diff options
-rw-r--r-- | arch/arc/include/asm/dwarf.h | 32 | ||||
-rw-r--r-- | arch/arc/kernel/Makefile | 9 | ||||
-rw-r--r-- | arch/arc/kernel/ctx_sw.c | 103 | ||||
-rw-r--r-- | arch/arc/kernel/ctx_sw_asm.S | 72 |
4 files changed, 61 insertions, 155 deletions
diff --git a/arch/arc/include/asm/dwarf.h b/arch/arc/include/asm/dwarf.h index 5f4de05bd4ee..a0d5ebe1bc3f 100644 --- a/arch/arc/include/asm/dwarf.h +++ b/arch/arc/include/asm/dwarf.h @@ -10,23 +10,31 @@ #ifdef ARC_DW2_UNWIND_AS_CFI -#define CFI_STARTPROC .cfi_startproc -#define CFI_ENDPROC .cfi_endproc -#define CFI_DEF_CFA .cfi_def_cfa -#define CFI_REGISTER .cfi_register -#define CFI_REL_OFFSET .cfi_rel_offset -#define CFI_UNDEFINED .cfi_undefined +#define CFI_STARTPROC .cfi_startproc +#define CFI_ENDPROC .cfi_endproc +#define CFI_DEF_CFA .cfi_def_cfa +#define CFI_DEF_CFA_OFFSET .cfi_def_cfa_offset +#define CFI_DEF_CFA_REGISTER .cfi_def_cfa_register +#define CFI_OFFSET .cfi_offset +#define CFI_REL_OFFSET .cfi_rel_offset +#define CFI_REGISTER .cfi_register +#define CFI_RESTORE .cfi_restore +#define CFI_UNDEFINED .cfi_undefined #else #define CFI_IGNORE # -#define CFI_STARTPROC CFI_IGNORE -#define CFI_ENDPROC CFI_IGNORE -#define CFI_DEF_CFA CFI_IGNORE -#define CFI_REGISTER CFI_IGNORE -#define CFI_REL_OFFSET CFI_IGNORE -#define CFI_UNDEFINED CFI_IGNORE +#define CFI_STARTPROC CFI_IGNORE +#define CFI_ENDPROC CFI_IGNORE +#define CFI_DEF_CFA CFI_IGNORE +#define CFI_DEF_CFA_OFFSET CFI_IGNORE +#define CFI_DEF_CFA_REGISTER CFI_IGNORE +#define CFI_OFFSET CFI_IGNORE +#define CFI_REL_OFFSET CFI_IGNORE +#define CFI_REGISTER CFI_IGNORE +#define CFI_RESTORE CFI_IGNORE +#define CFI_UNDEFINED CFI_IGNORE #endif /* !ARC_DW2_UNWIND_AS_CFI */ diff --git a/arch/arc/kernel/Makefile b/arch/arc/kernel/Makefile index 0723d888ac44..95fbf9364c67 100644 --- a/arch/arc/kernel/Makefile +++ b/arch/arc/kernel/Makefile @@ -5,6 +5,8 @@ obj-y := head.o arcksyms.o setup.o irq.o reset.o ptrace.o process.o devtree.o obj-y += signal.o traps.o sys.o troubleshoot.o stacktrace.o disasm.o +obj-y += ctx_sw_asm.o + obj-$(CONFIG_ISA_ARCOMPACT) += entry-compact.o intc-compact.o obj-$(CONFIG_ISA_ARCV2) += entry-arcv2.o intc-arcv2.o @@ -24,11 +26,4 @@ ifdef CONFIG_ISA_ARCOMPACT CFLAGS_fpu.o += -mdpfp endif -ifdef CONFIG_ARC_DW2_UNWIND -CFLAGS_ctx_sw.o += -fno-omit-frame-pointer -obj-y += ctx_sw.o -else -obj-y += ctx_sw_asm.o -endif - extra-y := vmlinux.lds diff --git a/arch/arc/kernel/ctx_sw.c b/arch/arc/kernel/ctx_sw.c deleted file mode 100644 index 40d89440b7e4..000000000000 --- a/arch/arc/kernel/ctx_sw.c +++ /dev/null @@ -1,103 +0,0 @@ -// SPDX-License-Identifier: GPL-2.0-only -/* - * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) - * - * Vineetg: Aug 2009 - * -"C" version of lowest level context switch asm macro called by schedular - * gcc doesn't generate the dward CFI info for hand written asm, hence can't - * backtrace out of it (e.g. tasks sleeping in kernel). - * So we cheat a bit by writing almost similar code in inline-asm. - * -This is a hacky way of doing things, but there is no other simple way. - * I don't want/intend to extend unwinding code to understand raw asm - */ - -#include <asm/asm-offsets.h> -#include <asm/switch_to.h> -#include <linux/sched/debug.h> - -#define KSP_WORD_OFF ((TASK_THREAD + THREAD_KSP) / 4) - -struct task_struct *__sched -__switch_to(struct task_struct *prev_task, struct task_struct *next_task) -{ - unsigned int tmp; - unsigned int prev = (unsigned int)prev_task; - unsigned int next = (unsigned int)next_task; - - __asm__ __volatile__( - /* FP/BLINK save generated by gcc (standard function prologue */ - "st.a r13, [sp, -4] \n\t" - "st.a r14, [sp, -4] \n\t" - "st.a r15, [sp, -4] \n\t" - "st.a r16, [sp, -4] \n\t" - "st.a r17, [sp, -4] \n\t" - "st.a r18, [sp, -4] \n\t" - "st.a r19, [sp, -4] \n\t" - "st.a