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| author |   H. Peter Anvin <hpa@zytor.com> | 2012-02-19 07:56:26 -0800 |
|---|---|---|
| committer | H. Peter Anvin <hpa@zytor.com> | 2012-02-20 12:52:05 -0800 |
| commit | fca460f95e928bae373daa8295877b6905bc62b8 (patch) | |
| tree | 96247518911543b252f4a79cfdf578001473ff3d /arch/x86/include/asm/syscall.h | |
| parent | x32: Add rt_sigframe_x32 (diff) | |
| download | linux-dev-fca460f95e928bae373daa8295877b6905bc62b8.tar.xz linux-dev-fca460f95e928bae373daa8295877b6905bc62b8.zip | |
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.h | 5 |
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, |