diff options
Diffstat (limited to 'arch/um/sys-x86_64/syscall_table.c')
| -rw-r--r-- | arch/um/sys-x86_64/syscall_table.c | 43 |
1 files changed, 30 insertions, 13 deletions
diff --git a/arch/um/sys-x86_64/syscall_table.c b/arch/um/sys-x86_64/syscall_table.c index 71b2ae4ad5de..c128eb897008 100644 --- a/arch/um/sys-x86_64/syscall_table.c +++ b/arch/um/sys-x86_64/syscall_table.c @@ -1,5 +1,7 @@ -/* System call table for UML/x86-64, copied from arch/x86_64/kernel/syscall.c - * with some changes for UML. */ +/* + * System call table for UML/x86-64, copied from arch/x86_64/kernel/syscall.c + * with some changes for UML. + */ #include <linux/linkage.h> #include <linux/sys.h> @@ -8,22 +10,26 @@ #define __NO_STUBS -/* Below you can see, in terms of #define's, the differences between the x86-64 - * and the UML syscall table. */ +/* + * Below you can see, in terms of #define's, the differences between the x86-64 + * and the UML syscall table. + */ /* Not going to be implemented by UML, since we have no hardware. */ #define stub_iopl sys_ni_syscall #define sys_ioperm sys_ni_syscall -/* The UML TLS problem. Note that x86_64 does not implement this, so the below - * is needed only for the ia32 compatibility. */ -/*#define sys_set_thread_area sys_ni_syscall -#define sys_get_thread_area sys_ni_syscall*/ +/* + * The UML TLS problem. Note that x86_64 does not implement this, so the below + * is needed only for the ia32 compatibility. + */ /* On UML we call it this way ("old" means it's not mmap2) */ #define sys_mmap old_mmap -/* On x86-64 sys_uname is actually sys_newuname plus a compatibility trick. - * See arch/x86_64/kernel/sys_x86_64.c */ +/* + * On x86-64 sys_uname is actually sys_newuname plus a compatibility trick. + * See arch/x86_64/kernel/sys_x86_64.c + */ #define sys_uname sys_uname64 #define stub_clone sys_clone @@ -46,8 +52,19 @@ typedef void (*sys_call_ptr_t)(void); extern void sys_ni_syscall(void); -sys_call_ptr_t sys_call_table[UM_NR_syscall_max+1] __cacheline_aligned = { - /* Smells like a like a compiler bug -- it doesn't work when the & below is removed. */ - [0 ... UM_NR_syscall_max] = &sys_ni_syscall, +/* + * We used to have a trick here which made sure that holes in the + * x86_64 table were filled in with sys_ni_syscall, but a comment in + * unistd_64.h says that holes aren't allowed, so the trick was + * removed. + * The trick looked like this + * [0 ... UM_NR_syscall_max] = &sys_ni_syscall + * before including unistd_64.h - the later initializations overwrote + * the sys_ni_syscall filler. + */ + +sys_call_ptr_t sys_call_table[] __cacheline_aligned = { #include <asm-x86/unistd_64.h> }; + +int syscall_table_size = sizeof(sys_call_table); |