Commit graph

84 commits

Author SHA1 Message Date
Jesus Sanchez-Palencia 3b01e04379 x86: Add a fake IRQ7 handler to avoid spurious interrupts
The 8259a PIC has a well known problem of generating flaky
IRQ7 interrupts. The correct solution is to always check
if an IRQ7 interrupt is real or not by probing the PIC's ISR
register. This check is only mandatory if the IRQ7 is actually
being used by the system. More importantly, the handler should
NEVER send and EOI if the interrupt was spurious.

This patch addresses this issue by implementing a fake empty
handler for this IRQ and, as stated, NOT sending the EOI.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia afd9b5b0b7 x86: Add APIs to 8259 PIC driver
This commit implements pic_eoi(int irq) and a helper macro PIC_INT(irq).
This first checks which PICs should be 'acked' given an IRQ number, while
the macro returns the actual system interrupt number for the IRQ according
to the offset used on the PIC initialization.
2015-12-21 08:06:14 -02:00
Andre Guedes 826ff7cb29 x86: Add pic_unmask_irq() helper
This patch implements the pic_unmask_irq() helper and uses it where
applicable. This function zeros the corresponding bit from the IRQ
number in IMR register.

This patch doesn't implement the pic_mask_irq() helper since it is not
useful at this moment.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia d70f67cd60 galileo: Add PIT driver
This patch adds a driver for the 8254 Programmable Interrupt Timer (PIT).
The driver introduced by this patch programs the PIT to generate interrupt
periodically. The interrupt frequency can be configured by the user.

On each PIT interrupt, a callback configured by the user is called. As
expected, that callback is executed in interrupt context so the user
should be aware of what it is not supposed to do (e.g. to call blocking
functions).

Issues marked as FIXME are all related to missing APIs on the PIC driver
so they will be addressed by a future commit.
2015-12-21 08:06:14 -02:00
Andre Guedes 5f47bafc6a x86: Add Real-Time Clock Driver
This patch adds a driver for Real-Time Clock (RTC). The RTC timer is
suitable to implement some operating system features such as the
system clock. Actually, the RTC will be used to implement the system
clock in galileo platform.

The driver introduced by this patch programs the RTC to generate
interrupt periodically. The interrupt frequency can be configured by the
user. On each RTC interrupt, a callback configured by the user is called.
As expected, that callback is executed in interrupt context so the user
should be aware of what it is not supposed to do (e.g. to call blocking
functions).

This patch also adds the inb() helper function to helpers.h. The helpers
is a wrapper for assembly 'in' instruction.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia 11098501d8 x86: Initialize the 8259 PIC
The Programmable Interrupt Controller is a chip responsible for
translating hardware interrupts to system interrupts. When it
receives an Interrupt Request (IRQ), it triggers the appropriate
interrupt line reaching the appropriate IDT gate, following a
previously setup offset.

There are 2 daisy-chained PICs. PIC1 handles IRQs 0-7 and PIC2
handles IRQs 8-15. If no vector offset is set, an IRQ0, for instance,
would trigger the interrupt 0, clashing with the "Division by zero exception"
handler. Thus the IRQs must be remapped.

This patch implements the PICs initialization through their 4
Initialization Command Words (ICWs) in a very "canonical" way:
- ICW1: the initializing command;
- ICW2: the vector offset for the PIC1 and PIC2 (we add an offset of 32 positions);
- ICW3: the inter-PICs wiring setup (we connect PIC2 to PIC1's IRQ2);
- ICW4: extra systems information (we set PIC1 as Master and PIC2 as slave).

It then masks the Interrupt Mask Register, blocking all IRQs but #2 initially.
These must be unmasked on demand. The IMR is 8-bits long, so setting the n^th bit to 1
would DISABLE the IRQ n while setting it to 0 would ENABLE IRQ n.

As stated, this is an implementation of the legacy 8259 PIC. More
investigation is needed so we decide if it is enough or if we need
the (newer) APIC implementation instead.

This patch also adds the outb() helper function to helpers.h. The helpers
is a wrapper for assembly 'out' instruction.

Finally, since we now properly support hardware interrupts, this patch
also enables IRQs in platform main().

