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kernel: Move per-cpu _kernel_t fields into separate struct

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When in SMP mode, the nested/irq_stack/current fields are specific to
the current CPU and not to the kernel as a whole, so we need an array
of these.  Place them in a _cpu_t struct and implement a
_arch_curr_cpu() function to retrieve the pointer.

When not in SMP mode, the first CPU's fields are defined as a unioned
with the first _cpu_t record.  This permits compatibility with legacy
assembly on other platforms.  Long term, all users, including
uniprocessor architectures, should be updated to use the new scheme.

Fundamentally this is just renaming: the structure layout and runtime
code do not change on any existing platforms and won't until someone
defines a second CPU.

Signed-off-by: Andy Ross <andrew.j.ross@intel.com>
This commit is contained in:
Andy Ross 2018-01-25 16:39:35 -08:00 committed by Anas Nashif
parent 9c62cc677d
commit e694656345
7 changed files with 70 additions and 18 deletions
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2
arch/xtensa/core/xtensa-asm2-util.S
View file

@ -232,7 +232,7 @@ _switch_restore_pc:
*/
.align 4
_handle_excint:
EXCINT_HANDLER MISC0, ___kernel_t_nested_OFFSET, ___kernel_t_irq_stack_OFFSET
EXCINT_HANDLER MISC0, ___cpu_t_nested_OFFSET, ___cpu_t_irq_stack_OFFSET
/* Define the actual vectors for the hardware-defined levels with
* DEF_EXCINT. These load a C handler address and jump to our handler

8
arch/xtensa/core/xtensa-asm2.c
View file

@ -140,16 +140,16 @@ static void dump_stack(int *stack)
#if CONFIG_XTENSA_ASM2
static inline void *restore_stack(void *interrupted_stack)
{
if (!_is_preempt(_kernel.current)) {
if (!_is_preempt(_current)) {
return interrupted_stack;
}
int key = irq_lock();
_kernel.current->switch_handle = interrupted_stack;
_kernel.current = _get_next_ready_thread();
_current->switch_handle = interrupted_stack;
_current = _get_next_ready_thread();
void *ret = _kernel.current->switch_handle;
void *ret = _current->switch_handle;
irq_unlock(key);

22
arch/xtensa/include/kernel_arch_func.h
View file

@ -28,6 +28,15 @@ extern void _xt_coproc_init(void);
extern K_THREAD_STACK_DEFINE(_interrupt_stack, CONFIG_ISR_STACK_SIZE);
static ALWAYS_INLINE _cpu_t *_arch_curr_cpu(void)
{
void *val;
__asm__ volatile("rsr.misc0 %0" : "=r"(val));
return val;
}
/**
*
* @brief Performs architecture-specific initialization
@ -40,11 +49,13 @@ extern K_THREAD_STACK_DEFINE(_interrupt_stack, CONFIG_ISR_STACK_SIZE);
*/
static ALWAYS_INLINE void kernel_arch_init(void)
{
_kernel.nested = 0;
_cpu_t *cpu0 = &_kernel.cpus[0];
cpu0->nested = 0;
#if CONFIG_XTENSA_ASM2
_kernel.irq_stack = (K_THREAD_STACK_BUFFER(_interrupt_stack) +
CONFIG_ISR_STACK_SIZE);
cpu0->irq_stack = (K_THREAD_STACK_BUFFER(_interrupt_stack) +
CONFIG_ISR_STACK_SIZE);
/* The asm2 scheme keeps the kernel pointer in MISC0 for easy
* access. That saves 4 bytes of immediate value to store the
@ -52,9 +63,8 @@ static ALWAYS_INLINE void kernel_arch_init(void)
* this record is a per-CPU thing and having it stored in a SR
* already is a big win.
*/
void *cpuptr = &_kernel;
__asm__ volatile("wsr.MISC0 %0; rsync" : : "r"(cpu0));
__asm__ volatile("wsr.MISC0 %0; rsync" : : "r"(cpuptr));
#endif
#if !defined(CONFIG_XTENSA_ASM2) && XCHAL_CP_NUM > 0
@ -102,7 +112,7 @@ static inline void _IntLibInit(void)
}
#endif
#define _is_in_isr() (_kernel.nested != 0)
#define _is_in_isr() (_arch_curr_cpu()->nested != 0)
#endif /* _ASMLANGUAGE */

