Commit 51ef2a4d authored Dec 05, 2023 by H. Peter Anvin (Intel) Committed by Borislav Petkov (AMD) Jan 31, 2024

x86/fred: Let ret_from_fork_asm() jmp to asm_fred_exit_user when FRED is enabled



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>
Signed-off-by: Xin Li <xin3.li@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Shan Kang <shan.kang@intel.com>
Link: https://lore.kernel.org/r/20231205105030.8698-29-xin3.li@intel.com

parent 8f4a29b0

arch/x86/entry/entry_64.S

+6 −0

Original line number	Diff line number	Diff line
		@@ -247,7 +247,13 @@ 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

arch/x86/entry/entry_64_fred.S

+1 −0

Original line number	Diff line number	Diff line
		@@ -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)