r20, [sp, -4] \n\t" - "st.a r21, [sp, -4] \n\t" - "st.a r22, [sp, -4] \n\t" - "st.a r23, [sp, -4] \n\t" - "st.a r24, [sp, -4] \n\t" - "st.a r25, [sp, -4] \n\t" - - /* set ksp of outgoing task in tsk->thread.ksp */ -#if KSP_WORD_OFF <= 255 - "st.as sp, [%3, %1] \n\t" -#else - /* - * Workaround for NR_CPUS=4k - * %1 is bigger than 255 (S9 offset for st.as) - */ - "add2 r24, %3, %1 \n\t" - "st sp, [r24] \n\t" -#endif - - /* - * setup _current_task with incoming tsk. - * optionally, set caching reg to that as well - * For SMP extra work to get to &_current_task[cpu] - * (open coded SET_CURR_TASK_ON_CPU) - */ -#ifndef CONFIG_SMP - "st %2, [@_current_task] \n\t" -#else - "lr r24, [identity] \n\t" - "lsr r24, r24, 8 \n\t" - "bmsk r24, r24, 7 \n\t" - "add2 r24, @_current_task, r24 \n\t" - "st %2, [r24] \n\t" -#endif -#ifdef CONFIG_ARC_CURR_IN_REG - "mov gp, %2 \n\t" -#endif - - /* get ksp of incoming task from tsk->thread.ksp */ - "ld.as sp, [%2, %1] \n\t" - - /* start loading it's CALLEE reg file */ - "ld.ab r25, [sp, 4] \n\t" - "ld.ab r24, [sp, 4] \n\t" - "ld.ab r23, [sp, 4] \n\t" - "ld.ab r22, [sp, 4] \n\t" - "ld.ab r21, [sp, 4] \n\t" - "ld.ab r20, [sp, 4] \n\t" - "ld.ab r19, [sp, 4] \n\t" - "ld.ab r18, [sp, 4] \n\t" - "ld.ab r17, [sp, 4] \n\t" - "ld.ab r16, [sp, 4] \n\t" - "ld.ab r15, [sp, 4] \n\t" - "ld.ab r14, [sp, 4] \n\t" - "ld.ab r13, [sp, 4] \n\t" - - /* last (ret value) = prev : although for ARC it mov r0, r0 */ - "mov %0, %3 \n\t" - - /* FP/BLINK restore generated by gcc (standard func epilogue */ - - : "=r"(tmp) - : "n"(KSP_WORD_OFF), "r"(next), "r"(prev) - : "blink" - ); - - return (struct task_struct *)tmp; -} diff --git a/arch/arc/kernel/ctx_sw_asm.S b/arch/arc/kernel/ctx_sw_asm.S index 95cba6265e2b..59d779004e64 100644 --- a/arch/arc/kernel/ctx_sw_asm.S +++ b/arch/arc/kernel/ctx_sw_asm.S @@ -13,48 +13,54 @@ #define KSP_WORD_OFF ((TASK_THREAD + THREAD_KSP) / 4) -;################### Low Level Context Switch ########################## +; IN +; - r0: prev task (also current) +; - r1: next task +; OUT +; - r0: prev task (so r0 not touched) .section .sched.text,"ax",@progbits - .align 4 - .global __switch_to - .type __switch_to, @function -__switch_to: - CFI_STARTPROC - - /* Save regs on kernel mode stack of task */ - st.a blink, [sp, -4] - st.a fp, [sp, -4] +ENTRY_CFI(__switch_to) + + /* save kernel stack frame regs of @prev task */ + push blink + CFI_DEF_CFA_OFFSET 4 + CFI_OFFSET r31, -4 + + push fp + CFI_DEF_CFA_OFFSET 8 + CFI_OFFSET r27, -8 + + mov fp, sp + CFI_DEF_CFA_REGISTER r27 + + /* kernel mode callee regs of @prev */ SAVE_CALLEE_SAVED_KERNEL - /* Save the now KSP in task->thread.ksp */ + /* save final SP to @prev->thread.ksp */ #if KSP_WORD_OFF <= 255 st.as sp, [r0, KSP_WORD_OFF] #else /* Workaround for NR_CPUS=4k as ST.as can only take s9 offset */ - add2 r24, r0, KSP_WORD_OFF - st sp, [r24] + add2 r10, r0, KSP_WORD_OFF + st sp, [r10] #endif - /* - * Return last task in r0 (return reg) - * On ARC, Return reg = First Arg reg = r0. - * Since we already have last task in r0, - * don't need to do anything special to return it - */ - - /* - * switch to new task, contained in r1 - * Temp reg r3 is required to get the ptr to store val - */ - SET_CURR_TASK_ON_CPU r1, r3 - - /* reload SP with kernel mode stack pointer in task->thread.ksp */ - ld.as sp, [r1, KSP_WORD_OFF] - - /* restore the registers */ + /* update @next in _current_task[] and GP register caching it */ + SET_CURR_TASK_ON_CPU r1, r10 + + /* load SP from @next->thread.ksp */ + ld.as sp, [r1, KSP_WORD_OFF] + + /* restore callee regs, stack frame regs of @next */ RESTORE_CALLEE_SAVED_KERNEL - ld.ab fp, [sp, 4] - ld.ab blink, [sp, 4] - j [blink] + pop fp + CFI_RESTORE r27 + CFI_DEF_CFA r28, 4 + + pop blink + CFI_RESTORE r31 + CFI_DEF_CFA_OFFSET 0 + + j [blink] END_CFI(__switch_to) |