diff options
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/arc/Kconfig | 2 | ||||
| -rw-r--r-- | arch/arc/include/asm/arcregs.h | 20 | ||||
| -rw-r--r-- | arch/arc/include/asm/processor.h | 9 | ||||
| -rw-r--r-- | arch/arc/include/asm/ptrace.h | 8 | ||||
| -rw-r--r-- | arch/arc/include/asm/switch_to.h | 41 | ||||
| -rw-r--r-- | arch/arc/kernel/ctx_sw.c | 91 | ||||
| -rw-r--r-- | arch/arc/kernel/ctx_sw_asm.S | 58 | ||||
| -rw-r--r-- | arch/arc/kernel/entry.S | 15 | ||||
| -rw-r--r-- | arch/arc/kernel/fpu.c | 55 | ||||
| -rw-r--r-- | arch/arc/kernel/process.c | 193 |
10 files changed, 484 insertions, 8 deletions
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig index 8789de1..a4e9806 100644 --- a/arch/arc/Kconfig +++ b/arch/arc/Kconfig @@ -17,6 +17,8 @@ config ARC select GENERIC_FIND_FIRST_BIT # for now, we don't need GENERIC_IRQ_PROBE, CONFIG_GENERIC_IRQ_CHIP select GENERIC_IRQ_SHOW + select GENERIC_KERNEL_EXECVE + select GENERIC_KERNEL_THREAD select GENERIC_PENDING_IRQ if SMP select GENERIC_SMP_IDLE_THREAD select HAVE_GENERIC_HARDIRQS diff --git a/arch/arc/include/asm/arcregs.h b/arch/arc/include/asm/arcregs.h index 3fccb04..d764118 100644 --- a/arch/arc/include/asm/arcregs.h +++ b/arch/arc/include/asm/arcregs.h @@ -47,6 +47,17 @@ #define AUX_ITRIGGER 0x40d #define AUX_IPULSE 0x415 +/* + * Floating Pt Registers + * Status regs are read-only (build-time) so need not be saved/restored + */ +#define ARC_AUX_FP_STAT 0x300 +#define ARC_AUX_DPFP_1L 0x301 +#define ARC_AUX_DPFP_1H 0x302 +#define ARC_AUX_DPFP_2L 0x303 +#define ARC_AUX_DPFP_2H 0x304 +#define ARC_AUX_DPFP_STAT 0x305 + #ifndef __ASSEMBLY__ /* @@ -110,6 +121,15 @@ #endif +#ifdef CONFIG_ARC_FPU_SAVE_RESTORE +/* These DPFP regs need to be saved/restored across ctx-sw */ +struct arc_fpu { + struct { + unsigned int l, h; + } aux_dpfp[2]; +}; +#endif + #endif /* __ASEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/arc/include/asm/processor.h b/arch/arc/include/asm/processor.h index bf88cfb..860252e 100644 --- a/arch/arc/include/asm/processor.h +++ b/arch/arc/include/asm/processor.h @@ -29,6 +29,9 @@ struct thread_struct { unsigned long callee_reg; /* pointer to callee regs */ unsigned long fault_address; /* dbls as brkpt holder as well */ unsigned long cause_code; /* Exception Cause Code (ECR) */ +#ifdef CONFIG_ARC_FPU_SAVE_RESTORE + struct arc_fpu fpu; +#endif }; #define INIT_THREAD { \ @@ -54,12 +57,6 @@ unsigned long thread_saved_pc(struct task_struct *t); #define cpu_relax() do { } while (0) -/* - * Create a new kernel thread - */ - -extern int kernel_thread(int (*fn) (void *), void *arg, unsigned long flags); - #define copy_segments(tsk, mm) do { } while (0) #define release_segments(mm) do { } while (0) diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h index 4c93594..3afadef 100644 --- a/arch/arc/include/asm/ptrace.h +++ b/arch/arc/include/asm/ptrace.h @@ -91,6 +91,14 @@ struct callee_regs { #define in_syscall(regs) (((regs->orig_r8) >= 0 && \ (regs->orig_r8 <= NR_syscalls)) ? 1 : 0) +#define current_pt_regs() \ +({ \ + /* open-coded current_thread_info() */ \ + register unsigned long sp asm ("sp"); \ + unsigned long pg_start = (sp & ~(THREAD_SIZE - 1)); \ + (struct pt_regs *)(pg_start + THREAD_SIZE - 4) - 1; \ +}) + #endif /* !