powerpc/64s: Add support for software count cache flush

[mirror_ubuntu-bionic-kernel.git] / arch / powerpc / kernel / entry_64.S

diff --git a/arch/powerpc/kernel/entry_64.S b/arch/powerpc/kernel/entry_64.S
index 250bc8e822058f9ee4a0cf320150d355ed9516a2..7188fc900db6bd52b4aadfdbe72e4d493a6a4776 100644 (file)
--- a/arch/powerpc/kernel/entry_64.S
+++ b/arch/powerpc/kernel/entry_64.S
@@ -25,6 +25,7 @@
 #include <asm/page.h>
 #include <asm/mmu.h>
 #include <asm/thread_info.h>
+#include <asm/code-patching-asm.h>
 #include <asm/ppc_asm.h>
 #include <asm/asm-offsets.h>
 #include <asm/cputable.h>
@@ -497,6 +498,57 @@ _GLOBAL(ret_from_kernel_thread)
        li      r3,0
        b       .Lsyscall_exit
 
+#ifdef CONFIG_PPC_BOOK3S_64
+
+#define FLUSH_COUNT_CACHE      \
+1:     nop;                    \
+       patch_site 1b, patch__call_flush_count_cache
+
+
+#define BCCTR_FLUSH    .long 0x4c400420
+
+.macro nops number
+       .rept \number
+       nop
+       .endr
+.endm
+
+.balign 32
+.global flush_count_cache
+flush_count_cache:
+       /* Save LR into r9 */
+       mflr    r9
+
+       .rept 64
+       bl      .+4
+       .endr
+       b       1f
+       nops    6
+
+       .balign 32
+       /* Restore LR */
+1:     mtlr    r9
+       li      r9,0x7fff
+       mtctr   r9
+
+       BCCTR_FLUSH
+
+2:     nop
+       patch_site 2b patch__flush_count_cache_return
+
+       nops    3
+
+       .rept 278
+       .balign 32
+       BCCTR_FLUSH
+       nops    7
+       .endr
+
+       blr
+#else
+#define FLUSH_COUNT_CACHE
+#endif /* CONFIG_PPC_BOOK3S_64 */
+
 /*
  * This routine switches between two different tasks.  The process
  * state of one is saved on its kernel stack.  Then the state
@@ -528,6 +580,8 @@ _GLOBAL(_switch)
        std     r23,_CCR(r1)
        std     r1,KSP(r3)      /* Set old stack pointer */
 
+       FLUSH_COUNT_CACHE
+
        /*
         * On SMP kernels, care must be taken because a task may be
         * scheduled off CPUx and on to CPUy. Memory ordering must be