x86/entry: Convert Coprocessor segment overrun exception to IDTENTRY

Convert #OLD_MF to IDTENTRY:
  - Implement the C entry point with DEFINE_IDTENTRY
  - Emit the ASM stub with DECLARE_IDTENTRY
  - Remove the ASM idtentry in 64bit
  - Remove the open coded ASM entry code in 32bit
  - Fixup the XEN/PV code
  - Remove the old prototypes

No functional change.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexandre Chartre <alexandre.chartre@oracle.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20200505134905.838823510@linutronix.de

arch/x86/entry/entry_32.S

@@ -1318,13 +1318,6 @@ SYM_CODE_START(native_iret)
 SYM_CODE_END(native_iret)
 #endif
 
-SYM_CODE_START(coprocessor_segment_overrun)
-	ASM_CLAC
-	pushl	$0
-	pushl	$do_coprocessor_segment_overrun
-	jmp	common_exception
-SYM_CODE_END(coprocessor_segment_overrun)
-
 SYM_CODE_START(invalid_TSS)
 	ASM_CLAC
 	pushl	$do_invalid_TSS

arch/x86/entry/entry_64.S

@@ -1073,7 +1073,6 @@ apicinterrupt IRQ_WORK_VECTOR			irq_work_interrupt		smp_irq_work_interrupt
  */
 
 idtentry	X86_TRAP_BP		int3			do_int3				has_error_code=0
-idtentry	X86_TRAP_OLD_MF		coprocessor_segment_overrun	do_coprocessor_segment_overrun	has_error_code=0
 idtentry	X86_TRAP_TS		invalid_TSS		do_invalid_TSS			has_error_code=1
 idtentry	X86_TRAP_NP		segment_not_present	do_segment_not_present		has_error_code=1
 idtentry	X86_TRAP_SS		stack_segment		do_stack_segment		has_error_code=1

arch/x86/include/asm/idtentry.h

@@ -82,5 +82,6 @@ DECLARE_IDTENTRY(X86_TRAP_OF,		exc_overflow);
 DECLARE_IDTENTRY(X86_TRAP_BR,		exc_bounds);
 DECLARE_IDTENTRY(X86_TRAP_UD,		exc_invalid_op);
 DECLARE_IDTENTRY(X86_TRAP_NM,		exc_device_not_available);
+DECLARE_IDTENTRY(X86_TRAP_OLD_MF,	exc_coproc_segment_overrun);
 
 #endif

arch/x86/include/asm/traps.h

@@ -17,7 +17,6 @@ asmlinkage void int3(void);
 #ifdef CONFIG_X86_64
 asmlinkage void double_fault(void);
 #endif
-asmlinkage void coprocessor_segment_overrun(void);
 asmlinkage void invalid_TSS(void);
 asmlinkage void segment_not_present(void);
 asmlinkage void stack_segment(void);
@@ -37,7 +36,6 @@ asmlinkage void xen_xennmi(void);
 asmlinkage void xen_xendebug(void);
 asmlinkage void xen_int3(void);
 asmlinkage void xen_double_fault(void);
-asmlinkage void xen_coprocessor_segment_overrun(void);
 asmlinkage void xen_invalid_TSS(void);
 asmlinkage void xen_segment_not_present(void);
 asmlinkage void xen_stack_segment(void);
@@ -56,7 +54,6 @@ dotraplinkage void do_debug(struct pt_regs *regs, long error_code);
 dotraplinkage void do_nmi(struct pt_regs *regs, long error_code);
 dotraplinkage void do_int3(struct pt_regs *regs, long error_code);
 dotraplinkage void do_double_fault(struct pt_regs *regs, long error_code, unsigned long cr2);
-dotraplinkage void do_coprocessor_segment_overrun(struct pt_regs *regs, long error_code);
 dotraplinkage void do_invalid_TSS(struct pt_regs *regs, long error_code);
 dotraplinkage void do_segment_not_present(struct pt_regs *regs, long error_code);
 dotraplinkage void do_stack_segment(struct pt_regs *regs, long error_code);

arch/x86/kernel/idt.c

@@ -78,7 +78,7 @@ static const __initconst struct idt_data def_idts[] = {
 	INTG(X86_TRAP_BR,		asm_exc_bounds),
 	INTG(X86_TRAP_UD,		asm_exc_invalid_op),
 	INTG(X86_TRAP_NM,		asm_exc_device_not_available),
-	INTG(X86_TRAP_OLD_MF,		coprocessor_segment_overrun),
+	INTG(X86_TRAP_OLD_MF,		asm_exc_coproc_segment_overrun),
 	INTG(X86_TRAP_TS,		invalid_TSS),
 	INTG(X86_TRAP_NP,		segment_not_present),
 	INTG(X86_TRAP_SS,		stack_segment),

arch/x86/kernel/traps.c

@@ -246,6 +246,12 @@ DEFINE_IDTENTRY(exc_invalid_op)
 	handle_invalid_op(regs);
 }
 
+DEFINE_IDTENTRY(exc_coproc_segment_overrun)
+{
+	do_error_trap(regs, 0, "coprocessor segment overrun",
+		      X86_TRAP_OLD_MF, SIGFPE, 0, NULL);
+}
+
 #define IP ((void __user *)uprobe_get_trap_addr(regs))
 #define DO_ERROR(trapnr, signr, sicode, addr, str, name)		   \
 dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	   \
@@ -253,7 +259,6 @@ dotraplinkage void do_##name(struct pt_regs *regs, long error_code)	   \
 	do_error_trap(regs, error_code, str, trapnr, signr, sicode, addr); \
 }
 
-DO_ERROR(X86_TRAP_OLD_MF, SIGFPE,           0, NULL, "coprocessor segment overrun", coprocessor_segment_overrun)
 DO_ERROR(X86_TRAP_TS,     SIGSEGV,          0, NULL, "invalid TSS",         invalid_TSS)
 DO_ERROR(X86_TRAP_NP,     SIGBUS,           0, NULL, "segment not present", segment_not_present)
 DO_ERROR(X86_TRAP_SS,     SIGBUS,           0, NULL, "stack segment",       stack_segment)

arch/x86/xen/enlighten_pv.c

@@ -626,7 +626,7 @@ static struct trap_array_entry trap_array[] = {
 	TRAP_ENTRY(exc_bounds,				false ),
 	TRAP_ENTRY(exc_invalid_op,			false ),
 	TRAP_ENTRY(exc_device_not_available,		false ),
-	{ coprocessor_segment_overrun, xen_coprocessor_segment_overrun, false },
+	TRAP_ENTRY(exc_coproc_segment_overrun,		false ),
 	{ invalid_TSS,                 xen_invalid_TSS,                 false },
 	{ segment_not_present,         xen_segment_not_present,         false },
 	{ stack_segment,               xen_stack_segment,               false },

arch/x86/xen/xen-asm_64.S

@@ -38,7 +38,7 @@ xen_pv_trap asm_exc_bounds
 xen_pv_trap asm_exc_invalid_op
 xen_pv_trap asm_exc_device_not_available
 xen_pv_trap double_fault
-xen_pv_trap coprocessor_segment_overrun
+xen_pv_trap asm_exc_coproc_segment_overrun
 xen_pv_trap invalid_TSS
 xen_pv_trap segment_not_present
 xen_pv_trap stack_segment