/* SPDX-License-Identifier: GPL-2.0-or-later */
/*
* OpenRISC entry.S
*
* Linux architectural port borrowing liberally from similar works of
* others. All original copyrights apply as per the original source
* declaration.
*
* Modifications for the OpenRISC architecture:
* Copyright (C) 2003 Matjaz Breskvar <phoenix@bsemi.com>
* Copyright (C) 2005 Gyorgy Jeney <nog@bsemi.com>
* Copyright (C) 2010-2011 Jonas Bonn <jonas@southpole.se>
*/
#include <linux/linkage.h>
#include <asm/processor.h>
#include <asm/unistd.h>
#include <asm/thread_info.h>
#include <asm/errno.h>
#include <asm/spr_defs.h>
#include <asm/page.h>
#include <asm/mmu.h>
#include <asm/pgtable.h>
#include <asm/asm-offsets.h>
#define DISABLE_INTERRUPTS(t1,t2) \
l.mfspr t2,r0,SPR_SR ;\
l.movhi t1,hi(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
l.ori t1,t1,lo(~(SPR_SR_IEE|SPR_SR_TEE)) ;\
l.and t2,t2,t1 ;\
l.mtspr r0,t2,SPR_SR
#define ENABLE_INTERRUPTS(t1) \
l.mfspr t1,r0,SPR_SR ;\
l.ori t1,t1,lo(SPR_SR_IEE|SPR_SR_TEE) ;\
l.mtspr r0,t1,SPR_SR
/* =========================================================[ macros ]=== */
#ifdef CONFIG_TRACE_IRQFLAGS
/*
* Trace irq on/off creating a stack frame.
*/
#define TRACE_IRQS_OP(trace_op) \
l.sw -8(r1),r2 /* store frame pointer */ ;\
l.sw -4(r1),r9 /* store return address */ ;\
l.addi r2,r1,0 /* move sp to fp */ ;\
l.jal trace_op ;\
l.addi r1,r1,-8 ;\
l.ori r1,r2,0 /* restore sp */ ;\
l.lwz r9,-4(r1) /* restore return address */ ;\
l.lwz r2,-8(r1) /* restore fp */ ;\
/*
* Trace irq on/off and save registers we need that would otherwise be
* clobbered.
*/
#define TRACE_IRQS_SAVE(t1,trace_op) \
l.sw -12(r1),t1 /* save extra reg */ ;\
l.sw -8(r1),r2 /* store frame pointer */ ;\
l.sw -4(r1),r9 /* store return address */ ;\
l.addi r2,r1,0 /* move sp to fp */ ;\
l.jal trace_op ;\
l.addi r1,r1,-12 ;\
l.ori r1,r2,0 /* restore sp */ ;\
l.lwz r9,-4(r1) /* restore return address */ ;\
l.lwz r2,-8(r1) /* restore fp */ ;\
l.lwz t1,-12(r1) /* restore extra reg */
#define TRACE_IRQS_OFF TRACE_IRQS_OP(trace_hardirqs_off)
#define TRACE_IRQS_ON TRACE_IRQS_OP(trace_hardirqs_on)
#define TRACE_IRQS_ON_SYSCALL \
TRACE_IRQS_SAVE(r10,trace_hardirqs_on) ;\
l.lwz r3,PT_GPR3(r1) ;\
l.lwz r4,PT_GPR4(r1) ;\
l.lwz r5,PT_GPR5(r1) ;\
l.lwz r6,PT_GPR6(r1) ;\
l.lwz r7,PT_GPR7(r1) ;\
l.lwz r8,PT_GPR8(r1) ;\
l.lwz r11,PT_GPR11(r1)
#define TRACE_IRQS_OFF_ENTRY \
l.lwz r5,PT_SR(r1) ;\
l.andi r3,r5,(SPR_SR_IEE|SPR_SR_TEE) ;\
l.sfeq r5,r0 /* skip trace if irqs were already off */;\
l.bf 1f ;\
l.nop ;\
TRACE_IRQS_SAVE(r4,trace_hardirqs_off) ;\
1:
#else
#define TRACE_IRQS_OFF
#define TRACE_IRQS_ON
#define TRACE_IRQS_OFF_ENTRY
#define TRACE_IRQS_ON_SYSCALL
#endif
/*
* We need to disable interrupts at beginning of RESTORE_ALL
* since interrupt might come in after we've loaded EPC return address
* and overwrite EPC with address somewhere in RESTORE_ALL
* which is of course wrong!
