[PATCH 5.10 147/199] x86/entry: Fix noinstr fail

Greg Kroah-Hartman
2021-01-26T09:53:36Z

From: Peter Zijlstra <peterz@infradead.org>

commit 9caa7ff509add50959a793b811cc7c9339e281cd upstream.

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
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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

--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -73,10 +73,8 @@ static __always_inline void do_syscall_3
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_
* 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
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

/* 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;
}