__ASSEMBLY__ */ #endif /* __KERNEL__ */ diff --git a/arch/arc/include/asm/switch_to.h b/arch/arc/include/asm/switch_to.h new file mode 100644 index 0000000..1b171ab --- /dev/null +++ b/arch/arc/include/asm/switch_to.h @@ -0,0 +1,41 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#ifndef _ASM_ARC_SWITCH_TO_H +#define _ASM_ARC_SWITCH_TO_H + +#ifndef __ASSEMBLY__ + +#include <linux/sched.h> + +#ifdef CONFIG_ARC_FPU_SAVE_RESTORE + +extern void fpu_save_restore(struct task_struct *p, struct task_struct *n); +#define ARC_FPU_PREV(p, n) fpu_save_restore(p, n) +#define ARC_FPU_NEXT(t) + +#else + +#define ARC_FPU_PREV(p, n) +#define ARC_FPU_NEXT(n) + +#endif /* !CONFIG_ARC_FPU_SAVE_RESTORE */ + +struct task_struct *__switch_to(struct task_struct *p, struct task_struct *n); + +#define switch_to(prev, next, last) \ +do { \ + ARC_FPU_PREV(prev, next); \ + last = __switch_to(prev, next);\ + ARC_FPU_NEXT(next); \ + mb(); \ +} while (0) + +#endif + +#endif diff --git a/arch/arc/kernel/ctx_sw.c b/arch/arc/kernel/ctx_sw.c new file mode 100644 index 0000000..647e37a --- /dev/null +++ b/arch/arc/kernel/ctx_sw.c @@ -0,0 +1,91 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * 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 <linux/sched.h> + +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; + int num_words_to_skip = 1; + + __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" + "sub sp, sp, %4 \n\t" /* create gutter at top */ + + /* set ksp of outgoing task in tsk->thread.ksp */ + "st.as sp, [%3, %1] \n\t" + + "sync \n\t" + + /* + * setup _current_task with incoming tsk. + * optionally, set r25 to that as well + * For SMP extra work to get to &_current_task[cpu] + * (open coded SET_CURR_TASK_ON_CPU) + */ + "st %2, [@_current_task] \n\t" + + /* get ksp of incoming task from tsk->thread.ksp */ + "ld.as sp, [%2, %1] \n\t" + + /* start loading it's CALLEE reg file */ + + "add sp, sp, %4 \n\t" /* skip gutter at top */ + + "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"((TASK_THREAD + THREAD_KSP) / 4), "r"(next), "r"(prev), + "n"(num_words_to_skip * 4) + : "blink" + ); + + return (struct task_struct *)tmp; +} diff --git a/arch/arc/kernel/ctx_sw_asm.S b/arch/arc/kernel/ctx_sw_asm.S new file mode 100644 index 0000000..d897234 --- /dev/null +++ b/arch/arc/kernel/ctx_sw_asm.S @@ -0,0 +1,58 @@ +/* + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + * + * Vineetg: Aug 2009 + * -Moved core context switch macro out of entry.S into this file. + * -This is the more "natural" hand written assembler + */ + +#include <asm/entry.h> /* For the SAVE_* macros */ +#include <asm/asm-offsets.h> +#include <asm/linkage.h> + +;################### Low Level Context Switch ########################## + + .section .sched.text,"ax",@progbits + .align 4 + .global __switch_to + .type __switch_to, @function +__switch_to: + + /* Save regs on kernel mode stack of task */ + st.a blink, [sp, -4] + st.a fp, [sp, -4] + SAVE_CALLEE_SAVED_KERNEL + + /* Save the now KSP in task->thread.ksp */ + st.as sp, [r0, (TASK_THREAD + THREAD_KSP)/4] + + /* + * 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 + */ + + /* hardware memory barrier */ + sync + + /* + * 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, (TASK_THREAD + THREAD_KSP)/4] + + /* restore the registers */ + RESTORE_CALLEE_SAVED_KERNEL + ld.ab fp, [sp, 4] + ld.ab blink, [sp, 4] + j [blink] + +ARC_EXIT __switch_to diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 0b0a190..ed08ac1 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -566,8 +566,19 @@ ARC_ENTRY ret_from_fork ; when the forked child comes here from the __switch_to function ; r0 has the last task pointer. ; put last task in scheduler queue - bl @schedule_tail - b @ret_from_exception + bl @schedule_tail + + ; If kernel thread, jump to it's entry-point + ld r9, [sp, PT_status32] + brne r9, 0, 1f + + jl.d [r14] + mov r0, r13 ; arg to