Merge tag 'x86_alternatives_for_v6.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull x86 asm alternatives updates from Borislav Petkov:

 - Teach the static_call patching infrastructure to handle conditional
   tall calls properly which can be static calls too

 - Add proper struct alt_instr.flags which controls different aspects of
   insn patching behavior

* tag 'x86_alternatives_for_v6.3_rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/static_call: Add support for Jcc tail-calls
  x86/alternatives: Teach text_poke_bp() to patch Jcc.d32 instructions
  x86/alternatives: Introduce int3_emulate_jcc()
  x86/alternatives: Add alt_instr.flags

arch/x86/include/asm/alternative.h

@@ -6,8 +6,10 @@
 #include <linux/stringify.h>
 #include <asm/asm.h>
 
-#define ALTINSTR_FLAG_INV	(1 << 15)
-#define ALT_NOT(feat)		((feat) | ALTINSTR_FLAG_INV)
+#define ALT_FLAGS_SHIFT		16
+
+#define ALT_FLAG_NOT		BIT(0)
+#define ALT_NOT(feature)	((ALT_FLAG_NOT << ALT_FLAGS_SHIFT) | (feature))
 
 #ifndef __ASSEMBLY__
 
@@ -59,10 +61,27 @@
 	".long 999b - .\n\t"					\
 	".popsection\n\t"
 
+/*
+ * The patching flags are part of the upper bits of the @ft_flags parameter when
+ * specifying them. The split is currently like this:
+ *
+ * [31... flags ...16][15... CPUID feature bit ...0]
+ *
+ * but since this is all hidden in the macros argument being split, those fields can be
+ * extended in the future to fit in a u64 or however the need arises.
+ */
 struct alt_instr {
 	s32 instr_offset;	/* original instruction */
 	s32 repl_offset;	/* offset to replacement instruction */
-	u16 cpuid;		/* cpuid bit set for replacement */
+
+	union {
+		struct {
+			u32 cpuid: 16;	/* CPUID bit set for replacement */
+			u32 flags: 16;	/* patching control flags */
+		};
+		u32 ft_flags;
+	};
+
 	u8  instrlen;		/* length of original instruction */
 	u8  replacementlen;	/* length of new instruction */
 } __packed;
@@ -182,10 +201,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
 		" - (" alt_slen ")), 0x90\n"							\
 	alt_end_marker ":\n"
 
-#define ALTINSTR_ENTRY(feature, num)					      \
+#define ALTINSTR_ENTRY(ft_flags, num)					      \
 	" .long 661b - .\n"				/* label           */ \
 	" .long " b_replacement(num)"f - .\n"		/* new instruction */ \
-	" .word " __stringify(feature) "\n"		/* feature bit     */ \
+	" .4byte " __stringify(ft_flags) "\n"		/* feature + flags */ \
 	" .byte " alt_total_slen "\n"			/* source len      */ \
 	" .byte " alt_rlen(num) "\n"			/* replacement len */
 
@@ -194,20 +213,20 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	b_replacement(num)":\n\t" newinstr "\n" e_replacement(num) ":\n"
 
 /* alternative assembly primitive: */
-#define ALTERNATIVE(oldinstr, newinstr, feature)			\
+#define ALTERNATIVE(oldinstr, newinstr, ft_flags)			\
 	OLDINSTR(oldinstr, 1)						\
 	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(feature, 1)					\
+	ALTINSTR_ENTRY(ft_flags, 1)					\
 	".popsection\n"							\
 	".pushsection .altinstr_replacement, \"ax\"\n"			\
 	ALTINSTR_REPLACEMENT(newinstr, 1)				\
 	".popsection\n"
 
