[RFC PATCH 01/26] x86/paravirt: Specify subsection in PVOP macros

From: Ankur Arora
Date: Wed Apr 08 2020 - 01:05:41 EST

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Allow PVOP macros to specify a subsection such that _paravirt_alt() can
optionally put sites in .parainstructions.*.

Signed-off-by: Ankur Arora <ankur.a.arora@xxxxxxxxxx>
---
arch/x86/include/asm/paravirt_types.h | 158 +++++++++++++++++---------
1 file changed, 102 insertions(+), 56 deletions(-)

diff --git a/arch/x86/include/asm/paravirt_types.h b/arch/x86/include/asm/paravirt_types.h
index 732f62e04ddb..37e8f27a3b9d 100644
--- a/arch/x86/include/asm/paravirt_types.h
+++ b/arch/x86/include/asm/paravirt_types.h
@@ -337,6 +337,9 @@ struct paravirt_patch_template {
extern struct pv_info pv_info;
extern struct paravirt_patch_template pv_ops;

+/* Sub-section for .parainstructions */
+#define PV_SUFFIX ""
+
#define PARAVIRT_PATCH(x) \
(offsetof(struct paravirt_patch_template, x) / sizeof(void *))

@@ -350,9 +353,9 @@ extern struct paravirt_patch_template pv_ops;
* Generate some code, and mark it as patchable by the
* apply_paravirt() alternate instruction patcher.
*/
-#define _paravirt_alt(insn_string, type, clobber) \
+#define _paravirt_alt(sec, insn_string, type, clobber) \
"771:\n\t" insn_string "\n" "772:\n" \
- ".pushsection .parainstructions,\"a\"\n" \
+ ".pushsection .parainstructions" sec ",\"a\"\n" \
_ASM_ALIGN "\n" \
_ASM_PTR " 771b\n" \
" .byte " type "\n" \
@@ -361,8 +364,9 @@ extern struct paravirt_patch_template pv_ops;
".popsection\n"

/* Generate patchable code, with the default asm parameters. */
-#define paravirt_alt(insn_string) \
- _paravirt_alt(insn_string, "%c[paravirt_typenum]", "%c[paravirt_clobber]")
+#define paravirt_alt(sec, insn_string) \
+ _paravirt_alt(sec, 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"
@@ -414,7 +418,7 @@ int paravirt_disable_iospace(void);
* unfortunately, are quite a bit (r8 - r11)
*
* The call instruction itself is marked by placing its start address
- * and size into the .parainstructions section, so that
+ * and size into the .parainstructions* sections, so that
* apply_paravirt() in arch/i386/kernel/alternative.c can do the
* appropriate patching under the control of the backend pv_init_ops
* implementation.
@@ -512,7 +516,7 @@ int paravirt_disable_iospace(void);
})

-#define ____PVOP_CALL(rettype, op, clbr, call_clbr, extra_clbr, \
+#define ____PVOP_CALL(sec, rettype, op, clbr, call_clbr, extra_clbr, \
pre, post, ...) \
({ \
rettype __ret; \
@@ -522,7 +526,7 @@ int paravirt_disable_iospace(void);
/* since this condition will never hold */ \
if (sizeof(rettype) > sizeof(unsigned long)) { \
asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
+ paravirt_alt(sec, PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -532,7 +536,7 @@ int paravirt_disable_iospace(void);
__ret = (rettype)((((u64)__edx) << 32) | __eax); \
} else { \
asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
+ paravirt_alt(sec, PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -544,22 +548,22 @@ int paravirt_disable_iospace(void);
__ret; \
})

-#define __PVOP_CALL(rettype, op, pre, post, ...) \
- ____PVOP_CALL(rettype, op, CLBR_ANY, PVOP_CALL_CLOBBERS, \
+#define __PVOP_CALL(sec, rettype, op, pre, post, ...) \
+ ____PVOP_CALL(sec, rettype, op, CLBR_ANY, PVOP_CALL_CLOBBERS, \
EXTRA_CLOBBERS, pre, post, ##__VA_ARGS__)

-#define __PVOP_CALLEESAVE(rettype, op, pre, post, ...) \
- ____PVOP_CALL(rettype, op.func, CLBR_RET_REG, \
+#define __PVOP_CALLEESAVE(sec, rettype, op, pre, post, ...) \
+ ____PVOP_CALL(sec, rettype, op.func, CLBR_RET_REG, \
PVOP_CALLEE_CLOBBERS, , \
pre, post, ##__VA_ARGS__)