*/
#define RESTORE_ALL \
DISABLE_INTERRUPTS(r3,r4) ;\
l.lwz r3,PT_PC(r1) ;\
l.mtspr r0,r3,SPR_EPCR_BASE ;\
l.lwz r3,PT_SR(r1) ;\
l.mtspr r0,r3,SPR_ESR_BASE ;\
l.lwz r2,PT_GPR2(r1) ;\
l.lwz r3,PT_GPR3(r1) ;\
l.lwz r4,PT_GPR4(r1) ;\
l.lwz r5,PT_GPR5(r1) ;\
l.lwz r6,PT_GPR6(r1) ;\
l.lwz r7,PT_GPR7(r1) ;\
l.lwz r8,PT_GPR8(r1) ;\
l.lwz r9,PT_GPR9(r1) ;\
l.lwz r10,PT_GPR10(r1) ;\
l.lwz r11,PT_GPR11(r1) ;\
l.lwz r12,PT_GPR12(r1) ;\
l.lwz r13,PT_GPR13(r1) ;\
l.lwz r14,PT_GPR14(r1) ;\
l.lwz r15,PT_GPR15(r1) ;\
l.lwz r16,PT_GPR16(r1) ;\
l.lwz r17,PT_GPR17(r1) ;\
l.lwz r18,PT_GPR18(r1) ;\
l.lwz r19,PT_GPR19(r1) ;\
l.lwz r20,PT_GPR20(r1) ;\
l.lwz r21,PT_GPR21(r1) ;\
l.lwz r22,PT_GPR22(r1) ;\
l.lwz r23,PT_GPR23(r1) ;\
l.lwz r24,PT_GPR24(r1) ;\
l.lwz r25,PT_GPR25(r1) ;\
l.lwz r26,PT_GPR26(r1) ;\
l.lwz r27,PT_GPR27(r1) ;\
l.lwz r28,PT_GPR28(r1) ;\
l.lwz r29,PT_GPR29(r1) ;\
l.lwz r30,PT_GPR30(r1) ;\
l.lwz r31,PT_GPR31(r1) ;\
l.lwz r1,PT_SP(r1) ;\
l.rfe
#define EXCEPTION_ENTRY(handler) \
.global handler ;\
handler: ;\
/* r1, EPCR, ESR a already saved */ ;\
l.sw PT_GPR2(r1),r2 ;\
l.sw PT_GPR3(r1),r3 ;\
/* r4 already save */ ;\
l.sw PT_GPR5(r1),r5 ;\
l.sw PT_GPR6(r1),r6 ;\
l.sw PT_GPR7(r1),r7 ;\
l.sw PT_GPR8(r1),r8 ;\
l.sw PT_GPR9(r1),r9 ;\
/* r10 already saved */ ;\
l.sw PT_GPR11(r1),r11 ;\
/* r12 already saved */ ;\
l.sw PT_GPR13(r1),r13 ;\
l.sw PT_GPR14(r1),r14 ;\
l.sw PT_GPR15(r1),r15 ;\
l.sw PT_GPR16(r1),r16 ;\
l.sw PT_GPR17(r1),r17 ;\
l.sw PT_GPR18(r1),r18 ;\
l.sw PT_GPR19(r1),r19 ;\
l.sw PT_GPR20(r1),r20 ;\
l.sw PT_GPR21(r1),r21 ;\
l.sw PT_GPR22(r1),r22 ;\
l.sw PT_GPR23(r1),r23 ;\
l.sw PT_GPR24(r1),r24 ;\
l.sw PT_GPR25(r1),r25 ;\
l.sw PT_GPR26(r1),r26 ;\
l.sw PT_GPR27(r1),r27 ;\
l.sw PT_GPR28(r1),r28 ;\
l.sw PT_GPR29(r1),r29 ;\
/* r30 already save */ ;\
/* l.sw PT_GPR30(r1),r30*/ ;\
l.sw PT_GPR31(r1),r31 ;\
TRACE_IRQS_OFF_ENTRY ;\
/* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
l.addi r30,r0,-1 ;\
l.sw PT_ORIG_GPR11(r1),r30
#define UNHANDLED_EXCEPTION(handler,vector) \
.global handler ;\
handler: ;\
/* r1, EPCR, ESR already saved */ ;\
l.sw PT_GPR2(r1),r2 ;\
l.sw PT_GPR3(r1),r3 ;\
l.sw PT_GPR5(r1),r5 ;\
l.sw PT_GPR6(r1),r6 ;\
l.sw PT_GPR7(r1),r7 ;\
l.sw PT_GPR8(r1),r8 ;\
l.sw PT_GPR9(r1),r9 ;\
/* r10 already saved */ ;\
l.sw PT_GPR11(r1),r11 ;\
/* r12 already saved */ ;\
l.sw PT_GPR13(r1),r13 ;\
l.sw PT_GPR14(r1),r14 ;\
l.sw PT_GPR15(r1),r15 ;\
l.sw PT_GPR16(r1),r16 ;\
l.sw PT_GPR17(r1),r17 ;\
l.sw PT_GPR18(r1),r18 ;\
l.sw PT_GPR19(r1),r19 ;\
l.sw PT_GPR20(r1),r20 ;\
l.sw PT_GPR21(r1),r21 ;\
l.sw PT_GPR22(r1),r22 ;\
l.sw PT_GPR23(r1),r23 ;\
l.sw PT_GPR24(r1),r24 ;\
l.sw PT_GPR25(r1),r25 ;\
l.sw PT_GPR26(r1),r26 ;\
l.sw PT_GPR27(r1),r27 ;\
l.sw PT_GPR28(r1),r28 ;\
l.sw PT_GPR29(r1),r29 ;\
/* r31 already saved */ ;\
l.sw PT_GPR30(r1),r30 ;\
/* l.sw PT_GPR31(r1),r31 */ ;\
/* Store -1 in orig_gpr11 for non-syscall exceptions */ ;\
l.addi r30,r0,-1 ;\
l.sw PT_ORIG_GPR11(r1),r30 ;\
l.addi r3,r1,0 ;\
/* r4 is exception EA */ ;\
l.addi r5,r0,vector ;\
l.jal unhandled_exception ;\
l.nop ;\
l.j _ret_from_exception ;\
l.nop
/* clobbers 'reg' */
#define CLEAR_LWA_FLAG(reg) \
l.movhi reg,hi(lwa_flag) ;\
l.ori reg,reg,lo(lwa_flag) ;\
l.sw 0(reg),r0
/*
