Commit 125cfa0d authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'x86-entry-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip 

Pull x86 conversion to generic entry code from Thomas Gleixner:
 "The conversion of X86 syscall, interrupt and exception entry/exit
  handling to the generic code.

  Pretty much a straight-forward 1:1 conversion plus the consolidation
  of the KVM handling of pending work before entering guest mode"

* tag 'x86-entry-2020-08-04' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/kvm: Use __xfer_to_guest_mode_work_pending() in kvm_run_vcpu()
  x86/kvm: Use generic xfer to guest work function
  x86/entry: Cleanup idtentry_enter/exit
  x86/entry: Use generic interrupt entry/exit code
  x86/entry: Cleanup idtentry_entry/exit_user
  x86/entry: Use generic syscall exit functionality
  x86/entry: Use generic syscall entry function
  x86/ptrace: Provide pt_regs helper for entry/exit
  x86/entry: Move user return notifier out of loop
  x86/entry: Consolidate 32/64 bit syscall entry
  x86/entry: Consolidate check_user_regs()
  x86: Correct noinstr qualifiers
  x86/idtentry: Remove stale comment
parents 3f0d6ecd adb334d1

arch/x86/Kconfig

+1 −0
Original line number Diff line number Diff line
@@ -115,6 +115,7 @@ config X86 
	select GENERIC_CPU_AUTOPROBE

	select GENERIC_CPU_VULNERABILITIES

	select GENERIC_EARLY_IOREMAP

	select GENERIC_ENTRY

	select GENERIC_FIND_FIRST_BIT

	select GENERIC_IOMAP

	select GENERIC_IRQ_EFFECTIVE_AFF_MASK	if SMP

arch/x86/entry/common.c

+37 −595

File changed.

Preview size limit exceeded, changes collapsed.

arch/x86/entry/entry_32.S

+1 −1
Original line number Diff line number Diff line
@@ -846,7 +846,7 @@ SYM_CODE_START(ret_from_fork) 
2:

	/* When we fork, we trace the syscall return in the child, too. */

	movl    %esp, %eax

	call    syscall_return_slowpath

	call    syscall_exit_to_user_mode

	jmp     .Lsyscall_32_done



	/* kernel thread */

arch/x86/entry/entry_64.S

+1 −1
Original line number Diff line number Diff line
@@ -283,7 +283,7 @@ SYM_CODE_START(ret_from_fork) 
2:

	UNWIND_HINT_REGS

	movq	%rsp, %rdi

	call	syscall_return_slowpath	/* returns with IRQs disabled */

	call	syscall_exit_to_user_mode	/* returns with IRQs disabled */

	jmp	swapgs_restore_regs_and_return_to_usermode



1:

arch/x86/include/asm/entry-common.h

0 → 100644
+76 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: GPL-2.0-only */

#ifndef _ASM_X86_ENTRY_COMMON_H

#define _ASM_X86_ENTRY_COMMON_H



#include <linux/user-return-notifier.h>



#include <asm/nospec-branch.h>

#include <asm/io_bitmap.h>

#include <asm/fpu/api.h>



/* Check that the stack and regs on entry from user mode are sane. */

static __always_inline void arch_check_user_regs(struct pt_regs *regs)

{

	if (IS_ENABLED(CONFIG_DEBUG_ENTRY)) {

		/*

		 * Make sure that the entry code gave us a sensible EFLAGS

		 * register.  Native because we want to check the actual CPU

		 * state, not the interrupt state as imagined by Xen.

		 */

		unsigned long flags = native_save_fl();

		WARN_ON_ONCE(flags & (X86_EFLAGS_AC | X86_EFLAGS_DF |

				      X86_EFLAGS_NT));



		/* We think we came from user mode. Make sure pt_regs agrees. */

		WARN_ON_ONCE(!user_mode(regs));



		/*

		 * All entries from user mode (except #DF) should be on the

		 * normal thread stack and should have user pt_regs in the

		 * correct location.

		 */

		WARN_ON_ONCE(!on_thread_stack());

		WARN_ON_ONCE(regs != task_pt_regs(current));

	}

}

#define arch_check_user_regs arch_check_user_regs



#define ARCH_SYSCALL_EXIT_WORK		(_TIF_SINGLESTEP)



static inline void arch_exit_to_user_mode_prepare(struct pt_regs *regs,

						  unsigned long ti_work)

{

	if (ti_work & _TIF_USER_RETURN_NOTIFY)

		fire_user_return_notifiers();



	if (unlikely(ti_work & _TIF_IO_BITMAP))

		tss_update_io_bitmap();



	fpregs_assert_state_consistent();

	if (unlikely(ti_work & _TIF_NEED_FPU_LOAD))

		switch_fpu_return();



#ifdef CONFIG_COMPAT

	/*

	 * Compat syscalls set TS_COMPAT.  Make sure we clear it before

	 * returning to user mode.  We need to clear it *after* signal

	 * handling, because syscall restart has a fixup for compat

	 * syscalls.  The fixup is exercised by the ptrace_syscall_32

	 * selftest.

	 *

	 * We also need to clear TS_REGS_POKED_I386: the 32-bit tracer

	 * special case only applies after poking regs and before the

	 * very next return to user mode.

	 */

	current_thread_info()->status &= ~(TS_COMPAT | TS_I386_REGS_POKED);

#endif

}

#define arch_exit_to_user_mode_prepare arch_exit_to_user_mode_prepare



static __always_inline void arch_exit_to_user_mode(void)

{

	mds_user_clear_cpu_buffers();

}

#define arch_exit_to_user_mode arch_exit_to_user_mode



#endif

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