x86/syscall/64: Move 64-bit syscall dispatch code

Move the 64-bit syscall dispatch code to syscall_64.c.

No functional changes.

Signed-off-by: Brian Gerst <brgerst@gmail.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Sohil Mehta <sohil.mehta@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Link: https://lore.kernel.org/r/20250314151220.862768-4-brgerst@gmail.com

1 files changed, 0 insertions, 93 deletions

diff --git a/arch/x86/entry/common.c b/arch/x86/entry/common.c
index 183efabefe57..5bd448c0664f 100644
--- a/arch/x86/entry/common.c
+++ b/arch/x86/entry/common.c
@@ -32,99 +32,6 @@
 #include <asm/syscall.h>
 #include <asm/irq_stack.h>
 
-#ifdef CONFIG_X86_64
-
-static __always_inline bool do_syscall_x64(struct pt_regs *regs, int nr)
-{
-	/*
-	 * Convert negative numbers to very high and thus out of range
-	 * numbers for comparisons.
-	 */
-	unsigned int unr = nr;
-
-	if (likely(unr < NR_syscalls)) {
-		unr = array_index_nospec(unr, NR_syscalls);
-		regs->ax = x64_sys_call(regs, unr);
-		return true;
-	}
-	return false;
-}
-
-static __always_inline bool do_syscall_x32(struct pt_regs *regs, int nr)
-{
-	/*
-	 * Adjust the starting offset of the table, and convert numbers
-	 * < __X32_SYSCALL_BIT to very high and thus out of range
-	 * numbers for comparisons.
-	 */
-	unsigned int xnr = nr - __X32_SYSCALL_BIT;
-
-	if (IS_ENABLED(CONFIG_X86_X32_ABI) && likely(xnr < X32_NR_syscalls)) {
-		xnr = array_index_nospec(xnr, X32_NR_syscalls);
-		regs->ax = x32_sys_call(regs, xnr);
-		return true;
-	}
-	return false;
-}
-
-/* Returns true to return using SYSRET, or false to use IRET */
-__visible noinstr bool do_syscall_64(struct pt_regs *regs, int nr)
-{
-	add_random_kstack_offset();
-	nr = syscall_enter_from_user_mode(regs, nr);
-
-	instrumentation_begin();
-
-	if (!do_syscall_x64(regs, nr) && !do_syscall_x32(regs, nr) && nr != -1) {
-		/* Invalid system call, but still a system call. */
-		regs->ax = __x64_sys_ni_syscall(regs);
-	}
-
-	instrumentation_end();
-	syscall_exit_to_user_mode(regs);
-
-	/*
-	 * Check that the register state is valid for using SYSRET to exit
-	 * to userspace.  Otherwise use the slower but fully capable IRET
-	 * exit path.
-	 */
-
-	/* XEN PV guests always use the IRET path */
-	if (cpu_feature_enabled(X86_FEATURE_XENPV))
-		return false;
-
-	/* SYSRET requires RCX == RIP and R11 == EFLAGS */
-	if (unlikely(regs->cx != regs->ip || regs->r11 != regs->flags))
-		return false;
-
-	/* CS and SS must match the values set in MSR_STAR */
-	if (unlikely(regs->cs != __USER_CS || regs->ss != __USER_DS))
-		return false;
-
-	/*
-	 * On Intel CPUs, SYSRET with non-canonical RCX/RIP will #GP
-	 * in kernel space.  This essentially lets the user take over
-	 * the kernel, since userspace controls RSP.
-	 *
-	 * TASK_SIZE_MAX covers all user-accessible addresses other than
-	 * the deprecated vsyscall page.
-	 */
-	if (unlikely(regs->ip >= TASK_SIZE_MAX))
-		return false;
-
-	/*
-	 * SYSRET cannot restore RF.  It can restore TF, but unlike IRET,
-	 * restoring TF results in a trap from userspace immediately after
-	 * SYSRET.
-	 */
-	if (unlikely(regs->flags & (X86_EFLAGS_RF | X86_EFLAGS_TF)))
-		return false;
-
-	/* Use SYSRET to exit to userspace */
-	return true;
-}
-#endif
-
 SYSCALL_DEFINE0(ni_syscall)
 {
 	return -ENOSYS;