* NOTE: one should never assume that SPR_EPC, SPR_ESR, SPR_EEAR
* contain the same values as when exception we're handling
* occured. in fact they never do. if you need them use
* values saved on stack (for SPR_EPC, SPR_ESR) or content
* of r4 (for SPR_EEAR). for details look at EXCEPTION_HANDLE()
* in 'arch/openrisc/kernel/head.S'
*/
/* =====================================================[ exceptions] === */
/* ---[ 0x100: RESET exception ]----------------------------------------- */
EXCEPTION_ENTRY(_tng_kernel_start)
l.jal _start
l.andi r0,r0,0
/* ---[ 0x200: BUS exception ]------------------------------------------- */
EXCEPTION_ENTRY(_bus_fault_handler)
CLEAR_LWA_FLAG(r3)
/* r4: EA of fault (set by EXCEPTION_HANDLE) */
l.jal do_bus_fault
l.addi r3,r1,0 /* pt_regs */
l.j _ret_from_exception
l.nop
/* ---[ 0x300: Data Page Fault exception ]------------------------------- */
EXCEPTION_ENTRY(_dtlb_miss_page_fault_handler)
CLEAR_LWA_FLAG(r3)
l.and r5,r5,r0
l.j 1f
l.nop
EXCEPTION_ENTRY(_data_page_fault_handler)
CLEAR_LWA_FLAG(r3)
/* set up parameters for do_page_fault */
l.ori r5,r0,0x300 // exception vector
1:
l.addi r3,r1,0 // pt_regs
/* r4 set be EXCEPTION_HANDLE */ // effective address of fault
#ifdef CONFIG_OPENRISC_NO_SPR_SR_DSX
l.lwz r6,PT_PC(r3) // address of an offending insn
l.lwz r6,0(r6) // instruction that caused pf
l.srli r6,r6,26 // check opcode for jump insn
l.sfeqi r6,0 // l.j
l.bf 8f
l.sfeqi r6,1 // l.jal
l.bf 8f
l.sfeqi r6,3 // l.bnf
l.bf 8f
l.sfeqi r6,4 // l.bf
l.bf 8f
l.sfeqi r6,0x11 // l.jr
l.bf 8f
l.sfeqi r6,0x12 // l.jalr
l.bf 8f
l.nop
l.j 9f
l.nop
8: // offending insn is in delay slot
l.lwz r6,PT_PC(r3) // address of an offending insn
l.addi r6,r6,4
l.lwz r6,0(r6) // instruction that caused pf
l.srli r6,r6,26 // get opcode
9: // offending instruction opcode loaded in r6
#else
l.mfspr r6,r0,SPR_SR // SR
l.andi r6,r6,SPR_SR_DSX // check for delay slot exception
l.sfne r6,r0 // exception happened in delay slot
l.bnf 7f
l.lwz r6,PT_PC(r3) // address of an offending insn
l.addi r6,r6,4 // offending insn is in delay slot
7:
l.lwz r6,0(r6) // instruction that caused pf
l.srli r6,r6,26 // check opcode for write access
#endif
l.sfgeui r6,0x33 // check opcode for write access
l.bnf 1f
l.sfleui r6,0x37
l.bnf 1f
l.ori r6,r0,0x1 // write access
l.j 2f
l.nop
1: l.ori r6,r0,0x0 // !write access
2:
/* call fault.c handler in or32/mm/fault.c */
l.jal do_page_fault
l.nop
l.j _ret_from_exception
l.nop
/* ---[ 0x400: Insn Page Fault exception ]------------------------------- */
EXCEPTION_ENTRY(_itlb_miss_page_fault_handler)
CLEAR_LWA_FLAG(r3)
l.and r5,r5,r0
l.j 1f
l.nop
EXCEPTION_ENTRY(_insn_page_fault_handler)
CLEAR_LWA_FLAG(r3)
/* set up parameters for do_page_fault */
l.ori r5,r0,0x400 // exception vector
1:
l.addi r3,r1,0 // pt_regs
/* r4 set be EXCEPTION_HANDLE */ // effective address of fault
l.ori r6,r0,0x0 // !write access
/* call fault.c handler in or32/mm/fault.c */
l.jal do_page_fault
l.nop
l.j _ret_from_exception
l.nop
/* ---[ 0x500: Timer exception ]----------------------------------------- */
EXCEPTION_ENTRY(_timer_handler)
CLEAR_LWA_FLAG(r3)
l.jal timer_interrupt
l.addi r3,r1,0 /* pt_regs */
l.j _ret_from_intr
l.nop
