Commit 91eeafea authored by Thomas Gleixner's avatar Thomas Gleixner
Browse files

x86/entry: Switch page fault exception to IDTENTRY_RAW 



Convert page fault exceptions to IDTENTRY_RAW:

  - Implement the C entry point with DEFINE_IDTENTRY_RAW
  - Add the CR2 read into the exception handler
  - Add the idtentry_enter/exit_cond_rcu() invocations in
    in the regular page fault handler and in the async PF
    part.
  - Emit the ASM stub with DECLARE_IDTENTRY_RAW
  - Remove the ASM idtentry in 64-bit
  - Remove the CR2 read from 64-bit
  - Remove the open coded ASM entry code in 32-bit
  - Fix up the XEN/PV code
  - Remove the old prototypes

No functional change.

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/20200521202118.238455120@linutronix.de
parent 00cf8baf

arch/x86/entry/entry_32.S

+0 −30
Original line number Diff line number Diff line
@@ -1398,36 +1398,6 @@ BUILD_INTERRUPT3(hv_stimer0_callback_vector, HYPERV_STIMER0_VECTOR, 


#endif /* CONFIG_HYPERV */



SYM_CODE_START(page_fault)

	ASM_CLAC

	pushl	$do_page_fault

	jmp	common_exception_read_cr2

SYM_CODE_END(page_fault)



SYM_CODE_START_LOCAL_NOALIGN(common_exception_read_cr2)

	/* the function address is in %gs's slot on the stack */

	SAVE_ALL switch_stacks=1 skip_gs=1 unwind_espfix=1



	ENCODE_FRAME_POINTER



	/* fixup %gs */

	GS_TO_REG %ecx

	movl	PT_GS(%esp), %edi

	REG_TO_PTGS %ecx

	SET_KERNEL_GS %ecx



	GET_CR2_INTO(%ecx)			# might clobber %eax



	/* fixup orig %eax */

	movl	PT_ORIG_EAX(%esp), %edx		# get the error code

	movl	$-1, PT_ORIG_EAX(%esp)		# no syscall to restart



	TRACE_IRQS_OFF

	movl	%esp, %eax			# pt_regs pointer

	CALL_NOSPEC edi

	jmp	ret_from_exception

SYM_CODE_END(common_exception_read_cr2)



SYM_CODE_START_LOCAL_NOALIGN(common_exception)

	/* the function address is in %gs's slot on the stack */

	SAVE_ALL switch_stacks=1 skip_gs=1 unwind_espfix=1

arch/x86/entry/entry_64.S

+0 −19
Original line number Diff line number Diff line
@@ -506,15 +506,6 @@ SYM_CODE_END(spurious_entries_start) 
	call	error_entry

	UNWIND_HINT_REGS



	.if \vector == X86_TRAP_PF

		/*

		 * Store CR2 early so subsequent faults cannot clobber it. Use R12 as

		 * intermediate storage as RDX can be clobbered in enter_from_user_mode().

		 * GET_CR2_INTO can clobber RAX.

		 */

		GET_CR2_INTO(%r12);

	.endif



	.if \sane == 0

	TRACE_IRQS_OFF
@@ -533,10 +524,6 @@ SYM_CODE_END(spurious_entries_start) 
		movq	$-1, ORIG_RAX(%rsp)	/* no syscall to restart */

	.endif



	.if \vector == X86_TRAP_PF

		movq	%r12, %rdx		/* Move CR2 into 3rd argument */

	.endif



	call	\cfunc



	.if \sane == 0
@@ -1059,12 +1046,6 @@ apicinterrupt SPURIOUS_APIC_VECTOR spurious_interrupt smp_spurious_interrupt 
apicinterrupt IRQ_WORK_VECTOR			irq_work_interrupt		smp_irq_work_interrupt

#endif



/*

 * Exception entry points.

 */



idtentry	X86_TRAP_PF		page_fault		do_page_fault			has_error_code=1



/*

 * Reload gs selector with exception handling

 * edi:  new selector

arch/x86/include/asm/idtentry.h

+2 −1
Original line number Diff line number Diff line
@@ -388,6 +388,7 @@ DECLARE_IDTENTRY_ERRORCODE(X86_TRAP_AC, exc_alignment_check); 


/* Raw exception entries which need extra work */

DECLARE_IDTENTRY_RAW(X86_TRAP_BP,		exc_int3);

DECLARE_IDTENTRY_RAW_ERRORCODE(X86_TRAP_PF,	exc_page_fault);



#ifdef CONFIG_X86_MCE

DECLARE_IDTENTRY_MCE(X86_TRAP_MC,	exc_machine_check);

arch/x86/include/asm/traps.h

+0 −11
Original line number Diff line number Diff line
@@ -9,17 +9,6 @@ 
#include <asm/idtentry.h>

#include <asm/siginfo.h>			/* TRAP_TRACE, ... */



#define dotraplinkage __visible



asmlinkage void page_fault(void);

asmlinkage void async_page_fault(void);



#if defined(CONFIG_X86_64) && defined(CONFIG_XEN_PV)

asmlinkage void xen_page_fault(void);

#endif



dotraplinkage void do_page_fault(struct pt_regs *regs, unsigned long error_code, unsigned long address);



#ifdef CONFIG_X86_64

asmlinkage __visible notrace struct pt_regs *sync_regs(struct pt_regs *eregs);

asmlinkage __visible notrace

arch/x86/kernel/idt.c

+2 −2
Original line number Diff line number Diff line
@@ -62,7 +62,7 @@ static const __initconst struct idt_data early_idts[] = { 
	INTG(X86_TRAP_DB,		asm_exc_debug),

	SYSG(X86_TRAP_BP,		asm_exc_int3),

#ifdef CONFIG_X86_32

	INTG(X86_TRAP_PF,		page_fault),

	INTG(X86_TRAP_PF,		asm_exc_page_fault),

#endif

};
@@ -156,7 +156,7 @@ static const __initconst struct idt_data apic_idts[] = { 
 * stacks work only after cpu_init().

 */

static const __initconst struct idt_data early_pf_idts[] = {

	INTG(X86_TRAP_PF,		page_fault),

	INTG(X86_TRAP_PF,		asm_exc_page_fault),

};



/*

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