From 04dd17822334871b23ea2862f7798fb0e0007777 Mon Sep 17 00:00:00 2001
From: hc <hc@nodka.com>
Date: Sat, 11 May 2024 08:53:19 +0000
Subject: [PATCH] change otg to host mode
---
kernel/arch/x86/include/asm/text-patching.h | 122 ++++++++++++++++++++++++++++++++++++----
1 files changed, 110 insertions(+), 12 deletions(-)
diff --git a/kernel/arch/x86/include/asm/text-patching.h b/kernel/arch/x86/include/asm/text-patching.h
index 0bbb07e..b742178 100644
--- a/kernel/arch/x86/include/asm/text-patching.h
+++ b/kernel/arch/x86/include/asm/text-patching.h
@@ -18,7 +18,14 @@
#define __parainstructions_end NULL
#endif
-extern void *text_poke_early(void *addr, const void *opcode, size_t len);
+/*
+ * 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.
@@ -31,42 +38,133 @@
* 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.
+ * 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, void *handler);
+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 inline void int3_emulate_jmp(struct pt_regs *regs, unsigned long ip)
+static __always_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)
+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 inline void int3_emulate_call(struct pt_regs *regs, unsigned long func)
+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);
}
-#endif /* CONFIG_X86_64 */
+
+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 */
--
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