diff mbox series

[v4,24/34] x86/fred: let ret_from_fork() jmp to fred_exit_user when FRED is enabled

Message ID 20230302052511.1918-25-xin3.li@intel.com
State New
Headers
Series x86: enable FRED for x86-64 |

Commit Message

Li, Xin3 March 2, 2023, 5:25 a.m. UTC 
  From: "H. Peter Anvin (Intel)" <hpa@zytor.com>

Let ret_from_fork() jmp to 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 | 5 +++++
 1 file changed, 5 insertions(+)
diff mbox series

Patch

diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S
index 7ecd2aeeeffc..7ffd20578b8c 100644
--- a/arch/x86/entry/entry_64.S
+++ b/arch/x86/entry/entry_64.S
@@ -299,7 +299,12 @@  SYM_CODE_START_NOALIGN(ret_from_fork)
 	UNWIND_HINT_REGS
 	movq	%rsp, %rdi
 	call	syscall_exit_to_user_mode	/* returns with IRQs disabled */
+#ifdef CONFIG_X86_FRED
+	ALTERNATIVE "jmp swapgs_restore_regs_and_return_to_usermode", \
+		    "jmp fred_exit_user", X86_FEATURE_FRED
+#else
 	jmp	swapgs_restore_regs_and_return_to_usermode
+#endif
 
 1:
 	/* kernel thread */