-#define ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2)\
+#define ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
 	OLDINSTR_2(oldinstr, 1, 2)					\
 	".pushsection .altinstructions,\"a\"\n"				\
-	ALTINSTR_ENTRY(feature1, 1)					\
-	ALTINSTR_ENTRY(feature2, 2)					\
+	ALTINSTR_ENTRY(ft_flags1, 1)					\
+	ALTINSTR_ENTRY(ft_flags2, 2)					\
 	".popsection\n"							\
 	".pushsection .altinstr_replacement, \"ax\"\n"			\
 	ALTINSTR_REPLACEMENT(newinstr1, 1)				\
@@ -215,21 +234,22 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	".popsection\n"
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
-#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
+#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
 	ALTERNATIVE_2(oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
-		      newinstr_yes, feature)
-
-#define ALTERNATIVE_3(oldinsn, newinsn1, feat1, newinsn2, feat2, newinsn3, feat3) \
-	OLDINSTR_3(oldinsn, 1, 2, 3)						\
-	".pushsection .altinstructions,\"a\"\n"					\
-	ALTINSTR_ENTRY(feat1, 1)						\
-	ALTINSTR_ENTRY(feat2, 2)						\
-	ALTINSTR_ENTRY(feat3, 3)						\
-	".popsection\n"								\
-	".pushsection .altinstr_replacement, \"ax\"\n"				\
-	ALTINSTR_REPLACEMENT(newinsn1, 1)					\
-	ALTINSTR_REPLACEMENT(newinsn2, 2)					\
-	ALTINSTR_REPLACEMENT(newinsn3, 3)					\
+		      newinstr_yes, ft_flags)
+
+#define ALTERNATIVE_3(oldinsn, newinsn1, ft_flags1, newinsn2, ft_flags2, \
+			newinsn3, ft_flags3)				\
+	OLDINSTR_3(oldinsn, 1, 2, 3)					\
+	".pushsection .altinstructions,\"a\"\n"				\
+	ALTINSTR_ENTRY(ft_flags1, 1)					\
+	ALTINSTR_ENTRY(ft_flags2, 2)					\
+	ALTINSTR_ENTRY(ft_flags3, 3)					\
+	".popsection\n"							\
+	".pushsection .altinstr_replacement, \"ax\"\n"			\
+	ALTINSTR_REPLACEMENT(newinsn1, 1)				\
+	ALTINSTR_REPLACEMENT(newinsn2, 2)				\
+	ALTINSTR_REPLACEMENT(newinsn3, 3)				\
 	".popsection\n"
 
 /*
@@ -244,14 +264,14 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * For non barrier like inlines please define new variants
  * without volatile and memory clobber.
  */
-#define alternative(oldinstr, newinstr, feature)			\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature) : : : "memory")
+#define alternative(oldinstr, newinstr, ft_flags)			\
+	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags) : : : "memory")
 
-#define alternative_2(oldinstr, newinstr1, feature1, newinstr2, feature2) \
-	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1, newinstr2, feature2) ::: "memory")
+#define alternative_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) \
+	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2) ::: "memory")
 
-#define alternative_ternary(oldinstr, feature, newinstr_yes, newinstr_no) \
-	asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) ::: "memory")
+#define alternative_ternary(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
+	asm_inline volatile(ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) ::: "memory")
 
 /*
  * Alternative inline assembly with input.
@@ -261,8 +281,8 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Argument numbers start with 1.
  * Leaving an unused argument 0 to keep API compatibility.
  */
-#define alternative_input(oldinstr, newinstr, feature, input...)	\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature)	\
+#define alternative_input(oldinstr, newinstr, ft_flags, input...)	\
+	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
 		: : "i" (0), ## input)
 
 /*
@@ -273,20 +293,20 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Otherwise, if CPU has feature1, newinstr1 is used.
  * Otherwise, oldinstr is used.
  */
-#define alternative_input_2(oldinstr, newinstr1, feature1, newinstr2,	     \
-			   feature2, input...)				     \
-	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, feature1,     \
-		newinstr2, feature2)					     \
+#define alternative_input_2(oldinstr, newinstr1, ft_flags1, newinstr2,	     \
+			   ft_flags2, input...)				     \
+	asm_inline volatile(ALTERNATIVE_2(oldinstr, newinstr1, ft_flags1,     \
+		newinstr2, ft_flags2)					     \
 		: : "i" (0), ## input)
 
 /* Like alternative_input, but with a single output argument */
-#define alternative_io(oldinstr, newinstr, feature, output, input...)	\
-	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, feature)	\
+#define alternative_io(oldinstr, newinstr, ft_flags, output, input...)	\
+	asm_inline volatile (ALTERNATIVE(oldinstr, newinstr, ft_flags)	\
 		: output : "i" (0), ## input)
 