More information:
- Quark X1000 Datasheet, section 21.12, page 898.
- http://wiki.osdev.org/8259_PIC
- http://stanislavs.org/helppc/8259.html
2015-12-21 08:06:14 -02:00
Andre Guedes 604538ed62 x86: Set interrupt handler for Double Fault exception
This patch sets an interrupt handler for Double Fault exception during
CPU initialization. In case such exception is raised, we halt the system.
This way, we avoid the system to triple fault (due to an unhandled
interrupt for instance), leaving no trace about what cause the triple
fault.
2015-12-21 08:06:14 -02:00
Andre Guedes e28f400e0c x86: Introduce interrupt.h
This patch introduces the interrupt.h header file which provides some
helper macros to set a interrupt handler and disable/enable maskable
hardware interrupts.

Since there is no easy way to write an Interrupt Service Routines
(ISR) in C (for further information on this, see [1]), we introduce
the SET_INTERRUPT_HANDLER helper macro.

The macro does two things:
1) Defines an assembly trampolin to a C function that will, indeed,
   handle the interrupt.
2) Sets the corresponding interrupt gate descriptor in IDT.

The macro usage is pretty straightforward. The macro is defined as
SET_INTERRUPT_HANDLER(num, has_error_code, handler) where:
@num:             Interrupt number (0-255)
@has_error_code:  0 if processor doesn't push error code onto the
                  stack. Otherwise, set this argument to 1.
@handler:         Pointer to function that should be called once the
                  interrupt is raised. In case has_error_code == 0
                  the function prototype should be the following:
                  void handler(void)
                  Otherwise, it should be:
                  void handler(struct interrupt_context context)

For instance, let's say we want to set a handler for a device interrupt
(for example, interrupt number 101). Remember, hardware interrupts don't
have error code. So we should have something like this:

void interrupt_handler(void)
{
        /* Handling code here */
}

void my_device_init(void)
{
        ...

        SET_INTERRUPT_HANDLER(101, 0, interrupt_handler);

        ...
}

Now, let's say we want to set an interrupt handler for Page Fault
(interrupt number 14). Some exceptions, such as Page Fault, pushes an
error code onto the stack and may require registers values in order
to be properly be handled. Thus, the code should look like this:

void pagefault_handler(struct interrupt_context context)
{
        /* Handling code here */
}

void init_memory(void)
{
        ...

        SET_INTERRUPT_HANDLER(14, 1, pagefault_handler);

        ...
}

For further information about exceptions and error code, refer to Intel
Combined Manual, Vol. 3, Sections 6.3 and 6.13.

Finally, we don't define any API to unregister interrupt handlers since
we believe that it wouldn't be useful at all, at least at this moment.
Considering Contiki's context, interrupt handler registration is pretty
"static" and defined at compile-time by platform code (or the device
drivers used by the platform).

[1] http://wiki.osdev.org/Interrupt_Service_Routines
2015-12-21 08:06:14 -02:00
Andre Guedes f6644d9208 x86: CPU Initialization
This patch defines the cpu_init() function which should encapsulate
all code related to x86 CPU initialization. For now, this function
initializes GDT and IDT.
2015-12-21 08:06:14 -02:00
Andre Guedes 13d92cf67a x86: Initialize Interrupt Descriptor Table
This patch adds code to handle Interrupt Descriptor Table (IDT)
initialization. The IDT is initialized with null descriptors
therefore any interrupt at this point will cause a triple fault.
The IDT initialization is part of x86 CPU initialization.

Strictly speaking, there is no need to use attribute packed in struct
intr_gate_desc however we use it for readability reasons.
2015-12-21 08:06:14 -02:00
Andre Guedes b8feaea30d x86: Add helpers.h
This patch adds the helpers.h. This file should contain only x86-related
helper functions and macros. For now, we define the BIT macro and halt()
helpers which will be used in upcoming patches.

Additionally, this patch also changes loader.S to call the halt().
2015-12-21 08:06:14 -02:00
Andre Guedes 41bca35c1e x86: Initialize Global Descriptor Table
This patch adds code to initialize the Global Descriptor Table. For
simplicity, the memory is organized following the flat model. Thus,
memory appears to Contiki as a single, continuous address space. Code,
data, and stack are all contained in this address space (so called
linear address space).

The macros to manipulate bits from segment descriptor and the
set_descriptor() helper are based on the ones described in [1].

[1] http://wiki.osdev.org/GDT_Tutorial
2015-12-21 08:06:14 -02:00
Andre Guedes 7e13081776 galileo: Print elf sections sizes after build
This patch changes Galileo's buildsystem to print the elf sections
sizes after a new image is built. This way we can easily track how
these sections increase or decrease after any change.

