[PATCH 1/6] i386/pc386: configurable size of descriptor tables
Gedare Bloom
gedare at rtems.org
Tue Nov 18 16:06:45 UTC 2014
On Tue, Nov 18, 2014 at 10:46 AM, Jan Dolezal <dolezj21 at fel.cvut.cz> wrote:
> Hello Gedare,
> thank you very much for fast and valuable response.
>
> I made most of the changes you suggested.
>
>
> On 12.11.2014 16:20, Gedare Bloom wrote:
>>
>> On Wed, Nov 12, 2014 at 10:07 AM, Jan Dolezal <dolezj21 at fel.cvut.cz>wrote:
>>>
>>> ---
>>> c/src/lib/libbsp/i386/pc386/Makefile.am | 1 +
>>> c/src/lib/libbsp/i386/pc386/configure.ac | 5 +++++
>>> c/src/lib/libbsp/i386/pc386/include/bsp.h | 6 ++----
>>> c/src/lib/libbsp/i386/pc386/include/bsptblsizes.h | 25
>>> ++++++++++++++++++++++
>>> c/src/lib/libbsp/i386/pc386/preinstall.am | 4 ++++
>>> c/src/lib/libbsp/i386/pc386/startup/ldsegs.S | 26
>>> +++++++++++++++++++----
>>> 6 files changed, 59 insertions(+), 8 deletions(-)
>>> create mode 100644 c/src/lib/libbsp/i386/pc386/include/bsptblsizes.h
>>>
>>> diff --git a/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> b/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> index 22ba5e9..9c901df 100644
>>> --- a/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> +++ b/c/src/lib/libbsp/i386/pc386/Makefile.am
>>> @@ -15,6 +15,7 @@ include_bspdir = $(includedir)/bsp
>>> dist_project_lib_DATA = bsp_specs
>>>
>>> include_HEADERS = include/bsp.h
>>> +include_HEADERS += include/bsptblsizes.h
>>
>> This header should probably be nested under bsp at least.
>
> changed to
> include/bsp/tblsizes.h
>
>
>>
>>> include_HEADERS += include/tm27.h
>>>
>>> nodist_include_HEADERS = include/bspopts.h
>>> diff --git a/c/src/lib/libbsp/i386/pc386/configure.ac
>>> b/c/src/lib/libbsp/i386/pc386/configure.ac
>>> index 1125c7c..ecec056 100644
>>> --- a/c/src/lib/libbsp/i386/pc386/configure.ac
>>> +++ b/c/src/lib/libbsp/i386/pc386/configure.ac
>>> @@ -82,6 +82,11 @@ RTEMS_BSPOPTS_HELP([USE_CIRRUS_GD5446],
>>> NOTE: This has only been tested on Qemu.])
>>> AM_CONDITIONAL(USE_CIRRUS_GD5446,test "$USE_CIRRUS_GD5446" = "1")
>>>
>>> +RTEMS_BSPOPTS_SET([NUM_APP_DRV_GDT_DESCRIPTORS],[*],[0])
>>> +RTEMS_BSPOPTS_HELP([NUM_APP_DRV_GDT_DESCRIPTORS],
>>> +[Defines how many descriptors in GDT may be allocated for application
>>> or
>>> + driver usage.])
>>> +
>>> if test X${CLOCK_DRIVER_USE_TSC} = X1 -a X${CLOCK_DRIVER_USE_8254} =
>>> X1 ; then
>>> AC_MSG_ERROR([pc386 both TSC and 8254 specified for clock driver])
>>> fi
>>> diff --git a/c/src/lib/libbsp/i386/pc386/include/bsp.h
>>> b/c/src/lib/libbsp/i386/pc386/include/bsp.h
>>> index 21aa054..3425a6d 100644
>>> --- a/c/src/lib/libbsp/i386/pc386/include/bsp.h
>>> +++ b/c/src/lib/libbsp/i386/pc386/include/bsp.h
>>> @@ -51,6 +51,7 @@
>>>
>>> #include <bspopts.h>
>>> #include <bsp/default-initial-extension.h>
>>> +#include <bsptblsizes.h>
>>>
>>> #include <rtems.h>
>>> #include <rtems/iosupp.h>
>>> @@ -166,11 +167,8 @@ extern int rtems_3c509_driver_attach(struct
>>> rtems_bsdnet_ifconfig *config);
>>>
> /*-------------------------------------------------------------------------+
>>>
>>> | External Variables.