/* ---[ 0x600: Alignment exception ]-------------------------------------- */
EXCEPTION_ENTRY(_alignment_handler)
CLEAR_LWA_FLAG(r3)
/* r4: EA of fault (set by EXCEPTION_HANDLE) */
l.jal do_unaligned_access
l.addi r3,r1,0 /* pt_regs */
l.j _ret_from_exception
l.nop
#if 0
EXCEPTION_ENTRY(_alignment_handler)
// l.mfspr r2,r0,SPR_EEAR_BASE /* Load the effective address */
l.addi r2,r4,0
// l.mfspr r5,r0,SPR_EPCR_BASE /* Load the insn address */
l.lwz r5,PT_PC(r1)
l.lwz r3,0(r5) /* Load insn */
l.srli r4,r3,26 /* Shift left to get the insn opcode */
l.sfeqi r4,0x00 /* Check if the load/store insn is in delay slot */
l.bf jmp
l.sfeqi r4,0x01
l.bf jmp
l.sfeqi r4,0x03
l.bf jmp
l.sfeqi r4,0x04
l.bf jmp
l.sfeqi r4,0x11
l.bf jr
l.sfeqi r4,0x12
l.bf jr
l.nop
l.j 1f
l.addi r5,r5,4 /* Increment PC to get return insn address */
jmp:
l.slli r4,r3,6 /* Get the signed extended jump length */
l.srai r4,r4,4
l.lwz r3,4(r5) /* Load the real load/store insn */
l.add r5,r5,r4 /* Calculate jump target address */
l.j 1f
l.srli r4,r3,26 /* Shift left to get the insn opcode */
jr:
l.slli r4,r3,9 /* Shift to get the reg nb */
l.andi r4,r4,0x7c
l.lwz r3,4(r5) /* Load the real load/store insn */
l.add r4,r4,r1 /* Load the jump register value from the stack */
l.lwz r5,0(r4)
l.srli r4,r3,26 /* Shift left to get the insn opcode */
1:
// l.mtspr r0,r5,SPR_EPCR_BASE
l.sw PT_PC(r1),r5
l.sfeqi r4,0x26
l.bf lhs
l.sfeqi r4,0x25
l.bf lhz
l.sfeqi r4,0x22
l.bf lws
l.sfeqi r4,0x21
l.bf lwz
l.sfeqi r4,0x37
l.bf sh
l.sfeqi r4,0x35
l.bf sw
l.nop
1: l.j 1b /* I don't know what to do */
l.nop
lhs: l.lbs r5,0(r2)
l.slli r5,r5,8
l.lbz r6,1(r2)
l.or r5,r5,r6
l.srli r4,r3,19
l.andi r4,r4,0x7c
l.add r4,r4,r1
l.j align_end
l.sw 0(r4),r5
lhz: l.lbz r5,0(r2)
l.slli r5,r5,8
l.lbz r6,1(r2)
l.or r5,r5,r6
l.srli r4,r3,19
l.andi r4,r4,0x7c
l.add r4,r4,r1
l.j align_end
l.sw 0(r4),r5
lws: l.lbs r5,0(r2)
l.slli r5,r5,24
l.lbz r6,1(r2)
l.slli r6,r6,16
l.or r5,r5,r6
l.lbz r6,2(r2)
l.slli r6,r6,8
l.or r5,r5,r6
l.lbz r6,3(r2)
l.or r5,r5,r6
l.srli r4,r3,19
l.andi r4,r4,0x7c
l.add r4,r4,r1
l.j align_end
l.sw 0(r4),r5
lwz: l.lbz r5,0(r2)
l.slli r5,r5,24
l.lbz r6,1(r2)
l.slli r6,r6,16
l.or r5,r5,r6
l.lbz r6,2(r2)
l.slli r6,r6,8
l.or r5,r5,r6
l.lbz r6,3(r2)
l.or r5,r5,r6
l.srli r4,r3,19
l.andi r4,r4,0x7c
l.add r4,r4,r1
l.j align_end
l.sw 0(r4),r5
sh:
l.srli r4,r3,9
l.andi r4,r4,0x7c
l.add r4,r4,r1
l.lwz r5,0(r4)
l.sb 1(r2),r5
l.srli r5,r5,8
l.j align_end
l.sb 0(r2),r5
sw:
l.srli r4,r3,9
l.andi r4,r4,0x7c
l.add r4,r4,r1
l.lwz r5,0(r4)
l.sb 3(r2),r5
l.srli r5,r5,8
l.sb 2(r2),r5
l.srli r5,r5,8
l.sb 1(r2),r5
l.srli r5,r5,8
l.j align_end
l.sb 0(r2),r5
align_end:
l.j _ret_from_intr
l.nop
#endif
/* ---[ 0x700: Illegal insn exception ]---------------------------------- */
EXCEPTION_ENTRY(_illegal_instruction_handler)
/* r4: EA of fault (set by EXCEPTION_HANDLE) */
l.jal do_illegal_instruction
l.addi r3,r1,0 /* pt_regs */
l.j _ret_from_exception
l.nop
/* ---[ 0x800: External interrupt exception ]---------------------------- */
EXCEPTION_ENTRY(_external_irq_handler)
#ifdef CONFIG_OPENRISC_ESR_EXCEPTION_BUG_CHECK
l.lwz r4,PT_SR(r1) // were interrupts enabled ?
l.andi r4,r4,SPR_SR_IEE
l.sfeqi r4,0
l.bnf 1f // ext irq enabled, all ok.
