x86: Prepare inline-asm for straight-line-speculation

Replace all ret/retq instructions with ASM_RET in preparation of
making it more than a single instruction.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Link: https://lore.kernel.org/r/20211204134907.964635458@infradead.org

diff --git a/arch/x86/include/asm/linkage.h b/arch/x86/include/asm/linkage.h
index 3651117..ebddec2 100644 (file)
--- a/arch/x86/include/asm/linkage.h
+++ b/arch/x86/include/asm/linkage.h
@@ -18,6 +18,10 @@
 #define __ALIGN_STR    __stringify(__ALIGN)
 #endif
 
+#else /* __ASSEMBLY__ */
+
+#define ASM_RET        "ret\n\t"
+
 #endif /* __ASSEMBLY__ */
 
 #endif /* _ASM_X86_LINKAGE_H */

diff --git a/arch/x86/include/asm/paravirt.h b/arch/x86/include/asm/paravirt.h
index 21c4a69..ce1148c 100644 (file)
--- a/arch/x86/include/asm/paravirt.h
+++ b/arch/x86/include/asm/paravirt.h
@@ -671,7 +671,7 @@ bool __raw_callee_save___native_vcpu_is_preempted(long cpu);
            "call " #func ";"                                           \
            PV_RESTORE_ALL_CALLER_REGS                                  \
            FRAME_END                                                   \
-           "ret;"                                                      \
+           ASM_RET                                                     \
            ".size " PV_THUNK_NAME(func) ", .-" PV_THUNK_NAME(func) ";" \
            ".popsection")
 

diff --git a/arch/x86/include/asm/qspinlock_paravirt.h b/arch/x86/include/asm/qspinlock_paravirt.h
index 159622e..1474cf9 100644 (file)
--- a/arch/x86/include/asm/qspinlock_paravirt.h
+++ b/arch/x86/include/asm/qspinlock_paravirt.h
@@ -48,7 +48,7 @@ asm    (".pushsection .text;"
        "jne   .slowpath;"
        "pop   %rdx;"
        FRAME_END
-       "ret;"
+       ASM_RET
        ".slowpath: "
        "push   %rsi;"
        "movzbl %al,%esi;"
@@ -56,7 +56,7 @@ asm    (".pushsection .text;"
        "pop    %rsi;"
        "pop    %rdx;"
        FRAME_END
-       "ret;"
+       ASM_RET
        ".size " PV_UNLOCK ", .-" PV_UNLOCK ";"
        ".popsection");
 

diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 23fb4d5..175cde6 100644 (file)
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -714,7 +714,7 @@ asm (
 "      .type           int3_magic, @function\n"
 "int3_magic:\n"
 "      movl    $1, (%" _ASM_ARG1 ")\n"
-"      ret\n"
+       ASM_RET
 "      .size           int3_magic, .-int3_magic\n"
 "      .popsection\n"
 );

diff --git a/arch/x86/kernel/kprobes/core.c b/arch/x86/kernel/kprobes/core.c
index fce99e2..6290712 100644 (file)
--- a/arch/x86/kernel/kprobes/core.c
+++ b/arch/x86/kernel/kprobes/core.c
@@ -1051,7 +1051,7 @@ asm(
        "       addl $4, %esp\n"
        "       popfl\n"
 #endif
-       "       ret\n"
+       ASM_RET
        ".size __kretprobe_trampoline, .-__kretprobe_trampoline\n"
 );
 NOKPROBE_SYMBOL(__kretprobe_trampoline);

