path: root/arch/powerpc/kernel/entry_64.S

/*
 *  PowerPC version 
 *    Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
 *  Rewritten by Cort Dougan (cort@cs.nmt.edu) for PReP
 *    Copyright (C) 1996 Cort Dougan <cort@cs.nmt.edu>
 *  Adapted for Power Macintosh by Paul Mackerras.
 *  Low-level exception handlers and MMU support
 *  rewritten by Paul Mackerras.
 *    Copyright (C) 1996 Paul Mackerras.
 *  MPC8xx modifications Copyright (C) 1997 Dan Malek (dmalek@jlc.net).
 *
 *  This file contains the system call entry code, context switch
 *  code, and exception/interrupt return code for PowerPC.
 *
 *  This program is free software; you can redistribute it and/or
 *  modify it under the terms of the GNU General Public License
 *  as published by the Free Software Foundation; either version
 *  2 of the License, or (at your option) any later version.
 */

#include <linux/errno.h>
#include <asm/unistd.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/thread_info.h>
#include <asm/ppc_asm.h>
#include <asm/asm-offsets.h>
#include <asm/cputable.h>
#include <asm/firmware.h>
#include <asm/bug.h>
#include <asm/ptrace.h>
#include <asm/irqflags.h>
#include <asm/ftrace.h>

/*
 * System calls.
 */
	.section	".toc","aw"
.SYS_CALL_TABLE:
	.tc .sys_call_table[TC],.sys_call_table

/* This value is used to mark exception frames on the stack. */
exception_marker:
	.tc	ID_EXC_MARKER[TC],STACK_FRAME_REGS_MARKER

	.section	".text"
	.align 7

#undef SHOW_SYSCALLS

	.globl system_call_common
system_call_common:
	andi.	r10,r12,MSR_PR
	mr	r10,r1
	addi	r1,r1,-INT_FRAME_SIZE
	beq-	1f
	ld	r1,PACAKSAVE(r13)
1:	std	r10,0(r1)
	std	r11,_NIP(r1)
	std	r12,_MSR(r1)
	std	r0,GPR0(r1)
	std	r10,GPR1(r1)
	ACCOUNT_CPU_USER_ENTRY(r10, r11)
	/*
	 * This "crclr so" clears CR0.SO, which is the error indication on
	 * return from this system call.  There must be no cmp instruction
	 * between it and the "mfcr r9" below, otherwise if XER.SO is set,
	 * CR0.SO will get set, causing all system calls to appear to fail.
	 */
	crclr	so
	std	r2,GPR2(r1)
	std	r3,GPR3(r1)
	std	r4,GPR4(r1)
	std	r5,GPR5(r1)
	std	r6,GPR6(r1)
	std	r7,GPR7(r1)
	std	r8,GPR8(r1)
	li	r11,0
	std	r11,GPR9(r1)
	std	r11,GPR10(r1)
	std	r11,GPR11(r1)
	std	r11,GPR12(r1)
	std	r9,GPR13(r1)
	mfcr	r9
	mflr	r10
	li	r11,0xc01
	std	r9,_CCR(r1)
	std	r10,_LINK(r1)
	std	r11,_TRAP(r1)
	mfxer	r9
	mfctr	r10
	std	r9,_XER(r1)
	std	r10,_CTR(r1)
	std	r3,ORIG_GPR3(r1)
	ld	r2,PACATOC(r13)
	addi	r9,r1,STACK_FRAME_OVERHEAD
	ld	r11,exception_marker@toc(r2)
	std	r11,-16(r9)		/* "regshere" marker */
#ifdef CONFIG_TRACE_IRQFLAGS
	bl	.trace_hardirqs_on
	REST_GPR(0,r1)
	REST_4GPRS(3,r1)
	REST_2GPRS(7,r1)
	addi	r9,r1,STACK_FRAME_OVERHEAD
	ld	r12,_MSR(r1)
#endif /* CONFIG_TRACE_IRQFLAGS */
	li	r10,1
	stb	r10,PACASOFTIRQEN(r13)
	stb	r10,PACAHARDIRQEN(r13)
	std	r10,SOFTE(r1)
#ifdef CONFIG_PPC_ISERIES
BEGIN_FW_FTR_SECTION
	/* Hack for handling interrupts when soft-enabling on iSeries */
	cmpdi	cr1,r0,0x5555		/* syscall 0x5555 */
	andi.	r10,r12,MSR_PR		/* from kernel */
	crand	4*cr0+eq,4*cr1+eq,4*cr0+eq
	bne	2f
	b	hardware_interrupt_entry
2:
END_FW_FTR_SECTION_IFSET(FW_FEATURE_ISERIES)
#endif /* CONFIG_PPC_ISERIES */
	mfmsr	r11
	ori	r11,r11,MSR_EE
	mtmsrd	r11,1

#ifdef SHOW_SYSCALLS
	bl	.do_show_syscall
	REST_GPR(0,r1)
	REST_4GPRS(3,r1)
	REST_2GPRS(7,r1)
	addi	r9,r1,STACK_FRAME_OVERHEAD
#endif
	clrrdi	r11,r1,THREAD_SHIFT
	ld	r10,TI_FLAGS(r11)
	andi.	r11,r10,_TIF_SYSCALL_T_OR_A
	bne-	syscall_dotrace
syscall_dotrace_cont:
	cmpldi	0,r0,NR_syscalls
	bge-	syscall_enosys

system_call:			/* label this so stack traces look sane */
/*
 * Need to vector to 32 Bit or default sys_call_table here,
 * based on caller's run-mode / personality.
 */
	ld	r11,.SYS_CALL_TABLE@toc(2)
	andi.	r10,r10,_TIF_32BIT
	beq	15f
	addi	r11,r11,8	/* use 32-bit syscall entries */
	clrldi	r3,r3,32
	clrldi	r4,r4,32
	clrldi	r5,r5,32
	clrldi	r6,r6,32
	clrldi	r7,r7,32
	clrldi	r8,r8,32
15:
	slwi	r0,r0,4
	ldx	r10,r11,r0	/* Fetch system call handler [ptr] */
	mtctr   r10
	bctrl			/* Call handler */

syscall_exit:
	std	r3,RESULT(r1)