l.nop
l.addi r1,r1,-0x8
l.movhi r3,hi(42f)
l.ori r3,r3,lo(42f)
l.sw 0x0(r1),r3
l.jal printk
l.sw 0x4(r1),r4
l.addi r1,r1,0x8
.section .rodata, "a"
42:
.string "\n\rESR interrupt bug: in _external_irq_handler (ESR %x)\n\r"
.align 4
.previous
l.ori r4,r4,SPR_SR_IEE // fix the bug
// l.sw PT_SR(r1),r4
1:
#endif
CLEAR_LWA_FLAG(r3)
l.addi r3,r1,0
l.movhi r8,hi(do_IRQ)
l.ori r8,r8,lo(do_IRQ)
l.jalr r8
l.nop
l.j _ret_from_intr
l.nop
/* ---[ 0x900: DTLB miss exception ]------------------------------------- */
/* ---[ 0xa00: ITLB miss exception ]------------------------------------- */
/* ---[ 0xb00: Range exception ]----------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0xb00,0xb00)
/* ---[ 0xc00: Syscall exception ]--------------------------------------- */
/*
* Syscalls are a special type of exception in that they are
* _explicitly_ invoked by userspace and can therefore be
* held to conform to the same ABI as normal functions with
* respect to whether registers are preserved across the call
* or not.
*/
/* Upon syscall entry we just save the callee-saved registers
* and not the call-clobbered ones.
*/
_string_syscall_return:
.string "syscall return %ld \n\r\0"
.align 4
ENTRY(_sys_call_handler)
/* r1, EPCR, ESR a already saved */
l.sw PT_GPR2(r1),r2
/* r3-r8 must be saved because syscall restart relies
* on us being able to restart the syscall args... technically
* they should be clobbered, otherwise
*/
l.sw PT_GPR3(r1),r3
/*
* r4 already saved
* r4 holds the EEAR address of the fault, use it as screatch reg and
* then load the original r4
*/
CLEAR_LWA_FLAG(r4)
l.lwz r4,PT_GPR4(r1)
l.sw PT_GPR5(r1),r5
l.sw PT_GPR6(r1),r6
l.sw PT_GPR7(r1),r7
l.sw PT_GPR8(r1),r8
l.sw PT_GPR9(r1),r9
/* r10 already saved */
l.sw PT_GPR11(r1),r11
/* orig_gpr11 must be set for syscalls */
l.sw PT_ORIG_GPR11(r1),r11
/* r12,r13 already saved */
/* r14-r28 (even) aren't touched by the syscall fast path below
* so we don't need to save them. However, the functions that return
* to userspace via a call to switch() DO need to save these because
* switch() effectively clobbers them... saving these registers for
* such functions is handled in their syscall wrappers (see fork, vfork,
* and clone, below).
/* r30 is the only register we clobber in the fast path */
/* r30 already saved */
/* l.sw PT_GPR30(r1),r30 */
_syscall_check_trace_enter:
/* syscalls run with interrupts enabled */
TRACE_IRQS_ON_SYSCALL
ENABLE_INTERRUPTS(r29) // enable interrupts, r29 is temp
/* If TIF_SYSCALL_TRACE is set, then we want to do syscall tracing */
l.lwz r30,TI_FLAGS(r10)
l.andi r30,r30,_TIF_SYSCALL_TRACE
l.sfne r30,r0
l.bf _syscall_trace_enter
l.nop
_syscall_check:
/* Ensure that the syscall number is reasonable */
l.sfgeui r11,__NR_syscalls
l.bf _syscall_badsys
l.nop
_syscall_call:
l.movhi r29,hi(sys_call_table)
l.ori r29,r29,lo(sys_call_table)
l.slli r11,r11,2
l.add r29,r29,r11
l.lwz r29,0(r29)
l.jalr r29
l.nop
_syscall_return:
/* All syscalls return here... just pay attention to ret_from_fork
* which does it in a round-about way.
*/
l.sw PT_GPR11(r1),r11 // save return value
#if 0
_syscall_debug:
l.movhi r3,hi(_string_syscall_return)
l.ori r3,r3,lo(_string_syscall_return)
l.ori r27,r0,1
l.sw -4(r1),r27
l.sw -8(r1),r11
l.addi r1,r1,-8
l.movhi r27,hi(printk)
l.ori r27,r27,lo(printk)
l.jalr r27
l.nop
l.addi r1,r1,8
#endif
_syscall_check_trace_leave:
/* r30 is a callee-saved register so this should still hold the
* _TIF_SYSCALL_TRACE flag from _syscall_check_trace_enter above...
* _syscall_trace_leave expects syscall result to be in pt_regs->r11.
*/
l.sfne r30,r0
l.bf _syscall_trace_leave
l.nop
/* This is where the exception-return code begins... interrupts need to be
* disabled the rest of the way here because we can't afford to miss any
* interrupts that set NEED_RESCHED or SIGNALPENDING... really true? */
_syscall_check_work:
/* Here we need to disable interrupts */
DISABLE_INTERRUPTS(r27,r29)
TRACE_IRQS_OFF
l.lwz r30,TI_FLAGS(r10)
l.andi r30,r30,_TIF_WORK_MASK
l.sfne r30,r0
l.bnf _syscall_resume_userspace
l.nop
/* Work pending follows a different return path, so we need to
* make sure that all the call-saved registers get into pt_regs
* before branching...