 /* Like alternative_io, but for replacing a direct call with another one. */
-#define alternative_call(oldfunc, newfunc, feature, output, input...)	\
-	asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", feature) \
+#define alternative_call(oldfunc, newfunc, ft_flags, output, input...)	\
+	asm_inline volatile (ALTERNATIVE("call %P[old]", "call %P[new]", ft_flags) \
 		: output : [old] "i" (oldfunc), [new] "i" (newfunc), ## input)
 
 /*
@@ -295,10 +315,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * Otherwise, if CPU has feature1, function1 is used.
  * Otherwise, old function is used.
  */
-#define alternative_call_2(oldfunc, newfunc1, feature1, newfunc2, feature2,   \
+#define alternative_call_2(oldfunc, newfunc1, ft_flags1, newfunc2, ft_flags2,   \
 			   output, input...)				      \
-	asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", feature1,\
-		"call %P[new2]", feature2)				      \
+	asm_inline volatile (ALTERNATIVE_2("call %P[old]", "call %P[new1]", ft_flags1,\
+		"call %P[new2]", ft_flags2)				      \
 		: output, ASM_CALL_CONSTRAINT				      \
 		: [old] "i" (oldfunc), [new1] "i" (newfunc1),		      \
 		  [new2] "i" (newfunc2), ## input)
@@ -347,10 +367,10 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * enough information for the alternatives patching code to patch an
  * instruction. See apply_alternatives().
  */
-.macro altinstruction_entry orig alt feature orig_len alt_len
+.macro altinstr_entry orig alt ft_flags orig_len alt_len
 	.long \orig - .
 	.long \alt - .
-	.word \feature
+	.4byte \ft_flags
 	.byte \orig_len
 	.byte \alt_len
 .endm
@@ -361,7 +381,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * @newinstr. ".skip" directive takes care of proper instruction padding
  * in case @newinstr is longer than @oldinstr.
  */
-.macro ALTERNATIVE oldinstr, newinstr, feature
+.macro ALTERNATIVE oldinstr, newinstr, ft_flags
 140:
 	\oldinstr
 141:
@@ -369,7 +389,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
 142:
 
 	.pushsection .altinstructions,"a"
-	altinstruction_entry 140b,143f,\feature,142b-140b,144f-143f
+	altinstr_entry 140b,143f,\ft_flags,142b-140b,144f-143f
 	.popsection
 
 	.pushsection .altinstr_replacement,"ax"
@@ -399,7 +419,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
  * has @feature1, it replaces @oldinstr with @newinstr1. If CPU has
  * @feature2, it replaces @oldinstr with @feature2.
  */
-.macro ALTERNATIVE_2 oldinstr, newinstr1, feature1, newinstr2, feature2
+.macro ALTERNATIVE_2 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2
 140:
 	\oldinstr
 141:
@@ -408,8 +428,8 @@ static inline int alternatives_text_reserved(void *start, void *end)
 142:
 
 	.pushsection .altinstructions,"a"
-	altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f
-	altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f
+	altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
+	altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
 	.popsection
 
 	.pushsection .altinstr_replacement,"ax"
@@ -421,7 +441,7 @@ static inline int alternatives_text_reserved(void *start, void *end)
 	.popsection
 .endm
 
-.macro ALTERNATIVE_3 oldinstr, newinstr1, feature1, newinstr2, feature2, newinstr3, feature3
+.macro ALTERNATIVE_3 oldinstr, newinstr1, ft_flags1, newinstr2, ft_flags2, newinstr3, ft_flags3
 140:
 	\oldinstr
 141:
@@ -430,9 +450,9 @@ static inline int alternatives_text_reserved(void *start, void *end)
 142:
 
 	.pushsection .altinstructions,"a"
-	altinstruction_entry 140b,143f,\feature1,142b-140b,144f-143f
-	altinstruction_entry 140b,144f,\feature2,142b-140b,145f-144f
-	altinstruction_entry 140b,145f,\feature3,142b-140b,146f-145f
+	altinstr_entry 140b,143f,\ft_flags1,142b-140b,144f-143f
+	altinstr_entry 140b,144f,\ft_flags2,142b-140b,145f-144f
+	altinstr_entry 140b,145f,\ft_flags3,142b-140b,146f-145f
 	.popsection
 
