Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 72 insertions, 0 deletions

diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
new file mode 100644
index 000000000..0bbb07eae
--- /dev/null
+++ b/arch/x86/include/asm/text-patching.h
@@ -0,0 +1,72 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _ASM_X86_TEXT_PATCHING_H
+#define _ASM_X86_TEXT_PATCHING_H
+
+#include <linux/types.h>
+#include <linux/stddef.h>
+#include <asm/ptrace.h>
+
+struct paravirt_patch_site;
+#ifdef CONFIG_PARAVIRT
+void apply_paravirt(struct paravirt_patch_site *start,
+		    struct paravirt_patch_site *end);
+#else
+static inline void apply_paravirt(struct paravirt_patch_site *start,
+				  struct paravirt_patch_site *end)
+{}
+#define __parainstructions	NULL
+#define __parainstructions_end	NULL
+#endif
+
+extern void *text_poke_early(void *addr, const void *opcode, size_t len);
+
+/*
+ * Clear and restore the kernel write-protection flag on the local CPU.
+ * Allows the kernel to edit read-only pages.
+ * Side-effect: any interrupt handler running between save and restore will have
+ * the ability to write to read-only pages.
+ *
+ * Warning:
+ * Code patching in the UP case is safe if NMIs and MCE handlers are stopped and
+ * no thread can be preempted in the instructions being modified (no iret to an
+ * invalid instruction possible) or if the instructions are changed from a
+ * consistent state to another consistent state atomically.
+ * On the local CPU you need to be protected again NMI or MCE handlers seeing an
+ * inconsistent instruction while you patch.
+ */
+extern void *text_poke(void *addr, const void *opcode, size_t len);
+extern int poke_int3_handler(struct pt_regs *regs);
+extern void *text_poke_bp(void *addr, const void *opcode, size_t len, void *handler);
+extern int after_bootmem;
+
+#ifndef CONFIG_UML_X86
+static inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
+{
+	regs->ip = ip;
+}
+
+#define INT3_INSN_SIZE 1
+#define CALL_INSN_SIZE 5
+
+#ifdef CONFIG_X86_64
+static inline void int3_emulate_push(struct pt_regs *regs, unsigned long val)
+{
+	/*
+	 * The int3 handler in entry_64.S adds a gap between the
+	 * stack where the break point happened, and the saving of
+	 * pt_regs. We can extend the original stack because of
+	 * this gap. See the idtentry macro's create_gap option.
+	 */
+	regs->sp -= sizeof(unsigned long);
+	*(unsigned long *)regs->sp = val;
+}
+
+static inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
+{
+	int3_emulate_push(regs, regs->ip - INT3_INSN_SIZE + CALL_INSN_SIZE);
+	int3_emulate_jmp(regs, func);
+}
+#endif /* CONFIG_X86_64 */
+#endif /* !CONFIG_UML_X86 */
+
+#endif /* _ASM_X86_TEXT_PATCHING_H */