@ -370,10 +370,10 @@ int irq_init_percpu_irqstack(unsigned int cpu)
}
}
```
```
Here we go over all the CPUs one-by-one and setup the `hardirq_stack_ptr`.
Here we go over all the CPUs one-by-one and setup the `hardirq_stack_ptr`.
Where `map_irq_stack` is called to initialize the `hardirq_stack_ptr`,
Where `map_irq_stack` is called to initialize the `hardirq_stack_ptr`,
to point onto the `irq_backing_store` of the current CPU with an offset of IRQ\_STACK\_SIZE,
to point onto the `irq_stack_backing_store` of the current CPU with an offset of IRQ\_STACK\_SIZE,
either with guard pages or without when KASan is enabled.
either with guard pages or without when KASan is enabled.
After the initialization of the interrupt stack, we need to initialize the gs register within [arch/x86/kernel/cpu/common.c](https://github.com/torvalds/linux/blob/16f73eb02d7e1765ccab3d2018e0bd98eb93d973/arch/x86/kernel/cpu/common.c):
After the initialization of the interrupt stack, we need to initialize the gs register within [arch/x86/kernel/cpu/common.c](https://github.com/torvalds/linux/blob/16f73eb02d7e1765ccab3d2018e0bd98eb93d973/arch/x86/kernel/cpu/common.c):
Ok, now we know a little about tracing, but more info will be in the separate part about `lockdep` and `tracing`. You can see that the both `local_disable_irq` macros have the same part - `raw_local_irq_disable`. This macro defined in the [arch/x86/include/asm/irqflags.h](https://github.com/torvalds/linux/blob/16f73eb02d7e1765ccab3d2018e0bd98eb93d973/arch/x86/include/asm/irqflags.h) and expands to the call of the:
Ok, now we know a little about tracing, but more info will be in the separate part about `lockdep` and `tracing`. You can see that the both `local_irq_disable` macros have the same part - `raw_local_irq_disable`. This macro defined in the [arch/x86/include/asm/irqflags.h](https://github.com/torvalds/linux/blob/16f73eb02d7e1765ccab3d2018e0bd98eb93d973/arch/x86/include/asm/irqflags.h) and expands to the call of the:
The second function is `exception_exit` defined in the same [include/linux/context_tracking.h](https://github.com/torvalds/linux/tree/master/include/linux/context_tracking.h) file and checks that context tracking is enabled and call the `contert_tracking_enter` function if the previous context was `user`:
The second function is `exception_exit` defined in the same [include/linux/context_tracking.h](https://github.com/torvalds/linux/tree/master/include/linux/context_tracking.h) file and checks that context tracking is enabled and call the `context_tracking_enter` function if the previous context was `user`:
We already saw implementation of the `ALLOC_PT_GREGS_ON_STACK` macro in the third part of the interrupts [chapter](https://0xax.gitbook.io/linux-insides/summary/interrupts/linux-interrupts-3). This macro defined in the [arch/x86/entry/calling.h](https://github.com/torvalds/linux/blob/16f73eb02d7e1765ccab3d2018e0bd98eb93d973/arch/x86/entry/calling.h) and yet another allocates `120` bytes on stack for the general purpose registers, from the `rdi` to the `r15`:
We already saw implementation of the `ALLOC_PT_GPREGS_ON_STACK` macro in the third part of the interrupts [chapter](https://0xax.gitbook.io/linux-insides/summary/interrupts/linux-interrupts-3). This macro defined in the [arch/x86/entry/calling.h](https://github.com/torvalds/linux/blob/16f73eb02d7e1765ccab3d2018e0bd98eb93d973/arch/x86/entry/calling.h) and yet another allocates `120` bytes on stack for the general purpose registers, from the `rdi` to the `r15`: