kernel.git/arch/arm/vfp, branch linux-3.2.y

ARM: VFP: fix emulation of second VFP instruction

2013-03-20T15:03:17Z

commit 5e4ba617c1b584b2e376f31a63bd4e734109318a upstream. Martin Storsjö reports that the sequence: ee312ac1 vsub.f32 s4, s3, s2 ee702ac0 vsub.f32 s5, s1, s0 e59f0028 ldr r0, [pc, #40] ee111a90 vmov r1, s3 on Raspberry Pi (implementor 41 architecture 1 part 20 variant b rev 5) where s3 is a denormal and s2 is zero results in incorrect behaviour - the instruction "vsub.f32 s5, s1, s0" is not executed: VFP: bounce: trigger ee111a90 fpexc d0000780 VFP: emulate: INST=0xee312ac1 SCR=0x00000000 ... As we can see, the instruction triggering the exception is the "vmov" instruction, and we emulate the "vsub.f32 s4, s3, s2" but fail to properly take account of the FPEXC_FP2V flag in FPEXC. This is because the test for the second instruction register being valid is bogus, and will always skip emulation of the second instruction. Reported-by: Martin Storsjö Tested-by: Martin Storsjö Signed-off-by: Russell King Signed-off-by: Ben Hutchings

ARM: 7627/1: Predicate preempt logic on PREEMP_COUNT not PREEMPT alone

2013-02-06T04:33:35Z

commit 568dca15aa2a0f4ddee255894ec393a159f13147 upstream. Patrik Kluba reports that the preempt count becomes invalid due to the preempt_enable() call being unbalanced with a preempt_disable() call in the vfp assembly routines. This happens because preempt_enable() and preempt_disable() update preempt counts under PREEMPT_COUNT=y but the vfp assembly routines do so under PREEMPT=y. In a configuration where PREEMPT=n and DEBUG_ATOMIC_SLEEP=y, PREEMPT_COUNT=y and so the preempt_enable() call in VFP_bounce() keeps subtracting from the preempt count until it goes negative. Fix this by always using PREEMPT_COUNT to decided when to update preempt counts in the ARM assembly code. Signed-off-by: Stephen Boyd Reported-by: Patrik Kluba Tested-by: Patrik Kluba Signed-off-by: Russell King Signed-off-by: Ben Hutchings

ARM: 7566/1: vfp: fix save and restore when running on pre-VFPv3 and CONFIG_VFPv3 set

2013-01-03T03:32:49Z

commit 39141ddfb63a664f26d3f42f64ee386e879b492c upstream. After commit 846a136881b8f73c1f74250bf6acfaa309cab1f2 ("ARM: vfp: fix saving d16-d31 vfp registers on v6+ kernels"), the OMAP 2430SDP board started crashing during boot with omap2plus_defconfig: [ 3.875122] mmcblk0: mmc0:e624 SD04G 3.69 GiB [ 3.915954] mmcblk0: p1 [ 4.086639] Internal error: Oops - undefined instruction: 0 [#1] SMP ARM [ 4.093719] Modules linked in: [ 4.096954] CPU: 0 Not tainted (3.6.0-02232-g759e00b #570) [ 4.103149] PC is at vfp_reload_hw+0x1c/0x44 [ 4.107666] LR is at __und_usr_fault_32+0x0/0x8 It turns out that the context save/restore fix unmasked a latent bug in commit 5aaf254409f8d58229107b59507a8235b715a960 ("ARM: 6203/1: Make VFPv3 usable on ARMv6"). When CONFIG_VFPv3 is set, but the kernel is booted on a pre-VFPv3 core, the code attempts to save and restore the d16-d31 VFP registers. These are only present on non-D16 VFPv3+, so this results in an undefined instruction exception. The code didn't crash before commit 846a136 because the save and restore code was only touching d0-d15, present on all VFP. Fix by implementing a request from Russell King to add a new HWCAP flag that affirmatively indicates the presence of the d16-d31 registers: http://marc.info/?l=linux-arm-kernel&m=135013547905283&w=2 and some feedback from Måns to clarify the name of the HWCAP flag. Signed-off-by: Paul Walmsley Cc: Tony Lindgren Cc: Catalin Marinas Cc: Dave Martin Cc: Måns Rullgård Signed-off-by: Russell King [bwh: Backported to 3.2: adjust filename] Signed-off-by: Ben Hutchings