payload + +1: + ; special case of kernel_thread entry point returning back due to + ; kernel_execve() - pretend return from syscall to ret to userland + b ret_from_exception ARC_EXIT ret_from_fork ;################### Special Sys Call Wrappers ########################## diff --git a/arch/arc/kernel/fpu.c b/arch/arc/kernel/fpu.c new file mode 100644 index 0000000..f352e51 --- /dev/null +++ b/arch/arc/kernel/fpu.c @@ -0,0 +1,55 @@ +/* + * fpu.c - save/restore of Floating Point Unit Registers on task switch + * + * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com) + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/sched.h> +#include <asm/switch_to.h> + +/* + * To save/restore FPU regs, simplest scheme would use LR/SR insns. + * However since SR serializes the pipeline, an alternate "hack" can be used + * which uses the FPU Exchange insn (DEXCL) to r/w FPU regs. + * + * Store to 64bit dpfp1 reg from a pair of core regs: + * dexcl1 0, r1, r0 ; where r1:r0 is the 64 bit val + * + * Read from dpfp1 into pair of core regs (w/o clobbering dpfp1) + * mov_s r3, 0 + * daddh11 r1, r3, r3 ; get "hi" into r1 (dpfp1 unchanged) + * dexcl1 r0, r1, r3 ; get "low" into r0 (dpfp1 low clobbered) + * dexcl1 0, r1, r0 ; restore dpfp1 to orig value + * + * However we can tweak the read, so that read-out of outgoing task's FPU regs + * and write of incoming task's regs happen in one shot. So all the work is + * done before context switch + */ + +void fpu_save_restore(struct task_struct *prev, struct task_struct *next) +{ + unsigned int *saveto = &prev->thread.fpu.aux_dpfp[0].l; + unsigned int *readfrom = &next->thread.fpu.aux_dpfp[0].l; + + const unsigned int zero = 0; + + __asm__ __volatile__( + "daddh11 %0, %2, %2\n" + "dexcl1 %1, %3, %4\n" + : "=&r" (*(saveto + 1)), /* early clobber must here */ + "=&r" (*(saveto)) + : "r" (zero), "r" (*(readfrom + 1)), "r" (*(readfrom)) + ); + + __asm__ __volatile__( + "daddh22 %0, %2, %2\n" + "dexcl2 %1, %3, %4\n" + : "=&r"(*(saveto + 3)), /* early clobber must here */ + "=&r"(*(saveto + 2)) + : "r" (zero), "r" (*(readfrom + 3)), "r" (*(readfrom + 2)) + ); +} diff --git a/arch/arc/kernel/process.c b/arch/arc/kernel/process.c index 4d14e56..279e080 100644 --- a/arch/arc/kernel/process.c +++ b/arch/arc/kernel/process.c @@ -40,3 +40,196 @@ SYSCALL_DEFINE0(arc_gettls) { return task_thread_info(current)->thr_ptr; } + +static inline void arch_idle(void) +{ + /* sleep, but enable all interrupts before committing */ + __asm__("sleep 0x3"); +} + +void cpu_idle(void) +{ + /* Since we SLEEP in idle loop, TIF_POLLING_NRFLAG can't be set */ + + /* endless idle loop with no priority at all */ + while (1) { + tick_nohz_idle_enter(); + rcu_idle_enter(); + +doze: + local_irq_disable(); + if (!need_resched()) { + arch_idle(); + goto doze; + } else { + local_irq_enable(); + } + + rcu_idle_exit(); + tick_nohz_idle_exit(); + + schedule_preempt_disabled(); + } +} + +asmlinkage void ret_from_fork(void); + +/* Layout of Child kernel mode stack as setup at the end of this function is + * + * | ... | + * | ... | + * | unused | + * | | + * ------------------ <==== top of Stack (thread.ksp) + * | UNUSED 1 word| + * ------------------ + * | r25 | + * ~ ~ + * | --to-- | (CALLEE Regs of user mode) + * | r13 | + * ------------------ + * | fp | + * | blink | @ret_from_fork + * ------------------ + * | | + * ~ ~ + * ~ ~ + * | | + * ------------------ + * | r12 | + * ~ ~ + * | --to-- | (scratch Regs of user mode) + * | r0 | + * ------------------ + * | UNUSED 1 word| + * ------------------ <===== END of PAGE + */ +int copy_thread(unsigned