 	.pushsection .altinstr_replacement,"ax"
@@ -447,9 +467,9 @@ static inline int alternatives_text_reserved(void *start, void *end)
 .endm
 
 /* If @feature is set, patch in @newinstr_yes, otherwise @newinstr_no. */
-#define ALTERNATIVE_TERNARY(oldinstr, feature, newinstr_yes, newinstr_no) \
+#define ALTERNATIVE_TERNARY(oldinstr, ft_flags, newinstr_yes, newinstr_no) \
 	ALTERNATIVE_2 oldinstr, newinstr_no, X86_FEATURE_ALWAYS,	\
-	newinstr_yes, feature
+	newinstr_yes, ft_flags
 
 #endif /* __ASSEMBLY__ */
 

arch/x86/include/asm/text-patching.h

@@ -184,6 +184,37 @@ void int3_emulate_ret(struct pt_regs *regs)
 	unsigned long ip = int3_emulate_pop(regs);
 	int3_emulate_jmp(regs, ip);
 }
+
+static __always_inline
+void int3_emulate_jcc(struct pt_regs *regs, u8 cc, unsigned long ip, unsigned long disp)
+{
+	static const unsigned long jcc_mask[6] = {
+		[0] = X86_EFLAGS_OF,
+		[1] = X86_EFLAGS_CF,
+		[2] = X86_EFLAGS_ZF,
+		[3] = X86_EFLAGS_CF | X86_EFLAGS_ZF,
+		[4] = X86_EFLAGS_SF,
+		[5] = X86_EFLAGS_PF,
+	};
+
+	bool invert = cc & 1;
+	bool match;
+
+	if (cc < 0xc) {
+		match = regs->flags & jcc_mask[cc >> 1];
+	} else {
+		match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^
+			((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT);
+		if (cc >= 0xe)
+			match = match || (regs->flags & X86_EFLAGS_ZF);
+	}
+
+	if ((match && !invert) || (!match && invert))
+		ip += disp;
+
+	int3_emulate_jmp(regs, ip);
+}
+
 #endif /* !CONFIG_UML_X86 */
 
 #endif /* _ASM_X86_TEXT_PATCHING_H */

arch/x86/kernel/alternative.c

@@ -282,27 +282,25 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 	 */
 	for (a = start; a < end; a++) {
 		int insn_buff_sz = 0;
-		/* Mask away "NOT" flag bit for feature to test. */
-		u16 feature = a->cpuid & ~ALTINSTR_FLAG_INV;
 
 		instr = (u8 *)&a->instr_offset + a->instr_offset;
 		replacement = (u8 *)&a->repl_offset + a->repl_offset;
 		BUG_ON(a->instrlen > sizeof(insn_buff));
-		BUG_ON(feature >= (NCAPINTS + NBUGINTS) * 32);
+		BUG_ON(a->cpuid >= (NCAPINTS + NBUGINTS) * 32);
 
 		/*
 		 * Patch if either:
 		 * - feature is present
-		 * - feature not present but ALTINSTR_FLAG_INV is set to mean,
+		 * - feature not present but ALT_FLAG_NOT is set to mean,
 		 *   patch if feature is *NOT* present.
 		 */
-		if (!boot_cpu_has(feature) == !(a->cpuid & ALTINSTR_FLAG_INV))
+		if (!boot_cpu_has(a->cpuid) == !(a->flags & ALT_FLAG_NOT))
 			goto next;
 
 		DPRINTK("feat: %s%d*32+%d, old: (%pS (%px) len: %d), repl: (%px, len: %d)",
-			(a->cpuid & ALTINSTR_FLAG_INV) ? "!" : "",
-			feature >> 5,
-			feature & 0x1f,
+			(a->flags & ALT_FLAG_NOT) ? "!" : "",
+			a->cpuid >> 5,
+			a->cpuid & 0x1f,
 			instr, instr, a->instrlen,
 			replacement, a->replacementlen);
 
@@ -340,6 +338,12 @@ void __init_or_module noinline apply_alternatives(struct alt_instr *start,
 	}
 }
 
+static inline bool is_jcc32(struct insn *insn)
+{
+	/* Jcc.d32 second opcode byte is in the range: 0x80-0x8f */
+	return insn->opcode.bytes[0] == 0x0f && (insn->opcode.bytes[1] & 0xf0) == 0x80;
+}
+
 #if defined(CONFIG_RETPOLINE) && defined(CONFIG_OBJTOOL)
 
