[PATCH v2 02/22] x86/kvm: Fix fastop function ELF metadata

From: Josh Poimboeuf
Date: Wed Jul 17 2019 - 21:37:15 EST


Some of the fastop functions, e.g. em_setcc(), are actually just used as
global labels which point to blocks of functions. The global labels are
incorrectly annotated as functions. Also the functions themselves don't
have size annotations.

Fixes a bunch of warnings like the following:

arch/x86/kvm/emulate.o: warning: objtool: seto() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: em_setcc() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: setno() is missing an ELF size annotation
arch/x86/kvm/emulate.o: warning: objtool: setc() is missing an ELF size annotation

Signed-off-by: Josh Poimboeuf <jpoimboe@xxxxxxxxxx>
Acked-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
---
Cc: Paolo Bonzini <pbonzini@xxxxxxxxxx>
Cc: Radim KrÄmÃÅ <rkrcmar@xxxxxxxxxx>
---
arch/x86/kvm/emulate.c | 44 +++++++++++++++++++++++++++++-------------
1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 8e409ad448f9..718f7d9afedc 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -312,29 +312,42 @@ static void invalidate_registers(struct x86_emulate_ctxt *ctxt)

static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *));

-#define FOP_FUNC(name) \
+#define __FOP_FUNC(name) \
".align " __stringify(FASTOP_SIZE) " \n\t" \
".type " name ", @function \n\t" \
name ":\n\t"

-#define FOP_RET "ret \n\t"
+#define FOP_FUNC(name) \
+ __FOP_FUNC(#name)
+
+#define __FOP_RET(name) \
+ "ret \n\t" \
+ ".size " name ", .-" name "\n\t"
+
+#define FOP_RET(name) \
+ __FOP_RET(#name)

#define FOP_START(op) \
extern void em_##op(struct fastop *fake); \
asm(".pushsection .text, \"ax\" \n\t" \
".global em_" #op " \n\t" \
- FOP_FUNC("em_" #op)
+ ".align " __stringify(FASTOP_SIZE) " \n\t" \
+ "em_" #op ":\n\t"

#define FOP_END \
".popsection")

+#define __FOPNOP(name) \
+ __FOP_FUNC(name) \
+ __FOP_RET(name)
+
#define FOPNOP() \
- FOP_FUNC(__stringify(__UNIQUE_ID(nop))) \
- FOP_RET
+ __FOPNOP(__stringify(__UNIQUE_ID(nop)))

#define FOP1E(op, dst) \
- FOP_FUNC(#op "_" #dst) \
- "10: " #op " %" #dst " \n\t" FOP_RET
+ __FOP_FUNC(#op "_" #dst) \
+ "10: " #op " %" #dst " \n\t" \
+ __FOP_RET(#op "_" #dst)

#define FOP1EEX(op, dst) \
FOP1E(op, dst) _ASM_EXTABLE(10b, kvm_fastop_exception)
@@ -366,8 +379,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *));
FOP_END

#define FOP2E(op, dst, src) \
- FOP_FUNC(#op "_" #dst "_" #src) \
- #op " %" #src ", %" #dst " \n\t" FOP_RET
+ __FOP_FUNC(#op "_" #dst "_" #src) \
+ #op " %" #src ", %" #dst " \n\t" \
+ __FOP_RET(#op "_" #dst "_" #src)

#define FASTOP2(op) \
FOP_START(op) \
@@ -405,8 +419,9 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *));
FOP_END

#define FOP3E(op, dst, src, src2) \
- FOP_FUNC(#op "_" #dst "_" #src "_" #src2) \
- #op " %" #src2 ", %" #src ", %" #dst " \n\t" FOP_RET
+ __FOP_FUNC(#op "_" #dst "_" #src "_" #src2) \
+ #op " %" #src2 ", %" #src ", %" #dst " \n\t"\
+ __FOP_RET(#op "_" #dst "_" #src "_" #src2)

/* 3-operand, word-only, src2=cl */
#define FASTOP3WCL(op) \
@@ -423,7 +438,7 @@ static int fastop(struct x86_emulate_ctxt *ctxt, void (*fop)(struct fastop *));
".type " #op ", @function \n\t" \
#op ": \n\t" \
#op " %al \n\t" \
- FOP_RET
+ __FOP_RET(#op)

asm(".pushsection .fixup, \"ax\"\n"
".global kvm_fastop_exception \n"
@@ -449,7 +464,10 @@ FOP_SETCC(setle)
FOP_SETCC(setnle)
FOP_END;

-FOP_START(salc) "pushf; sbb %al, %al; popf \n\t" FOP_RET
+FOP_START(salc)
+FOP_FUNC(salc)
+"pushf; sbb %al, %al; popf \n\t"
+FOP_RET(salc)
FOP_END;

/*
--
2.20.1