Linux-aarch64-向量表
arm64(aarch64)的中断入口
总结
- 部分汇编码，由宏kernel_ventry定义
- el0t_64_irq
- el0t_64_irq_handler
- ret_to_user/kernel
相关两个宏定义：下面 \el，对宏参数展开
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101.macro entry_handler el:req, ht:req, regsize:req, label:req
SYM_CODE_START_LOCAL(el\el\ht\()_\regsize\()_\label)
kernel_entry \el, \regsize
mov x0, sp
bl el\el\ht\()_\regsize\()_\label\()_handler // 这里先调用el0t_64_irq_handler[在entry-common.c中定义]，bl是带返回的跳转[lr存储返回地址]
.if \el == 0
b ret_to_user // 返回用户空间
.else
b ret_to_kernel // 返回内核空间
.endif
SYM_CODE_END(el\el\ht\()_\regsize\()_\label)
.endm
// 这里使用上面的宏，定义了不同等级的异常入口：例如，el0t_64_irq， el0t_32_sync
/*
* Early exception handlers
*/
entry_handler 1, t, 64, sync
entry_handler 1, t, 64, irq
entry_handler 1, t, 64, fiq
entry_handler 1, t, 64, error
entry_handler 1, h, 64, sync
entry_handler 1, h, 64, irq
entry_handler 1, h, 64, fiq
entry_handler 1, h, 64, error
entry_handler 0, t, 64, sync
entry_handler 0, t, 64, irq
entry_handler 0, t, 64, fiq
entry_handler 0, t, 64, error
entry_handler 0, t, 32, sync
entry_handler 0, t, 32, irq
entry_handler 0, t, 32, fiq
entry_handler 0, t, 32, error
// 下面的宏使用，定义了向量表
/*
* Exception vectors.
*/
.pushsection ".entry.text", "ax"
.align 11
SYM_CODE_START(vectors)
kernel_ventry 1, t, 64, sync // Synchronous EL1t
kernel_ventry 1, t, 64, irq // IRQ EL1t
kernel_ventry 1, t, 64, fiq // FIQ EL1t
kernel_ventry 1, t, 64, error // Error EL1t
kernel_ventry 1, h, 64, sync // Synchronous EL1h
kernel_ventry 1, h, 64, irq // IRQ EL1h
kernel_ventry 1, h, 64, fiq // FIQ EL1h
kernel_ventry 1, h, 64, error // Error EL1h
kernel_ventry 0, t, 64, sync // Synchronous 64-bit EL0
kernel_ventry 0, t, 64, irq // IRQ 64-bit EL0
kernel_ventry 0, t, 64, fiq // FIQ 64-bit EL0
kernel_ventry 0, t, 64, error // Error 64-bit EL0
kernel_ventry 0, t, 32, sync // Synchronous 32-bit EL0
kernel_ventry 0, t, 32, irq // IRQ 32-bit EL0
kernel_ventry 0, t, 32, fiq // FIQ 32-bit EL0
kernel_ventry 0, t, 32, error // Error 32-bit EL0
SYM_CODE_END(vectors)
.macro kernel_ventry, el:req, ht:req, regsize:req, label:req
.align 7
.Lventry_start\@:
.if \el == 0
/*
* This must be the first instruction of the EL0 vector entries. It is
* skipped by the trampoline vectors, to trigger the cleanup.
*/
b .Lskip_tramp_vectors_cleanup\@
.if \regsize == 64
mrs x30, tpidrro_el0
msr tpidrro_el0, xzr
.else
mov x30, xzr
.endif
.Lskip_tramp_vectors_cleanup\@:
.endif
sub sp, sp, #PT_REGS_SIZE
#ifdef CONFIG_VMAP_STACK
/*
* Test whether the SP has overflowed, without corrupting a GPR.
* Task and IRQ stacks are aligned so that SP & (1 << THREAD_SHIFT)
* should always be zero.
*/
add sp, sp, x0 // sp' = sp + x0
sub x0, sp, x0 // x0' = sp' - x0 = (sp + x0) - x0 = sp
tbnz x0, #THREAD_SHIFT, 0f
sub x0, sp, x0 // x0'' = sp' - x0' = (sp + x0) - sp = x0
sub sp, sp, x0 // sp'' = sp' - x0 = (sp + x0) - x0 = sp
b el\el\ht\()_\regsize\()_\label // 前面如果成功的话，会跳转到相应的前面定义的elnt_size_name：el0t_64_irq
0:
......
Linux-aarch64-向量表
http://example.com/2024/07/10/Linux-aarch64-向量表/