linux.git/arch/nds32/kernel/stacktrace.c, branch v4.17 Linux kernel source tree nds32: Fix the symbols undefined issue by exporting them. 2018-05-23T05:26:20+00:00 Greentime Hu greentime@andestech.com 2018-04-19T07:45:45+00:00 e3f4624388731eb475ef7494b43440b3ad9269e1 It broke the 'allmodconfig' build. LD vmlinux SYSMAP System.map Building modules, stage 2. MODPOST 5028 modules ERROR: "flush_dcache_page" [net/sunrpc/xprtrdma/rpcrdma.ko] undefined! ERROR: "empty_zero_page" [net/ceph/libceph.ko] undefined! ERROR: "save_stack_trace" [kernel/backtracetest.ko] undefined! ERROR: "clear_page" [fs/ocfs2/dlm/ocfs2_dlm.ko] undefined! ERROR: "copy_page" [fs/nilfs2/nilfs2.ko] undefined! ... Signed-off-by: Greentime Hu <greentime@andestech.com> Acked-by: Arnd Bergmann <arnd@arndb.de> 
It broke the 'allmodconfig' build.
  LD      vmlinux
  SYSMAP  System.map
  Building modules, stage 2.
  MODPOST 5028 modules
ERROR: "flush_dcache_page" [net/sunrpc/xprtrdma/rpcrdma.ko] undefined!
ERROR: "empty_zero_page" [net/ceph/libceph.ko] undefined!
ERROR: "save_stack_trace" [kernel/backtracetest.ko] undefined!
ERROR: "clear_page" [fs/ocfs2/dlm/ocfs2_dlm.ko] undefined!
ERROR: "copy_page" [fs/nilfs2/nilfs2.ko] undefined!
...

Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
nds32: Exception handling 2018-02-22T02:44:31+00:00 Greentime Hu greentime@andestech.com 2017-10-24T06:42:02+00:00 2923f5ea7738cb9f5372bb9d7ac9886cf4193003 This patch includes the exception/interrupt entries, pt_reg structure and related accessors. /* Unaligned accessing handling*/ Andes processors cannot load/store information which is not naturally aligned on the bus, i.e., loading a 4 byte data whose start address must be divisible by 4. If unaligned data accessing is happened, data unaligned exception will be triggered and user will get SIGSEGV or kernel oops according to the unaligned address. In order to make user be able to load/store data from an unaligned address, software load/store emulation is implemented in arch/nds32/mm/alignment.c to address data unaligned exception. Unaligned accessing handling is disabled by default because it is not a normal case. User can enable this feature by following steps. A. Compile time: 1. Enable kernel config CONFIG_ALIGNMENT_TRAP B. Run time: 1. Enter /proc/sys/nds32/unaligned_acess folder 2. Write 1 to file enable_mode to enable unaligned accessing handling. User can disable it by writing 0 to this file. 3. Write 1 to file debug to show which unaligned address is under processing. User can disable it by writing 0 to this file. However, unaligned accessing handler cannot work if this unaligned address is not accessible such as protection violation. On this condition, the default behaviors for addressing data unaligned exception still happen Signed-off-by: Vincent Chen <vincentc@andestech.com> Signed-off-by: Greentime Hu <greentime@andestech.com> Acked-by: Arnd Bergmann <arnd@arndb.de> 
This patch includes the exception/interrupt entries, pt_reg structure and
related accessors.

/* Unaligned accessing handling*/
Andes processors cannot load/store information which is not naturally
aligned on the bus, i.e., loading a 4 byte data whose start address must
be divisible by 4. If unaligned data accessing is happened, data
unaligned exception will be triggered and user will get SIGSEGV or
kernel oops according to the unaligned address. In order to make user be
able to load/store data from an unaligned address, software load/store
emulation is implemented in arch/nds32/mm/alignment.c to address data
unaligned exception.

Unaligned accessing handling is disabled by default because it is not a
normal case. User can enable this feature by following steps.

A. Compile time:
    1. Enable kernel config CONFIG_ALIGNMENT_TRAP
B. Run time:
    1. Enter /proc/sys/nds32/unaligned_acess folder
    2. Write 1 to file enable_mode to enable unaligned accessing
       handling. User can disable it by writing 0 to this file.
    3. Write 1 to file debug to show which unaligned address is under
       processing. User can disable it by writing 0 to this file.

However, unaligned accessing handler cannot work if this unaligned
address is not accessible such as protection violation. On this
condition, the default behaviors for addressing data unaligned exception
still happen

Signed-off-by: Vincent Chen <vincentc@andestech.com>
Signed-off-by: Greentime Hu <greentime@andestech.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>