*/
l.sw PT_GPR14(r1),r14
l.sw PT_GPR16(r1),r16
l.sw PT_GPR18(r1),r18
l.sw PT_GPR20(r1),r20
l.sw PT_GPR22(r1),r22
l.sw PT_GPR24(r1),r24
l.sw PT_GPR26(r1),r26
l.sw PT_GPR28(r1),r28
/* _work_pending needs to be called with interrupts disabled */
l.j _work_pending
l.nop
_syscall_resume_userspace:
// ENABLE_INTERRUPTS(r29)
/* This is the hot path for returning to userspace from a syscall. If there's
* work to be done and the branch to _work_pending was taken above, then the
* return to userspace will be done via the normal exception return path...
* that path restores _all_ registers and will overwrite the "clobbered"
* registers with whatever garbage is in pt_regs -- that's OK because those
* registers are clobbered anyway and because the extra work is insignificant
* in the context of the extra work that _work_pending is doing.
/* Once again, syscalls are special and only guarantee to preserve the
* same registers as a normal function call */
/* The assumption here is that the registers r14-r28 (even) are untouched and
* don't need to be restored... be sure that that's really the case!
*/
/* This is still too much... we should only be restoring what we actually
* clobbered... we should even be using 'scratch' (odd) regs above so that
* we don't need to restore anything, hardly...
*/
l.lwz r2,PT_GPR2(r1)
/* Restore args */
/* r3-r8 are technically clobbered, but syscall restart needs these
* to be restored...
*/
l.lwz r3,PT_GPR3(r1)
l.lwz r4,PT_GPR4(r1)
l.lwz r5,PT_GPR5(r1)
l.lwz r6,PT_GPR6(r1)
l.lwz r7,PT_GPR7(r1)
l.lwz r8,PT_GPR8(r1)
l.lwz r9,PT_GPR9(r1)
l.lwz r10,PT_GPR10(r1)
l.lwz r11,PT_GPR11(r1)
/* r30 is the only register we clobber in the fast path */
l.lwz r30,PT_GPR30(r1)
/* Here we use r13-r19 (odd) as scratch regs */
l.lwz r13,PT_PC(r1)
l.lwz r15,PT_SR(r1)
l.lwz r1,PT_SP(r1)
/* Interrupts need to be disabled for setting EPCR and ESR
* so that another interrupt doesn't come in here and clobber
* them before we can use them for our l.rfe */
DISABLE_INTERRUPTS(r17,r19)
l.mtspr r0,r13,SPR_EPCR_BASE
l.mtspr r0,r15,SPR_ESR_BASE
l.rfe
/* End of hot path!
* Keep the below tracing and error handling out of the hot path...
*/
_syscall_trace_enter:
/* Here we pass pt_regs to do_syscall_trace_enter. Make sure
* that function is really getting all the info it needs as
* pt_regs isn't a complete set of userspace regs, just the
* ones relevant to the syscall...
*
* Note use of delay slot for setting argument.
*/
l.jal do_syscall_trace_enter
l.addi r3,r1,0
/* Restore arguments (not preserved across do_syscall_trace_enter)
* so that we can do the syscall for real and return to the syscall
* hot path.
*/
l.lwz r11,PT_GPR11(r1)
l.lwz r3,PT_GPR3(r1)
l.lwz r4,PT_GPR4(r1)
l.lwz r5,PT_GPR5(r1)
l.lwz r6,PT_GPR6(r1)
l.lwz r7,PT_GPR7(r1)
l.j _syscall_check
l.lwz r8,PT_GPR8(r1)
_syscall_trace_leave:
l.jal do_syscall_trace_leave
l.addi r3,r1,0
l.j _syscall_check_work
l.nop
_syscall_badsys:
/* Here we effectively pretend to have executed an imaginary
* syscall that returns -ENOSYS and then return to the regular
* syscall hot path.
* Note that "return value" is set in the delay slot...
