diff options
| author | Ingo Molnar <mingo@kernel.org> | 2025-04-09 23:11:26 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2025-04-14 08:18:29 +0200 |
| commit | 22aafe3bcb67472effdea1ccf0df20280192bbaf (patch) | |
| tree | 809bc2c253bb1b7ae02ade81b6431f66e2e96951 /arch/x86/kernel/fpu/xstate.c | |
| parent | c360bdc593b8a8b6e94166026728764085919cff (diff) | |
x86/fpu: Remove init_task FPU state dependencies, add debugging warning for PF_KTHREAD tasks
init_task's FPU state initialization was a bit of a hack:
__x86_init_fpu_begin = .;
. = __x86_init_fpu_begin + 128*PAGE_SIZE;
__x86_init_fpu_end = .;
But the init task isn't supposed to be using the FPU context
in any case, so remove the hack and add in some debug warnings.
As Linus noted in the discussion, the init task (and other
PF_KTHREAD tasks) *can* use the FPU via kernel_fpu_begin()/_end(),
but they don't need the context area because their FPU use is not
preemptible or reentrant, and they don't return to user-space.
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Chang S. Bae <chang.seok.bae@intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Uros Bizjak <ubizjak@gmail.com>
Link: https://lore.kernel.org/r/20250409211127.3544993-8-mingo@kernel.org
Diffstat (limited to 'arch/x86/kernel/fpu/xstate.c')
| -rw-r--r-- | arch/x86/kernel/fpu/xstate.c | 3 |
1 files changed, 0 insertions, 3 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 253da5aec915..4c771b9bd270 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -870,9 +870,6 @@ void __init fpu__init_system_xstate(unsigned int legacy_size) if (err) goto out_disable; - /* Reset the state for the current task */ - fpstate_reset(x86_task_fpu(current)); - /* * Update info used for ptrace frames; use standard-format size and no * supervisor xstates: |