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Diffstat (limited to 'arch/sh/kernel/cpu/sh3/entry.S')
| -rw-r--r-- | arch/sh/kernel/cpu/sh3/entry.S | 509 |
1 files changed, 509 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 0000000000..b1f5b3c58a --- /dev/null +++ b/arch/sh/kernel/cpu/sh3/entry.S @@ -0,0 +1,509 @@ +/* SPDX-License-Identifier: GPL-2.0 + * + * arch/sh/kernel/cpu/sh3/entry.S + * + * Copyright (C) 1999, 2000, 2002 Niibe Yutaka + * Copyright (C) 2003 - 2012 Paul Mundt + */ +#include <linux/sys.h> +#include <linux/errno.h> +#include <linux/linkage.h> +#include <asm/asm-offsets.h> +#include <asm/thread_info.h> +#include <asm/unistd.h> +#include <cpu/mmu_context.h> +#include <asm/page.h> +#include <asm/cache.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 # + * + */ +/* 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_handle_tlbmiss + mov #0, r5 + + .align 2 +ENTRY(tlb_miss_store) + bra call_handle_tlbmiss + mov #FAULT_CODE_WRITE, r5 + + .align 2 +ENTRY(initial_page_write) + bra call_handle_tlbmiss + mov #FAULT_CODE_INITIAL, r5 + + .align 2 +ENTRY(tlb_protection_violation_load) + bra call_do_page_fault + mov #FAULT_CODE_PROT, r5 + + .align 2 +ENTRY(tlb_protection_violation_store) + bra call_do_page_fault + mov #(FAULT_CODE_PROT | FAULT_CODE_WRITE), r5 + +call_handle_tlbmiss: + mov.l 1f, r0 + mov r5, r8 + mov.l @r0, r6 + mov.l 2f, r0 + sts pr, r10 + jsr @r0 + mov r15, r4 + ! + tst r0, r0 + bf/s 0f + lds r10, pr + rts + nop +0: + mov r8, r5 +call_do_page_fault: + mov.l 1f, r0 + mov.l @r0, r6 + + mov.l 3f, r0 + mov.l 4f, r1 + mov r15, r4 + jmp @r0 + lds r1, pr + + .align 2 +1: .long MMU_TEA +2: .long handle_tlbmiss +3: .long do_page_fault +4: .long ret_from_exception + + .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 */ +ENTRY(sh_bios_handler) + mov.l 1f, r8 + bsr restore_regs + nop + + lds k2, pr ! restore pr + mov k4, r15 + ! + mov.l 2f, k0 + mov.l @k0, k0 + jmp @k0 + ldc k3, ssr + .align 2 +1: .long 0x300000f0 +2: .long gdb_vbr_vector +#endif /* CONFIG_SH_STANDARD_BIOS */ + +! restore_regs() +! - restore r0, r1, r2, r3, r4, r5, r6, r7 from the stack +! - switch bank +! - restore r8, r9, r10, r11, r12, r13, r14, r15 from the stack +! - restore spc, pr*, ssr, gbr, mach, macl, skip default tra +! k2 returns original pr +! k3 returns original sr +! k4 returns original stack pointer +! r8 passes SR bitmask, overwritten with restored data on return +! r9 trashed +! BL=0 on entry, on exit BL=1 (depending on r8). + +ENTRY(restore_regs) + 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, r9 + or r8, r9 + ldc r9, sr + ! + 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 + mov.l @r15+, k2 ! original PR + mov.l @r15+, k3 ! original SR + ldc.l @r15+, gbr + lds.l @r15+, mach + lds.l @r15+, macl + rts + add #4, r15 ! Skip syscall number + +restore_all: + mov.l 7f, r8 + bsr restore_regs + nop + + lds k2, pr ! restore pr + ! + ! Calculate new SR value + mov k3, k2 ! original SR value + mov #0xfffffff0, k1 + extu.b k1, k1 + not k1, k1 + and k1, k2 ! Mask original 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 + ! + mov k4, r15 + rte + nop + + .align 2 +5: .long 0x00001000 ! DSP +7: .long 0x30000000 + +! common exception handler +#include "../../entry-common.S" + +! Exception Vector Base +! +! Should be aligned page boundary. +! + .balign 4096,0,4096 +ENTRY(vbr_base) + .long 0 +! +! 0x100: General exception vector +! + .balign 256,0,256 +general_exception: + bra handle_exception + sts pr, k3 ! save original pr value in k3 + +! prepare_stack() +! - roll back gRB +! - switch to kernel stack +! k0 returns original sp (after roll back) +! k1 trashed +! k2 trashed + +prepare_stack: +#ifdef CONFIG_GUSA + ! Check for roll back gRB (User and Kernel) + mov r15, k0 + shll k0 + bf/s 1f + shll k0 + bf/s 1f + stc spc, k1 + stc r0_bank, k0 + cmp/hs k0, k1 ! test k1 (saved PC) >= k0 (saved r0) + bt/s 2f + stc r1_bank, k1 + + add #-2, k0 + add r15, k0 + ldc k0, spc ! PC = saved r0 + r15 - 2 +2: mov k1, r15 ! SP = r1 +1: +#endif + ! Switch to kernel stack if needed + 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 >> 10), k1 + shll8 k1 ! k1 := THREAD_SIZE + shll2 k1 + add current, k1 + mov k1, r15 ! change to kernel stack + ! +1: + rts + nop + +! +! 