[PATCH v5 06/16] riscv/cfi: Add prctl definitions for RISC-V CFI

[Gabriel Ravier]

On 6/28/26 9:02 AM, Jesse Huang wrote:
> These operations are for setting/retrieving/locking the status of the
> landing pad and the shadow stack extensions.
> ---
>   .../unix/sysv/linux/riscv/include/asm/prctl.h | 43 +++++++++++++++++++
>   1 file changed, 43 insertions(+)
>   create mode 100644 sysdeps/unix/sysv/linux/riscv/include/asm/prctl.h
>
> diff --git a/sysdeps/unix/sysv/linux/riscv/include/asm/prctl.h b/sysdeps/unix/sysv/linux/riscv/include/asm/prctl.h
> new file mode 100644
> index 0000000000..30a37452e1
> --- /dev/null
> +++ b/sysdeps/unix/sysv/linux/riscv/include/asm/prctl.h
> @@ -0,0 +1,43 @@

AIUI every file should have a copyright header? At least an include guard x)

> +/*
> + * Get the current shadow stack configuration for the current thread,
> + * this will be the value configured via PR_SET_SHADOW_STACK_STATUS.
> + */
> +#define PR_GET_SHADOW_STACK_STATUS	74
> +
> +/*
> + * Set the current shadow stack configuration.  Enabling the shadow
> + * stack will cause a shadow stack to be allocated for the thread.
> + */
> +#define PR_SET_SHADOW_STACK_STATUS	75
> +# define PR_SHADOW_STACK_ENABLE		(1UL << 0)
> +# define PR_SHADOW_STACK_WRITE		(1UL << 1)
> +# define PR_SHADOW_STACK_PUSH		(1UL << 2)
> +
> +/*
> + * Prevent further changes to the specified shadow stack
> + * configuration.  All bits may be locked via this call, including
> + * undefined bits.
> + */
> +#define PR_LOCK_SHADOW_STACK_STATUS	76
> +
> +/*
> + * Get or set the control flow integrity (CFI) configuration for the
> + * current thread.
> + *
> + * Some per-thread control flow integrity settings are not yet
> + * controlled through this prctl(); see for example
> + * PR_{GET,SET,LOCK}_SHADOW_STACK_STATUS
> + */
> +#define PR_GET_CFI	80
> +#define PR_SET_CFI	81
> +
> +/*
> + * Forward-edge CFI variants (excluding ARM64 BTI, which has its own
> + * prctl()s).
> + */
> +#define PR_CFI_BRANCH_LANDING_PADS	0
> +
> +/* Return and control values for PR_{GET,SET}_CFI */
> +# define PR_CFI_ENABLE		(1UL << 0)
> +# define PR_CFI_DISABLE		(1UL << 1)
> +# define PR_CFI_LOCK		(1UL << 2)