[v1] MIPS: jump_label: Fix compat branch range check

[PATCH] MIPS: jump_label: Fix compat branch range check

Posted by Jiaxun Yang 3 years, 5 months ago

Cast upper bound of branch range to long to do signed compare,
avoid negtive offset trigger this warning.

Fixes: 9b6584e35f40 ("MIPS: jump_label: Use compact branches for >= r6")
Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Cc: stable@vger.kernel.org
---
 arch/mips/kernel/jump_label.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c
index 71a882c8c6eb..f7978d50a2ba 100644
--- a/arch/mips/kernel/jump_label.c
+++ b/arch/mips/kernel/jump_label.c
@@ -56,7 +56,7 @@ void arch_jump_label_transform(struct jump_entry *e,
 			 * The branch offset must fit in the instruction's 26
 			 * bit field.
 			 */
-			WARN_ON((offset >= BIT(25)) ||
+			WARN_ON((offset >= (long)BIT(25)) ||
 				(offset < -(long)BIT(25)));
 
 			insn.j_format.opcode = bc6_op;
-- 
2.34.1

Re: [PATCH] MIPS: jump_label: Fix compat branch range check

Posted by Philippe Mathieu-Daudé 3 years, 5 months ago

On 29/10/22 22:35, Jiaxun Yang wrote:
> Cast upper bound of branch range to long to do signed compare,
> avoid negtive offset trigger this warning.

Typo "negative".

> Fixes: 9b6584e35f40 ("MIPS: jump_label: Use compact branches for >= r6")
> Signed-off-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
> Cc: stable@vger.kernel.org
> ---
>   arch/mips/kernel/jump_label.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/mips/kernel/jump_label.c b/arch/mips/kernel/jump_label.c
> index 71a882c8c6eb..f7978d50a2ba 100644
> --- a/arch/mips/kernel/jump_label.c
> +++ b/arch/mips/kernel/jump_label.c
> @@ -56,7 +56,7 @@ void arch_jump_label_transform(struct jump_entry *e,
>   			 * The branch offset must fit in the instruction's 26
>   			 * bit field.
>   			 */
> -			WARN_ON((offset >= BIT(25)) ||
> +			WARN_ON((offset >= (long)BIT(25)) ||
>   				(offset < -(long)BIT(25)));

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>