long clone_flags, + unsigned long usp, unsigned long arg, + struct task_struct *p) +{ + struct pt_regs *c_regs; /* child's pt_regs */ + unsigned long *childksp; /* to unwind out of __switch_to() */ + struct callee_regs *c_callee; /* child's callee regs */ + struct callee_regs *parent_callee; /* paren't callee */ + struct pt_regs *regs = current_pt_regs(); + + /* Mark the specific anchors to begin with (see pic above) */ + c_regs = task_pt_regs(p); + childksp = (unsigned long *)c_regs - 2; /* 2 words for FP/BLINK */ + c_callee = ((struct callee_regs *)childksp) - 1; + + /* + * __switch_to() uses thread.ksp to start unwinding stack + * For kernel threads we don't need to create callee regs, the + * stack layout nevertheless needs to remain the same. + * Also, since __switch_to anyways unwinds callee regs, we use + * this to populate kernel thread entry-pt/args into callee regs, + * so that ret_from_kernel_thread() becomes simpler. + */ + p->thread.ksp = (unsigned long)c_callee; /* THREAD_KSP */ + + /* __switch_to expects FP(0), BLINK(return addr) at top */ + childksp[0] = 0; /* fp */ + childksp[1] = (unsigned long)ret_from_fork; /* blink */ + + if (unlikely(p->flags & PF_KTHREAD)) { + memset(c_regs, 0, sizeof(struct pt_regs)); + + c_callee->r13 = arg; /* argument to kernel thread */ + c_callee->r14 = usp; /* function */ + + return 0; + } + + /*--------- User Task Only --------------*/ + + /* __switch_to expects FP(0), BLINK(return addr) at top of stack */ + childksp[0] = 0; /* for POP fp */ + childksp[1] = (unsigned long)ret_from_fork; /* for POP blink */ + + /* Copy parents pt regs on child's kernel mode stack */ + *c_regs = *regs; + + if (usp) + c_regs->sp = usp; + + c_regs->r0 = 0; /* fork returns 0 in child */ + + parent_callee = ((struct callee_regs *)regs) - 1; + *c_callee = *parent_callee; + + if (unlikely(clone_flags & CLONE_SETTLS)) { + /* + * set task's userland tls data ptr from 4th arg + * clone C-lib call is difft from clone sys-call + */ + task_thread_info(p)->thr_ptr = regs->r3; + } else { + /* Normal fork case: set parent's TLS ptr in child */ + task_thread_info(p)->thr_ptr = + task_thread_info(current)->thr_ptr; + } + + return 0; +} + +/* + * Some archs flush debug and FPU info here + */ +void flush_thread(void) +{ +} + +/* + * Free any architecture-specific thread data structures, etc. + */ +void exit_thread(void) +{ +} + +int dump_fpu(struct pt_regs *regs, elf_fpregset_t *fpu) +{ + return 0; +} + +/* + * API: expected by schedular Code: If thread is sleeping where is that. + * What is this good for? it will be always the scheduler or ret_from_fork. + * So we hard code that anyways. + */ +unsigned long thread_saved_pc(struct task_struct *t) +{ + struct pt_regs *regs = task_pt_regs(t); + unsigned long blink = 0; + + /* + * If the thread being queried for in not itself calling this, then it + * implies it is not executing, which in turn implies it is sleeping, + * which in turn implies it got switched OUT by the schedular. + * In that case, it's kernel mode blink can reliably retrieved as per + * the picture above (right above pt_regs). + */ + if (t != current && t->state != TASK_RUNNING) + blink = *((unsigned int *)regs - 1); + + return blink; +} + +int elf_check_arch(const struct elf32_hdr *x) +{ + unsigned int eflags; + + if (x->e_machine != EM_ARCOMPACT) + return 0; + + eflags = x->e_flags; + if ((eflags & EF_ARC_OSABI_MSK) < EF_ARC_OSABI_V2) { + pr_err("ABI mismatch - you need newer toolchain\n"); + force_sigsegv(SIGSEGV, current); + return 0; + } + + return 1; +} +EXPORT_SYMBOL(elf_check_arch); |