Commit 4ab13be5 authored Sep 03, 2025 by Andrew Cooper Committed by Dave Hansen Oct 13, 2025

x86/fred: Fix 64bit identifier in fred_ss



FRED can only be enabled in Long Mode.  This is the 64bit mode (as opposed to
compatibility mode) identifier, rather than being something hard-wired at 1.

No functional change.

Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Reviewed-by: Xin Li (Intel) <xin@zytor.com>
Reviewed-by: H. Peter Anvin (Intel) <hpa@zytor.com>
Acked-by: H. Peter Anvin (Intel) <hpa@zytor.com>

parent 3a866087

arch/x86/entry/entry_fred.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -78,13 +78,13 @@ static noinstr void fred_intx(struct pt_regs *regs)
		static __always_inline void fred_other(struct pt_regs *regs)
		{
		/* The compiler can fold these conditions into a single test */
		if (likely(regs->fred_ss.vector == FRED_SYSCALL && regs->fred_ss.lm)) {
		if (likely(regs->fred_ss.vector == FRED_SYSCALL && regs->fred_ss.l)) {
		regs->orig_ax = regs->ax;
		regs->ax = -ENOSYS;
		do_syscall_64(regs, regs->orig_ax);
		return;
		} else if (ia32_enabled() &&
		likely(regs->fred_ss.vector == FRED_SYSENTER && !regs->fred_ss.lm)) {
		likely(regs->fred_ss.vector == FRED_SYSENTER && !regs->fred_ss.l)) {
		regs->orig_ax = regs->ax;
		regs->ax = -ENOSYS;
		do_fast_syscall_32(regs);

arch/x86/include/asm/fred.h

+1 −1

Original line number	Diff line number	Diff line
		@@ -79,7 +79,7 @@ static __always_inline void fred_entry_from_kvm(unsigned int type, unsigned int
		.type = type,
		.vector = vector,
		.nmi = type == EVENT_TYPE_NMI,
		.lm = 1,
		.l = 1,
		};

		asm_fred_entry_from_kvm(ss);

arch/x86/include/asm/ptrace.h

+2 −2

Original line number	Diff line number	Diff line
		@@ -84,8 +84,8 @@ struct fred_ss {
		: 4,
		/* Event was incident to enclave execution */
		enclave : 1,
		/* CPU was in long mode */
		lm : 1,
		/* CPU was in 64-bit mode */
		l : 1,
		/*
		* Nested exception during FRED delivery, not set
		* for #DF.