From 2f7c68cb55ecb7331f2381deb497c27155f32faf Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Wed, 03 Jan 2024 09:43:39 +0000
Subject: [PATCH] update kernel to 5.10.198
---
kernel/arch/x86/kernel/fpu/core.c | 67 +++++++++++++--------------------
1 files changed, 26 insertions(+), 41 deletions(-)
diff --git a/kernel/arch/x86/kernel/fpu/core.c b/kernel/arch/x86/kernel/fpu/core.c
index 571220a..835b948 100644
--- a/kernel/arch/x86/kernel/fpu/core.c
+++ b/kernel/arch/x86/kernel/fpu/core.c
@@ -25,17 +25,7 @@
*/
union fpregs_state init_fpstate __read_mostly;
-/*
- * Track whether the kernel is using the FPU state
- * currently.
- *
- * This flag is used:
- *
- * - by IRQ context code to potentially use the FPU
- * if it's unused.
- *
- * - to debug kernel_fpu_begin()/end() correctness
- */
+/* Track in-kernel FPU usage */
static DEFINE_PER_CPU(bool, in_kernel_fpu);
/*
@@ -43,42 +33,37 @@
*/
DEFINE_PER_CPU(struct fpu *, fpu_fpregs_owner_ctx);
-static bool kernel_fpu_disabled(void)
-{
- return this_cpu_read(in_kernel_fpu);
-}
-
-static bool interrupted_kernel_fpu_idle(void)
-{
- return !kernel_fpu_disabled();
-}
-
-/*
- * Were we in user mode (or vm86 mode) when we were
- * interrupted?
- *
- * Doing kernel_fpu_begin/end() is ok if we are running
- * in an interrupt context from user mode - we'll just
- * save the FPU state as required.
- */
-static bool interrupted_user_mode(void)
-{
- struct pt_regs *regs = get_irq_regs();
- return regs && user_mode(regs);
-}
-
/*
* Can we use the FPU in kernel mode with the
* whole "kernel_fpu_begin/end()" sequence?
- *
- * It's always ok in process context (ie "not interrupt")
- * but it is sometimes ok even from an irq.
*/
bool irq_fpu_usable(void)
{
- return !in_interrupt() ||
- interrupted_user_mode() ||
- interrupted_kernel_fpu_idle();
+ if (WARN_ON_ONCE(in_nmi()))
+ return false;
+
+ /* In kernel FPU usage already active? */
+ if (this_cpu_read(in_kernel_fpu))
+ return false;
+
+ /*
+ * When not in NMI or hard interrupt context, FPU can be used in:
+ *
+ * - Task context except from within fpregs_lock()'ed critical
+ * regions.
+ *
+ * - Soft interrupt processing context which cannot happen
+ * while in a fpregs_lock()'ed critical region.
+ */
+ if (!in_irq())
+ return true;
+
+ /*
+ * In hard interrupt context it's safe when soft interrupts
+ * are enabled, which means the interrupt did not hit in
+ * a fpregs_lock()'ed critical region.
+ */
+ return !softirq_count();
}
EXPORT_SYMBOL(irq_fpu_usable);
--
Gitblit v1.6.2