/allwinner-h3-dramc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/hw/misc/allwinner-h3-dramc.c b/hw/misc/allwinner-h3-dramc.c
index 2b5260260e..1d37cf422c 100644
--- a/hw/misc/allwinner-h3-dramc.c
+++ b/hw/misc/allwinner-h3-dramc.c
@@ -85,8 +85,8 @@ static void allwinner_h3_dramc_map_rows(AwH3DramCtlState *s, uint8_t row_bits,
 
     } else if (row_bits_actual) {
         /* Row bits not matching ram_size, install the rows mirror */
-        hwaddr row_mirror = s->ram_addr + ((1 << (row_bits_actual +
-                                                  bank_bits)) * page_size);
+        hwaddr row_mirror = s->ram_addr + ((1ULL << (row_bits_actual +
+                                                     bank_bits)) * page_size);
 
         memory_region_set_enabled(&s->row_mirror_alias, true);
         memory_region_set_address(&s->row_mirror_alias, row_mirror);
-- 
2.17.1

Re: [PATCH v2] hw/misc/allwinner-h3-dramc: enforce 64-bit multiply when calculating row mirror address

[Peter Maydell]

On Mon, 23 Mar 2020 at 19:29, Niek Linnenbank <nieklinnenbank@gmail.com> wrote:
>
> The allwinner_h3_dramc_map_rows function simulates row addressing behavior
> when bootloader software attempts to detect the amount of available SDRAM.
>
> Currently the line that calculates the 64-bit address of the mirrored row
> uses a signed 32-bit multiply operation that in theory could result in the
> upper 32-bit be all 1s. This commit ensures that the row mirror address
> is calculated using only 64-bit operations.
>
> Reported-by: Peter Maydell <peter.maydell@linaro.org>
> Signed-off-by: Niek Linnenbank <nieklinnenbank@gmail.com>
> ---
>  hw/misc/allwinner-h3-dramc.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)



Applied to target-arm.next, thanks.

-- PMM