From b8995a18417088bb53f87c49d200ec72a9dd4ec1 Mon Sep 17 00:00:00 2001 From: Will Deacon Date: Fri, 17 May 2024 12:55:55 +0100 Subject: [PATCH] Revert "arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD" This reverts commit 2632e25217696712681dd1f3ecc0d71624ea3b23. Johannes (and others) report data corruption with dm-crypt on Apple M1 which has been bisected to this change. Revert the offending commit while we figure out what's going on. Cc: stable@vger.kernel.org Reported-by: Johannes Nixdorf Link: https://lore.kernel.org/all/D1B7GPIR9K1E.5JFV37G0YTIF@shadowice.org/ Signed-off-by: Will Deacon --- arch/arm64/include/asm/processor.h | 1 - arch/arm64/kernel/fpsimd.c | 18 ------------------ 2 files changed, 19 deletions(-) diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index f77371232d8c6..4f122b932ccac 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -171,7 +171,6 @@ struct thread_struct { struct debug_info debug; /* debugging */ struct user_fpsimd_state kernel_fpsimd_state; - unsigned int kernel_fpsimd_cpu; #ifdef CONFIG_ARM64_PTR_AUTH struct ptrauth_keys_user keys_user; #ifdef CONFIG_ARM64_PTR_AUTH_KERNEL diff --git a/arch/arm64/kernel/fpsimd.c b/arch/arm64/kernel/fpsimd.c index ebb0158997cab..e9d70dc915117 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1509,30 +1509,12 @@ void do_fpsimd_exc(unsigned long esr, struct pt_regs *regs) static void fpsimd_load_kernel_state(struct task_struct *task) { - struct cpu_fp_state *last = this_cpu_ptr(&fpsimd_last_state); - - /* - * Elide the load if this CPU holds the most recent kernel mode - * FPSIMD context of the current task. - */ - if (last->st == &task->thread.kernel_fpsimd_state && - task->thread.kernel_fpsimd_cpu == smp_processor_id()) - return; - fpsimd_load_state(&task->thread.kernel_fpsimd_state); } static void fpsimd_save_kernel_state(struct task_struct *task) { - struct cpu_fp_state cpu_fp_state = { - .st = &task->thread.kernel_fpsimd_state, - .to_save = FP_STATE_FPSIMD, - }; - fpsimd_save_state(&task->thread.kernel_fpsimd_state); - fpsimd_bind_state_to_cpu(&cpu_fp_state); - - task->thread.kernel_fpsimd_cpu = smp_processor_id(); } void fpsimd_thread_switch(struct task_struct *next) -- 2.30.2