linux-stable.git/arch/arm, branch v3.2.27 Linux kernel stable tree ARM: Fix undefined instruction exception handling 2012-08-09T23:25:06+00:00 Russell King rmk+kernel@arm.linux.org.uk 2012-07-30T18:42:10+00:00 83358b9b1d3438293794224b14787a806031cf98 commit 15ac49b65024f55c4371a53214879a9c77c4fbf9 upstream. While trying to get a v3.5 kernel booted on the cubox, I noticed that VFP does not work correctly with VFP bounce handling. This is because of the confusion over 16-bit vs 32-bit instructions, and where PC is supposed to point to. The rule is that FP handlers are entered with regs->ARM_pc pointing at the _next_ instruction to be executed. However, if the exception is not handled, regs->ARM_pc points at the faulting instruction. This is easy for ARM mode, because we know that the next instruction and previous instructions are separated by four bytes. This is not true of Thumb2 though. Since all FP instructions are 32-bit in Thumb2, it makes things easy. We just need to select the appropriate adjustment. Do this by moving the adjustment out of do_undefinstr() into the assembly code, as only the assembly code knows whether it's dealing with a 32-bit or 16-bit instruction. Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 15ac49b65024f55c4371a53214879a9c77c4fbf9 upstream.

While trying to get a v3.5 kernel booted on the cubox, I noticed that
VFP does not work correctly with VFP bounce handling.  This is because
of the confusion over 16-bit vs 32-bit instructions, and where PC is
supposed to point to.

The rule is that FP handlers are entered with regs->ARM_pc pointing at
the _next_ instruction to be executed.  However, if the exception is
not handled, regs->ARM_pc points at the faulting instruction.

This is easy for ARM mode, because we know that the next instruction and
previous instructions are separated by four bytes.  This is not true of
Thumb2 though.

Since all FP instructions are 32-bit in Thumb2, it makes things easy.
We just need to select the appropriate adjustment.  Do this by moving
the adjustment out of do_undefinstr() into the assembly code, as only
the assembly code knows whether it's dealing with a 32-bit or 16-bit
instruction.

Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: 7478/1: errata: extend workaround for erratum #720789 2012-08-09T23:25:06+00:00 Will Deacon will.deacon@arm.com 2012-07-20T17:24:55+00:00 1b48195822f358b7b5e44369cfa34463f0b9e09f commit 5a783cbc48367cfc7b65afc75430953dfe60098f upstream. Commit cdf357f1 ("ARM: 6299/1: errata: TLBIASIDIS and TLBIMVAIS operations can broadcast a faulty ASID") replaced by-ASID TLB flushing operations with all-ASID variants to workaround A9 erratum #720789. This patch extends the workaround to include the tlb_range operations, which were overlooked by the original patch. Tested-by: Steve Capper <steve.capper@arm.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 5a783cbc48367cfc7b65afc75430953dfe60098f upstream.

Commit cdf357f1 ("ARM: 6299/1: errata: TLBIASIDIS and TLBIMVAIS
operations can broadcast a faulty ASID") replaced by-ASID TLB flushing
operations with all-ASID variants to workaround A9 erratum #720789.

This patch extends the workaround to include the tlb_range operations,
which were overlooked by the original patch.

Tested-by: Steve Capper <steve.capper@arm.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP 2012-08-09T23:25:05+00:00 Colin Cross ccross@android.com 2012-07-20T01:03:42+00:00 cdab6eed39be615703f582831765e14fb0452842 commit 24b35521b8ddf088531258f06f681bb7b227bf47 upstream. vfp_pm_suspend should save the VFP state in suspend after any lazy context switch. If it only saves when the VFP is enabled, the state can get lost when, on a UP system: Thread 1 uses the VFP Context switch occurs to thread 2, VFP is disabled but the VFP context is not saved Thread 2 initiates suspend vfp_pm_suspend is called with the VFP disabled, and the unsaved VFP context of Thread 1 in the registers Modify vfp_pm_suspend to save the VFP context whenever vfp_current_hw_state is not NULL. Includes a fix from Ido Yariv <ido@wizery.com>, who pointed out that on SMP systems, the state pointer can be pointing to a freed task struct if a task exited on another cpu, fixed by using #ifndef CONFIG_SMP in the new if clause. Cc: Barry Song <bs14@csr.com> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: Ido Yariv <ido@wizery.com> Cc: Daniel Drake <dsd@laptop.org> Cc: Will Deacon <will.deacon@arm.com> Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 24b35521b8ddf088531258f06f681bb7b227bf47 upstream.

vfp_pm_suspend should save the VFP state in suspend after
any lazy context switch.  If it only saves when the VFP is enabled,
the state can get lost when, on a UP system:
  Thread 1 uses the VFP
  Context switch occurs to thread 2, VFP is disabled but the
     VFP context is not saved
  Thread 2 initiates suspend
  vfp_pm_suspend is called with the VFP disabled, and the unsaved
     VFP context of Thread 1 in the registers

Modify vfp_pm_suspend to save the VFP context whenever
vfp_current_hw_state is not NULL.

