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authorH. Peter Anvin <hpa@zytor.com>2012-02-19 07:56:26 -0800
committerH. Peter Anvin <hpa@zytor.com>2012-02-20 12:52:05 -0800
commitfca460f95e928bae373daa8295877b6905bc62b8 (patch)
tree96247518911543b252f4a79cfdf578001473ff3d /arch/x86/include/asm/syscall.h
parent9d3897630e14b3d33bcb24a3c0fa9d60a01d3058 (diff)
x32: Handle the x32 system call flag
x32 shares most system calls with x86-64, but unfortunately some subsystem (the input subsystem is the chief offender) which require is_compat() when operating with a 32-bit userspace. The input system actually has text files in sysfs whose meaning is dependent on sizeof(long) in userspace! We could solve this by having two completely disjoint system call tables; requiring that each system call be duplicated. This patch takes a different approach: we add a flag to the system call number; this flag doesn't affect the system call dispatch but requests compat treatment from affected subsystems for the duration of the system call. The change of cmpq to cmpl is safe since it immediately follows the and. Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Diffstat (limited to 'arch/x86/include/asm/syscall.h')
-rw-r--r--arch/x86/include/asm/syscall.h5
1 files changed, 3 insertions, 2 deletions
diff --git a/arch/x86/include/asm/syscall.h b/arch/x86/include/asm/syscall.h
index d962e5652a73..386b78686c4d 100644
--- a/arch/x86/include/asm/syscall.h
+++ b/arch/x86/include/asm/syscall.h
@@ -16,6 +16,7 @@
#include <linux/sched.h>
#include <linux/err.h>
#include <asm/asm-offsets.h> /* For NR_syscalls */
+#include <asm/unistd.h>
extern const unsigned long sys_call_table[];
@@ -26,13 +27,13 @@ extern const unsigned long sys_call_table[];
*/
static inline int syscall_get_nr(struct task_struct *task, struct pt_regs *regs)
{
- return regs->orig_ax;
+ return regs->orig_ax & __SYSCALL_MASK;
}
static inline void syscall_rollback(struct task_struct *task,
struct pt_regs *regs)
{
- regs->ax = regs->orig_ax;
+ regs->ax = regs->orig_ax & __SYSCALL_MASK;
}
static inline long syscall_get_error(struct task_struct *task,