[PATCH v4 0/4] introduce generic implementation of macros from bug.h

[Oleksii Kurochko <oleksii.kurochko@xxxxxxxxx>]

The patch series is based on the patch [1].

A large part of the content of the bug.h is repeated among all
architectures (especially x86 and RISCV have the same implementation), so it
was created a new config CONFIG_GENERIC_BUG_FRAME which is used to
introduce generic implementation of do_bug_frame() and move x86's <asm/bug.h>
to <xen/common/...> with the following changes:
  * Add inclusion of arch-specific header <asm/bug.h>
  * Rename the guard and remove x86 specific changes
  * Wrap macros BUG_FRAME/run_in_exception_handler/WARN/BUG/assert_failed/etc
    into #ifndef "BUG_FRAME/run_in_exception_handler/WARN/BUG/assert_failed/etc"
    thereby each architecture can override the generic implementation of macros.
  * Add #if{n}def __ASSEMBLY__ ... #endif
  * Introduce BUG_FRAME_STRUCTURE define to be able to change the structure of 
bug
    frame
  * Introduce BUG_INSTR and BUG_ASM_CONST to make _ASM_BUGFRAME_TEXT reusable 
between
    architectures
  * Make macros related to bug frame structure more generic.

RISC-V will be switched to use <xen/bug.h> and in the future, it will use common
the version of do_bug_frame() when xen/common will work for RISC-V.

[1]: 
https://lore.kernel.org/xen-devel/74973920d8722df3ce533979314564f331acf16e.1677687247.git.oleksii.kurochko@xxxxxxxxx/

---
Changes in V4:
 * Introduce and use generic BUG_DEBUGGER_TRAP_FATAL(regs) mnacros which is 
used to deal with
   debugger_trap_fatal(TRAP_invalid_op, regs) where TRAP_invalid_op is 
x86-specific.
 * Add comment what do_bug_frame() returns.
 * Do refactoring of do_bug_frame():
     * invert the condition 'if ( region )' in do_bug_frame() to reduce the 
indention.
                 * change type of variable i from 'unsigned int' to 'size_t' as 
it  is compared with
                   n_bugs which has type 'size_t'
 * Remove '#include <xen/stringify.h>' from <xen/bug.h> as it doesn't need any 
more after switch to
   x86 implementation.
 * Remove '#include <xen/errno.h>' as it isn't needed any more
 * Move bug_*() macros inside '#ifndef BUG_FRAME_STRUCT'
 * Add <xen/lib.h> to fix compile issue with BUILD_ON()...
 * Add documentation for BUG_ASM_CONST.
 * Defines BUG_DISP_WIDTH, BUG_LINE_LO_WIDTH, BUG_LINE_HI_WIDTH were moved into
   "ifndef BUG_FRAME_STRUCT" in <xen/bug.h> as they are specific for 'struct 
bug_frame' and so should
   co-exist together. So the defines were back to <asm/bug.h> until 
BUG_FRAME_STRUCT will be defined in
         <asm/bug.h>.
 * Switch ARM implementation to generic one
 * Remove BUG_FN_REG from arm{16,32}/bug.h as it isn't needed after switch to 
generic implementation
 * Back comment /* !__ASSEMBLY__ */ for #else case in <asm/bug.h>
 * Remove changes related to x86/.../asm/debuger.h as do_bug_frame() prototype 
was updated and cpu_user_regs
         isn't const any more.

---
Changes in V3:
 * Nothing was done with the comment in <xen/bug.h> before 
run_in_exception_handler
   but I think it can be changed during the merge.
 * Add debugger_trap_fatal() to do_bug_frame(). It simplifies usage of
   do_bug_frame() for x86 so making handle_bug_frame() and find_bug_frame()
   not needed anymore.
 * Update do_bug_frame() to return -EINVAL if something goes wrong; otherwise
   id of bug_frame
 * Update _ASM_BUGFRAME_TEXT to make it more portable.
 * Drop unnecessary comments.
 * Update patch 2 not to break compilation: move some parts from patches 3 and 4
   to patch 2
 * As prototype and what do_bug_frame() returns was changed so patch 3 and 4
   was updated to use a new version of do_bug_frame
 * Change debugger_trap_fatal() prototype for x86 to align with prototype in
   <xen/debugger.h>
---
Changes in V2:
  * Update cover letter.
  * Switch to x86 implementation as generic as it is more compact ( at least 
from the point of view of bug frame structure).
  * Put [PATCH v1 4/4] xen: change <asm/bug.h> to <xen/bug.h> as second patch,
    update the patch to change all <asm/bug.h> to <xen/bug.h> among the whole 
project
    to not break compilation.
  * Rename CONFIG_GENERIC_DO_BUG_FRAME to CONFIG_GENERIC_BUG_FRAME.
  * Change the macro bug_loc(b) to avoid the need for a cast:
    #define bug_loc(b) ((unsigned long)(b) + (b)->loc_disp)
  * Rename BUG_FRAME_STUFF to BUG_FRAME_STRUCT
  * Make macros related to bug frame structure more generic.
  * Rename bug_file() in ARM implementation to bug_ptr() as generic 
do_bug_frame() uses
    bug_ptr().
  * Introduce BUG_INSTR and MODIFIER to make _ASM_BUGFRAME_TEXT reusable 
between x86 and
    RISC-V.
  * Rework do_invalid_op() in x86 ( re-use handle_bug_frame() and 
find_bug_frame() )
---
Oleksii Kurochko (4):
  xen: introduce CONFIG_GENERIC_BUG_FRAME
  xen: change <asm/bug.h> to <xen/bug.h>
  xen/arm: switch ARM to use generic implementation of bug.h
  xen/x86: switch x86 to use generic implemetation of bug.h

 xen/arch/arm/Kconfig                 |   1 +
 xen/arch/arm/arm32/traps.c           |   2 +-
 xen/arch/arm/include/asm/arm32/bug.h |   2 -
 xen/arch/arm/include/asm/arm64/bug.h |   2 -
 xen/arch/arm/include/asm/bug.h       |  88 +--------------
 xen/arch/arm/include/asm/div64.h     |   2 +-
 xen/arch/arm/include/asm/traps.h     |   2 -
 xen/arch/arm/traps.c                 |  81 +-------------
 xen/arch/arm/vgic/vgic-v2.c          |   2 +-
 xen/arch/arm/vgic/vgic.c             |   2 +-
 xen/arch/x86/Kconfig                 |   1 +
 xen/arch/x86/acpi/cpufreq/cpufreq.c  |   2 +-
 xen/arch/x86/include/asm/asm_defns.h |   2 +-
 xen/arch/x86/include/asm/bug.h       |  84 +-------------
 xen/arch/x86/traps.c                 |  81 ++------------
 xen/common/Kconfig                   |   3 +
 xen/common/Makefile                  |   1 +
 xen/common/bug.c                     | 103 +++++++++++++++++
 xen/drivers/cpufreq/cpufreq.c        |   2 +-
 xen/include/xen/bug.h                | 158 +++++++++++++++++++++++++++
 xen/include/xen/lib.h                |   2 +-
 21 files changed, 289 insertions(+), 334 deletions(-)
 create mode 100644 xen/common/bug.c
 create mode 100644 xen/include/xen/bug.h

-- 
2.39.0