On Mon, Dec 23, 2024 at 10:15:25PM +0800, Kaixiong Yu wrote:
> This moves all mmap related sysctls to mm/mmap.c, as part of the
> kernel/sysctl.c cleaning, also move the variable declaration from
> kernel/sysctl.c into mm/mmap.c.
>
> Signed-off-by: Kaixiong Yu <yukaixiong@xxxxxxxxxx>
> Reviewed-by: Kees Cook <kees@xxxxxxxxxx>
Looks good to me, thanks!
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@xxxxxxxxxx>
> ---
> v4:
> - const qualify struct ctl_table mmap_table
> v3:
> - change the title
> v2:
> - fix sysctl_max_map_count undeclared issue in mm/nommu.c
> ---
> ---
> kernel/sysctl.c | 50 +--------------------------------------------
> mm/mmap.c | 54 +++++++++++++++++++++++++++++++++++++++++++++++++
> 2 files changed, 55 insertions(+), 49 deletions(-)
>
> diff --git a/kernel/sysctl.c b/kernel/sysctl.c
> index aea3482106e0..9c245898f535 100644
> --- a/kernel/sysctl.c
> +++ b/kernel/sysctl.c
> @@ -127,12 +127,6 @@ enum sysctl_writes_mode {
>
> static enum sysctl_writes_mode sysctl_writes_strict = SYSCTL_WRITES_STRICT;
> #endif /* CONFIG_PROC_SYSCTL */
> -
> -#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
> - defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
> -int sysctl_legacy_va_layout;
> -#endif
> -
> #endif /* CONFIG_SYSCTL */
>
> /*
> @@ -2037,16 +2031,7 @@ static struct ctl_table vm_table[] = {
> .extra1 = SYSCTL_ONE,
> .extra2 = SYSCTL_FOUR,
> },
> -#ifdef CONFIG_MMU
> - {
> - .procname = "max_map_count",
> - .data = &sysctl_max_map_count,
> - .maxlen = sizeof(sysctl_max_map_count),
> - .mode = 0644,
> - .proc_handler = proc_dointvec_minmax,
> - .extra1 = SYSCTL_ZERO,
> - },
> -#else
> +#ifndef CONFIG_MMU
> {
> .procname = "nr_trim_pages",
> .data = &sysctl_nr_trim_pages,
> @@ -2064,17 +2049,6 @@ static struct ctl_table vm_table[] = {
> .proc_handler = proc_dointvec_minmax,
> .extra1 = SYSCTL_ZERO,
> },
Nitty, but this bit belongs in mm/nommu.c?
> -#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
> - defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
> - {
> - .procname = "legacy_va_layout",
> - .data = &sysctl_legacy_va_layout,
> - .maxlen = sizeof(sysctl_legacy_va_layout),
> - .mode = 0644,
> - .proc_handler = proc_dointvec_minmax,
> - .extra1 = SYSCTL_ZERO,
> - },
> -#endif
> #ifdef CONFIG_MMU
> {
> .procname = "mmap_min_addr",
> @@ -2100,28 +2074,6 @@ static struct ctl_table vm_table[] = {
> .extra1 = SYSCTL_ZERO,
> },
> #endif
> -#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
> - {
> - .procname = "mmap_rnd_bits",
> - .data = &mmap_rnd_bits,
> - .maxlen = sizeof(mmap_rnd_bits),
> - .mode = 0600,
> - .proc_handler = proc_dointvec_minmax,
> - .extra1 = (void *)&mmap_rnd_bits_min,
> - .extra2 = (void *)&mmap_rnd_bits_max,
> - },
> -#endif
> -#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
> - {
> - .procname = "mmap_rnd_compat_bits",
> - .data = &mmap_rnd_compat_bits,
> - .maxlen = sizeof(mmap_rnd_compat_bits),
> - .mode = 0600,
> - .proc_handler = proc_dointvec_minmax,
> - .extra1 = (void *)&mmap_rnd_compat_bits_min,
> - .extra2 = (void *)&mmap_rnd_compat_bits_max,
> - },
> -#endif
> };
>
> int __init sysctl_init_bases(void)
> diff --git a/mm/mmap.c b/mm/mmap.c
> index aef835984b1c..cc579aafd7ba 100644
> --- a/mm/mmap.c
> +++ b/mm/mmap.c
> @@ -1603,6 +1603,57 @@ struct vm_area_struct *_install_special_mapping(
> &special_mapping_vmops);
> }
>
> +#ifdef CONFIG_SYSCTL
> +#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
> + defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
> +int sysctl_legacy_va_layout;
> +#endif
> +
> +static const struct ctl_table mmap_table[] = {
> + {
> + .procname = "max_map_count",
> + .data = &sysctl_max_map_count,
> + .maxlen = sizeof(sysctl_max_map_count),
> + .mode = 0644,
> + .proc_handler = proc_dointvec_minmax,
> + .extra1 = SYSCTL_ZERO,
> + },
> +#if defined(HAVE_ARCH_PICK_MMAP_LAYOUT) || \
> + defined(CONFIG_ARCH_WANT_DEFAULT_TOPDOWN_MMAP_LAYOUT)
> + {
> + .procname = "legacy_va_layout",
> + .data = &sysctl_legacy_va_layout,
> + .maxlen = sizeof(sysctl_legacy_va_layout),
> + .mode = 0644,
> + .proc_handler = proc_dointvec_minmax,
> + .extra1 = SYSCTL_ZERO,
> + },
> +#endif
> +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_BITS
> + {
> + .procname = "mmap_rnd_bits",
> + .data = &mmap_rnd_bits,
> + .maxlen = sizeof(mmap_rnd_bits),
> + .mode = 0600,
> + .proc_handler = proc_dointvec_minmax,
> + .extra1 = (void *)&mmap_rnd_bits_min,
> + .extra2 = (void *)&mmap_rnd_bits_max,
> + },
> +#endif
> +#ifdef CONFIG_HAVE_ARCH_MMAP_RND_COMPAT_BITS
> + {
> + .procname = "mmap_rnd_compat_bits",
> + .data = &mmap_rnd_compat_bits,
> + .maxlen = sizeof(mmap_rnd_compat_bits),
> + .mode = 0600,
> + .proc_handler = proc_dointvec_minmax,
> + .extra1 = (void *)&mmap_rnd_compat_bits_min,
> + .extra2 = (void *)&mmap_rnd_compat_bits_max,
> + },
> +#endif
> +};
> +#endif /* CONFIG_SYSCTL */
> +
> /*
> * initialise the percpu counter for VM
> */
> @@ -1612,6 +1663,9 @@ void __init mmap_init(void)
>
> ret = percpu_counter_init(&vm_committed_as, 0, GFP_KERNEL);
> VM_BUG_ON(ret);
> +#ifdef CONFIG_SYSCTL
> + register_sysctl_init("vm", mmap_table);
> +#endif
> }
>
> /*
> --
> 2.34.1
>
