From: Francis Laniel <flaniel@linux.microsoft.com>
Date: Wed, 8 Jun 2022 17:24:46 +0100
Subject: arm64: Do not forget syscall when starting a new thread.
Git-commit: de6921856f99c11d3986c6702d851e1328d4f7f6
Patch-mainline: v6.0-rc1
References: git-fixes

Enable tracing of the execve*() system calls with the
syscalls:sys_exit_execve tracepoint by removing the call to
forget_syscall() when starting a new thread and preserving the value of
regs->syscallno across exec.

Signed-off-by: Francis Laniel <flaniel@linux.microsoft.com>
Link: https://lore.kernel.org/r/20220608162447.666494-2-flaniel@linux.microsoft.com
Signed-off-by: Will Deacon <will@kernel.org>
Acked-by: Ivan T. Ivanov <iivanov@suse.de>
---
 arch/arm64/include/asm/processor.h |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -145,8 +145,9 @@ struct thread_struct {
 
 static inline void start_thread_common(struct pt_regs *regs, unsigned long pc)
 {
+	s32 previous_syscall = regs->syscallno;
 	memset(regs, 0, sizeof(*regs));
-	forget_syscall(regs);
+	regs->syscallno = previous_syscall;
 	regs->pc = pc;
 }