Commit 3ffdfdce authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/entry: Move paranoid irq tracing out of ASM code 



The last step to remove the irq tracing cruft from ASM. Ignore #DF as the
maschine is going to die anyway.

Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
Acked-by: default avatarAndy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/20200521202120.414043330@linutronix.de
parent 9628f26b

arch/x86/entry/entry_64.S

+0 −13
Original line number Diff line number Diff line
@@ -16,7 +16,6 @@ 
 *

 * Some macro usage:

 * - SYM_FUNC_START/END:Define functions in the symbol table.

 * - TRACE_IRQ_*:	Trace hardirq state for lock debugging.

 * - idtentry:		Define exception entry points.

 */

#include <linux/linkage.h>
@@ -107,11 +106,6 @@ SYM_CODE_END(native_usergs_sysret64) 


SYM_CODE_START(entry_SYSCALL_64)

	UNWIND_HINT_EMPTY

	/*

	 * Interrupts are off on entry.

	 * We do not frame this tiny irq-off block with TRACE_IRQS_OFF/ON,

	 * it is too small to ever cause noticeable irq latency.

	 */



	swapgs

	/* tss.sp2 is scratch space. */
@@ -462,8 +456,6 @@ SYM_CODE_START(\asmsym) 


	UNWIND_HINT_REGS



	TRACE_IRQS_OFF



	movq	%rsp, %rdi		/* pt_regs pointer */



	.if \vector == X86_TRAP_DB
@@ -881,17 +873,13 @@ SYM_CODE_END(paranoid_entry) 
 */

SYM_CODE_START_LOCAL(paranoid_exit)

	UNWIND_HINT_REGS

	DISABLE_INTERRUPTS(CLBR_ANY)

	TRACE_IRQS_OFF

	testl	%ebx, %ebx			/* swapgs needed? */

	jnz	.Lparanoid_exit_no_swapgs

	TRACE_IRQS_IRETQ

	/* Always restore stashed CR3 value (see paranoid_entry) */

	RESTORE_CR3	scratch_reg=%rbx save_reg=%r14

	SWAPGS_UNSAFE_STACK

	jmp	restore_regs_and_return_to_kernel

.Lparanoid_exit_no_swapgs:

	TRACE_IRQS_IRETQ

	/* Always restore stashed CR3 value (see paranoid_entry) */

	RESTORE_CR3	scratch_reg=%rbx save_reg=%r14

	jmp restore_regs_and_return_to_kernel
@@ -1292,7 +1280,6 @@ end_repeat_nmi: 
	call	paranoid_entry

	UNWIND_HINT_REGS



	/* paranoidentry exc_nmi(), 0; without TRACE_IRQS_OFF */

	movq	%rsp, %rdi

	movq	$-1, %rsi

	call	exc_nmi

arch/x86/kernel/cpu/mce/core.c

+3 −0
Original line number Diff line number Diff line
@@ -1922,7 +1922,10 @@ static __always_inline void exc_machine_check_kernel(struct pt_regs *regs) 
	 * that out because it's an indirect call. Annotate it.

	 */

	instrumentation_begin();

	trace_hardirqs_off_prepare();

	machine_check_vector(regs);

	if (regs->flags & X86_EFLAGS_IF)

		trace_hardirqs_on_prepare();

	instrumentation_end();

	nmi_exit();

}

arch/x86/kernel/nmi.c

+3 −0
Original line number Diff line number Diff line
@@ -330,6 +330,7 @@ static noinstr void default_do_nmi(struct pt_regs *regs) 
	__this_cpu_write(last_nmi_rip, regs->ip);



	instrumentation_begin();

	trace_hardirqs_off_prepare();



	handled = nmi_handle(NMI_LOCAL, regs);

	__this_cpu_add(nmi_stats.normal, handled);
@@ -416,6 +417,8 @@ static noinstr void default_do_nmi(struct pt_regs *regs) 
		unknown_nmi_error(reason, regs);



out:

	if (regs->flags & X86_EFLAGS_IF)

		trace_hardirqs_on_prepare();

	instrumentation_end();

}

arch/x86/kernel/traps.c

+11 −0
Original line number Diff line number Diff line
@@ -634,8 +634,11 @@ DEFINE_IDTENTRY_RAW(exc_int3) 
	} else {

		nmi_enter();

		instrumentation_begin();

		trace_hardirqs_off_prepare();

		if (!do_int3(regs))

			die("int3", regs, 0);

		if (regs->flags & X86_EFLAGS_IF)

			trace_hardirqs_on_prepare();

		instrumentation_end();

		nmi_exit();

	}
@@ -850,6 +853,10 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, 
					     unsigned long dr6)

{

	nmi_enter();

	instrumentation_begin();

	trace_hardirqs_off_prepare();

	instrumentation_end();



	/*

	 * The SDM says "The processor clears the BTF flag when it

	 * generates a debug exception."  Clear TIF_BLOCKSTEP to keep
@@ -871,6 +878,10 @@ static __always_inline void exc_debug_kernel(struct pt_regs *regs, 
	if (dr6)

		handle_debug(regs, dr6, false);



	instrumentation_begin();

	if (regs->flags & X86_EFLAGS_IF)

		trace_hardirqs_on_prepare();

	instrumentation_end();

	nmi_exit();

}