*/
l.j _syscall_return
l.addi r11,r0,-ENOSYS
/******* END SYSCALL HANDLING *******/
/* ---[ 0xd00: Trap exception ]------------------------------------------ */
UNHANDLED_EXCEPTION(_vector_0xd00,0xd00)
/* ---[ 0xe00: Trap exception ]------------------------------------------ */
EXCEPTION_ENTRY(_trap_handler)
CLEAR_LWA_FLAG(r3)
/* r4: EA of fault (set by EXCEPTION_HANDLE) */
l.jal do_trap
l.addi r3,r1,0 /* pt_regs */
l.j _ret_from_exception
l.nop
/* ---[ 0xf00: Reserved exception ]-------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0xf00,0xf00)
/* ---[ 0x1000: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1000,0x1000)
/* ---[ 0x1100: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1100,0x1100)
/* ---[ 0x1200: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1200,0x1200)
/* ---[ 0x1300: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1300,0x1300)
/* ---[ 0x1400: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1400,0x1400)
/* ---[ 0x1500: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1500,0x1500)
/* ---[ 0x1600: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1600,0x1600)
/* ---[ 0x1700: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1700,0x1700)
/* ---[ 0x1800: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1800,0x1800)
/* ---[ 0x1900: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1900,0x1900)
/* ---[ 0x1a00: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1a00,0x1a00)
/* ---[ 0x1b00: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1b00,0x1b00)
/* ---[ 0x1c00: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1c00,0x1c00)
/* ---[ 0x1d00: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1d00,0x1d00)
/* ---[ 0x1e00: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1e00,0x1e00)
/* ---[ 0x1f00: Reserved exception ]------------------------------------- */
UNHANDLED_EXCEPTION(_vector_0x1f00,0x1f00)
/* ========================================================[ return ] === */
_resume_userspace:
DISABLE_INTERRUPTS(r3,r4)
TRACE_IRQS_OFF
l.lwz r4,TI_FLAGS(r10)
l.andi r13,r4,_TIF_WORK_MASK
l.sfeqi r13,0
l.bf _restore_all
l.nop
_work_pending:
l.lwz r5,PT_ORIG_GPR11(r1)
l.sfltsi r5,0
l.bnf 1f
l.nop
l.andi r5,r5,0
1:
l.jal do_work_pending
l.ori r3,r1,0 /* pt_regs */
l.sfeqi r11,0
l.bf _restore_all
l.nop
l.sfltsi r11,0
l.bnf 1f
l.nop
l.and r11,r11,r0
l.ori r11,r11,__NR_restart_syscall
l.j _syscall_check_trace_enter
l.nop
1:
l.lwz r11,PT_ORIG_GPR11(r1)
/* Restore arg registers */
l.lwz r3,PT_GPR3(r1)
l.lwz r4,PT_GPR4(r1)
l.lwz r5,PT_GPR5(r1)
l.lwz r6,PT_GPR6(r1)
l.lwz r7,PT_GPR7(r1)
l.j _syscall_check_trace_enter
l.lwz r8,PT_GPR8(r1)
_restore_all:
#ifdef CONFIG_TRACE_IRQFLAGS
l.lwz r4,PT_SR(r1)
l.andi r3,r4,(SPR_SR_IEE|SPR_SR_TEE)
l.sfeq r3,r0 /* skip trace if irqs were off */
l.bf skip_hardirqs_on
l.nop
TRACE_IRQS_ON
skip_hardirqs_on:
#endif
RESTORE_ALL
/* This returns to userspace code */
ENTRY(_ret_from_intr)
ENTRY(_ret_from_exception)
l.lwz r4,PT_SR(r1)
l.andi r3,r4,SPR_SR_SM
l.sfeqi r3,0
l.bnf _restore_all
l.nop
l.j _resume_userspace
l.nop
ENTRY(ret_from_fork)
l.jal schedule_tail
l.nop
/* Check if we are a kernel thread */
l.sfeqi r20,0
l.bf 1f
l.nop
/* ...we are a kernel thread so invoke the requested callback */
l.jalr r20
l.or r3,r22,r0
1:
/* _syscall_returns expect r11 to contain return value */
l.lwz r11,PT_GPR11(r1)
/* The syscall fast path return expects call-saved registers
* r12-r28 to be untouched, so we restore them here as they
* will have been effectively clobbered when arriving here
* via the call to switch()
*/
l.lwz r12,PT_GPR12(r1)
l.lwz r14,PT_GPR14(r1)
l.lwz r16,PT_GPR16(r1)
l.lwz r18,PT_GPR18(r1)
l.lwz r20,PT_GPR20(r1)
l.lwz r22,PT_GPR22(r1)
l.lwz r24,PT_GPR24(r1)
l.lwz r26,PT_GPR26(r1)
l.lwz r28,PT_GPR28(r1)
l.j _syscall_return
l.nop
/* ========================================================[ switch ] === */
/*
* This routine switches between two different tasks. The process
* state of one is saved on its kernel stack. Then the state
* of the other is restored from its kernel stack. The memory
* management hardware is updated to the second process's state.
* Finally, we can return to the second process, via the 'return'.
*
* Note: there are two ways to get to the "going out" portion
* of this code; either by coming in via the entry (_switch)
* or via "fork" which must set up an environment equivalent
* to the "_switch" path. If you change this (or in particular, the
* SAVE_REGS macro), you'll have to change the fork code also.
*/
/* _switch MUST never lay on page boundry, cause it runs from
* effective addresses and beeing interrupted by iTLB miss would kill it.
* dTLB miss seams to never accour in the bad place since data accesses
* are from task structures which are always page aligned.
*
* The problem happens in RESTORE_ALL_NO_R11 where we first set the EPCR
* register, then load the previous register values and only at the end call
* the l.rfe instruction. If get TLB miss in beetwen the EPCR register gets
* garbled and we end up calling l.rfe with the wrong EPCR. (same probably
* holds for ESR)
*
* To avoid this problems it is sufficient to align _switch to
* some nice round number smaller than it's size...
*/
/* ABI rules apply here... we either enter _switch via schedule() or via
* an imaginary call to which we shall return at return_from_fork. Either
* way, we are a function call and only need to preserve the callee-saved
* registers when we return. As such, we don't need to save the registers
* on the stack that we won't be returning as they were...
