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arch/riscv: Get current CPU properly instead of assuming single CPU

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isr.S code currently gets CPU information from global `_kernel` assuming
there's only one CPU. In order to prepare for upcoming SMP support,
change code to actually get current CPU information.

Signed-off-by: Ederson de Souza <ederson.desouza@intel.com>
This commit is contained in:
Ederson de Souza 2021-12-20 13:10:51 -08:00 • committed by Anas Nashif
commit 8686ab5472
2 changed files with 47 additions and 39 deletions
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84
arch/riscv/core/isr.S
View file

@ -215,6 +215,12 @@
li temp, MSTATUS_MPP ;\
and ret, ret, temp ;
#define GET_CPU(ret, temp) \
csrr ret, mhartid ;\
li temp, ___cpu_t_SIZEOF ;\
mul temp, temp, ret ;\
la ret, _kernel ;\
add ret, ret, temp ;
/* imports */
GDATA(_sw_isr_table)
@ -302,8 +308,8 @@ SECTION_FUNC(exception.entry, __irq_wrapper)
#if defined(CONFIG_FPU) && defined(CONFIG_FPU_SHARING)
/* Assess whether floating-point registers need to be saved. */
la t0, _kernel
RV_OP_LOADREG t0, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG t0, ___cpu_t_current_OFFSET(t0)
RV_OP_LOADREG t0, _thread_offset_to_user_options(t0)
andi t0, t0, K_FP_REGS
RV_OP_STOREREG t0, __z_arch_esf_t_fp_state_OFFSET(sp)
@ -332,8 +338,8 @@ skip_store_fp_caller_saved:
WAS_NOT_USER(t0, t1)
bnez t0, is_priv_sp
la t0, _kernel
RV_OP_LOADREG t1, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG t1, ___cpu_t_current_OFFSET(t0)
/* Save user stack pointer */
#ifdef CONFIG_PMP_STACK_GUARD
@ -432,8 +438,8 @@ user_fault:
la ra, no_reschedule_user_fault
/* Switch to privilege stack */
la t0, _kernel
RV_OP_LOADREG t1, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG t1, ___cpu_t_current_OFFSET(t0)
RV_OP_LOADREG t0, _thread_offset_to_priv_stack_start(t1)
RV_OP_STOREREG sp, _thread_offset_to_user_sp(t1) /* Update user SP */
addi sp, t0, CONFIG_PRIVILEGED_STACK_SIZE
@ -536,8 +542,8 @@ skip_fp_move_kernel_syscall:
is_user_syscall:
#ifdef CONFIG_PMP_STACK_GUARD
la t0, _kernel
RV_OP_LOADREG a0, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG a0, ___cpu_t_current_OFFSET(t0)
jal ra, z_riscv_configure_stack_guard
#endif /* CONFIG_PMP_STACK_GUARD */
@ -581,8 +587,8 @@ skip_fp_copy_user_syscall:
RV_OP_LOADREG a7, __z_arch_esf_t_a7_OFFSET(sp)
/* Switch to privilege stack */
la t0, _kernel
RV_OP_LOADREG t1, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG t1, ___cpu_t_current_OFFSET(t0)
RV_OP_LOADREG t0, _thread_offset_to_priv_stack_start(t1)
RV_OP_STOREREG sp, _thread_offset_to_user_sp(t1) /* Update user SP */
addi sp, t0, CONFIG_PRIVILEGED_STACK_SIZE
@ -615,8 +621,8 @@ return_from_syscall:
no_reschedule_user_fault:
/* Restore user stack */
la t0, _kernel
RV_OP_LOADREG t1, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG t1, ___cpu_t_current_OFFSET(t0)
RV_OP_LOADREG sp, _thread_offset_to_user_sp(t1)
/* Update a0 (return value) to user stack. */
@ -667,8 +673,8 @@ is_interrupt:
addi t0, sp, 0
/* Switch to interrupt stack */
la t2, _kernel
RV_OP_LOADREG sp, _kernel_offset_to_irq_stack(t2)
GET_CPU(t2, t3)
RV_OP_LOADREG sp, ___cpu_t_irq_stack_OFFSET(t2)
/*
* Save thread stack pointer on interrupt stack
@ -677,14 +683,14 @@ is_interrupt:
addi sp, sp, -16
RV_OP_STOREREG t0, 0x00(sp)
#else
la t2, _kernel
GET_CPU(t2, t3)
#endif /* !CONFIG_USERSPACE && !CONFIG_PMP_STACK_GUARD */
on_irq_stack:
