[PATCH] x86: always use SYSCALL_DEFINE*

From: Tautschnig, Michael
Date: Sat Mar 10 2018 - 15:56:01 EST


All syscall arguments are passed in as types of the same byte size as
unsigned long (width of full registers). Using a smaller type without a
cast may result in losing bits of information. SYSCALL_DEFINE* introduce
adequate type casts. All definitions of syscalls in x86 except for those
patched here have already been using the appropriate SYSCALL_DEFINE*.

Signed-off-by: Michael Tautschnig <tautschn@xxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: H. Peter Anvin <hpa@xxxxxxxxx>
Cc: Jaswinder Singh <jaswinder@xxxxxxxxxxxxx>
Cc: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
arch/x86/kernel/ioport.c | 3 ++-
arch/x86/kernel/signal.c | 5 +++--
2 files changed, 5 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/ioport.c b/arch/x86/kernel/ioport.c
index 2f72330..d98b2a3 100644
--- a/arch/x86/kernel/ioport.c
+++ b/arch/x86/kernel/ioport.c
@@ -23,7 +23,8 @@
/*
* this changes the io permissions bitmap in the current task.
*/
-asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on)
+SYSCALL_DEFINE3(sys_ioperm, unsigned long, from, unsigned long, num, int,
+ turn_on)
{
struct thread_struct *t = &current->thread;
struct tss_struct *tss;
diff --git a/arch/x86/kernel/signal.c b/arch/x86/kernel/signal.c
index b9e00e8..40ba242 100644
--- a/arch/x86/kernel/signal.c
+++ b/arch/x86/kernel/signal.c
@@ -25,6 +25,7 @@
#include <linux/user-return-notifier.h>
#include <linux/uprobes.h>
#include <linux/context_tracking.h>
+#include <linux/syscalls.h>

#include <asm/processor.h>
#include <asm/ucontext.h>
@@ -601,7 +602,7 @@ static int x32_setup_rt_frame(struct ksignal *ksig,
* Do a signal return; undo the signal stack.
*/
#ifdef CONFIG_X86_32
-asmlinkage unsigned long sys_sigreturn(void)
+SYSCALL_DEFINE0(sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct sigframe __user *frame;
@@ -633,7 +634,7 @@ asmlinkage unsigned long sys_sigreturn(void)
}
#endif /* CONFIG_X86_32 */

-asmlinkage long sys_rt_sigreturn(void)
+SYSCALL_DEFINE0(rt_sigreturn)
{
struct pt_regs *regs = current_pt_regs();
struct rt_sigframe __user *frame;
--
2.7.3.AMZN



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