[PATCH v3 04/12] Revert "x86/paravirt: Work around GCC inlining bugs when compiling paravirt ops"

From: Masahiro Yamada
Date: Mon Dec 17 2018 - 11:11:09 EST


This reverts commit 494b5168f2de009eb80f198f668da374295098dd.

The in-kernel workarounds will be replaced with GCC's new
"asm inline" syntax.

Signed-off-by: Masahiro Yamada <yamada.masahiro@xxxxxxxxxxxxx>
---

arch/x86/include/asm/paravirt_types.h | 56 ++++++++++++++++++-----------------
arch/x86/kernel/macros.S | 1 -
2 files changed, 29 insertions(+), 28 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 26942ad..488c596 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -348,11 +348,23 @@ extern struct paravirt_patch_template pv_ops;
#define paravirt_clobber(clobber) \
[paravirt_clobber] "i" (clobber)

+/*
+ * Generate some code, and mark it as patchable by the
+ * apply_paravirt() alternate instruction patcher.
+ */
+#define _paravirt_alt(insn_string, type, clobber) \
+ "771:\n\t" insn_string "\n" "772:\n" \
+ ".pushsection .parainstructions,\"a\"\n" \
+ _ASM_ALIGN "\n" \
+ _ASM_PTR " 771b\n" \
+ " .byte " type "\n" \
+ " .byte 772b-771b\n" \
+ " .short " clobber "\n" \
+ ".popsection\n"
+
/* Generate patchable code, with the default asm parameters. */
-#define paravirt_call \
- "PARAVIRT_CALL type=\"%c[paravirt_typenum]\"" \
- " clobber=\"%c[paravirt_clobber]\"" \
- " pv_opptr=\"%c[paravirt_opptr]\";"
+#define paravirt_alt(insn_string) \
+ _paravirt_alt(insn_string, "%c[paravirt_typenum]", "%c[paravirt_clobber]")

/* Simple instruction patching code. */
#define NATIVE_LABEL(a,x,b) "\n\t.globl " a #x "_" #b "\n" a #x "_" #b ":\n\t"
@@ -373,6 +385,16 @@ unsigned native_patch(u8 type, void *ibuf, unsigned long addr, unsigned len);
int paravirt_disable_iospace(void);

/*
+ * This generates an indirect call based on the operation type number.
+ * The type number, computed in PARAVIRT_PATCH, is derived from the
+ * offset into the paravirt_patch_template structure, and can therefore be
+ * freely converted back into a structure offset.
+ */
+#define PARAVIRT_CALL \
+ ANNOTATE_RETPOLINE_SAFE \
+ "call *%c[paravirt_opptr];"
+
+/*
* These macros are intended to wrap calls through one of the paravirt
* ops structs, so that they can be later identified and patched at
* runtime.
@@ -509,7 +531,7 @@ int paravirt_disable_iospace(void);
/* since this condition will never hold */ \
if (sizeof(rettype) > sizeof(unsigned long)) { \
asm volatile(pre \
- paravirt_call \
+ paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -519,7 +541,7 @@ int paravirt_disable_iospace(void);
__ret = (rettype)((((u64)__edx) << 32) | __eax); \
} else { \
asm volatile(pre \
- paravirt_call \
+ paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -546,7 +568,7 @@ int paravirt_disable_iospace(void);
PVOP_VCALL_ARGS; \
PVOP_TEST_NULL(op); \
asm volatile(pre \
- paravirt_call \
+ paravirt_alt(PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -664,26 +686,6 @@ struct paravirt_patch_site {
extern struct paravirt_patch_site __parainstructions[],
__parainstructions_end[];

-#else /* __ASSEMBLY__ */
-
-/*
- * This generates an indirect call based on the operation type number.
- * The type number, computed in PARAVIRT_PATCH, is derived from the
- * offset into the paravirt_patch_template structure, and can therefore be
- * freely converted back into a structure offset.
- */
-.macro PARAVIRT_CALL type:req clobber:req pv_opptr:req
-771: ANNOTATE_RETPOLINE_SAFE
- call *\pv_opptr
-772: .pushsection .parainstructions,"a"
- _ASM_ALIGN
- _ASM_PTR 771b
- .byte \type
- .byte 772b-771b
- .short \clobber
- .popsection
-.endm
-
#endif /* __ASSEMBLY__ */

#endif /* _ASM_X86_PARAVIRT_TYPES_H */
diff --git a/arch/x86/kernel/macros.S b/arch/x86/kernel/macros.S
index 71d8b71..66ccb8e 100644
--- a/arch/x86/kernel/macros.S
+++ b/arch/x86/kernel/macros.S
@@ -10,4 +10,3 @@
#include <asm/refcount.h>
#include <asm/alternative-asm.h>
#include <asm/bug.h>
-#include <asm/paravirt.h>
--
2.7.4