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Diffstat (limited to 'arch/sh/kernel/cpu/sh3/entry.S')
| -rw-r--r-- | arch/sh/kernel/cpu/sh3/entry.S | 526 |
1 files changed, 526 insertions, 0 deletions
diff --git a/arch/sh/kernel/cpu/sh3/entry.S b/arch/sh/kernel/cpu/sh3/entry.S new file mode 100644 index 000000000000..8bcd63f9f351 --- /dev/null +++ b/arch/sh/kernel/cpu/sh3/entry.S @@ -0,0 +1,526 @@ +/* + * arch/sh/kernel/entry.S + * + * Copyright (C) 1999, 2000, 2002 Niibe Yutaka + * Copyright (C) 2003 - 2006 Paul Mundt + * + * This file is subject to the terms and conditions of the GNU General Public + * License. See the file "COPYING" in the main directory of this archive + * for more details. + */ +#include <linux/sys.h> +#include <linux/errno.h> +#include <linux/linkage.h> +#include <asm/asm-offsets.h> +#include <asm/thread_info.h> +#include <asm/cpu/mmu_context.h> +#include <asm/unistd.h> + +! NOTE: +! GNU as (as of 2.9.1) changes bf/s into bt/s and bra, when the address +! to be jumped is too far, but it causes illegal slot exception. + +/* + * entry.S contains the system-call and fault low-level handling routines. + * This also contains the timer-interrupt handler, as well as all interrupts + * and faults that can result in a task-switch. + * + * NOTE: This code handles signal-recognition, which happens every time + * after a timer-interrupt and after each system call. + * + * NOTE: This code uses a convention that instructions in the delay slot + * of a transfer-control instruction are indented by an extra space, thus: + * + * jmp @k0 ! control-transfer instruction + * ldc k1, ssr ! delay slot + * + * Stack layout in 'ret_from_syscall': + * ptrace needs to have all regs on the stack. + * if the order here is changed, it needs to be + * updated in ptrace.c and ptrace.h + * + * r0 + * ... + * r15 = stack pointer + * spc + * pr + * ssr + * gbr + * mach + * macl + * syscall # + * + */ +#if defined(CONFIG_KGDB_NMI) +NMI_VEC = 0x1c0 ! Must catch early for debounce +#endif + +/* Offsets to the stack */ +OFF_R0 = 0 /* Return value. New ABI also arg4 */ +OFF_R1 = 4 /* New ABI: arg5 */ +OFF_R2 = 8 /* New ABI: arg6 */ +OFF_R3 = 12 /* New ABI: syscall_nr */ +OFF_R4 = 16 /* New ABI: arg0 */ +OFF_R5 = 20 /* New ABI: arg1 */ +OFF_R6 = 24 /* New ABI: arg2 */ +OFF_R7 = 28 /* New ABI: arg3 */ +OFF_SP = (15*4) +OFF_PC = (16*4) +OFF_SR = (16*4+8) +OFF_TRA = (16*4+6*4) + + +#define k0 r0 +#define k1 r1 +#define k2 r2 +#define k3 r3 +#define k4 r4 + +#define g_imask r6 /* r6_bank1 */ +#define k_g_imask r6_bank /* r6_bank1 */ +#define current r7 /* r7_bank1 */ + +#include <asm/entry-macros.S> + +/* + * Kernel mode register usage: + * k0 scratch + * k1 scratch + * k2 scratch (Exception code) + * k3 scratch (Return address) + * k4 scratch + * k5 reserved + * k6 Global Interrupt Mask (0--15 << 4) + * k7 CURRENT_THREAD_INFO (pointer to current thread info) + */ + +! +! TLB Miss / Initial Page write exception handling +! _and_ +! TLB hits, but the access violate the protection. +! It can be valid access, such as stack grow and/or C-O-W. +! +! +! Find the pmd/pte entry and loadtlb +! If it's not found, cause address error (SEGV) +! +! Although this could be written in assembly language (and it'd be faster), +! this first version depends *much* on C implementation. +! + +#if defined(CONFIG_MMU) + .align 2 +ENTRY(tlb_miss_load) + bra call_dpf + mov #0, r5 + + .align 2 +ENTRY(tlb_miss_store) + bra call_dpf + mov #1, r5 + + .align 2 +ENTRY(initial_page_write) + bra call_dpf + mov #1, r5 + + .align 2 +ENTRY(tlb_protection_violation_load) + bra call_dpf + mov #0, r5 + + .align 2 +ENTRY(tlb_protection_violation_store) + bra call_dpf + mov #1, r5 + +call_dpf: + mov.l 1f, r0 + mov r5, r8 + mov.l @r0, r6 + mov r6, r9 + mov.l 2f, r0 + sts pr, r10 + jsr @r0 + mov r15, r4 + ! + tst r0, r0 + bf/s 0f + lds r10, pr + rts + nop +0: sti + mov.l 3f, r0 + mov r9, r6 + mov r8, r5 + jmp @r0 + mov r15, r4 + + .align 2 +1: .long MMU_TEA +2: .long __do_page_fault +3: .long do_page_fault + + .align 2 +ENTRY(address_error_load) + bra call_dae + mov #0,r5 ! writeaccess = 0 + + .align 2 +ENTRY(address_error_store) + bra call_dae + mov #1,r5 ! writeaccess = 1 + + .align 2 +call_dae: + mov.l 1f, r0 + mov.l @r0, r6 ! address + mov.l 2f, r0 + jmp @r0 + mov r15, r4 ! regs + + .align 2 +1: .long MMU_TEA +2: .long do_address_error +#endif /* CONFIG_MMU */ + +#if defined(CONFIG_SH_STANDARD_BIOS) + /* Unwind the stack and jmp to the debug entry */ +debug_kernel_fw: + mov.l @r15+, r0 + mov.l @r15+, r1 + mov.l @r15+, r2 + mov.l @r15+, r3 + mov.l @r15+, r4 + mov.l @r15+, r5 + mov.l @r15+, r6 + mov.l @r15+, r7 + stc sr, r8 + mov.l 1f, r9 ! BL =1, RB=1, IMASK=0x0F + or r9, r8 + ldc r8, sr ! here, change the register bank + mov.l @r15+, r8 + mov.l @r15+, r9 + mov.l @r15+, r10 + mov.l @r15+, r11 + mov.l @r15+, r12 + mov.l @r15+, r13 + mov.l @r15+, r14 + mov.l @r15+, k0 + ldc.l @r15+, spc + lds.l @r15+, pr + mov.l @r15+, k1 + ldc.l @r15+, gbr + lds.l @r15+, mach + lds.l @r15+, macl + mov k0, r15 + ! + mov.l 2f, k0 + mov.l @k0, k0 + jmp @k0 + ldc k1, ssr + .align 2 +1: .long 0x300000f0 +2: .long gdb_vbr_vector +#endif /* CONFIG_SH_STANDARD_BIOS */ + +restore_all: + mov.l @r15+, r0 + mov.l @r15+, r1 + mov.l @r15+, r2 + mov.l @r15+, r3 + mov.l @r15+, r4 + mov.l @r15+, r5 + mov.l @r15+, r6 + mov.l @r15+, r7 + ! + stc sr, r8 + mov.l 7f, r9 + or r9, r8 ! BL =1, RB=1 + ldc r8, sr ! here, change the register bank + ! + mov.l @r15+, r8 + mov.l @r15+, r9 + mov.l @r15+, r10 + mov.l @r15+, r11 + mov.l @r15+, r12 + mov.l @r15+, r13 + mov.l @r15+, r14 + mov.l @r15+, k4 ! original stack pointer + ldc.l @r15+, spc + lds.l @r15+, pr + mov.l @r15+, k3 ! original SR + ldc.l @r15+, gbr + lds.l @r15+, mach + lds.l @r15+, macl + add #4, r15 ! Skip syscall number + ! +#ifdef CONFIG_SH_DSP + mov.l @r15+, k0 ! DSP mode marker + mov.l 5f, k1 + cmp/eq k0, k1 ! Do we have a DSP stack frame? + bf skip_restore + + stc sr, k0 ! Enable CPU DSP mode + or k1, k0 ! (within kernel it may be disabled) + ldc k0, sr + mov r2, k0 ! Backup r2 + + ! Restore DSP registers from stack + mov r15, r2 + movs.l @r2+, a1 + movs.l @r2+, a0g + movs.l @r2+, a1g + movs.l @r2+, m0 + movs.l @r2+, m1 + mov r2, r15 + + lds.l @r15+, a0 + lds.l @r15+, x0 + lds.l @r15+, x1 + lds.l @r15+, y0 + lds.l @r15+, y1 + lds.l @r15+, dsr + ldc.l @r15+, rs + ldc.l @r15+, re + ldc.l @r15+, mod + + mov k0, r2 ! Restore r2 +skip_restore: +#endif + ! + ! Calculate new SR value + mov k3, k2 ! original SR value + mov #0xf0, k1 + extu.b k1, k1 + not k1, k1 + and k1, k2 ! Mask orignal SR value + ! + mov k3, k0 ! Calculate IMASK-bits + shlr2 k0 + and #0x3c, k0 + cmp/eq #0x3c, k0 + bt/s 6f + shll2 k0 + mov g_imask, k0 + ! +6: or k0, k2 ! Set the IMASK-bits + ldc k2, ssr + ! +#if defined(CONFIG_KGDB_NMI) + ! Clear in_nmi + mov.l 6f, k0 + mov #0, k1 + mov.b k1, @k0 +#endif + mov.l @r15+, k2 ! restore EXPEVT + mov k4, r15 + rte + nop + + .align 2 +5: .long 0x00001000 ! DSP +7: .long 0x30000000 + +! common exception handler +#include "../../entry.S" + +! Exception Vector Base +! +! Should be aligned page boundary. +! + .balign 4096,0,4096 +ENTRY(vbr_base) + .long 0 +! + .balign 256,0,256 +general_exception: + mov.l 1f, k2 + mov.l 2f, k3 + bra handle_exception + mov.l @k2, k2 + .align 2 +1: .long EXPEVT +2: .long ret_from_exception +! +! + .balign 1024,0,1024 +tlb_miss: + mov.l 1f, k2 + mov.l 4f, k3 + bra handle_exception + mov.l @k2, k2 +! + .balign 512,0,512 +interrupt: + mov.l 2f, k2 + mov.l 3f, k3 +#if defined(CONFIG_KGDB_NMI) + ! Debounce (filter nested NMI) + mov.l @k2, k0 + mov.l 5f, k1 + cmp/eq k1, k0 + bf 0f + mov.l 6f, k1 + tas.b @k1 + bt 0f + rte + nop + .align 2 +5: .long NMI_VEC +6: .long in_nmi +0: +#endif /* defined(CONFIG_KGDB_NMI) */ + bra handle_exception + mov #-1, k2 ! interrupt exception marker + + .align 2 +1: .long EXPEVT +2: .long INTEVT +3: .long ret_from_irq +4: .long ret_from_exception + +! +! + .align 2 +ENTRY(handle_exception) + ! Using k0, k1 for scratch registers (r0_bank1, r1_bank), + ! save all registers onto stack. + ! + stc ssr, k0 ! Is it from kernel space? + shll k0 ! Check MD bit (bit30) by shifting it into... + shll k0 ! ...the T bit + bt/s 1f ! It's a kernel to kernel transition. + mov r15, k0 ! save original stack to k0 + /* User space to kernel */ + mov #(THREAD_SIZE >> 8), k1 + shll8 k1 ! k1 := THREAD_SIZE + add current, k1 + mov k1, r15 ! change to kernel stack + ! +1: mov.l 2f, k1 + ! +#ifdef CONFIG_SH_DSP + mov.l r2, @-r15 ! Save r2, we need another reg + stc sr, k4 + mov.l 1f, r2 + tst r2, k4 ! Check if in DSP mode + mov.l @r15+, r2 ! Restore r2 now + bt/s skip_save + mov #0, k4 ! Set marker for no stack frame + + mov r2, k4 ! Backup r2 (in k4) for later + + ! Save DSP registers on stack + stc.l mod, @-r15 + stc.l re, @-r15 + stc.l rs, @-r15 + sts.l dsr, @-r15 + sts.l y1, @-r15 + sts.l y0, @-r15 + sts.l x1, @-r15 + sts.l x0, @-r15 + sts.l a0, @-r15 + + ! GAS is broken, does not generate correct "movs.l Ds,@-As" instr. + + ! FIXME: Make sure that this is still the case with newer toolchains, + ! as we're not at all interested in supporting ancient toolchains at + ! this point. -- PFM. + + mov r15, r2 + .word 0xf653 ! movs.l a1, @-r2 + .word 0xf6f3 ! movs.l a0g, @-r2 + .word 0xf6d3 ! movs.l a1g, @-r2 + .word 0xf6c3 ! movs.l m0, @-r2 + .word 0xf6e3 ! movs.l m1, @-r2 + mov r2, r15 + + mov k4, r2 ! Restore r2 + mov.l 1f, k4 ! Force DSP stack frame +skip_save: + mov.l k4, @-r15 ! Push DSP mode marker onto stack +#endif + ! Save the user registers on the stack. + mov.l k2, @-r15 ! EXPEVT + + mov #-1, k4 + mov.l k4, @-r15 ! set TRA (default: -1) + ! + sts.l macl, @-r15 + sts.l mach, @-r15 + stc.l gbr, @-r15 + stc.l ssr, @-r15 + sts.l pr, @-r15 + stc.l spc, @-r15 + ! + lds k3, pr ! Set the return address to pr + ! + mov.l k0, @-r15 ! save orignal stack + mov.l r14, @-r15 + mov.l r13, @-r15 + mov.l r12, @-r15 + mov.l r11, @-r15 + mov.l r10, @-r15 + mov.l r9, @-r15 + mov.l r8, @-r15 + ! + stc sr, r8 ! Back to normal register bank, and + or k1, r8 ! Block all interrupts + mov.l 3f, k1 + and k1, r8 ! ... + ldc r8, sr ! ...changed here. + ! + mov.l r7, @-r15 + mov.l r6, @-r15 + mov.l r5, @-r15 + mov.l r4, @-r15 + mov.l r3, @-r15 + mov.l r2, @-r15 + mov.l r1, @-r15 + mov.l r0, @-r15 + + /* + * This gets a bit tricky.. in the INTEVT case we don't want to use + * the VBR offset as a destination in the jump call table, since all + * of the destinations are the same. In this case, (interrupt) sets + * a marker in r2 (now r2_bank since SR.RB changed), which we check + * to determine the exception type. For all other exceptions, we + * forcibly read EXPEVT from memory and fix up the jump address, in + * the interrupt exception case we jump to do_IRQ() and defer the + * INTEVT read until there. As a bonus, we can also clean up the SR.RB + * checks that do_IRQ() was doing.. + */ + stc r2_bank, r8 + cmp/pz r8 + bf interrupt_exception + shlr2 r8 + shlr r8 + mov.l 4f, r9 + add r8, r9 + mov.l @r9, r9 + jmp @r9 + nop + rts + nop + + .align 2 +1: .long 0x00001000 ! DSP=1 +2: .long 0x000080f0 ! FD=1, IMASK=15 +3: .long 0xcfffffff ! RB=0, BL=0 +4: .long exception_handling_table + +interrupt_exception: + mov.l 1f, r9 + jmp @r9 + nop + rts + nop + + .align 2 +1: .long do_IRQ + + .align 2 +ENTRY(exception_none) + rts + nop |