/* Increment _kernel.cpus[0].nested variable */
lw t3, _kernel_offset_to_nested(t2)
/* Increment _current_cpu.nested variable */
lw t3, ___cpu_t_nested_OFFSET(t2)
addi t3, t3, 1
sw t3, _kernel_offset_to_nested(t2)
sw t3, ___cpu_t_nested_OFFSET(t2)
#ifdef CONFIG_IRQ_OFFLOAD
/*
@ -736,13 +742,13 @@ call_irq:
jalr ra, t1, 0
on_thread_stack:
/* Get reference to _kernel */
la t1, _kernel
/* Get reference to _current_cpu */
GET_CPU(t1, t2)
/* Decrement _kernel.cpus[0].nested variable */
lw t2, _kernel_offset_to_nested(t1)
/* Decrement _current_cpu.nested variable */
lw t2, ___cpu_t_nested_OFFSET(t1)
addi t2, t2, -1
sw t2, _kernel_offset_to_nested(t1)
sw t2, ___cpu_t_nested_OFFSET(t1)
#if !defined(CONFIG_USERSPACE) && !defined(CONFIG_PMP_STACK_GUARD)
/* Restore thread stack pointer */
@ -752,7 +758,7 @@ on_thread_stack:
#ifdef CONFIG_STACK_SENTINEL
call z_check_stack_sentinel
la t1, _kernel
GET_CPU(t1, t2)
#endif
#ifdef CONFIG_PREEMPT_ENABLED
@ -760,8 +766,8 @@ on_thread_stack:
* Check if we need to perform a reschedule
*/
/* Get pointer to _kernel.current */
RV_OP_LOADREG t2, _kernel_offset_to_current(t1)
/* Get pointer to _current_cpu.current */
RV_OP_LOADREG t2, ___cpu_t_current_OFFSET(t1)
/*
* Check if next thread to schedule is current thread.
@ -774,7 +780,7 @@ on_thread_stack:
#endif /* CONFIG_PREEMPT_ENABLED */
#ifdef CONFIG_PMP_STACK_GUARD
RV_OP_LOADREG a0, _kernel_offset_to_current(t1)
RV_OP_LOADREG a0, ___cpu_t_current_OFFSET(t1)
jal ra, z_riscv_configure_stack_guard
/*
@ -828,19 +834,19 @@ reschedule:
* has a chance to run. If this happens, the current thread and the
* target thread will be the same.
*/
la t0, _kernel
RV_OP_LOADREG t2, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG t2, ___cpu_t_current_OFFSET(t0)
RV_OP_LOADREG t3, _kernel_offset_to_ready_q_cache(t0)
beq t2, t3, no_reschedule_resched
#if CONFIG_INSTRUMENT_THREAD_SWITCHING
call z_thread_mark_switched_out
#endif
/* Get reference to _kernel */
la t0, _kernel
/* Get reference to current CPU */
GET_CPU(t0, t1)
/* Get pointer to _kernel.current */
RV_OP_LOADREG t1, _kernel_offset_to_current(t0)
/* Get pointer to current thread */
RV_OP_LOADREG t1, ___cpu_t_current_OFFSET(t0)
#ifdef CONFIG_USERSPACE
/*
@ -893,9 +899,9 @@ skip_callee_saved_reg:
RV_OP_LOADREG t1, _kernel_offset_to_ready_q_cache(t0)
/*
* Set _kernel.current to new thread loaded in t1
* Set _current_cpu.current to new thread loaded in t1
*/
RV_OP_STOREREG t1, _kernel_offset_to_current(t0)
RV_OP_STOREREG t1, ___cpu_t_current_OFFSET(t0)
/* Switch to new thread stack */
RV_OP_LOADREG sp, _thread_offset_to_sp(t1)
@ -937,8 +943,8 @@ skip_load_fp_callee_saved:
#endif /* CONFIG_PMP_STACK_GUARD */
#ifdef CONFIG_USERSPACE
/* t0 still reference to _kernel */
/* t1 still pointer to _kernel.current */
/* t0 still reference to _current_cpu */
/* t1 still pointer to _current_cpu.current */
/* Check the thread mode */
WAS_NOT_USER(t2, t4)
@ -1018,8 +1024,8 @@ no_reschedule:
li t0, MSTATUS_MPRV
csrc mstatus, t0
la t0, _kernel
RV_OP_LOADREG a0, _kernel_offset_to_current(t0)
GET_CPU(t0, t1)
RV_OP_LOADREG a0, ___cpu_t_current_OFFSET(t0)
jal ra, z_riscv_configure_user_allowed_stack
/* Set user mode variable */

2
arch/riscv/core/offsets/offsets.c
View file

@ -131,4 +131,6 @@ GEN_ABSOLUTE_SYM(__z_arch_esf_t_SIZEOF, STACK_ROUND_UP(sizeof(z_arch_esf_t)));
GEN_ABSOLUTE_SYM(_K_THREAD_NO_FLOAT_SIZEOF,
STACK_ROUND_UP(sizeof(struct k_thread)));
GEN_ABSOLUTE_SYM(___cpu_t_SIZEOF, sizeof(_cpu_t));
GEN_ABS_SYM_END