From a5969cabbb4660eab42b6ef0412cbbd1200cf14d Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 12 Oct 2024 07:10:09 +0000
Subject: [PATCH] 修改led为gpio
---
kernel/arch/x86/include/asm/sync_core.h | 82 +++++++++++++++++++++++++++++++++++++++++
1 files changed, 82 insertions(+), 0 deletions(-)
diff --git a/kernel/arch/x86/include/asm/sync_core.h b/kernel/arch/x86/include/asm/sync_core.h
index 43b5e02..ab7382f 100644
--- a/kernel/arch/x86/include/asm/sync_core.h
+++ b/kernel/arch/x86/include/asm/sync_core.h
@@ -5,6 +5,88 @@
#include <linux/preempt.h>
#include <asm/processor.h>
#include <asm/cpufeature.h>
+#include <asm/special_insns.h>
+
+#ifdef CONFIG_X86_32
+static inline void iret_to_self(void)
+{
+ asm volatile (
+ "pushfl\n\t"
+ "pushl %%cs\n\t"
+ "pushl $1f\n\t"
+ "iret\n\t"
+ "1:"
+ : ASM_CALL_CONSTRAINT : : "memory");
+}
+#else
+static inline void iret_to_self(void)
+{
+ unsigned int tmp;
+
+ asm volatile (
+ "mov %%ss, %0\n\t"
+ "pushq %q0\n\t"
+ "pushq %%rsp\n\t"
+ "addq $8, (%%rsp)\n\t"
+ "pushfq\n\t"
+ "mov %%cs, %0\n\t"
+ "pushq %q0\n\t"
+ "pushq $1f\n\t"
+ "iretq\n\t"
+ "1:"
+ : "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+}
+#endif /* CONFIG_X86_32 */
+
+/*
+ * This function forces the icache and prefetched instruction stream to
+ * catch up with reality in two very specific cases:
+ *
+ * a) Text was modified using one virtual address and is about to be executed
+ * from the same physical page at a different virtual address.
+ *
+ * b) Text was modified on a different CPU, may subsequently be
+ * executed on this CPU, and you want to make sure the new version
+ * gets executed. This generally means you're calling this in an IPI.
+ *
+ * If you're calling this for a different reason, you're probably doing
+ * it wrong.
+ *
+ * Like all of Linux's memory ordering operations, this is a
+ * compiler barrier as well.
+ */
+static inline void sync_core(void)
+{
+ /*
+ * The SERIALIZE instruction is the most straightforward way to
+ * do this, but it is not universally available.
+ */
+ if (static_cpu_has(X86_FEATURE_SERIALIZE)) {
+ serialize();
+ return;
+ }
+
+ /*
+ * For all other processors, there are quite a few ways to do this.
+ * IRET-to-self is nice because it works on every CPU, at any CPL
+ * (so it's compatible with paravirtualization), and it never exits
+ * to a hypervisor. The only downsides are that it's a bit slow
+ * (it seems to be a bit more than 2x slower than the fastest
+ * options) and that it unmasks NMIs. The "push %cs" is needed,
+ * because in paravirtual environments __KERNEL_CS may not be a
+ * valid CS value when we do IRET directly.
+ *
+ * In case NMI unmasking or performance ever becomes a problem,
+ * the next best option appears to be MOV-to-CR2 and an
+ * unconditional jump. That sequence also works on all CPUs,
+ * but it will fault at CPL3 (i.e. Xen PV).
+ *
+ * CPUID is the conventional way, but it's nasty: it doesn't
+ * exist on some 486-like CPUs, and it usually exits to a
+ * hypervisor.
+ */
+ iret_to_self();
+}
/*
* Ensure that a core serializing instruction is issued before returning
--
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