doc: Add EARLY flag to early-parsed kernel boot parameters
authorPaul E. McKenney <paulmck@kernel.org>
Sun, 26 Nov 2023 19:06:10 +0000 (11:06 -0800)
committerBoqun Feng <boqun.feng@gmail.com>
Wed, 14 Feb 2024 15:53:50 +0000 (07:53 -0800)
commit600716592a3a6de8bfcf3a0625d75cda8dce3ced
tree7a3f4e2615b4427c646d68684d7cbb8d683105b2
parent739337d482f12b9eff062586ba64f008fcc6efba
doc: Add EARLY flag to early-parsed kernel boot parameters

Kernel boot parameters declared with early_param() are parsed before
embedded parameters are extracted from initrd, and early_param()
parameters are not helpful when embedded in initrd.  Therefore,
mark early_param() kernel boot parameters with "EARLY" in
kernel-parameters.txt.

The following early_param() calls declare kernel boot parameters that
are undocumented:

early_param("atmel.pm_modes", at91_pm_modes_select);
early_param("mem_fclk_21285", early_fclk);
early_param("ecc", early_ecc);
early_param("cachepolicy", early_cachepolicy);
early_param("nodebugmon", early_debug_disable);
early_param("kfence.sample_interval", parse_kfence_early_init);
early_param("additional_cpus", setup_additional_cpus);
early_param("stram_pool", atari_stram_setup);
early_param("disable_octeon_edac", disable_octeon_edac);
early_param("rd_start", rd_start_early);
early_param("rd_size", rd_size_early);
early_param("coherentio", setcoherentio);
early_param("nocoherentio", setnocoherentio);
early_param("fadump", early_fadump_param);
early_param("fadump_reserve_mem", early_fadump_reserve_mem);
early_param("no_stf_barrier", handle_no_stf_barrier);
early_param("no_rfi_flush", handle_no_rfi_flush);
early_param("smt-enabled", early_smt_enabled);
early_param("ppc_pci_reset_phbs", pci_reset_phbs_setup);
early_param("ps3fb", early_parse_ps3fb);
early_param("ps3flash", early_parse_ps3flash);
early_param("novx", disable_vector_extension);
early_param("nobp", nobp_setup_early);
early_param("nospec", nospec_setup_early);
early_param("possible_cpus", _setup_possible_cpus);
early_param("stp", early_parse_stp);
early_param("nopfault", nopfault);
early_param("nmi_mode", nmi_mode_setup);
early_param("sh_mv", early_parse_mv);
early_param("pmb", early_pmb);
early_param("hvirq", early_hvirq_major);
early_param("cfi", cfi_parse_cmdline);
early_param("disableapic", setup_disableapic);
early_param("noapictimer", parse_disable_apic_timer);
early_param("disable_cpu_apicid", apic_set_disabled_cpu_apicid);
early_param("uv_memblksize", parse_mem_block_size);
early_param("retbleed", retbleed_parse_cmdline);
early_param("no-kvmclock-vsyscall", parse_no_kvmclock_vsyscall);
early_param("update_mptable", update_mptable_setup);
early_param("alloc_mptable", parse_alloc_mptable_opt);
early_param("possible_cpus", _setup_possible_cpus);
early_param("lsmsi", early_parse_ls_scfg_msi);
early_param("nokgdbroundup", opt_nokgdbroundup);
early_param("kgdbcon", opt_kgdb_con);
early_param("kasan", early_kasan_flag);
early_param("kasan.mode", early_kasan_mode);
early_param("kasan.vmalloc", early_kasan_flag_vmalloc);
early_param("kasan.page_alloc.sample", early_kasan_flag_page_alloc_sample);
early_param("kasan.page_alloc.sample.order", early_kasan_flag_page_alloc_sample_order);
early_param("kasan.fault", early_kasan_fault);
early_param("kasan.stacktrace", early_kasan_flag_stacktrace);
early_param("kasan.stack_ring_size", early_kasan_flag_stack_ring_size);
early_param("accept_memory", accept_memory_parse);
early_param("page_table_check", early_page_table_check_param);
sh_early_platform_init("earlytimer", &sh_cmt_device_driver);
early_param_on_off("gbpages", "nogbpages", direct_gbpages, CONFIG_X86_DIRECT_GBPAGES);

These are not necessarily bugs, given that some kernel boot parameters
are intended for deep debugging rather than general use.

This work does not cover all of the kernel boot parameters declared using
cmdline_find_option() and cmdline_find_option_bool().  If these are in
fact guaranteed to be early (which appears to be the case), they can be
added in a later version of this patch.

Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Petr Malat <oss@malat.biz>
Cc: Randy Dunlap <rdunlap@infradead.org>
Cc: <linux-doc@vger.kernel.org>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
Documentation/admin-guide/kernel-parameters.rst
Documentation/admin-guide/kernel-parameters.txt