b36292e232
Interrupts where not correctly masked while in kernel, which breaks one of the current main assumptions. Also remove some duplication on ARM asm files, and add a function to check the status of ARM irqs (not compiled by default) Change-Id: I3c25d2b388f93fd8fe423998b94b3c4f140ba831
295 lines
7.2 KiB
ArmAsm
295 lines
7.2 KiB
ArmAsm
/* This file is part of the lowest layer of the MINIX kernel. (The other part
|
|
* is "proc.c".) The lowest layer does process switching and message handling.
|
|
*
|
|
* Kernel is entered either because of kernel-calls, ipc-calls, interrupts or
|
|
* exceptions. TSS is set so that the kernel stack is loaded. The user context is
|
|
* saved to the proc table and the handler of the event is called. Once the
|
|
* handler is done, switch_to_user() function is called to pick a new process,
|
|
* finish what needs to be done for the next process to run, sets its context
|
|
* and switch to userspace.
|
|
*/
|
|
|
|
#include "kernel/kernel.h" /* configures the kernel */
|
|
|
|
/* sections */
|
|
|
|
#include <machine/vm.h>
|
|
#include "kernel/kernel.h"
|
|
#include <minix/config.h>
|
|
#include <minix/const.h>
|
|
#include <minix/com.h>
|
|
#include <machine/asm.h>
|
|
#include <machine/interrupt.h>
|
|
#include "archconst.h"
|
|
#include "kernel/const.h"
|
|
#include "kernel/proc.h"
|
|
#include "sconst.h"
|
|
#include <machine/multiboot.h>
|
|
#include <machine/ipcconst.h>
|
|
#include <machine/cpu.h>
|
|
#include "omap_intr.h"
|
|
|
|
#include "arch_proto.h" /* K_STACK_SIZE */
|
|
|
|
IMPORT(svc_stack)
|
|
|
|
/*
|
|
* Adjust lr, switch to SVC mode, and push pc/psr when exception triggered
|
|
* The 'lr_offset' argument holds the adjustment. It differs based on
|
|
* which mode the CPU is in.
|
|
*/
|
|
.macro switch_to_svc lr_offset
|
|
sub lr, lr, #\lr_offset
|
|
srsdb sp!, #MODE_SVC
|
|
cps #MODE_SVC
|
|
.endm
|
|
|
|
/*
|
|
* Test if the exception/interrupt occured in the kernel.
|
|
* Jump to 'label' argument if it occurred in the kernel.
|
|
*
|
|
* NOTE: switch_to_svc must be called first
|
|
*/
|
|
.macro test_int_in_kernel, label
|
|
push {r3}
|
|
ldr r3, [sp, #8] /* spsr */
|
|
orr r3, r3, #(PSR_F | PSR_I) /* mask interrupts on return */
|
|
str r3, [sp, #8] /* spsr */
|
|
and r3, r3, #PSR_MODE_MASK
|
|
cmp r3, #MODE_USR
|
|
pop {r3}
|
|
bne \label /* In-kernel handling */
|
|
.endm
|
|
|
|
/* Save the register context to the proc structure */
|
|
.macro save_process_ctx
|
|
add sp, sp, #8 /* srsdb pushed cpsr and pc on the stack */
|
|
ldr lr, [sp] /* lr = proc_ptr */
|
|
stm lr, {r0-r14}^ /* proc_ptr->p_reg.r0-r14 = r0-r14 */
|
|
ldr r12, [sp, #-8] /* r12 = pc stored on the stack */
|
|
str r12, [lr, #PCREG] /* proc_ptr->p_reg.pc = r12 */
|
|
ldr r12, [sp, #-4] /* r12 = cpsr stored on the stack */
|
|
str r12, [lr, #PSREG] /* proc_ptr->p_reg.psr = r12 */
|
|
.endm
|
|
|
|
.macro exception_handler exc_name, exc_num, lr_offset
|
|
ENTRY(\exc_name\()_entry)
|
|
switch_to_svc \lr_offset
|
|
test_int_in_kernel \exc_name\()_entry_nested
|
|
|
|
\exc_name\()entry_from_user:
|
|
save_process_ctx
|
|
|
|
/* save the pointer to the current process */
|
|
ldr fp, [sp]
|
|
/* save the exception pc (saved lr_user) */
|
|
ldr r4, [fp, #PCREG]
|
|
|
|
/* stop user process cycles */
|
|
mov r0, fp /* first param: caller proc ptr */
|
|
mov fp, #0 /* for stack trace */
|
|
bl _C_LABEL(context_stop)
|
|
|
|
/*
|
|
* push a pointer to the interrupt state pushed by the cpu and the
|
|
* vector number pushed by the vector handler just before calling
|
|
* exception_entry and call the exception handler.
