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Subject[PATCH 3/4] x86/cpu: Refactor sync_core() for readability
Date
Instead of having #ifdef/#endif blocks inside sync_core() for X86_64 and
X86_32, implement the new function iret_to_self() with two versions.

In this manner, avoid having to use even more more #ifdef/#endif blocks
when adding support for SERIALIZE in sync_core().

Cc: Andy Lutomirski <luto@kernel.org>
Cc: Cathy Zhang <cathy.zhang@intel.com>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Kyung Min Park <kyung.min.park@intel.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: "Ravi V. Shankar" <ravi.v.shankar@intel.com>
Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Cc: linux-edac@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Co-developed-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
---
arch/x86/include/asm/special_insns.h | 1 -
arch/x86/include/asm/sync_core.h | 56 ++++++++++++++++------------
2 files changed, 32 insertions(+), 25 deletions(-)

diff --git a/arch/x86/include/asm/special_insns.h b/arch/x86/include/asm/special_insns.h
index eb8e781c4353..59a3e13204c3 100644
--- a/arch/x86/include/asm/special_insns.h
+++ b/arch/x86/include/asm/special_insns.h
@@ -234,7 +234,6 @@ static inline void clwb(volatile void *__p)

#define nop() asm volatile ("nop")

-
#endif /* __KERNEL__ */

#endif /* _ASM_X86_SPECIAL_INSNS_H */
diff --git a/arch/x86/include/asm/sync_core.h b/arch/x86/include/asm/sync_core.h
index 9c5573f2c333..fdb5b356e59b 100644
--- a/arch/x86/include/asm/sync_core.h
+++ b/arch/x86/include/asm/sync_core.h
@@ -6,6 +6,37 @@
#include <asm/processor.h>
#include <asm/cpufeature.h>

+#ifdef CONFIG_X86_32
+static inline void iret_to_self(void)
+{
+ asm volatile (
+ "pushfl\n\t"
+ "pushl %%cs\n\t"
+ "pushl $1f\n\t"
+ "iret\n\t"
+ "1:"
+ : ASM_CALL_CONSTRAINT : : "memory");
+}
+#else
+static inline void iret_to_self(void)
+{
+ unsigned int tmp;
+
+ asm volatile (
+ "mov %%ss, %0\n\t"
+ "pushq %q0\n\t"
+ "pushq %%rsp\n\t"
+ "addq $8, (%%rsp)\n\t"
+ "pushfq\n\t"
+ "mov %%cs, %0\n\t"
+ "pushq %q0\n\t"
+ "pushq $1f\n\t"
+ "iretq\n\t"
+ "1:"
+ : "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
+}
+#endif /* CONFIG_X86_32 */
+
/*
* This function forces the icache and prefetched instruction stream to
* catch up with reality in two very specific cases:
@@ -44,30 +75,7 @@ static inline void sync_core(void)
* Like all of Linux's memory ordering operations, this is a
* compiler barrier as well.
*/
-#ifdef CONFIG_X86_32
- asm volatile (
- "pushfl\n\t"
- "pushl %%cs\n\t"
- "pushl $1f\n\t"
- "iret\n\t"
- "1:"
- : ASM_CALL_CONSTRAINT : : "memory");
-#else
- unsigned int tmp;
-
- asm volatile (
- "mov %%ss, %0\n\t"
- "pushq %q0\n\t"
- "pushq %%rsp\n\t"
- "addq $8, (%%rsp)\n\t"
- "pushfq\n\t"
- "mov %%cs, %0\n\t"
- "pushq %q0\n\t"
- "pushq $1f\n\t"
- "iretq\n\t"
- "1:"
- : "=&r" (tmp), ASM_CALL_CONSTRAINT : : "cc", "memory");
-#endif
+ iret_to_self();
}

/*
--
2.17.1
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