8
arch/xtensa/soc/esp32/soc.c
View file

@ -11,6 +11,7 @@
#include <xtensa/config/core-isa.h>
#include <xtensa/corebits.h>
#include <kernel_structs.h>
#include <string.h>
#include <toolchain/gcc.h>
#include <zephyr/types.h>
@ -60,6 +61,13 @@ void __attribute__((section(".iram1"))) __start(void)
/* Disable CPU1 while we figure out how to have SMP in Zephyr. */
*app_cpu_config_reg &= ~DPORT_APPCPU_CLKGATE_EN;
/* Initialize the architecture CPU pointer. Some of the
* initialization code wants a valid _current before
* kernel_arch_init() is invoked.
*/
__asm__ volatile("wsr.MISC0 %0; rsync" : : "r"(&_kernel.cpus[0]));
/* Start Zephyr */
_Cstart();

10
kernel/include/kernel_offsets.h
View file

@ -17,14 +17,20 @@
GEN_ABS_SYM_BEGIN(_OffsetAbsSyms)
#ifndef CONFIG_SMP
GEN_OFFSET_SYM(_kernel_t, current);
GEN_OFFSET_SYM(_kernel_t, nested);
GEN_OFFSET_SYM(_kernel_t, irq_stack);
#endif
GEN_OFFSET_SYM(_cpu_t, current);
GEN_OFFSET_SYM(_cpu_t, nested);
GEN_OFFSET_SYM(_cpu_t, irq_stack);
#if defined(CONFIG_THREAD_MONITOR)
GEN_OFFSET_SYM(_kernel_t, threads);
#endif
GEN_OFFSET_SYM(_kernel_t, nested);
GEN_OFFSET_SYM(_kernel_t, irq_stack);
#ifdef CONFIG_SYS_POWER_MANAGEMENT
GEN_OFFSET_SYM(_kernel_t, idle);
#endif

32
kernel/include/kernel_structs.h
View file

@ -79,8 +79,7 @@ struct _ready_q {
typedef struct _ready_q _ready_q_t;
struct _kernel {
struct _cpu {
/* nested interrupt count */
u32_t nested;
@ -89,6 +88,30 @@ struct _kernel {
/* currently scheduled thread */
struct k_thread *current;
};
typedef struct _cpu _cpu_t;
struct _kernel {
/* For compatibility with pre-SMP code, union the first CPU
* record with the legacy fields so code can continue to use
* the "_kernel.XXX" expressions and assembly offsets.
*/
union {
struct _cpu cpus[CONFIG_MP_NUM_CPUS];
#ifndef CONFIG_SMP
struct {
/* nested interrupt count */
u32_t nested;
/* interrupt stack pointer base */
char *irq_stack;
/* currently scheduled thread */
struct k_thread *current;
};
#endif
};
#ifdef CONFIG_SYS_CLOCK_EXISTS
/* queue of timeouts */
@ -131,7 +154,12 @@ typedef struct _kernel _kernel_t;
extern struct _kernel _kernel;
#ifdef CONFIG_SMP
#define _current (_arch_curr_cpu()->current)
#else
#define _current _kernel.current
#endif
#define _ready_q _kernel.ready_q
#define _timeout_q _kernel.timeout_q
#define _threads _kernel.threads

6
kernel/include/kswap.h
View file

@ -34,7 +34,7 @@ static inline unsigned int _Swap(unsigned int key)
struct k_thread *new_thread, *old_thread;
int ret;
old_thread = _kernel.current;
old_thread = _current;
_check_stack_sentinel();
_update_time_slice_before_swap();
@ -43,11 +43,11 @@ static inline unsigned int _Swap(unsigned int key)
old_thread->swap_retval = -EAGAIN;
_kernel.current = new_thread;
_current = new_thread;
_arch_switch(new_thread->switch_handle,
&old_thread->switch_handle);
ret =_kernel.current->swap_retval;
ret = _current->swap_retval;
irq_unlock(key);