*/
.align 0x400
ENTRY(_switch)
/* We don't store SR as _switch only gets called in a context where
* the SR will be the same going in and coming out... */
/* Set up new pt_regs struct for saving task state */
l.addi r1,r1,-(INT_FRAME_SIZE)
/* No need to store r1/PT_SP as it goes into KSP below */
l.sw PT_GPR2(r1),r2
l.sw PT_GPR9(r1),r9
/* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
* and expects r12 to be callee-saved... */
l.sw PT_GPR12(r1),r12
l.sw PT_GPR14(r1),r14
l.sw PT_GPR16(r1),r16
l.sw PT_GPR18(r1),r18
l.sw PT_GPR20(r1),r20
l.sw PT_GPR22(r1),r22
l.sw PT_GPR24(r1),r24
l.sw PT_GPR26(r1),r26
l.sw PT_GPR28(r1),r28
l.sw PT_GPR30(r1),r30
l.addi r11,r10,0 /* Save old 'current' to 'last' return value*/
/* We use thread_info->ksp for storing the address of the above
* structure so that we can get back to it later... we don't want
* to lose the value of thread_info->ksp, though, so store it as
* pt_regs->sp so that we can easily restore it when we are made
* live again...
*/
/* Save the old value of thread_info->ksp as pt_regs->sp */
l.lwz r29,TI_KSP(r10)
l.sw PT_SP(r1),r29
/* Swap kernel stack pointers */
l.sw TI_KSP(r10),r1 /* Save old stack pointer */
l.or r10,r4,r0 /* Set up new current_thread_info */
l.lwz r1,TI_KSP(r10) /* Load new stack pointer */
/* Restore the old value of thread_info->ksp */
l.lwz r29,PT_SP(r1)
l.sw TI_KSP(r10),r29
/* ...and restore the registers, except r11 because the return value
* has already been set above.
*/
l.lwz r2,PT_GPR2(r1)
l.lwz r9,PT_GPR9(r1)
/* No need to restore r10 */
/* ...and do not restore r11 */
/* This is wrong, r12 shouldn't be here... but GCC is broken for the time being
* and expects r12 to be callee-saved... */
l.lwz r12,PT_GPR12(r1)
l.lwz r14,PT_GPR14(r1)
l.lwz r16,PT_GPR16(r1)
l.lwz r18,PT_GPR18(r1)
l.lwz r20,PT_GPR20(r1)
l.lwz r22,PT_GPR22(r1)
l.lwz r24,PT_GPR24(r1)
l.lwz r26,PT_GPR26(r1)
l.lwz r28,PT_GPR28(r1)
l.lwz r30,PT_GPR30(r1)
/* Unwind stack to pre-switch state */
l.addi r1,r1,(INT_FRAME_SIZE)
/* Return via the link-register back to where we 'came from', where
* that may be either schedule(), ret_from_fork(), or
* ret_from_kernel_thread(). If we are returning to a new thread,
* we are expected to have set up the arg to schedule_tail already,
* hence we do so here unconditionally:
*/
l.lwz r3,TI_TASK(r3) /* Load 'prev' as schedule_tail arg */
l.jr r9
l.nop
/* ==================================================================== */
/* These all use the delay slot for setting the argument register, so the
* jump is always happening after the l.addi instruction.
*
* These are all just wrappers that don't touch the link-register r9, so the
* return from the "real" syscall function will return back to the syscall
* code that did the l.jal that brought us here.
*/
/* fork requires that we save all the callee-saved registers because they
* are all effectively clobbered by the call to _switch. Here we store
* all the registers that aren't touched by the syscall fast path and thus
* weren't saved there.
*/
_fork_save_extra_regs_and_call:
l.sw PT_GPR14(r1),r14
l.sw PT_GPR16(r1),r16
l.sw PT_GPR18(r1),r18
l.sw PT_GPR20(r1),r20
l.sw PT_GPR22(r1),r22
l.sw PT_GPR24(r1),r24
l.sw PT_GPR26(r1),r26
l.jr r29
l.sw PT_GPR28(r1),r28
ENTRY(__sys_clone)
l.movhi r29,hi(sys_clone)
l.ori r29,r29,lo(sys_clone)
l.j _fork_save_extra_regs_and_call
l.addi r7,r1,0
ENTRY(__sys_fork)
l.movhi r29,hi(sys_fork)
l.ori r29,r29,lo(sys_fork)
l.j _fork_save_extra_regs_and_call
l.addi r3,r1,0
ENTRY(sys_rt_sigreturn)
l.jal _sys_rt_sigreturn
l.addi r3,r1,0
l.sfne r30,r0
l.bnf _no_syscall_trace
l.nop
l.jal do_syscall_trace_leave
l.addi r3,r1,0
_no_syscall_trace:
l.j _resume_userspace
l.nop
/* This is a catch-all syscall for atomic instructions for the OpenRISC 1000.
* The functions takes a variable number of parameters depending on which
* particular flavour of atomic you want... parameter 1 is a flag identifying
* the atomic in question. Currently, this function implements the
* following variants:
*
* XCHG:
* @flag: 1
* @ptr1:
* @ptr2:
* Atomically exchange the values in pointers 1 and 2.
*
*/
ENTRY(sys_or1k_atomic)
/* FIXME: This ignores r3 and always does an XCHG */
DISABLE_INTERRUPTS(r17,r19)
l.lwz r29,0(r4)
l.lwz r27,0(r5)
l.sw 0(r4),r27
l.sw 0(r5),r29
ENABLE_INTERRUPTS(r17)
l.jr r9
l.or r11,r0,r0
/* ============================================================[ EOF ]=== */