|
|
*/
|
|
mov r0, #0 /* it's not a nested exception */
|
|
mov r1, r4 /* saved lr */
|
|
mov r2, #\exc_num /* vector number */
|
|
bl _C_LABEL(exception_handler)
|
|
|
|
b _C_LABEL(switch_to_user)
|
|
|
|
\exc_name\()_entry_nested:
|
|
push {r0-r12, lr}
|
|
mov r0, #1 /* it's a nested exception */
|
|
add r1, sp, #56 /* saved lr */
|
|
mov r2, #\exc_num /* vector number */
|
|
bl _C_LABEL(exception_handler)
|
|
pop {r0-r12, lr}
|
|
rfeia sp!
|
|
.endm
|
|
|
|
|
|
/* Exception handlers */
|
|
exception_handler data_abort DATA_ABORT_VECTOR 8
|
|
exception_handler prefetch_abort PREFETCH_ABORT_VECTOR 4
|
|
exception_handler undefined_inst UNDEFINED_INST_VECTOR 4
|
|
|
|
|
|
ENTRY(irq_entry)
|
|
switch_to_svc 4
|
|
test_int_in_kernel irq_entry_from_kernel
|
|
|
|
irq_entry_from_user:
|
|
save_process_ctx
|
|
|
|
/* save the pointer to the current process */
|
|
ldr fp, [sp]
|
|
|
|
push {fp} /* save caller proc ptr */
|
|
|
|
/* stop user process cycles */
|
|
mov r0, fp /* first param: caller proc ptr */
|
|
mov fp, #0 /* for stack trace */
|
|
bl _C_LABEL(context_stop)
|
|
|
|
/* get irq num */
|
|
ldr r3, =OMAP3_INTR_SIR_IRQ
|
|
ldr r0, [r3]
|
|
and r0, r0, #OMAP3_INTR_ACTIVEIRQ_MASK /* irq */
|
|
/* call handler */
|
|
bl _C_LABEL(irq_handle) /* irq_handle(irq) */
|
|
|
|
pop {fp} /* caller proc ptr */
|
|
|
|
/* allow new interrupts */
|
|
mov r1, #OMAP3_INTR_NEWIRQAGR
|
|
ldr r3, =OMAP3_INTR_CONTROL
|
|
str r1, [r3]
|
|
|
|
/* data synchronization barrier */
|
|
dsb
|
|
|
|
b _C_LABEL(switch_to_user)
|
|
|
|
irq_entry_from_kernel:
|
|
push {r0-r12, lr}
|
|
bl _C_LABEL(context_stop_idle)
|
|
|
|
/* get irq num */
|
|
ldr r3, =OMAP3_INTR_SIR_IRQ
|
|
ldr r0, [r3]
|
|
and r0, r0, #OMAP3_INTR_ACTIVEIRQ_MASK /* irq */
|
|
/* call handler */
|
|
bl _C_LABEL(irq_handle) /* irq_handle(irq) */
|
|
|
|
/* allow new interrupts */
|
|
mov r1, #OMAP3_INTR_NEWIRQAGR
|
|
ldr r3, =OMAP3_INTR_CONTROL
|
|
str r1, [r3]
|
|
|
|
/* data synchronization barrier */
|
|
dsb
|
|
|
|
pop {r0-r12, lr}
|
|
rfeia sp!
|
|
|
|
|
|
/*
|
|
* supervisor call (SVC) kernel entry point
|
|
*/
|
|
ENTRY(svc_entry)
|
|
srsdb sp!, #MODE_SVC
|
|
save_process_ctx
|
|
|
|
/* save the pointer to the current process */
|
|
ldr fp, [sp]
|
|
|
|
cmp r3, #KERVEC
|
|
beq kernel_call_entry
|
|
cmp r3, #IPCVEC
|
|
beq ipc_entry
|
|
b invalid_svc
|
|
|
|
/*
|
|
* kernel call is only from a process to kernel
|
|
*/
|
|
ENTRY(kernel_call_entry)
|
|
/*
|
|
* pass the syscall arguments from userspace to the handler.
|
|
* save_process_ctx() does not clobber these registers, they are still
|
|
* set as the userspace has set them
|
|
*/
|
|
push {fp} /* save caller proc ptr */
|
|
push {r0} /* save msg ptr so it's not clobbered */
|
|
|
|
/* stop user process cycles */
|
|
mov r0, fp /* first param: caller proc ptr */
|
|
mov fp, #0 /* for stack trace */
|
|
bl _C_LABEL(context_stop)
|
|
|
|
pop {r0} /* first param: msg ptr */
|
|
pop {r1} /* second param: caller proc ptr */
|
|
bl _C_LABEL(kernel_call)
|
|
|
|
b _C_LABEL(switch_to_user)
|
|
|
|
/*
|
|
* IPC is only from a process to kernel
|
|
*/
|
|
ENTRY(ipc_entry)
|
|
/*
|
|
* pass the syscall arguments from userspace to the handler.
|
|
* save_process_ctx() does not clobber these registers, they are still
|
|
* set as the userspace have set them
|
|
*/
|
|
push {fp} /* save caller proc ptr */
|
|
push {r0-r2} /* save regs so they're not clobbered */
|
|
|
|
/* stop user process cycles */
|
|
mov r0, fp /* first param: caller proc ptr */
|
|
mov fp, #0 /* for stack trace */
|
|
bl _C_LABEL(context_stop)
|
|
|
|
pop {r0-r2} /* restore regs */
|
|
bl _C_LABEL(do_ipc)
|
|
|
|
/* restore the current process pointer and save the return value */
|
|
pop {fp} /* caller proc ptr */
|
|
str r0, [fp, #REG0]
|
|
|
|
b _C_LABEL(switch_to_user)
|
|
|
|
ENTRY(invalid_svc)
|
|
b .
|
|
|
|
ENTRY(restore_user_context)
|
|
/* sp holds the proc ptr */
|
|
mov sp, r0
|
|
|
|
/* Set SPSR and LR for return */
|
|
ldr r0, [sp, #PSREG]
|
|
msr spsr_fsxc, r0
|
|
ldr lr, [sp, #PCREG]
|
|
|
|
/* Restore user-mode registers from proc struct */
|
|
ldm sp, {r0-r14}^
|
|
|
|
ldr sp, =_C_LABEL(svc_stack)
|
|
ldr sp, [sp]
|
|
|
|
/* To user mode! */
|
|
movs pc, lr
|
|
|
|
/*===========================================================================*/
|
|
/* data */
|
|
/*===========================================================================*/
|
|
|
|
.data
|
|
.short 0x526F /* this must be the first data entry (magic #) */
|
|
.bss
|
|
.data
|
|
.balign 4
|
|
k_initial_stack:
|
|
.space K_STACK_SIZE
|
|
LABEL(__k_unpaged_k_initial_stktop)
|
|
|
|
/*
|
|
* the kernel stack
|
|
*/
|
|
k_boot_stack:
|
|
.space K_STACK_SIZE /* kernel stack */ /* FIXME use macro here */
|
|
LABEL(k_boot_stktop) /* top of kernel stack */
|
|
|
|
.balign K_STACK_SIZE
|
|
LABEL(k_stacks_start)
|
|
|
|
/* two pages for each stack, one for data, other as a sandbox */
|
|
.space 2 * (K_STACK_SIZE * CONFIG_MAX_CPUS)
|
|
|
|
LABEL(k_stacks_end)
|
|
|
|
/* top of kernel stack */
|