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| author | Vineet Gupta <vgupta@synopsys.com> | 2013-01-23 16:30:36 +0530 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2013-02-15 23:16:06 +0530 |
| commit | 2e651ea1596b0ee25af4fcdc4cd13cbb33ffc254 (patch) | |
| tree | 51210f1cd80327a00e2fd4b0d20849b6329925d6 /arch/arc/kernel/entry.S | |
| parent | bf14e3b979a01cd7298d631736f965fe83c6e2bc (diff) | |
| download | linux-2e651ea1596b0ee25af4fcdc4cd13cbb33ffc254.tar.bz2 | |
ARC: Unaligned access emulation
ARC700 doesn't natively support unaligned access, but can be emulated
-Unaligned Access Exception
-Disassembly at the Fault address to find the exact insn (long/short)
Also per Arnd's comment, we runtime control it using 2 sysctl knobs:
* SYSCTL_ARCH_UNALIGN_ALLOW: Runtime enable/disble
* SYSCTL_ARCH_UNALIGN_NO_WARN: Warn on each emulation attempt
Originally contributed by Tim Yao <tim.yao@amlogic.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Cc: Tim Yao <tim.yao@amlogic.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Diffstat (limited to 'arch/arc/kernel/entry.S')
| -rw-r--r-- | arch/arc/kernel/entry.S | 13 |
1 files changed, 13 insertions, 0 deletions
diff --git a/arch/arc/kernel/entry.S b/arch/arc/kernel/entry.S index 021cfa46a1dc..f8efade15368 100644 --- a/arch/arc/kernel/entry.S +++ b/arch/arc/kernel/entry.S @@ -7,6 +7,9 @@ * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. * + * vineetg: May 2011 + * -Userspace unaligned access emulation + * * vineetg: Feb 2011 (ptrace low level code fixes) * -traced syscall return code (r0) was not saved into pt_regs for restoring * into user reg-file when traded task rets to user space. @@ -387,7 +390,17 @@ ARC_ENTRY EV_TLBProtV mov r1, r4 ; faulting address mov r2, sp ; pt_regs +#ifdef CONFIG_ARC_MISALIGN_ACCESS + SAVE_CALLEE_SAVED_USER + mov r3, sp ; callee_regs +#endif + bl do_misaligned_access + +#ifdef CONFIG_ARC_MISALIGN_ACCESS + DISCARD_CALLEE_SAVED_USER +#endif + b ret_from_exception ARC_EXIT EV_TLBProtV |