diff options
| author | Will Deacon <will@kernel.org> | 2024-05-22 13:53:05 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-05-30 10:48:40 +0300 |
| commit | 7453b91881a77aa0ec9674daeeb8b9d2928a3891 (patch) | |
| tree | a7e8c6b03ba8fb621c1c08a4238d9cdcb4cd9683 | |
| parent | e003c485ac82a9f8de4204912ed059ac6dd4257c (diff) | |
| download | linux-7453b91881a77aa0ec9674daeeb8b9d2928a3891.tar.xz | |
Reapply "arm64: fpsimd: Implement lazy restore for kernel mode FPSIMD"
commit f481bb32d60e45fb3d19ea68ce79c5629f3fc3a0 upstream.
This reverts commit b8995a18417088bb53f87c49d200ec72a9dd4ec1.
Ard managed to reproduce the dm-crypt corruption problem and got to the
bottom of it, so re-apply the problematic patch in preparation for
fixing things properly.
Cc: stable@vger.kernel.org
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/include/asm/processor.h | 1 | ||||
| -rw-r--r-- | arch/arm64/kernel/fpsimd.c | 18 |
2 files changed, 19 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h index ce6eebd6c08b..5b0a04810b23 100644 --- a/arch/arm64/include/asm/processor.h +++ b/arch/arm64/include/asm/processor.h @@ -169,6 +169,7 @@ 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 6e1c935df5c6..5e7b0eb4687e 100644 --- a/arch/arm64/kernel/fpsimd.c +++ b/arch/arm64/kernel/fpsimd.c @@ -1492,12 +1492,30 @@ 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(); } /* |