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From:   Sasha Levin <sashal@kernel.org>
To:     linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc:     Francis Laniel <flaniel@linux.microsoft.com>,
        Will Deacon <will@kernel.org>, Sasha Levin <sashal@kernel.org>,
        catalin.marinas@arm.com, broonie@kernel.org, keescook@chromium.org,
        christophe.leroy@csgroup.eu, mark.rutland@arm.com,
        linux-arm-kernel@lists.infradead.org
Subject: [PATCH AUTOSEL 5.19 08/58] arm64: Do not forget syscall when starting a new thread.
Date:   Sun,  7 Aug 2022 21:30:26 -0400
Message-Id: <20220808013118.313965-8-sashal@kernel.org>
In-Reply-To: <20220808013118.313965-1-sashal@kernel.org>
References: <20220808013118.313965-1-sashal@kernel.org>
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From: Francis Laniel <flaniel@linux.microsoft.com>

[ Upstream commit de6921856f99c11d3986c6702d851e1328d4f7f6 ]

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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 arch/arm64/include/asm/processor.h | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/include/asm/processor.h b/arch/arm64/include/asm/processor.h
index 9e58749db21d..86eb0bfe3b38 100644
--- a/arch/arm64/include/asm/processor.h
+++ b/arch/arm64/include/asm/processor.h
@@ -272,8 +272,9 @@ void tls_preserve_current_state(void);
 
 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;
 
 	if (system_uses_irq_prio_masking())
-- 
2.35.1