-#define ____PVOP_VCALL(op, clbr, call_clbr, extra_clbr, pre, post, ...) \
+#define ____PVOP_VCALL(sec, op, clbr, call_clbr, extra_clbr, pre, post, ...) \
({ \
PVOP_VCALL_ARGS; \
PVOP_TEST_NULL(op); \
asm volatile(pre \
- paravirt_alt(PARAVIRT_CALL) \
+ paravirt_alt(sec, PARAVIRT_CALL) \
post \
: call_clbr, ASM_CALL_CONSTRAINT \
: paravirt_type(op), \
@@ -568,85 +572,127 @@ int paravirt_disable_iospace(void);
: "memory", "cc" extra_clbr); \
})

-#define __PVOP_VCALL(op, pre, post, ...) \
- ____PVOP_VCALL(op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
+#define __PVOP_VCALL(sec, op, pre, post, ...) \
+ ____PVOP_VCALL(sec, op, CLBR_ANY, PVOP_VCALL_CLOBBERS, \
VEXTRA_CLOBBERS, \
pre, post, ##__VA_ARGS__)

-#define __PVOP_VCALLEESAVE(op, pre, post, ...) \
- ____PVOP_VCALL(op.func, CLBR_RET_REG, \
+#define __PVOP_VCALLEESAVE(sec, op, pre, post, ...) \
+ ____PVOP_VCALL(sec, op.func, CLBR_RET_REG, \
PVOP_VCALLEE_CLOBBERS, , \
pre, post, ##__VA_ARGS__)

-#define PVOP_CALL0(rettype, op) \
- __PVOP_CALL(rettype, op, "", "")
-#define PVOP_VCALL0(op) \
- __PVOP_VCALL(op, "", "")
+#define _PVOP_CALL0(sec, rettype, op) \
+ __PVOP_CALL(sec, rettype, op, "", "")
+#define _PVOP_VCALL0(sec, op) \
+ __PVOP_VCALL(sec, op, "", "")

-#define PVOP_CALLEE0(rettype, op) \
- __PVOP_CALLEESAVE(rettype, op, "", "")
-#define PVOP_VCALLEE0(op) \
- __PVOP_VCALLEESAVE(op, "", "")
+#define _PVOP_CALLEE0(sec, rettype, op) \
+ __PVOP_CALLEESAVE(sec, rettype, op, "", "")
+#define _PVOP_VCALLEE0(sec, op) \
+ __PVOP_VCALLEESAVE(sec, op, "", "")

-#define PVOP_CALL1(rettype, op, arg1) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
-#define PVOP_VCALL1(op, arg1) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1))
+#define _PVOP_CALL1(sec, rettype, op, arg1) \
+ __PVOP_CALL(sec, rettype, op, "", "", PVOP_CALL_ARG1(arg1))
+#define _PVOP_VCALL1(sec, op, arg1) \
+ __PVOP_VCALL(sec, op, "", "", PVOP_CALL_ARG1(arg1))

-#define PVOP_CALLEE1(rettype, op, arg1) \
- __PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1))
-#define PVOP_VCALLEE1(op, arg1) \
- __PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1))
+#define _PVOP_CALLEE1(sec, rettype, op, arg1) \
+ __PVOP_CALLEESAVE(sec, rettype, op, "", "", PVOP_CALL_ARG1(arg1))
+#define _PVOP_VCALLEE1(sec, op, arg1) \
+ __PVOP_VCALLEESAVE(sec, op, "", "", PVOP_CALL_ARG1(arg1))

-
-#define PVOP_CALL2(rettype, op, arg1, arg2) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
+#define _PVOP_CALL2(sec, rettype, op, arg1, arg2) \
+ __PVOP_CALL(sec, rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))
-#define PVOP_VCALL2(op, arg1, arg2) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
+#define _PVOP_VCALL2(sec, op, arg1, arg2) \
+ __PVOP_VCALL(sec, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))

-#define PVOP_CALLEE2(rettype, op, arg1, arg2) \
- __PVOP_CALLEESAVE(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
+#define _PVOP_CALLEE2(sec, rettype, op, arg1, arg2) \
+ __PVOP_CALLEESAVE(sec, rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))
-#define PVOP_VCALLEE2(op, arg1, arg2) \
- __PVOP_VCALLEESAVE(op, "", "", PVOP_CALL_ARG1(arg1), \
+#define _PVOP_VCALLEE2(sec, op, arg1, arg2) \
+ __PVOP_VCALLEESAVE(sec, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2))

-#define PVOP_CALL3(rettype, op, arg1, arg2, arg3) \
- __PVOP_CALL(rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
+#define _PVOP_CALL3(sec, rettype, op, arg1, arg2, arg3) \
+ __PVOP_CALL(sec, rettype, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))
-#define PVOP_VCALL3(op, arg1, arg2, arg3) \
- __PVOP_VCALL(op, "", "", PVOP_CALL_ARG1(arg1), \
+#define _PVOP_VCALL3(sec, op, arg1, arg2, arg3) \
+ __PVOP_VCALL(sec, op, "", "", PVOP_CALL_ARG1(arg1), \
PVOP_CALL_ARG2(arg2), PVOP_CALL_ARG3(arg3))

/* This is the only difference in x86_64. We can make it much simpler */
#ifdef CONFIG_X86_32
-#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
- __PVOP_CALL(rettype, op, \
+#define _PVOP_CALL4(sec, rettype, op, arg1, arg2, arg3, arg4) \
+ __PVOP_CALL(sec, rettype, op, \
"push %[_arg4];", "lea 4(%%esp),%%esp;", \
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), [_arg4] "mr" ((u32)(arg4)))
-#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
- __PVOP_VCALL(op, \
+#define _PVOP_VCALL4(sec, op, arg1, arg2, arg3, arg4) \
+ __PVOP_VCALL(sec, op, \
"push %[_arg4];", "lea 4(%%esp),%%esp;", \
"0" ((u32)(arg1)), "1" ((u32)(arg2)), \
"2" ((u32)(arg3)), [_arg4] "mr" ((u32)(arg4)))
#else
-#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
- __PVOP_CALL(rettype, op, "", "", \
+#define _PVOP_CALL4(sec, rettype, op, arg1, arg2, arg3, arg4) \
+ __PVOP_CALL(sec, rettype, op, "", "", \
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
-#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
- __PVOP_VCALL(op, "", "", \
+#define _PVOP_VCALL4(sec, op, arg1, arg2, arg3, arg4) \
+ __PVOP_VCALL(sec, op, "", "", \
PVOP_CALL_ARG1(arg1), PVOP_CALL_ARG2(arg2), \
PVOP_CALL_ARG3(arg3), PVOP_CALL_ARG4(arg4))
#endif

+/*
+ * PVOP macros for .parainstructions
+ */
+#define PVOP_CALL0(rettype, op) \
+ _PVOP_CALL0(PV_SUFFIX, rettype, op)
+#define PVOP_VCALL0(op) \
+ _PVOP_VCALL0(PV_SUFFIX, op)
+
+#define PVOP_CALLEE0(rettype, op) \
+ _PVOP_CALLEE0(PV_SUFFIX, rettype, op)
+#define PVOP_VCALLEE0(op) \
+ _PVOP_VCALLEE0(PV_SUFFIX, op)
+
+#define PVOP_CALL1(rettype, op, arg1) \
+ _PVOP_CALL1(PV_SUFFIX, rettype, op, arg1)
+#define PVOP_VCALL1(op, arg1) \
+ _PVOP_VCALL1(PV_SUFFIX, op, arg1)
+
+#define PVOP_CALLEE1(rettype, op, arg1) \
+ _PVOP_CALLEE1(PV_SUFFIX, rettype, op, arg1)
+#define PVOP_VCALLEE1(op, arg1) \
+ _PVOP_VCALLEE1(PV_SUFFIX, op, arg1)
+
+#define PVOP_CALL2(rettype, op, arg1, arg2) \
+ _PVOP_CALL2(PV_SUFFIX, rettype, op, arg1, arg2)
+#define PVOP_VCALL2(op, arg1, arg2) \
+ _PVOP_VCALL2(PV_SUFFIX, op, arg1, arg2)
+
+#define PVOP_CALLEE2(rettype, op, arg1, arg2) \
+ _PVOP_CALLEE2(PV_SUFFIX, rettype, op, arg1, arg2)
+#define PVOP_VCALLEE2(op, arg1, arg2) \
+ _PVOP_VCALLEE2(PV_SUFFIX, op, arg1, arg2)
+
+#define PVOP_CALL3(rettype, op, arg1, arg2, arg3) \
+ _PVOP_CALL3(PV_SUFFIX, rettype, op, arg1, arg2, arg3)
+#define PVOP_VCALL3(op, arg1, arg2, arg3) \
+ _PVOP_VCALL3(PV_SUFFIX, op, arg1, arg2, arg3)
+
+#define PVOP_CALL4(rettype, op, arg1, arg2, arg3, arg4) \
+ _PVOP_CALL4(PV_SUFFIX, rettype, op, arg1, arg2, arg3, arg4)
+#define PVOP_VCALL4(op, arg1, arg2, arg3, arg4) \
+ _PVOP_VCALL4(PV_SUFFIX, op, arg1, arg2, arg3, arg4)
+
/* Lazy mode for batching updates / context switch */
enum paravirt_lazy_mode {
PARAVIRT_LAZY_NONE,
@@ -667,7 +713,7 @@ u64 _paravirt_ident_64(u64);

#define paravirt_nop ((void *)_paravirt_nop)

-/* These all sit in the .parainstructions section to tell us what to patch. */
+/* These all sit in .parainstructions* sections to tell us what to patch. */
struct paravirt_patch_site {
u8 *instr; /* original instructions */
u8 type; /* type of this instruction */
--
2.20.1

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