diff options
Diffstat (limited to 'arch/ppc64/kernel/vdso64/datapage.S')
| -rw-r--r-- | arch/ppc64/kernel/vdso64/datapage.S | 68 |
1 files changed, 68 insertions, 0 deletions
diff --git a/arch/ppc64/kernel/vdso64/datapage.S b/arch/ppc64/kernel/vdso64/datapage.S new file mode 100644 index 00000000000..18afd971c9d --- /dev/null +++ b/arch/ppc64/kernel/vdso64/datapage.S @@ -0,0 +1,68 @@ +/* + * 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 <linux/config.h> +#include <asm/processor.h> +#include <asm/ppc_asm.h> +#include <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 V_LOCAL_FUNC(__get_datapage) + mtlr r12 + addi r3,r3,CFG_SYSCALL_MAP64 + cmpli cr0,r4,0 + beqlr + li r0,__NR_syscalls + stw r0,0(r4) + blr + .cfi_endproc +V_FUNCTION_END(__kernel_get_syscall_map) |