Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::3:7 as permitted sender) client-ip=2620:137:e000::3:7;
From:   Xin Li <xin3.li@intel.com>
To:     linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-edac@vger.kernel.org, linux-hyperv@vger.kernel.org,
        kvm@vger.kernel.org, xen-devel@lists.xenproject.org
Cc:     tglx@linutronix.de, mingo@redhat.com, bp@alien8.de,
        dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com,
        luto@kernel.org, pbonzini@redhat.com, seanjc@google.com,
        peterz@infradead.org, jgross@suse.com, ravi.v.shankar@intel.com,
        mhiramat@kernel.org, andrew.cooper3@citrix.com,
        jiangshanlai@gmail.com, nik.borisov@suse.com
Subject: [PATCH v12 30/37] x86/fred: Let ret_from_fork_asm() jmp to asm_fred_exit_user when FRED is enabled
Date:   Mon,  2 Oct 2023 23:24:51 -0700
Message-Id: <20231003062458.23552-31-xin3.li@intel.com>
In-Reply-To: <20231003062458.23552-1-xin3.li@intel.com>
References: <20231003062458.23552-1-xin3.li@intel.com>
MIME-Version: 1.0
Content-Transfer-Encoding: 8bit
Precedence: bulk

From: "H. Peter Anvin (Intel)" <hpa@zytor.com>

Let ret_from_fork_asm() jmp to asm_fred_exit_user when FRED is enabled,
otherwise the existing IDT code is chosen.

Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Tested-by: Shan Kang <shan.kang@intel.com>
Signed-off-by: Xin Li <xin3.li@intel.com>
---
 arch/x86/entry/entry_64.S      | 6 ++++++
 arch/x86/entry/entry_64_fred.S | 1 +
 2 files changed, 7 insertions(+)

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index aa4214703091..7f408deef00f 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -309,7 +309,13 @@ SYM_CODE_START(ret_from_fork_asm)
 	 * and unwind should work normally.
 	 */
 	UNWIND_HINT_REGS
+
+#ifdef CONFIG_X86_FRED
+	ALTERNATIVE "jmp swapgs_restore_regs_and_return_to_usermode", \
+		    "jmp asm_fred_exit_user", X86_FEATURE_FRED
+#else
 	jmp	swapgs_restore_regs_and_return_to_usermode
+#endif
 SYM_CODE_END(ret_from_fork_asm)
 .popsection
 
diff --git a/arch/x86/entry/entry_64_fred.S b/arch/x86/entry/entry_64_fred.S
index 37a1dd5e8ace..5781c3411b44 100644
--- a/arch/x86/entry/entry_64_fred.S
+++ b/arch/x86/entry/entry_64_fred.S
@@ -32,6 +32,7 @@
 SYM_CODE_START_NOALIGN(asm_fred_entrypoint_user)
 	FRED_ENTER
 	call	fred_entry_from_user
+SYM_INNER_LABEL(asm_fred_exit_user, SYM_L_GLOBAL)
 	FRED_EXIT
 	ERETU
 SYM_CODE_END(asm_fred_entrypoint_user)
-- 
2.34.1