linux-stable.git/arch/arc/kernel/unaligned.c, branch v3.16.67 Linux kernel stable tree ARC: [arcompact] brown paper bag bug in unaligned access delay slot fixup 2017-03-16T02:27:10+00:00 Vineet Gupta Vineet.Gupta1@synopsys.com 2017-02-07T17:44:58+00:00 2e441d9dc99f0ad0d839c4933bfd46c7938e31ea commit a524c218bc94c705886a0e0fedeee45d1931da32 upstream. Reported-by: Jo-Philipp Wich <jo@mein.io> Fixes: 9aed02feae57bf7 ("ARC: [arcompact] handle unaligned access delay slot") Cc: linux-kernel@vger.kernel.org Cc: linux-snps-arc@lists.infradead.org Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a524c218bc94c705886a0e0fedeee45d1931da32 upstream.

Reported-by: Jo-Philipp Wich <jo@mein.io>
Fixes: 9aed02feae57bf7 ("ARC: [arcompact] handle unaligned access delay slot")
Cc: linux-kernel@vger.kernel.org
Cc: linux-snps-arc@lists.infradead.org
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARC: [arcompact] handle unaligned access delay slot corner case 2017-03-16T02:27:07+00:00 Vineet Gupta vgupta@synopsys.com 2017-01-27T18:45:27+00:00 e15d8e5a5e167ffed0056c753c81eac17e3ea709 commit 9aed02feae57bf7a40cb04ea0e3017cb7a998db4 upstream. After emulating an unaligned access in delay slot of a branch, we pretend as the delay slot never happened - so return back to actual branch target (or next PC if branch was not taken). Curently we did this by handling STATUS32.DE, we also need to clear the BTA.T bit, which is disregarded when returning from original misaligned exception, but could cause weirdness if it took the interrupt return path (in case interrupt was acive too) One ARC700 customer ran into this when enabling unaligned access fixup for kernel mode accesses as well Signed-off-by: Vineet Gupta <vgupta@synopsys.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 9aed02feae57bf7a40cb04ea0e3017cb7a998db4 upstream.

After emulating an unaligned access in delay slot of a branch, we
pretend as the delay slot never happened - so return back to actual
branch target (or next PC if branch was not taken).

Curently we did this by handling STATUS32.DE, we also need to clear the
BTA.T bit, which is disregarded when returning from original misaligned
exception, but could cause weirdness if it took the interrupt return
path (in case interrupt was acive too)

One ARC700 customer ran into this when enabling unaligned access fixup
for kernel mode accesses as well

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARC: Handle zero-overhead-loop in unaligned access handler 2013-09-27T10:58:23+00:00 Mischa Jonker mjonker@synopsys.com 2013-09-26T13:44:56+00:00 c11eb222fd7d4db91196121dbf854178505d2751 If a load or store is the last instruction in a zero-overhead-loop, and it's misaligned, the loop would execute only once. This fixes that problem. Signed-off-by: Mischa Jonker <mjonker@synopsys.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
If a load or store is the last instruction in a zero-overhead-loop, and
it's misaligned, the loop would execute only once.

This fixes that problem.

Signed-off-by: Mischa Jonker <mjonker@synopsys.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: Handle un-aligned user space access in BE. 2013-09-05T05:01:11+00:00 Noam Camus noamc@ezchip.com 2012-09-10T12:13:19+00:00 7d669a193bc0f44c20054687a3bf9ff82ad001a7 Adding endian awarness to un-aligned access exception handling. Signed-off-by: Noam Camus <noamc@ezchip.com> Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
Adding endian awarness to un-aligned access exception handling.

Signed-off-by: Noam Camus <noamc@ezchip.com>
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: Remove explicit passing around of ECR 2013-06-26T10:00:50+00:00 Vineet Gupta vgupta@synopsys.com 2013-06-12T09:43:40+00:00 38a9ff6d247cf9afcbe55ea245b650b8955029fd With ECR now part of pt_regs * No need to propagate from lowest asm handlers as arg * No need to save it in tsk->thread.cause_code * Avoid bit chopping to access the bit-fields More code consolidation, cleanup Signed-off-by: Vineet Gupta <vgupta@synopsys.com> 
With ECR now part of pt_regs

* No need to propagate from lowest asm handlers as arg
* No need to save it in tsk->thread.cause_code
* Avoid bit chopping to access the bit-fields

More code consolidation, cleanup

Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
ARC: Unaligned access emulation 2013-02-15T17:46:06+00:00 Vineet Gupta vgupta@synopsys.com 2013-01-23T11:00:36+00:00 2e651ea1596b0ee25af4fcdc4cd13cbb33ffc254 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> 
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>