x86/entry: Fix noinstr fail

  vmlinux.o: warning: objtool: __do_fast_syscall_32()+0x47: call to syscall_enter_from_user_mode_work() leaves .noinstr.text section

Fixes: 4facb95b7ada ("x86/entry: Unbreak 32bit fast syscall")
Reported-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20210106144017.472696632@infradead.org

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 18d8f17..0904f56 100644 (file)
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -73,10 +73,8 @@ static __always_inline void do_syscall_32_irqs_on(struct pt_regs *regs,
                                                  unsigned int nr)
 {
        if (likely(nr < IA32_NR_syscalls)) {
-               instrumentation_begin();
                nr = array_index_nospec(nr, IA32_NR_syscalls);
                regs->ax = ia32_sys_call_table[nr](regs);
-               instrumentation_end();
        }
 }
 
@@ -91,8 +89,11 @@ __visible noinstr void do_int80_syscall_32(struct pt_regs *regs)
         * or may not be necessary, but it matches the old asm behavior.
         */
        nr = (unsigned int)syscall_enter_from_user_mode(regs, nr);
+       instrumentation_begin();
 
        do_syscall_32_irqs_on(regs, nr);
+
+       instrumentation_end();
        syscall_exit_to_user_mode(regs);
 }
 
@@ -121,11 +122,12 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)
                res = get_user(*(u32 *)&regs->bp,
                       (u32 __user __force *)(unsigned long)(u32)regs->sp);
        }
-       instrumentation_end();
 
        if (res) {
                /* User code screwed up. */
                regs->ax = -EFAULT;
+
+               instrumentation_end();
                syscall_exit_to_user_mode(regs);
                return false;
        }
@@ -135,6 +137,8 @@ static noinstr bool __do_fast_syscall_32(struct pt_regs *regs)
 
        /* Now this is just like a normal syscall. */
        do_syscall_32_irqs_on(regs, nr);
+
+       instrumentation_end();
        syscall_exit_to_user_mode(regs);
        return true;
 }