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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /arch/powerpc/kernel/vdso32/datapage.S
Initial import
Diffstat (limited to 'arch/powerpc/kernel/vdso32/datapage.S')
-rw-r--r--arch/powerpc/kernel/vdso32/datapage.S85
1 files changed, 85 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/vdso32/datapage.S b/arch/powerpc/kernel/vdso32/datapage.S
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index 000000000..dc21e891d
--- /dev/null
+++ b/arch/powerpc/kernel/vdso32/datapage.S
@@ -0,0 +1,85 @@
+/*
+ * Access to the shared data page by the vDSO & syscall map
+ *
+ * Copyright (C) 2004 Benjamin Herrenschmuidt (benh@kernel.crashing.org), IBM Corp.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version
+ * 2 of the License, or (at your option) any later version.
+ */
+
+#include <asm/processor.h>
+#include <asm/ppc_asm.h>
+#include <asm/asm-offsets.h>
+#include <asm/unistd.h>
+#include <asm/vdso.h>
+
+ .text
+V_FUNCTION_BEGIN(__get_datapage)
+ .cfi_startproc
+ /* We don't want that exposed or overridable as we want other objects
+ * to be able to bl directly to here
+ */
+ .protected __get_datapage
+ .hidden __get_datapage
+
+ mflr r0
+ .cfi_register lr,r0
+
+ bcl 20,31,1f
+ .global __kernel_datapage_offset;
+__kernel_datapage_offset:
+ .long 0
+1:
+ mflr r3
+ mtlr r0
+ lwz r0,0(r3)
+ add r3,r0,r3
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__get_datapage)
+
+/*
+ * void *__kernel_get_syscall_map(unsigned int *syscall_count) ;
+ *
+ * returns a pointer to the syscall map. the map is agnostic to the
+ * size of "long", unlike kernel bitops, it stores bits from top to
+ * bottom so that memory actually contains a linear bitmap
+ * check for syscall N by testing bit (0x80000000 >> (N & 0x1f)) of
+ * 32 bits int at N >> 5.
+ */
+V_FUNCTION_BEGIN(__kernel_get_syscall_map)
+ .cfi_startproc
+ mflr r12
+ .cfi_register lr,r12
+ mr r4,r3
+ bl __get_datapage@local
+ mtlr r12
+ addi r3,r3,CFG_SYSCALL_MAP32
+ cmpli cr0,r4,0
+ beqlr
+ li r0,__NR_syscalls
+ stw r0,0(r4)
+ crclr cr0*4+so
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__kernel_get_syscall_map)
+
+/*
+ * void unsigned long long __kernel_get_tbfreq(void);
+ *
+ * returns the timebase frequency in HZ
+ */
+V_FUNCTION_BEGIN(__kernel_get_tbfreq)
+ .cfi_startproc
+ mflr r12
+ .cfi_register lr,r12
+ bl __get_datapage@local
+ lwz r4,(CFG_TB_TICKS_PER_SEC + 4)(r3)
+ lwz r3,CFG_TB_TICKS_PER_SEC(r3)
+ mtlr r12
+ crclr cr0*4+so
+ blr
+ .cfi_endproc
+V_FUNCTION_END(__kernel_get_tbfreq)