From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Wed, 14 Jun 2023 01:39:46 +0200 Subject: [PATCH] x86/fpu: Move FPU initialization into arch_cpu_finalize_init() Initializing the FPU during the early boot process is a pointless exercise. Early boot is convoluted and fragile enough. Nothing requires that the FPU is set up early. It has to be initialized before fork_init() because the task_struct size depends on the FPU register buffer size. Move the initialization to arch_cpu_finalize_init() which is the perfect place to do so. No functional change. This allows to remove quite some of the custom early command line parsing, but that's subject to the next installment. Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20230613224545.902376621@linutronix.de (cherry picked from commit b81fac906a8f9e682e513ddd95697ec7a20878d4) CVE-2022-40982 Signed-off-by: Thadeu Lima de Souza Cascardo Acked-by: Roxana Nicolescu Acked-by: Stefan Bader Signed-off-by: Stefan Bader (cherry picked from commit 010f3814ec351195c9d0a9a408798f9c66fdb906) Signed-off-by: Stoiko Ivanov --- arch/x86/kernel/cpu/common.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 794eb851cb0d..9b53d1cb424d 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -1596,8 +1596,6 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) sld_setup(c); - fpu__init_system(); - #ifdef CONFIG_X86_32 /* * Regardless of whether PCID is enumerated, the SDM says @@ -2283,8 +2281,6 @@ void cpu_init(void) doublefault_init_cpu_tss(); - fpu__init_cpu(); - if (is_uv_system()) uv_cpu_init(); @@ -2300,6 +2296,7 @@ void cpu_init_secondary(void) */ cpu_init_exception_handling(); cpu_init(); + fpu__init_cpu(); } #endif @@ -2394,6 +2391,13 @@ void __init arch_cpu_finalize_init(void) '0' + (boot_cpu_data.x86 > 6 ? 6 : boot_cpu_data.x86); } + /* + * Must be before alternatives because it might set or clear + * feature bits. + */ + fpu__init_system(); + fpu__init_cpu(); + alternative_instructions(); if (IS_ENABLED(CONFIG_X86_64)) {