0x400: Instruction and Data TLB miss exception vector +! + .balign 1024,0,1024 +tlb_miss: + sts pr, k3 ! save original pr value in k3 + +handle_exception: + mova exception_data, k0 + + ! Setup stack and save DSP context (k0 contains original r15 on return) + bsr prepare_stack + PREF(k0) + + ! Save registers / Switch to bank 0 + mov.l 5f, k2 ! vector register address + mov.l 1f, k4 ! SR bits to clear in k4 + bsr save_regs ! needs original pr value in k3 + mov.l @k2, k2 ! read out vector and keep in k2 + +handle_exception_special: + setup_frame_reg + + ! Setup return address and jump to exception handler + mov.l 7f, r9 ! fetch return address + stc r2_bank, r0 ! k2 (vector) + mov.l 6f, r10 + shlr2 r0 + shlr r0 + mov.l @(r0, r10), r10 + jmp @r10 + lds r9, pr ! put return address in pr + + .align L1_CACHE_SHIFT + +! save_regs() +! - save default tra, macl, mach, gbr, ssr, pr* and spc on the stack +! - save r15*, r14, r13, r12, r11, r10, r9, r8 on the stack +! - switch bank +! - save r7, r6, r5, r4, r3, r2, r1, r0 on the stack +! k0 contains original stack pointer* +! k1 trashed +! k3 passes original pr* +! k4 passes SR bitmask +! BL=1 on entry, on exit BL=0. + +ENTRY(save_regs) + mov #-1, r1 + mov.l k1, @-r15 ! set TRA (default: -1) + sts.l macl, @-r15 + sts.l mach, @-r15 + stc.l gbr, @-r15 + stc.l ssr, @-r15 + mov.l k3, @-r15 ! original pr in k3 + stc.l spc, @-r15 + + mov.l k0, @-r15 ! original stack pointer in k0 + 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 + + mov.l 0f, k3 ! SR bits to set in k3 + + ! fall-through + +! save_low_regs() +! - modify SR for bank switch +! - save r7, r6, r5, r4, r3, r2, r1, r0 on the stack +! k3 passes bits to set in SR +! k4 passes bits to clear in SR + +ENTRY(save_low_regs) + stc sr, r8 + or k3, r8 + and k4, r8 + ldc r8, sr + + 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 + rts + mov.l r0, @-r15 + +! +! 0x600: Interrupt / NMI vector +! + .balign 512,0,512 +ENTRY(handle_interrupt) + sts pr, k3 ! save original pr value in k3 + mova exception_data, k0 + + ! Setup stack and save DSP context (k0 contains original r15 on return) + bsr prepare_stack + PREF(k0) + + ! Save registers / Switch to bank 0 + mov.l 1f, k4 ! SR bits to clear in k4 + bsr save_regs ! needs original pr value in k3 + mov #-1, k2 ! default vector kept in k2 + + setup_frame_reg + + stc sr, r0 ! get status register + shlr2 r0 + and #0x3c, r0 + cmp/eq #0x3c, r0 + bf 9f + TRACE_IRQS_OFF +9: + + ! Setup return address and jump to do_IRQ + mov.l 4f, r9 ! fetch return address + lds r9, pr ! put return address in pr + mov.l 2f, r4 + mov.l 3f, r9 + mov.l @r4, r4 ! pass INTEVT vector as arg0 + + shlr2 r4 + shlr r4 + mov r4, r0 ! save vector->jmp table offset for later + + shlr2 r4 ! vector to IRQ# conversion + + mov #0x10, r5 + cmp/hs r5, r4 ! is it a valid IRQ? + bt 10f + + /* + * We got here as a result of taking the INTEVT path for something + * that isn't a valid hard IRQ, therefore we bypass the do_IRQ() + * path and special case the event dispatch instead. This is the + * expected path for the NMI (and any other brilliantly implemented + * exception), which effectively wants regular exception dispatch + * but is unfortunately reported through INTEVT rather than + * EXPEVT. Grr. + */ + mov.l 6f, r9 + mov.l @(r0, r9), r9 + jmp @r9 + mov r15, r8 ! trap handlers take saved regs in r8 + +10: + jmp @r9 ! Off to do_IRQ() we go. + mov r15, r5 ! pass saved registers as arg1 + +ENTRY(exception_none) + rts + nop + + .align L1_CACHE_SHIFT +exception_data: +0: .long 0x000080f0 ! FD=1, IMASK=15 +1: .long 0xcfffffff ! RB=0, BL=0 +2: .long INTEVT +3: .long do_IRQ +4: .long ret_from_irq +5: .long EXPEVT +6: .long exception_handling_table +7: .long ret_from_exception |