Includes a fix from Ido Yariv <ido@wizery.com>, who pointed out that on
SMP systems, the state pointer can be pointing to a freed task struct if
a task exited on another cpu, fixed by using #ifndef CONFIG_SMP in the
new if clause.

Cc: Barry Song <bs14@csr.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Ido Yariv <ido@wizery.com>
Cc: Daniel Drake <dsd@laptop.org>
Cc: Will Deacon <will.deacon@arm.com>
Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: 7476/1: vfp: only clear vfp state for current cpu in vfp_pm_suspend 2012-08-09T23:25:04+00:00 Colin Cross ccross@android.com 2012-07-20T01:03:43+00:00 fc257bc543a3b08545e2332574a12893f0e54c85 commit a84b895a2348f0dbff31b71ddf954f70a6cde368 upstream. vfp_pm_suspend runs on each cpu, only clear the hardware state pointer for the current cpu. Prevents a possible crash if one cpu clears the hw state pointer when another cpu has already checked if it is valid. Signed-off-by: Colin Cross <ccross@android.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a84b895a2348f0dbff31b71ddf954f70a6cde368 upstream.

vfp_pm_suspend runs on each cpu, only clear the hardware state
pointer for the current cpu.  Prevents a possible crash if one
cpu clears the hw state pointer when another cpu has already
checked if it is valid.

Signed-off-by: Colin Cross <ccross@android.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: 7467/1: mutex: use generic xchg-based implementation for ARMv6+ 2012-08-09T23:25:04+00:00 Will Deacon will.deacon@arm.com 2012-07-13T18:15:40+00:00 c51cf2421d129a98183c2e9fd2209fa96297f118 commit a76d7bd96d65fa5119adba97e1b58d95f2e78829 upstream. The open-coded mutex implementation for ARMv6+ cores suffers from a severe lack of barriers, so in the uncontended case we don't actually protect any accesses performed during the critical section. Furthermore, the code is largely a duplication of the ARMv6+ atomic_dec code but optimised to remove a branch instruction, as the mutex fastpath was previously inlined. Now that this is executed out-of-line, we can reuse the atomic access code for the locking (in fact, we use the xchg code as this produces shorter critical sections). This patch uses the generic xchg based implementation for mutexes on ARMv6+, which introduces barriers to the lock/unlock operations and also has the benefit of removing a fair amount of inline assembly code. Acked-by: Arnd Bergmann <arnd@arndb.de> Acked-by: Nicolas Pitre <nico@linaro.org> Reported-by: Shan Kang <kangshan0910@gmail.com> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a76d7bd96d65fa5119adba97e1b58d95f2e78829 upstream.

The open-coded mutex implementation for ARMv6+ cores suffers from a
severe lack of barriers, so in the uncontended case we don't actually
protect any accesses performed during the critical section.

Furthermore, the code is largely a duplication of the ARMv6+ atomic_dec
code but optimised to remove a branch instruction, as the mutex fastpath
was previously inlined. Now that this is executed out-of-line, we can
reuse the atomic access code for the locking (in fact, we use the xchg
code as this produces shorter critical sections).

This patch uses the generic xchg based implementation for mutexes on
ARMv6+, which introduces barriers to the lock/unlock operations and also
has the benefit of removing a fair amount of inline assembly code.

Acked-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Nicolas Pitre <nico@linaro.org>
Reported-by: Shan Kang <kangshan0910@gmail.com>
Signed-off-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: 7466/1: disable interrupt before spinning endlessly 2012-08-09T23:25:03+00:00 Shawn Guo shawn.guo@linaro.org 2012-07-13T07:19:34+00:00 2bd8f381a4382eaeef391e0a551230610bece057 commit 98bd8b96b26db3399a48202318dca4aaa2515355 upstream. The CPU will endlessly spin at the end of machine_halt and machine_restart calls. However, this will lead to a soft lockup warning after about 20 seconds, if CONFIG_LOCKUP_DETECTOR is enabled, as system timer is still alive. Disable interrupt before going to spin endlessly, so that the lockup warning will never be seen. Reported-by: Marek Vasut <marex@denx.de> Signed-off-by: Shawn Guo <shawn.guo@linaro.org> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 98bd8b96b26db3399a48202318dca4aaa2515355 upstream.