To achieve that, we define a custom linking rule which is pretty much
the same as the default linking rule define in Makefile.include, but
we run 'size' command after the image is built.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia 3a26d9dbc7 x86: Only add elfloader-x86.c to the platforms using it
Currently there are only one platform using CPU x86: Cooja. The
elfloader-x86.c is rather a POSIX implementation, so the Galileo port
won't use it for now. This patch fixes this by moving this source file to
be included by the platforms using it instead of the cpu's Makefile.
2015-12-21 08:06:14 -02:00
Jesus Sanchez-Palencia 5a0e2a7654 x86: Fix missing include warning due to memset usage 2015-12-21 08:06:14 -02:00
Adam Dunkels bb2dcaa057 A massive all-tree automated update of all double inclusion guard #defines that changes from using two underscores as a prefix, which are reserved, to not using two underscores as a prefix 2013-11-24 20:20:11 +01:00
simonduq 95ae5c5d51 avoid unnecessary symbols.c/h copying 2012-03-26 23:00:43 +02:00
Ilya Dmitrichenko 499d3052ee Fixed TARGET=native compilation issues on Darwin. 2012-03-02 15:15:42 -05:00
Oliver Schmidt f83fb3704b Replaced make-empty-symbols with empty-symbols.[c|h]
The symbol generation shell scripts cause CRLF issues on Windows/Cygwin again and again. Instead of fixing this yet again I opted to remove the symbol generation script at least for the "no symbols" scenario with two C source files to be copied.
2011-04-03 13:24:58 +02:00
adamdunkels 18486d4e3d Patch by Gideon Ernst: use explicit $(CONTIKI) path instead of implicit ../../ path to the mknmlist script 2009-09-03 17:41:58 +00:00
fros4943 4275ff4a9c added support for 64-bit architectures, as already added on the cooja mtarch clone (patch provided by Jesper Karlsson and David Gustafsson) 2009-03-13 15:02:23 +00:00
fros4943 da8ee90ef3 reverted last commit (sorry, committed wrong file.. :) 2009-03-13 14:49:10 +00:00
fros4943 d6ebba536c minor 64 bit fix: divide by sizeof(unsigned long) instead of constant 4 2009-03-13 14:40:07 +00:00
oliverschmidt 61f54204d7 Improved map file naming consistency. 2007-05-19 21:46:43 +00:00
oliverschmidt ae2073cac9 Factored out setup directory search path for source files into Makefile.include.
- All compilers used support the -I option for setting an include search directory.

- The Contiki source tree follows the (common) approach of placing declarations (in headerf iles) in the same directory as definitions (in source files).

As a result it makes sense to use the -I compiler option for just the same set of directories used for the vpath gnumake directive.

Note: I checked several builds but nevertheless one or the other might need some additional adjustsments. Sorry for the inconvenience.
2007-05-19 07:54:53 +00:00
oliverschmidt 237b1617b5 Factored out setup directory search path for source files into Makefile.include.
- Search target specific directories before CPU specific directories.
- Search CPU specific directories before generic directories.

Note: I checked several builds but nevertheless one or the other might need some additional adjustsments. Sorry for the inconvenience.
2007-05-13 08:41:11 +00:00
adamdunkels 7db75a8aa6 x86 elfloader 2007-03-28 20:27:13 +00:00
adamdunkels 8293e6215f Added elfloader-stub, symbols generation 2007-03-22 23:58:08 +00:00
adamdunkels b0b3e5d0d6 Redefined LD to gcc to make things compile. Removed generation of symbols.[ch] due to problematic builds (seemingly neverending loops). 2007-03-15 21:52:00 +00:00
adamdunkels 2e8431b3d9 Added generation of symbols.[ch] 2006-12-19 09:21:12 +00:00
adamdunkels e072e4084a Added a function for measuring stack usage 2006-09-26 20:56:42 +00:00
adamdunkels fbcb4a97c2 Made stacksize configurable via external definition 2006-09-01 22:56:02 +00:00
adamdunkels 8ee4f7fc3d Removed out-commented stuff from Makefiles 2006-06-24 06:23:47 +00:00
adamdunkels c9e808d638 Import of the contiki-2.x development code from the SICS internal CVS server 2006-06-17 22:41:10 +00:00