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x86: put ISR stubs in their own text section

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Rather than embedding the ISR stub directly inside the function that
invokes IRQ_CONNECT(), stick all the generated stubs in the
.text.irqstubs section.

In this way, we make things easier to debug since the stub code isn't
mixed in with the "calling" function's assembly, and we no longer
need an instruction to jump over it.

Since these are now in their own section and not embedded inside an
unrelated init function, we unconditionally generate descriptive
symbol names for each stub based on the name of the handler and the
IRQ line.

Example for HPET timer on IRQ #2:

00100440 T _timer_int_handler            <-- driver ISR
00100590 T _timer_int_handler_irq2_stub  <-- generated stub

Change-Id: I49425aef7775edbca8ad7f61d2d4f9c41cb0d39d
Signed-off-by: Andrew Boie <andrew.p.boie@intel.com>
This commit is contained in:
Andrew Boie 2016-07-27 09:44:31 -07:00 • committed by Inaky Perez-Gonzalez
commit 527cd1c5b4
1 changed files with 9 additions and 20 deletions
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29
include/arch/x86/arch.h
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@ -175,14 +175,6 @@ typedef struct s_isrList {
"pushl %[isr_param]\n\t"
#endif /* CONFIG_X86_IAMCU */
#ifdef CONFIG_KERNEL_EVENT_LOGGER_INTERRUPT
#define _IRQ_STUB_LABEL \
" .global %[isr]%P[irq]_stub\n\t" \
"%[isr]%P[irq]_stub:\n\t"
#else
#define _IRQ_STUB_LABEL
#endif
/**
* Code snippets for populating the vector ID and priority into the intList
*
@ -216,18 +208,15 @@ typedef struct s_isrList {
*
* Internally this function does a few things:
*
* 1. There is a block of inline assembly which is completely skipped over
* at runtime with an initial 'jmp' instruction.
*
* 2. There is a declaration of the interrupt parameters in the .intList
* 1. There is a declaration of the interrupt parameters in the .intList
* section, used by gen_idt to create the IDT. This does the same thing
* as the NANO_CPU_INT_REGISTER() macro, but is done in assembly as we
* need to populate the .fnc member with the address of the assembly
* IRQ stub that we generate immediately afterwards.
*
* 3. The IRQ stub itself is declared. It doesn't get run in the context
* of the calling function due to the initial 'jmp' instruction at the
* beginning of the assembly block, but a pointer to it gets saved in the IDT.
* 2. The IRQ stub itself is declared. The code will go in its own named
* section .text.irqstubs section (which eventually gets linked into 'text')
* and the stub shall be named (isr_name)_irq(irq_line)_stub
*
* The stub calls _IntEnt to save interrupted context and switch to the IRQ
* stack. There is a calling convention specific macro to populate the
@ -248,21 +237,21 @@ typedef struct s_isrList {
#define _ARCH_IRQ_CONNECT(irq_p, priority_p, isr_p, isr_param_p, flags_p) \
({ \
__asm__ __volatile__( \
"jmp 2f\n\t" \
".pushsection .intList\n\t" \
".long 1f\n\t" /* ISR_LIST.fnc */ \
".long %P[isr]_irq%P[irq]_stub\n\t" /* ISR_LIST.fnc */ \
".long %P[irq]\n\t" /* ISR_LIST.irq */ \
".long %P[priority]\n\t" /* ISR_LIST.priority */ \
".long %P[vector]\n\t" /* ISR_LIST.vec */ \
".long 0\n\t" /* ISR_LIST.dpl */ \
".popsection\n\t" \
"1:\n\t" \
_IRQ_STUB_LABEL \
".pushsection .text.irqstubs\n\t" \
".global %P[isr]_irq%P[irq]_stub\n\t" \
"%P[isr]_irq%P[irq]_stub:\n\t" \
"call _IntEnt\n\t" \
_ISR_ARG_ASM \
"call %P[isr]\n\t" \
"jmp _IntExitWithEoi\n\t" \
"2:\n\t" \
".popsection\n\t" \
: \
: [isr] "i" (isr_p), \
[isr_param] "i" (isr_param_p), \