[PATCH] x86: drop XSAVEOPT and CLWB build flags

[Alexander M. Merritt]

The new toolchain baseline knows both the XSAVEOPT and CLWB instructions.

Resolves: https://gitlab.com/xen-project/xen/-/work_items/205
Signed-off-by: Alexander M. Merritt <alexan...@edera.dev>
---
 xen/arch/x86/arch.mk              |  2 --
 xen/arch/x86/flushtlb.c           | 28 +---------------------------
 xen/arch/x86/include/asm/system.h |  7 -------
 3 files changed, 1 insertion(+), 36 deletions(-)

diff --git a/xen/arch/x86/arch.mk b/xen/arch/x86/arch.mk
index 258e459bec..baa83418bc 100644
--- a/xen/arch/x86/arch.mk
+++ b/xen/arch/x86/arch.mk
@@ -15,9 +15,7 @@ $(call as-option-add,CFLAGS,CC,"crc32 
%eax$(comma)%eax",-DHAVE_AS_SSE4_2)
 $(call as-option-add,CFLAGS,CC,"invept (%rax)$(comma)%rax",-DHAVE_AS_EPT)
 $(call as-option-add,CFLAGS,CC,"rdrand %eax",-DHAVE_AS_RDRAND)
 $(call as-option-add,CFLAGS,CC,"rdfsbase %rax",-DHAVE_AS_FSGSBASE)
-$(call as-option-add,CFLAGS,CC,"xsaveopt (%rax)",-DHAVE_AS_XSAVEOPT)
 $(call as-option-add,CFLAGS,CC,"rdseed %eax",-DHAVE_AS_RDSEED)
-$(call as-option-add,CFLAGS,CC,"clwb (%rax)",-DHAVE_AS_CLWB)
 $(call as-option-add,CFLAGS,CC,".equ \"x\"$(comma)1",-DHAVE_AS_QUOTED_SYM)
 $(call as-option-add,CFLAGS,CC,"invpcid (%rax)$(comma)%rax",-DHAVE_AS_INVPCID)
 $(call as-option-add,CFLAGS,CC,"movdiri %rax$(comma)(%rax)",-DHAVE_AS_MOVDIR)
diff --git a/xen/arch/x86/flushtlb.c b/xen/arch/x86/flushtlb.c
index 65be0474a8..962bb87d69 100644
--- a/xen/arch/x86/flushtlb.c
+++ b/xen/arch/x86/flushtlb.c
@@ -313,33 +313,7 @@ void cache_writeback(const void *addr, unsigned int size)
     clflush_size = current_cpu_data.x86_clflush_size ?: 16;
     addr -= (unsigned long)addr & (clflush_size - 1);
     for ( ; addr < end; addr += clflush_size )
-    {
-/*
- * The arguments to a macro must not include preprocessor directives. Doing so
- * results in undefined behavior, so we have to create some defines here in
- * order to avoid it.
- */
-#if defined(HAVE_AS_CLWB)
-# define CLWB_ENCODING "clwb %[p]"
-#elif defined(HAVE_AS_XSAVEOPT)
-# define CLWB_ENCODING "data16 xsaveopt %[p]" /* clwb */
-#else
-# define CLWB_ENCODING ".byte 0x66, 0x0f, 0xae, 0x30" /* clwb (%%rax) */
-#endif
-
-#define BASE_INPUT(addr) [p] "m" (*(const char *)(addr))
-#if defined(HAVE_AS_CLWB) || defined(HAVE_AS_XSAVEOPT)
-# define INPUT BASE_INPUT
-#else
-# define INPUT(addr) "a" (addr), BASE_INPUT(addr)
-#endif
-
-        asm volatile (CLWB_ENCODING :: INPUT(addr));
-
-#undef INPUT
-#undef BASE_INPUT
-#undef CLWB_ENCODING
-    }
+        asm volatile ("clwb %[p]" :: [p] "m" (*(const char *)(addr)));
 
     asm volatile ("sfence" ::: "memory");
 }
diff --git a/xen/arch/x86/include/asm/system.h 
b/xen/arch/x86/include/asm/system.h
index 8ceaaf45d1..c3529f99dd 100644
--- a/xen/arch/x86/include/asm/system.h
+++ b/xen/arch/x86/include/asm/system.h
@@ -28,14 +28,7 @@ static inline void clflushopt(const void *p)
 
 static inline void clwb(const void *p)
 {
-#if defined(HAVE_AS_CLWB)
     asm volatile ( "clwb %0" :: "m" (*(const char *)p) );
-#elif defined(HAVE_AS_XSAVEOPT)
-    asm volatile ( "data16 xsaveopt %0" :: "m" (*(const char *)p) );
-#else
-    asm volatile ( ".byte 0x66, 0x0f, 0xae, 0x32"
-                   :: "d" (p), "m" (*(const char *)p) );
-#endif
 }
 
 #define xchg(ptr,v) \
-- 
2.45.2