>>>
> +--------------------------------------------------------------------------*/
>>>
>>> -#define IDT_SIZE 256
>>> -#define GDT_SIZE 3
>>> -
>>
>> Why not just update these #defines with the new ones you have in
>
> bsptblsizes.h?
> It seemed to me that it is not necessary. I thought it is enough to have
> them in bsp/tblsizes.h and then use them here and in asm modules.
>
> Could you please post an example? I don't understand how should such an
> update look like.
>
Oh, to get the definitions in assembly complicates things. If bsp.h is
not ASM safe, then it makes sense to add the new header file that can
be used in both asm and C.
-Gedare
>
>>
>>> extern interrupt_gate_descriptor Interrupt_descriptor_table[IDT_SIZE];
>>> -extern segment_descriptors Global_descriptor_table [GDT_SIZE];
>>> +extern segment_descriptors _Global_descriptor_table [GDT_SIZE];
>>>
>>>
> /*-------------------------------------------------------------------------+
>>>
>>> | Function Prototypes.
>>> diff --git a/c/src/lib/libbsp/i386/pc386/include/bsptblsizes.h
>
> b/c/src/lib/libbsp/i386/pc386/include/bsptblsizes.h
>>>
>>> new file mode 100644
>>> index 0000000..ef51ae7
>>> --- /dev/null
>>> +++ b/c/src/lib/libbsp/i386/pc386/include/bsptblsizes.h
>>> @@ -0,0 +1,25 @@
>>> +/**
>>> + * @file
>>> + *
>>> + * @ingroup i386_pc386
>>> + *
>>> + * @brief Sizes of Global and Interrupt descriptor tables.
>>> + */
>>> +
>>> +/*
>>> + * Definitions related to the PC386 BSP.
>>> + * This header file is also used in assembler modules.
>>> + *
>>> + * Copyright (C) 2014 Jan Doležal (dolezj21 at fel.cvut.cz)
>>> + * CTU in Prague.
>>> + *
>>> + * The license and distribution terms for this file may be
>>> + * found in the file LICENSE in this distribution or at
>>> + * http://www.rtems.org/license/LICENSE.
>>> + */
>>> +
>>> +#include <bspopts.h>
>>> +
>>> +#define IDT_SIZE (256)
>>> +#define GDT_SIZE (3 + NUM_APP_DRV_GDT_DESCRIPTORS)
>>> +
>>> diff --git a/c/src/lib/libbsp/i386/pc386/preinstall.am
>
> b/c/src/lib/libbsp/i386/pc386/preinstall.am
>>>
>>> index 182f564..aff01dc 100644
>>> --- a/c/src/lib/libbsp/i386/pc386/preinstall.am
>>> +++ b/c/src/lib/libbsp/i386/pc386/preinstall.am
>>> @@ -41,6 +41,10 @@ $(PROJECT_INCLUDE)/bsp.h: include/bsp.h
>
> $(PROJECT_INCLUDE)/$(dirstamp)
>>>
>>> $(INSTALL_DATA) $< $(PROJECT_INCLUDE)/bsp.h
>>> PREINSTALL_FILES += $(PROJECT_INCLUDE)/bsp.h
>>>
>>> +$(PROJECT_INCLUDE)/bsptblsizes.h: include/bsptblsizes.h
>
> $(PROJECT_INCLUDE)/$(dirstamp)
>>>
>>> + $(INSTALL_DATA) $< $(PROJECT_INCLUDE)/bsptblsizes.h
>>> +PREINSTALL_FILES += $(PROJECT_INCLUDE)/bsptblsizes.h
>>> +
>>> $(PROJECT_INCLUDE)/tm27.h: include/tm27.h
>
> $(PROJECT_INCLUDE)/$(dirstamp)
>>>
