Adding upstream version 5.10.209.upstream/5.10.209

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

1 files changed, 170 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..b7421780e
--- /dev/null
+++ b/arch/x86/include/asm/text-patching.h
@@ -0,0 +1,170 @@
+/* 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
+
+/*
+ * Currently, the max observed size in the kernel code is
+ * JUMP_LABEL_NOP_SIZE/RELATIVEJUMP_SIZE, which are 5.
+ * Raise it if needed.
+ */
+#define POKE_MAX_OPCODE_SIZE	5
+
+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 against NMI or MCE handlers seeing
+ * an inconsistent instruction while you patch.
+ */
+extern void *text_poke(void *addr, const void *opcode, size_t len);
+extern void text_poke_sync(void);
+extern void *text_poke_kgdb(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, const void *emulate);
+
+extern void text_poke_queue(void *addr, const void *opcode, size_t len, const void *emulate);
+extern void text_poke_finish(void);
+
+#define INT3_INSN_SIZE		1
+#define INT3_INSN_OPCODE	0xCC
+
+#define RET_INSN_SIZE		1
+#define RET_INSN_OPCODE		0xC3
+
+#define CALL_INSN_SIZE		5
+#define CALL_INSN_OPCODE	0xE8
+
+#define JMP32_INSN_SIZE		5
+#define JMP32_INSN_OPCODE	0xE9
+
+#define JMP8_INSN_SIZE		2
+#define JMP8_INSN_OPCODE	0xEB
+
+#define DISP32_SIZE		4
+
+static __always_inline int text_opcode_size(u8 opcode)
+{
+	int size = 0;
+
+#define __CASE(insn)	\
+	case insn##_INSN_OPCODE: size = insn##_INSN_SIZE; break
+
+	switch(opcode) {
+	__CASE(INT3);
+	__CASE(RET);
+	__CASE(CALL);
+	__CASE(JMP32);
+	__CASE(JMP8);
+	}
+
+#undef __CASE
+
+	return size;
+}
+
+union text_poke_insn {
+	u8 text[POKE_MAX_OPCODE_SIZE];
+	struct {
+		u8 opcode;
+		s32 disp;
+	} __attribute__((packed));
+};
+
+static __always_inline
+void *text_gen_insn(u8 opcode, const void *addr, const void *dest)
+{
+	static union text_poke_insn insn; /* per instance */
+	int size = text_opcode_size(opcode);
+
+	insn.opcode = opcode;
+
+	if (size > 1) {
+		insn.disp = (long)dest - (long)(addr + size);
+		if (size == 2) {
+			/*
+			 * Ensure that for JMP9 the displacement
+			 * actually fits the signed byte.
+			 */
+			BUG_ON((insn.disp >> 31) != (insn.disp >> 7));
+		}
+	}
+
+	return &insn.text;
+}
+
+extern int after_bootmem;
+extern __ro_after_init struct mm_struct *poking_mm;
+extern __ro_after_init unsigned long poking_addr;
+
+#ifndef CONFIG_UML_X86
+static __always_inline
+void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
+{
+	regs->ip = ip;
+}
+
+static __always_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.
+	 *
+	 * Similarly entry_32.S will have a gap on the stack for (any) hardware
+	 * exception and pt_regs; see FIXUP_FRAME.
+	 */
+	regs->sp -= sizeof(unsigned long);
+	*(unsigned long *)regs->sp = val;
+}
+
+static __always_inline
+unsigned long int3_emulate_pop(struct pt_regs *regs)
+{
+	unsigned long val = *(unsigned long *)regs->sp;
+	regs->sp += sizeof(unsigned long);
+	return val;
+}
+
+static __always_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);
+}
+
+static __always_inline
+void int3_emulate_ret(struct pt_regs *regs)
+{
+	unsigned long ip = int3_emulate_pop(regs);
+	int3_emulate_jmp(regs, ip);
+}
+#endif /* !CONFIG_UML_X86 */
+
+#endif /* _ASM_X86_TEXT_PATCHING_H */