The following commit has been merged into the x86/asm branch of tip:

Commit-ID:     c94055fe93c8d00bfa23fa2cb9af080f7fc53aa0
Gitweb:        
https://git.kernel.org/tip/c94055fe93c8d00bfa23fa2cb9af080f7fc53aa0
Author:        Brian Gerst <brge...@gmail.com>
AuthorDate:    Mon, 20 Jul 2020 13:49:23 -07:00
Committer:     Thomas Gleixner <t...@linutronix.de>
CommitterDate: Thu, 23 Jul 2020 11:46:42 +02:00

x86/percpu: Clean up percpu_stable_op()

Use __pcpu_size_call_return() to simplify this_cpu_read_stable().
Also remove __bad_percpu_size() which is now unused.

Signed-off-by: Brian Gerst <brge...@gmail.com>
Signed-off-by: Nick Desaulniers <ndesaulni...@google.com>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Tested-by: Nick Desaulniers <ndesaulni...@google.com>
Tested-by: Sedat Dilek <sedat.di...@gmail.com>
Reviewed-by: Nick Desaulniers <ndesaulni...@google.com>
Acked-by: Linus Torvalds <torva...@linux-foundation.org>
Acked-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Acked-by: Dennis Zhou <den...@kernel.org>
Link: 
https://lkml.kernel.org/r/20200720204925.3654302-10-ndesaulni...@google.com

---
 arch/x86/include/asm/percpu.h | 41 +++++++++-------------------------
 1 file changed, 12 insertions(+), 29 deletions(-)

diff --git a/arch/x86/include/asm/percpu.h b/arch/x86/include/asm/percpu.h
index 7efc0b5..cf2b9c2 100644
--- a/arch/x86/include/asm/percpu.h
+++ b/arch/x86/include/asm/percpu.h
@@ -85,7 +85,6 @@
 
 /* For arch-specific code, we can use direct single-insn ops (they
  * don't give an lvalue though). */
-extern void __bad_percpu_size(void);
 
 #define __pcpu_type_1 u8
 #define __pcpu_type_2 u16
@@ -167,33 +166,13 @@ do {                                                      
                \
        (typeof(_var))(unsigned long) pfo_val__;                        \
 })
 
-#define percpu_stable_op(op, var)                      \
-({                                                     \
-       typeof(var) pfo_ret__;                          \
-       switch (sizeof(var)) {                          \
-       case 1:                                         \
-               asm(op "b "__percpu_arg(P1)",%0"        \
-                   : "=q" (pfo_ret__)                  \
-                   : "p" (&(var)));                    \
-               break;                                  \
-       case 2:                                         \
-               asm(op "w "__percpu_arg(P1)",%0"        \
-                   : "=r" (pfo_ret__)                  \
-                   : "p" (&(var)));                    \
-               break;                                  \
-       case 4:                                         \
-               asm(op "l "__percpu_arg(P1)",%0"        \
-                   : "=r" (pfo_ret__)                  \
-                   : "p" (&(var)));                    \
-               break;                                  \
-       case 8:                                         \
-               asm(op "q "__percpu_arg(P1)",%0"        \
-                   : "=r" (pfo_ret__)                  \
-                   : "p" (&(var)));                    \
-               break;                                  \
-       default: __bad_percpu_size();                   \
-       }                                               \
-       pfo_ret__;                                      \
+#define percpu_stable_op(size, op, _var)                               \
+({                                                                     \
+       __pcpu_type_##size pfo_val__;                                   \
+       asm(__pcpu_op2_##size(op, __percpu_arg(P[var]), "%[val]")       \
+           : [val] __pcpu_reg_##size("=", pfo_val__)                   \
+           : [var] "p" (&(_var)));                                     \
+       (typeof(_var))(unsigned long) pfo_val__;                        \
 })
 
 /*
@@ -258,7 +237,11 @@ do {                                                       
                \
  * per-thread variables implemented as per-cpu variables and thus
  * stable for the duration of the respective task.
  */
-#define this_cpu_read_stable(var)      percpu_stable_op("mov", var)
+#define this_cpu_read_stable_1(pcp)    percpu_stable_op(1, "mov", pcp)
+#define this_cpu_read_stable_2(pcp)    percpu_stable_op(2, "mov", pcp)
+#define this_cpu_read_stable_4(pcp)    percpu_stable_op(4, "mov", pcp)
+#define this_cpu_read_stable_8(pcp)    percpu_stable_op(8, "mov", pcp)
+#define this_cpu_read_stable(pcp)      
__pcpu_size_call_return(this_cpu_read_stable_, pcp)
 
 #define raw_cpu_read_1(pcp)            percpu_from_op(1, , "mov", pcp)
 #define raw_cpu_read_2(pcp)            percpu_from_op(2, , "mov", pcp)

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