ARM: 7483/1: vfp: only advertise VFPv4 in hwcaps if CONFIG_VFPv3 is enabled

2012-09-12T02:36:56Z

commit 3d9fb0038a9b02febb01efc79a4a5d97f1822a90 upstream. VFPv4 support depends on the VFPv3 context save/restore code, so only advertise support in the hwcaps if the kernel can actually handle it. Signed-off-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Ben Hutchings

ARM: Fix undefined instruction exception handling

2012-08-09T23:25:06Z

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 Signed-off-by: Russell King Signed-off-by: Ben Hutchings

ARM: 7477/1: vfp: Always save VFP state in vfp_pm_suspend on UP

2012-08-09T23:25:05Z

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 , 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 Cc: Catalin Marinas Cc: Ido Yariv Cc: Daniel Drake Cc: Will Deacon Signed-off-by: Colin Cross Signed-off-by: Russell King Signed-off-by: Ben Hutchings

ARM: 7476/1: vfp: only clear vfp state for current cpu in vfp_pm_suspend

2012-08-09T23:25:04Z

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 Signed-off-by: Russell King Signed-off-by: Ben Hutchings

ARM: 7417/1: vfp: ensure preemption is disabled when enabling VFP access

2012-05-20T21:56:46Z

commit 998de4acb2ba188d20768d1065658377a2e7d29b upstream. The vfp_enable function enables access to the VFP co-processor register space (cp10 and cp11) on the current CPU and must be called with preemption disabled. Unfortunately, the vfp_init late initcall does not disable preemption and can lead to an oops during boot if thread migration occurs at the wrong time and we end up attempting to access the FPSID on a CPU with VFP access disabled. This patch fixes the initcall to call vfp_enable from a non-preemptible context on each CPU and adds a BUG_ON(preemptible) to ensure that any similar problems are easily spotted in the future. Reported-by: Hyungwoo Yang Signed-off-by: Hyungwoo Yang Signed-off-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Ben Hutchings

arm: remove several unnecessary module.h include instances

2011-10-31T23:30:48Z

Building these files does not reveal a hidden need for any of these. Since module.h brings in the whole kitchen sink, it just needlessly adds 30k+ lines to the cpp burden. There are probably lots more, but ARM files of mach-* and plat-* don't get coverage via a simple yesconfig build. They will have to be cleaned up and tested via using their respective configs. Signed-off-by: Paul Gortmaker

Merge branch 'devel-stable' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm

2011-10-28T19:02:27Z

* 'devel-stable' of http://ftp.arm.linux.org.uk/pub/linux/arm/kernel/git-cur/linux-2.6-arm: (178 commits) ARM: 7139/1: fix compilation with CONFIG_ARM_ATAG_DTB_COMPAT and large TEXT_OFFSET ARM: gic, local timers: use the request_percpu_irq() interface ARM: gic: consolidate PPI handling ARM: switch from NO_MACH_MEMORY_H to NEED_MACH_MEMORY_H ARM: mach-s5p64x0: remove mach/memory.h ARM: mach-s3c64xx: remove mach/memory.h ARM: plat-mxc: remove mach/memory.h ARM: mach-prima2: remove mach/memory.h ARM: mach-zynq: remove mach/memory.h ARM: mach-bcmring: remove mach/memory.h ARM: mach-davinci: remove mach/memory.h ARM: mach-pxa: remove mach/memory.h ARM: mach-ixp4xx: remove mach/memory.h ARM: mach-h720x: remove mach/memory.h ARM: mach-vt8500: remove mach/memory.h ARM: mach-s5pc100: remove mach/memory.h ARM: mach-tegra: remove mach/memory.h ARM: plat-tcc: remove mach/memory.h ARM: mach-mmp: remove mach/memory.h ARM: mach-cns3xxx: remove mach/memory.h ... Fix up mostly pretty trivial conflicts in: - arch/arm/Kconfig - arch/arm/include/asm/localtimer.h - arch/arm/kernel/Makefile - arch/arm/mach-shmobile/board-ap4evb.c - arch/arm/mach-u300/core.c - arch/arm/mm/dma-mapping.c - arch/arm/mm/proc-v7.S - arch/arm/plat-omap/Kconfig largely due to some CONFIG option renaming (ie CONFIG_PM_SLEEP -> CONFIG_ARM_CPU_SUSPEND for the arm-specific suspend code etc) and addition of NEED_MACH_MEMORY_H next to HAVE_IDE.