The CPU will endlessly spin at the end of machine_halt and
machine_restart calls.  However, this will lead to a soft lockup
warning after about 20 seconds, if CONFIG_LOCKUP_DETECTOR is enabled,
as system timer is still alive.

Disable interrupt before going to spin endlessly, so that the lockup
warning will never be seen.

Reported-by: Marek Vasut <marex@denx.de>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: SAMSUNG: fix race in s3c_adc_start for ADC 2012-07-25T03:11:17+00:00 Todd Poynor toddpoynor@google.com 2012-07-13T06:30:48+00:00 3bbc9e1917b93542c0da222e06496f37d1e82182 commit 8265981bb439f3ecc5356fb877a6c2a6636ac88a upstream. Checking for adc->ts_pend already claimed should be done with the lock held. Signed-off-by: Todd Poynor <toddpoynor@google.com> Acked-by: Ben Dooks <ben-linux@fluff.org> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 8265981bb439f3ecc5356fb877a6c2a6636ac88a upstream.

Checking for adc->ts_pend already claimed should be done with the
lock held.

Signed-off-by: Todd Poynor <toddpoynor@google.com>
Acked-by: Ben Dooks <ben-linux@fluff.org>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: fix rcu stalls on SMP platforms 2012-07-12T03:32:11+00:00 Russell King rmk+kernel@arm.linux.org.uk 2012-01-19T15:20:58+00:00 bd00fcf3ec0c7fc0b194ba37a07564517fed11b8 commit 7deabca0acfe02b8e18f59a4c95676012f49a304 upstream. We can stall RCU processing on SMP platforms if a CPU sits in its idle loop for a long time. This happens because we don't call irq_enter() and irq_exit() around generic_smp_call_function_interrupt() and friends. Add the necessary calls, and remove the one from within ipi_timer(), so that they're all in a common place. Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 7deabca0acfe02b8e18f59a4c95676012f49a304 upstream.

We can stall RCU processing on SMP platforms if a CPU sits in its idle
loop for a long time.  This happens because we don't call irq_enter()
and irq_exit() around generic_smp_call_function_interrupt() and
friends.  Add the necessary calls, and remove the one from within
ipi_timer(), so that they're all in a common place.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: SAMSUNG: Fix for S3C2412 EBI memory mapping 2012-07-04T04:44:24+00:00 Jose Miguel Goncalves jose.goncalves@inov.pt 2012-05-11T21:11:49+00:00 53cee5b9ae7d411f5e2ebba2230937b598bf23e7 commit 3dca938656c7b0ff6b0717a5dde0f5f45e592be5 upstream. While upgrading the kernel on a S3C2412 based board I've noted that it was impossible to boot the board with a 2.6.32 or upper kernel. I've tracked down the problem to the EBI virtual memory mapping that is in conflict with the IO mapping definition in arch/arm/mach-s3c24xx/s3c2412.c. Signed-off-by: Jose Miguel Goncalves <jose.goncalves@inov.pt> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit 3dca938656c7b0ff6b0717a5dde0f5f45e592be5 upstream.

While upgrading the kernel on a S3C2412 based board I've noted
that it was impossible to boot the board with a 2.6.32 or upper
kernel. I've tracked down the problem to the EBI virtual memory
mapping that is in conflict with the IO mapping definition in
arch/arm/mach-s3c24xx/s3c2412.c.

Signed-off-by: Jose Miguel Goncalves <jose.goncalves@inov.pt>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
ARM: SAMSUNG: Should check for IS_ERR(clk) instead of NULL 2012-07-04T04:44:22+00:00 Jonghwan Choi jhbird.choi@samsung.com 2012-06-20T08:05:37+00:00 52c8c02cd596d6bd0a0a9313a6bc445b427f07d7 commit a5d8f4765f0e92ef027492a8cb979c5b8d45f2c3 upstream. On the error condition clk_get() returns ERR_PTR(). Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com> Signed-off-by: Kukjin Kim <kgene.kim@samsung.com> Signed-off-by: Ben Hutchings <ben@decadent.org.uk> 
commit a5d8f4765f0e92ef027492a8cb979c5b8d45f2c3 upstream.

On the error condition clk_get() returns ERR_PTR().

Signed-off-by: Jonghwan Choi <jhbird.choi@samsung.com>
Signed-off-by: Kukjin Kim <kgene.kim@samsung.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>