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* ARM: introduce handle_IRQ() not to dump exception stackRussell King - ARM Linux2011-07-121-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | On Mon, Jul 11, 2011 at 3:52 PM, Russell King - ARM Linux <linux@arm.linux.org.uk> wrote: ... > The __exception annotation on a function causes this to happen: > > [<c002406c>] (asm_do_IRQ+0x6c/0x8c) from [<c0024b84>] > (__irq_svc+0x44/0xcc) > Exception stack(0xc3897c78 to 0xc3897cc0) > 7c60: 4022d320 4022e000 > 7c80: 08000075 00001000 c32273c0 c03ce1c0 c2b49b78 4022d000 c2b420b4 00000001 > 7ca0: 00000000 c3897cfc 00000000 c3897cc0 c00afc54 c002edd8 00000013 ffffffff > > Where that stack dump represents the pt_regs for the exception which > happened. Any function found in while unwinding will cause this to > be printed. > > If you insert a C function between the IRQ assembly and asm_do_IRQ, > the > dump you get from asm_do_IRQ will be the stack for your function, > not > the pt_regs. That makes the feature useless. > When __irq_svc - or any of the other exception handling assembly code - calls the C code, the stack pointer will be pointing at the pt_regs structure. All the entry points into C code from the exception handling code are marked with __exception or __exception_irq_enter to indicate that they are one of the functions which has pt_regs above them. Normally, when you've entered asm_do_IRQ() you will have this stack layout (higher address towards top): pt_regs asm_do_IRQ frame If you insert a C function between the exception assembly code and asm_do_IRQ, you end up with this stack layout instead: pt_regs your function frame asm_do_IRQ frame This means when we unwind, we'll get to asm_do_IRQ, and rather than dumping out the pt_regs, we'll dump out your functions stack frame instead, because that's what is above the asm_do_IRQ stack frame rather than the expected pt_regs structure. The fix is to introduce handle_IRQ() for no exception stack dump, so it can be called with MULTI_IRQ_HANDLER is selected and a C function is between the assembly code and the actual IRQ handling code. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Eric Miao <eric.y.miao@gmail.com>
* ARM: 6197/2: preliminary support for sparse IRQeric miao2010-07-091-0/+2
| | | | | | | | | So to allow NR_IRQS to be dynamic and platforms to specify the number of IRQs really needed. Acked-by: Paul Mundt <lethal@linux-sh.org> Signed-off-by: Eric Miao <eric.y.miao@gmail.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* ARM: 6000/1: removing compilation warning comming from <asm/irq.h>viresh kumar2010-03-291-0/+1
| | | | | | | | | irq.h is using struct pt_regs *. Due to this compilation warning is comming. Removing this warning by adding declaration of struct pt_regs. Signed-off-by: Viresh Kumar <viresh.kumar@st.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* [ARM] give RiscPC a NR_IRQS definition and remove defaultRussell King2008-11-291-4/+0
| | | | | | | | RiscPC is the only platform using the default setting for NR_IRQS, so the default NR_IRQS doesn't really make sense; remove it and make RiscPC provide such a definition. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* [ARM] sparse: quieten arch/arm/kernel/irq.cRussell King2008-09-061-0/+4
| | | | Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* [ARM] Move include/asm-arm/arch-* to arch/arm/*/include/machRussell King2008-08-071-1/+1
| | | | | | This just leaves include/asm-arm/plat-* to deal with. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
* [ARM] move include/asm-arm to arch/arm/include/asmRussell King2008-08-021-0/+28
Move platform independent header files to arch/arm/include/asm, leaving those in asm/arch* and asm/plat* alone. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
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