 /*
@@ -378,12 +382,6 @@ static int emit_indirect(int op, int reg, u8 *bytes)
 	return i;
 }
 
-static inline bool is_jcc32(struct insn *insn)
-{
-	/* Jcc.d32 second opcode byte is in the range: 0x80-0x8f */
-	return insn->opcode.bytes[0] == 0x0f && (insn->opcode.bytes[1] & 0xf0) == 0x80;
-}
-
 static int emit_call_track_retpoline(void *addr, struct insn *insn, int reg, u8 *bytes)
 {
 	u8 op = insn->opcode.bytes[0];
@@ -1772,6 +1770,11 @@ void text_poke_sync(void)
 	on_each_cpu(do_sync_core, NULL, 1);
 }
 
+/*
+ * NOTE: crazy scheme to allow patching Jcc.d32 but not increase the size of
+ * this thing. When len == 6 everything is prefixed with 0x0f and we map
+ * opcode to Jcc.d8, using len to distinguish.
+ */
 struct text_poke_loc {
 	/* addr := _stext + rel_addr */
 	s32 rel_addr;
@@ -1893,6 +1896,10 @@ noinstr int poke_int3_handler(struct pt_regs *regs)
 		int3_emulate_jmp(regs, (long)ip + tp->disp);
 		break;
 
+	case 0x70 ... 0x7f: /* Jcc */
+		int3_emulate_jcc(regs, tp->opcode & 0xf, (long)ip, tp->disp);
+		break;
+
 	default:
 		BUG();
 	}
@@ -1966,16 +1973,26 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
 	 * Second step: update all but the first byte of the patched range.
 	 */
 	for (do_sync = 0, i = 0; i < nr_entries; i++) {
-		u8 old[POKE_MAX_OPCODE_SIZE] = { tp[i].old, };
+		u8 old[POKE_MAX_OPCODE_SIZE+1] = { tp[i].old, };
+		u8 _new[POKE_MAX_OPCODE_SIZE+1];
+		const u8 *new = tp[i].text;
 		int len = tp[i].len;
 
 		if (len - INT3_INSN_SIZE > 0) {
 			memcpy(old + INT3_INSN_SIZE,
 			       text_poke_addr(&tp[i]) + INT3_INSN_SIZE,
 			       len - INT3_INSN_SIZE);
+
+			if (len == 6) {
+				_new[0] = 0x0f;
+				memcpy(_new + 1, new, 5);
+				new = _new;
+			}
+
 			text_poke(text_poke_addr(&tp[i]) + INT3_INSN_SIZE,
-				  (const char *)tp[i].text + INT3_INSN_SIZE,
+				  new + INT3_INSN_SIZE,
 				  len - INT3_INSN_SIZE);
+
 			do_sync++;
 		}
 
@@ -2003,8 +2020,7 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
 		 * The old instruction is recorded so that the event can be
 		 * processed forwards or backwards.
 		 */
-		perf_event_text_poke(text_poke_addr(&tp[i]), old, len,
-				     tp[i].text, len);
+		perf_event_text_poke(text_poke_addr(&tp[i]), old, len, new, len);
 	}
 
 	if (do_sync) {
@@ -2021,10 +2037,15 @@ static void text_poke_bp_batch(struct text_poke_loc *tp, unsigned int nr_entries
 	 * replacing opcode.
 	 */
 	for (do_sync = 0, i = 0; i < nr_entries; i++) {
-		if (tp[i].text[0] == INT3_INSN_OPCODE)
+		u8 byte = tp[i].text[0];
+
+		if (tp[i].len == 6)
+			byte = 0x0f;
+
+		if (byte == INT3_INSN_OPCODE)
 			continue;
 
-		text_poke(text_poke_addr(&tp[i]), tp[i].text, INT3_INSN_SIZE);
+		text_poke(text_poke_addr(&tp[i]), &byte, INT3_INSN_SIZE);
 		do_sync++;
 	}
 
@@ -2042,9 +2063,11 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
 			       const void *opcode, size_t len, const void *emulate)
 {
 	struct insn insn;
-	int ret, i;
+	int ret, i = 0;
 
-	memcpy((void *)tp->text, opcode, len);
+	if (len == 6)
+		i = 1;
+	memcpy((void *)tp->text, opcode+i, len-i);
 	if (!emulate)
 		emulate = opcode;
 
@@ -2055,6 +2078,13 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
 	tp->len = len;
 	tp->opcode = insn.opcode.bytes[0];
 
+	if (is_jcc32(&insn)) {
+		/*
+		 * Map Jcc.d32 onto Jcc.d8 and use len to distinguish.
+		 */
+		tp->opcode = insn.opcode.bytes[1] - 0x10;
+	}
+
 	switch (tp->opcode) {
 	case RET_INSN_OPCODE:
 	case JMP32_INSN_OPCODE:
@@ -2071,7 +2101,6 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
 		BUG_ON(len != insn.length);
 	}
 
-
 	switch (tp->opcode) {
 	case INT3_INSN_OPCODE:
 	case RET_INSN_OPCODE:
@@ -2080,6 +2109,7 @@ static void text_poke_loc_init(struct text_poke_loc *tp, void *addr,
 	case CALL_INSN_OPCODE:
 	case JMP32_INSN_OPCODE:
 	case JMP8_INSN_OPCODE:
+	case 0x70 ... 0x7f: /* Jcc */
 		tp->disp = insn.immediate.value;
 		break;
 

arch/x86/kernel/kprobes/core.c

@@ -464,50 +464,26 @@ static void kprobe_emulate_call(struct kprobe *p, struct pt_regs *regs)
 }
 NOKPROBE_SYMBOL(kprobe_emulate_call);
 
-static nokprobe_inline
-void __kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs, bool cond)
+static void kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs)
 {
 	unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
 
-	if (cond)
-		ip += p->ainsn.rel32;
+	ip += p->ainsn.rel32;
 	int3_emulate_jmp(regs, ip);
 }
-
-static void kprobe_emulate_jmp(struct kprobe *p, struct pt_regs *regs)
-{
-	__kprobe_emulate_jmp(p, regs, true);
-}
 NOKPROBE_SYMBOL(kprobe_emulate_jmp);
 
-static const unsigned long jcc_mask[6] = {
-	[0] = X86_EFLAGS_OF,
-	[1] = X86_EFLAGS_CF,
-	[2] = X86_EFLAGS_ZF,
-	[3] = X86_EFLAGS_CF | X86_EFLAGS_ZF,
-	[4] = X86_EFLAGS_SF,
-	[5] = X86_EFLAGS_PF,
-};
-
 static void kprobe_emulate_jcc(struct kprobe *p, struct pt_regs *regs)
 {
-	bool invert = p->ainsn.jcc.type & 1;
-	bool match;
+	unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
 
-	if (p->ainsn.jcc.type < 0xc) {
-		match = regs->flags & jcc_mask[p->ainsn.jcc.type >> 1];
-	} else {
-		match = ((regs->flags & X86_EFLAGS_SF) >> X86_EFLAGS_SF_BIT) ^
-			((regs->flags & X86_EFLAGS_OF) >> X86_EFLAGS_OF_BIT);
-		if (p->ainsn.jcc.type >= 0xe)
-			match = match || (regs->flags & X86_EFLAGS_ZF);
-	}
-	__kprobe_emulate_jmp(p, regs, (match && !invert) || (!match && invert));
+	int3_emulate_jcc(regs, p->ainsn.jcc.type, ip, p->ainsn.rel32);
 }
 NOKPROBE_SYMBOL(kprobe_emulate_jcc);
 
 static void kprobe_emulate_loop(struct kprobe *p, struct pt_regs *regs)
 {
+	unsigned long ip = regs->ip - INT3_INSN_SIZE + p->ainsn.size;
 	bool match;
 
 	if (p->ainsn.loop.type != 3) {	/* LOOP* */
@@ -535,7 +511,9 @@ static void kprobe_emulate_loop(struct kprobe *p, struct pt_regs *regs)
 	else if (p->ainsn.loop.type == 1)	/* LOOPE */
 		match = match && (regs->flags & X86_EFLAGS_ZF);
 
-	__kprobe_emulate_jmp(p, regs, match);
+	if (match)
+		ip += p->ainsn.rel32;
+	int3_emulate_jmp(regs, ip);
 }
 NOKPROBE_SYMBOL(kprobe_emulate_loop);
 

arch/x86/kernel/static_call.c

@@ -9,6 +9,7 @@ enum insn_type {
 	NOP = 1,  /* site cond-call */
 	JMP = 2,  /* tramp / site tail-call */
 	RET = 3,  /* tramp / site cond-tail-call */
+	JCC = 4,
 };
 
 /*
@@ -25,12 +26,40 @@ static const u8 xor5rax[] = { 0x2e, 0x2e, 0x2e, 0x31, 0xc0 };
 
 static const u8 retinsn[] = { RET_INSN_OPCODE, 0xcc, 0xcc, 0xcc, 0xcc };
 
+static u8 __is_Jcc(u8 *insn) /* Jcc.d32 */
+{
+	u8 ret = 0;
+
+	if (insn[0] == 0x0f) {
+		u8 tmp = insn[1];
+		if ((tmp & 0xf0) == 0x80)
+			ret = tmp;
+	}
+
+	return ret;
+}
+
+extern void __static_call_return(void);
+
+asm (".global __static_call_return\n\t"
+     ".type __static_call_return, @function\n\t"
+     ASM_FUNC_ALIGN "\n\t"
+     "__static_call_return:\n\t"
+     ANNOTATE_NOENDBR
+     ANNOTATE_RETPOLINE_SAFE
+     "ret; int3\n\t"
+     ".size __static_call_return, . - __static_call_return \n\t");
+
 static void __ref __static_call_transform(void *insn, enum insn_type type,
 					  void *func, bool modinit)
 {
 	const void *emulate = NULL;
 	int size = CALL_INSN_SIZE;
 	const void *code;
+	u8 op, buf[6];
+
+	if ((type == JMP || type == RET) && (op = __is_Jcc(insn)))
+		type = JCC;
 
 	switch (type) {
 	case CALL:
@@ -57,6 +86,20 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
 		else
 			code = &retinsn;
 		break;
+
+	case JCC:
+		if (!func) {
+			func = __static_call_return;
+			if (cpu_feature_enabled(X86_FEATURE_RETHUNK))
+				func = x86_return_thunk;
+		}
+
+		buf[0] = 0x0f;
+		__text_gen_insn(buf+1, op, insn+1, func, 5);
+		code = buf;
+		size = 6;
+
+		break;
 	}
 
 	if (memcmp(insn, code, size) == 0)
@@ -68,9 +111,9 @@ static void __ref __static_call_transform(void *insn, enum insn_type type,
 	text_poke_bp(insn, code, size, emulate);
 }
 
-static void __static_call_validate(void *insn, bool tail, bool tramp)
+static void __static_call_validate(u8 *insn, bool tail, bool tramp)
 {
-	u8 opcode = *(u8 *)insn;
+	u8 opcode = insn[0];
 
 	if (tramp && memcmp(insn+5, tramp_ud, 3)) {
 		pr_err("trampoline signature fail");
@@ -79,7 +122,8 @@ static void __static_call_validate(void *insn, bool tail, bool tramp)
 
 	if (tail) {
 		if (opcode == JMP32_INSN_OPCODE ||
-		    opcode == RET_INSN_OPCODE)
+		    opcode == RET_INSN_OPCODE ||
+		    __is_Jcc(insn))
 			return;
 	} else {
 		if (opcode == CALL_INSN_OPCODE ||

tools/objtool/arch/x86/include/arch/special.h

@@ -11,11 +11,11 @@
 #define JUMP_NEW_OFFSET		4
 #define JUMP_KEY_OFFSET		8
 
-#define ALT_ENTRY_SIZE		12
+#define ALT_ENTRY_SIZE		14
 #define ALT_ORIG_OFFSET		0
 #define ALT_NEW_OFFSET		4
 #define ALT_FEATURE_OFFSET	8
-#define ALT_ORIG_LEN_OFFSET	10
-#define ALT_NEW_LEN_OFFSET	11
+#define ALT_ORIG_LEN_OFFSET	12
+#define ALT_NEW_LEN_OFFSET	13
 
 #endif /* _X86_ARCH_SPECIAL_H */