[tip: x86/urgent] x86/entry: Fix noinstr fail

[tip-bot2 for Peter Zijlstra]

The following commit has been merged into the x86/urgent branch of tip:

Commit-ID:     9caa7ff509add50959a793b811cc7c9339e281cd
Gitweb:        
https://git.kernel.org/tip/9caa7ff509add50959a793b811cc7c9339e281cd
Author:        Peter Zijlstra <pet...@infradead.org>
AuthorDate:    Wed, 06 Jan 2021 15:36:20 +01:00
Committer:     Thomas Gleixner <t...@linutronix.de>
CommitterDate: Tue, 12 Jan 2021 21:10:58 +01:00

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 <rdun...@infradead.org>
Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org>
Signed-off-by: Thomas Gleixner <t...@linutronix.de>
Link: https://lore.kernel.org/r/20210106144017.472696...@infradead.org

---
 arch/x86/entry/common.c | 10 +++++++---
 1 file changed, 7 insertions(+), 3 deletions(-)

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 18d8f17..0904f56 100644
--- 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;
 }