diff --git a/arch/x86/kernel/paravirt.c b/arch/x86/kernel/paravirt.c
index 7f7636a..4420499 100644 (file)
--- a/arch/x86/kernel/paravirt.c
+++ b/arch/x86/kernel/paravirt.c
@@ -41,7 +41,7 @@ extern void _paravirt_nop(void);
 asm (".pushsection .entry.text, \"ax\"\n"
      ".global _paravirt_nop\n"
      "_paravirt_nop:\n\t"
-     "ret\n\t"
+     ASM_RET
      ".size _paravirt_nop, . - _paravirt_nop\n\t"
      ".type _paravirt_nop, @function\n\t"
      ".popsection");
@@ -51,7 +51,7 @@ asm (".pushsection .entry.text, \"ax\"\n"
      ".global paravirt_ret0\n"
      "paravirt_ret0:\n\t"
      "xor %" _ASM_AX ", %" _ASM_AX ";\n\t"
-     "ret\n\t"
+     ASM_RET
      ".size paravirt_ret0, . - paravirt_ret0\n\t"
      ".type paravirt_ret0, @function\n\t"
      ".popsection");

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 28b1a4e..b026350 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -315,7 +315,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
        __FOP_FUNC(#name)
 
 #define __FOP_RET(name) \
-       "ret \n\t" \
+       ASM_RET \
        ".size " name ", .-" name "\n\t"
 
 #define FOP_RET(name) \
@@ -435,7 +435,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, fastop_t fop);
        __FOP_RET(#op)
 
 asm(".pushsection .fixup, \"ax\"\n"
-    "kvm_fastop_exception: xor %esi, %esi; ret\n"
+    "kvm_fastop_exception: xor %esi, %esi; " ASM_RET
     ".popsection");
 
 FOP_START(setcc)

diff --git a/arch/x86/lib/error-inject.c b/arch/x86/lib/error-inject.c
index be5b5fb..5208970 100644 (file)
--- a/arch/x86/lib/error-inject.c
+++ b/arch/x86/lib/error-inject.c
@@ -1,5 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 
+#include <linux/linkage.h>
 #include <linux/error-injection.h>
 #include <linux/kprobes.h>
 
@@ -10,7 +11,7 @@ asm(
        ".type just_return_func, @function\n"
        ".globl just_return_func\n"
        "just_return_func:\n"
-       "       ret\n"
+               ASM_RET
        ".size just_return_func, .-just_return_func\n"
 );
 

diff --git a/samples/ftrace/ftrace-direct-modify.c b/samples/ftrace/ftrace-direct-modify.c
index 690e4a9..bc8f0d6 100644 (file)
--- a/samples/ftrace/ftrace-direct-modify.c
+++ b/samples/ftrace/ftrace-direct-modify.c
@@ -31,7 +31,7 @@ asm (
 "      call my_direct_func1\n"
 "      leave\n"
 "      .size           my_tramp1, .-my_tramp1\n"
-"      ret\n"
+       ASM_RET
 "      .type           my_tramp2, @function\n"
 "      .globl          my_tramp2\n"
 "   my_tramp2:"
@@ -39,7 +39,7 @@ asm (
 "      movq %rsp, %rbp\n"
 "      call my_direct_func2\n"
 "      leave\n"
-"      ret\n"
+       ASM_RET
 "      .size           my_tramp2, .-my_tramp2\n"
 "      .popsection\n"
 );

diff --git a/samples/ftrace/ftrace-direct-too.c b/samples/ftrace/ftrace-direct-too.c
index 6e0de72..d1bec1c 100644 (file)
--- a/samples/ftrace/ftrace-direct-too.c
+++ b/samples/ftrace/ftrace-direct-too.c
@@ -31,7 +31,7 @@ asm (
 "      popq %rsi\n"
 "      popq %rdi\n"
 "      leave\n"
-"      ret\n"
+       ASM_RET
 "      .size           my_tramp, .-my_tramp\n"
 "      .popsection\n"
 );

diff --git a/samples/ftrace/ftrace-direct.c b/samples/ftrace/ftrace-direct.c
index a30aa42..51312e0 100644 (file)
--- a/samples/ftrace/ftrace-direct.c
+++ b/samples/ftrace/ftrace-direct.c
@@ -25,7 +25,7 @@ asm (
 "      call my_direct_func\n"
 "      popq %rdi\n"
 "      leave\n"
-"      ret\n"
+       ASM_RET
 "      .size           my_tramp, .-my_tramp\n"
 "      .popsection\n"
 );