target/7328: stack restoration for ARM interrupt("IRQ") attribute

[jean-marc.koller@csem.ch]

>Number:         7328
>Category:       target
>Synopsis:       stack restoration for  ARM interrupt("IRQ") attribute
>Confidential:   no
>Severity:       serious
>Priority:       medium
>Responsible:    unassigned
>State:          open
>Class:          wrong-code
>Submitter-Id:   net
>Arrival-Date:   Tue Jul 16 07:06:00 PDT 2002
>Closed-Date:
>Last-Modified:
>Originator:     Jean-Marc Koller, CSEM SA, Switzerland
>Release:        gcc 3.1 and "3.2 20020715 (experimental)"
>Organization:
>Environment:
SuSE Linux i686, gcc compiled for ARM-elf target
>Description:
On interrupt calls, the interrupt handler does not restore the interrupt stack pointer, thus leading to interrupt stack overflow.

The following C code:
"
void isr_IRQ()	__attribute__((interrupt("IRQ")));
extern void dummy();
void isr_IRQ()
{
	dummy();
}
"
generates:
"
isr_IRQ:
        @ Interrupt Service Routine.
        @ args = 0, pretend = 0, frame = 0
        @ frame_needed = 1, uses_anonymous_args = 0
        str     ip, [sp, #-4]!
        sub     lr, lr, #4
        mov     ip, sp
        stmfd   sp!, {r0, r1, r2, r3, fp, ip, lr, pc}
        sub     fp, ip, #4
        bl      dummy
        ldmea   fp, {r0, r1, r2, r3, fp, ip, pc}^
"
which doesn't restore sp on ldmea.
>How-To-Repeat:
arm-elf-gcc -Wall -S except_test.c -O2
>Fix:

>Release-Note:
>Audit-Trail:
>Unformatted:
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