On Thu, Aug 01, 2024 at 10:34:41AM +0200, Peter Zijlstra wrote:

On Wed, Jul 31, 2024 at 09:15:04PM -0400, Paul Moore wrote:

quoted

On Wed, Jul 31, 2024 at 5:34 PM KP Singh [off-list ref] wrote:

quoted

LSM indirect calls being are now replaced by static calls, this requires
a jumpt_table_init before early_security_init where LSM hooks and their
static calls and keys are initialized.

Fixes: 2732ad5ecd5b ("lsm: replace indirect LSM hook calls with static calls")
Signed-off-by: KP Singh <kpsingh@kernel.org>
---
 init/main.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

Does this look okay, static call folks?

Are we confused between jump_label/static_branch and static_call ?

quoted

quoted

diff --git a/init/main.c b/init/main.c
index 206acdde51f5..5bd45af7a49e 100644
--- a/init/main.c
+++ b/init/main.c

@@ -922,6 +922,8 @@ void start_kernel(void)
        boot_cpu_init();
        page_address_init();
        pr_notice("%s", linux_banner);
+       /* LSM and command line parameters use static keys */
+       jump_label_init();
        early_security_init();
        setup_arch(&command_line);
        setup_boot_config();

@@ -933,8 +935,6 @@ void start_kernel(void)
        boot_cpu_hotplug_init();

        pr_notice("Kernel command line: %s\n", saved_command_line);
-       /* parameters may set static keys */
-       jump_label_init();
        parse_early_param();
        after_dashes = parse_args("Booting kernel",
                                  static_command_line, __start___param,

Anyway, the scariest thing jump_label_init() does is
arch_jump_label_transform_static(). Which, IIRC, was used to optimize
NOPs on x86, which we've since removed.

Only csky and mips seem to still implement this hook, and they do
flush_icache() -- as one would expect.

If any of that is affected by the placement you propose, is something
you'd have to ask those architecture maintainers I'm afraid.

Aside from that I don't see a problem :-)