[PATCH] x86/prctl: Remove pointless task argument

Thomas Gleixner
2022-05-12T12:04:15Z

The functions invoked via do_arch_prctl_common() can only operate on
the current task and none of these function uses the task argument.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
arch/x86/include/asm/fpu/api.h | 3 +--
arch/x86/include/asm/proto.h | 3 +--
arch/x86/kernel/fpu/xstate.c | 5 +----
arch/x86/kernel/process.c | 9 ++++-----
arch/x86/kernel/process_32.c | 2 +-
arch/x86/kernel/process_64.c | 4 ++--
6 files changed, 10 insertions(+), 16 deletions(-)

--- a/arch/x86/include/asm/fpu/api.h
+++ b/arch/x86/include/asm/fpu/api.h
@@ -162,7 +162,6 @@ static inline bool fpstate_is_confidenti
}

/* prctl */
-struct task_struct;
-extern long fpu_xstate_prctl(struct task_struct *tsk, int option, unsigned long arg2);
+extern long fpu_xstate_prctl(int option, unsigned long arg2);

#endif /* _ASM_X86_FPU_API_H */
--- a/arch/x86/include/asm/proto.h
+++ b/arch/x86/include/asm/proto.h
@@ -38,7 +38,6 @@ void x86_configure_nx(void);

extern int reboot_force;

-long do_arch_prctl_common(struct task_struct *task, int option,
- unsigned long arg2);
+long do_arch_prctl_common(int option, unsigned long arg2);

#endif /* _ASM_X86_PROTO_H */
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1705,16 +1705,13 @@ EXPORT_SYMBOL_GPL(xstate_get_guest_group
* e.g. for AMX which requires XFEATURE_XTILE_CFG(17) and
* XFEATURE_XTILE_DATA(18) this would be XFEATURE_XTILE_DATA(18).
*/
-long fpu_xstate_prctl(struct task_struct *tsk, int option, unsigned long arg2)
+long fpu_xstate_prctl(int option, unsigned long arg2)
{
u64 __user *uptr = (u64 __user *)arg2;
u64 permitted, supported;
unsigned long idx = arg2;
bool guest = false;

- if (tsk != current)
- return -EPERM;
-
switch (option) {
case ARCH_GET_XCOMP_SUPP:
supported = fpu_user_cfg.max_features | fpu_user_cfg.legacy_features;
--- a/arch/x86/kernel/process.c
+++ b/arch/x86/kernel/process.c
@@ -332,7 +332,7 @@ static int get_cpuid_mode(void)
return !test_thread_flag(TIF_NOCPUID);
}

-static int set_cpuid_mode(struct task_struct *task, unsigned long cpuid_enabled)
+static int set_cpuid_mode(unsigned long cpuid_enabled)
{
if (!boot_cpu_has(X86_FEATURE_CPUID_FAULT))
return -ENODEV;
@@ -983,20 +983,19 @@ unsigned long __get_wchan(struct task_st
return addr;
}

-long do_arch_prctl_common(struct task_struct *task, int option,
- unsigned long arg2)
+long do_arch_prctl_common(int option, unsigned long arg2)
{
switch (option) {
case ARCH_GET_CPUID:
return get_cpuid_mode();
case ARCH_SET_CPUID:
- return set_cpuid_mode(task, arg2);
+ return set_cpuid_mode(arg2);
case ARCH_GET_XCOMP_SUPP:
case ARCH_GET_XCOMP_PERM:
case ARCH_REQ_XCOMP_PERM:
case ARCH_GET_XCOMP_GUEST_PERM:
case ARCH_REQ_XCOMP_GUEST_PERM:
- return fpu_xstate_prctl(task, option, arg2);
+ return fpu_xstate_prctl(option, arg2);
}

return -EINVAL;
--- a/arch/x86/kernel/process_32.c
+++ b/arch/x86/kernel/process_32.c
@@ -219,5 +219,5 @@ EXPORT_SYMBOL_GPL(start_thread);

SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
{
- return do_arch_prctl_common(current, option, arg2);
+ return do_arch_prctl_common(option, arg2);
}
--- a/arch/x86/kernel/process_64.c
+++ b/arch/x86/kernel/process_64.c
@@ -844,7 +844,7 @@ SYSCALL_DEFINE2(arch_prctl, int, option,

ret = do_arch_prctl_64(current, option, arg2);
if (ret == -EINVAL)
- ret = do_arch_prctl_common(current, option, arg2);
+ ret = do_arch_prctl_common(option, arg2);

return ret;
}
@@ -852,7 +852,7 @@ SYSCALL_DEFINE2(arch_prctl, int, option,
#ifdef CONFIG_IA32_EMULATION
COMPAT_SYSCALL_DEFINE2(arch_prctl, int, option, unsigned long, arg2)
{
- return do_arch_prctl_common(current, option, arg2);
+ return do_arch_prctl_common(option, arg2);
}
#endif