On Tue, Mar 23, 2021 at 6:18 AM Arnd Bergmann <a...@kernel.org> wrote:
>
> From: Arnd Bergmann <a...@arndb.de>
>
> When building with extra warnings enabled, clang points out a
> mistake in the error handling:
>
> drivers/irqchip/irq-gic-v3-mbi.c:306:21: error: result of comparison of
> constant 18446744073709551615 with expression of type 'phys_addr_t' (aka
> 'unsigned int') is always false
> [-Werror,-Wtautological-constant-out-of-range-compare]
Looks like based on CONFIG_PHYS_ADDR_T_64BIT, phys_addr_t can be u64
or u32, but of_translate_address always returns a u64. This is fine
for the current value of OF_BAD_ADDR, but I think there's a risk of
losing the top 32b of the return value of of_translate_address() here?
> if (mbi_phys_base == OF_BAD_ADDR) {
>
> Truncate the constant to the same type as the variable it gets compared
> to, to shut make the check work and void the warning.
>
> Fixes: 505287525c24 ("irqchip/gic-v3: Add support for Message Based
> Interrupts as an MSI controller")
> Signed-off-by: Arnd Bergmann <a...@arndb.de>
> ---
> drivers/irqchip/irq-gic-v3-mbi.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/irqchip/irq-gic-v3-mbi.c
> b/drivers/irqchip/irq-gic-v3-mbi.c
> index 563a9b366294..e81e89a81cb5 100644
> --- a/drivers/irqchip/irq-gic-v3-mbi.c
> +++ b/drivers/irqchip/irq-gic-v3-mbi.c
> @@ -303,7 +303,7 @@ int __init mbi_init(struct fwnode_handle *fwnode, struct
> irq_domain *parent)
> reg = of_get_property(np, "mbi-alias", NULL);
> if (reg) {
> mbi_phys_base = of_translate_address(np, reg);
> - if (mbi_phys_base == OF_BAD_ADDR) {
> + if (mbi_phys_base == (phys_addr_t)OF_BAD_ADDR) {
> ret = -ENXIO;
> goto err_free_mbi;
> }
> --
> 2.29.2
>
--
Thanks,
~Nick Desaulniers