>>> $(INSTALL_DATA) $< $(PROJECT_INCLUDE)/tm27.h
>>> PREINSTALL_FILES += $(PROJECT_INCLUDE)/tm27.h
>>> diff --git a/c/src/lib/libbsp/i386/pc386/startup/ldsegs.S
>
> b/c/src/lib/libbsp/i386/pc386/startup/ldsegs.S
>>>
>>> index 495d68a..8f2220d 100644
>>> --- a/c/src/lib/libbsp/i386/pc386/startup/ldsegs.S
>>> +++ b/c/src/lib/libbsp/i386/pc386/startup/ldsegs.S
>>> @@ -34,6 +34,15 @@
>>>
> +--------------------------------------------------------------------------*/
>>>
>>>
>>> #include <rtems/asm.h>
>>> +#include <bsptblsizes.h> /* contains sizes of GDT and IDT */
>>> +
>>> +#ifndef GDT_SIZE
>>> +#define GDT_SIZE (3)
>>> +#endif
>>> +
>>> +#ifndef IDT_SIZE
>>> +#define IDT_SIZE (256)
>>> +#endif
>>>
>> Adding ifndef here is redundant since they are unconditionally defined
>> in bsptblsizes.h
>
> removed
>
>>
>>>
> /*----------------------------------------------------------------------------+
>>>
>>> | CODE section
>>> @@ -167,6 +176,9 @@ next_step:
>>>
> /*---------------------------------------------------------------------------+
>>>
>>> | GDT itself
>>>
> +--------------------------------------------------------------------------*/
>>>
>>> +#if GDT_SIZE < 3
>>> +#error "GDT_SIZE must be at least 3"
>>> +#endif
>>>
>> Is there a way to use assert() type function in assembly or
>> preprocessor code? I'm just curious. This #if and #error is a good
>> thing to do at least, and I'm glad to see that you have it!
>
> I'm sorry, but I'm not aware of that possibility.
>
>
>>
>>> BEGIN_DATA
>>> .p2align 4
>>> @@ -186,11 +198,17 @@ SYM (_Global_descriptor_table):
>>> .word 0xffff, 0
>>> .byte 0, 0x92, 0xcf, 0
>>>
>>> + /* allocated space for user segments */
>>> + .rept (GDT_SIZE - 3)
>>> + .word 0,0,0,0
>>> + .endr
>>> +
>>>
> /*---------------------------------------------------------------------------+
>>>
>>> | Descriptor of GDT
>>>
> +--------------------------------------------------------------------------*/
>>>
>>> -SYM (gdtdesc):
>>> - .word (3*8 - 1)
>>> + PUBLIC(gdtdesc)
>>> +SYM(gdtdesc):
>>> + .word (GDT_SIZE*8 - 1)
>>> .long SYM (_Global_descriptor_table)
>>>
>>>
> /*---------------------------------------------------------------------------+
>>>
>>> @@ -200,7 +218,7 @@ SYM (gdtdesc):
>>>
>>> PUBLIC(Interrupt_descriptor_table)
>>> SYM(Interrupt_descriptor_table):
>>> - .rept 256
>>> + .rept IDT_SIZE
>>> .word 0,0,0,0
>>> .endr
>>>
>>> @@ -211,7 +229,7 @@ SYM(Interrupt_descriptor_table):
>>> .p2align 4
>>> PUBLIC(IDT_Descriptor)
>>> SYM(IDT_Descriptor):
>>> - .word (256*8 - 1)
>>> + .word (IDT_SIZE*8 - 1)
>>> .long SYM (Interrupt_descriptor_table)
>>>
>>> END_DATA
>>> --
>>> 1.9.1
>>>
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>
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