kernel/arch/powerpc/include/asm/rtas.h, branch linux-4.3.y

powerpc/rtas: Introduce rtas_get_sensor_fast() for IRQ handlers

2015-07-23T09:43:11Z

The EPOW interrupt handler uses rtas_get_sensor(), which in turn uses rtas_busy_delay() to wait for RTAS becoming ready in case it is necessary. But rtas_busy_delay() is annotated with might_sleep() and thus may not be used by interrupts handlers like the EPOW handler! This leads to the following BUG when CONFIG_DEBUG_ATOMIC_SLEEP is enabled: BUG: sleeping function called from invalid context at arch/powerpc/kernel/rtas.c:496 in_atomic(): 1, irqs_disabled(): 1, pid: 0, name: swapper/1 CPU: 1 PID: 0 Comm: swapper/1 Not tainted 4.2.0-rc2-thuth #6 Call Trace: [c00000007ffe7b90] [c000000000807670] dump_stack+0xa0/0xdc (unreliable) [c00000007ffe7bc0] [c0000000000e1f14] ___might_sleep+0x134/0x180 [c00000007ffe7c20] [c00000000002aec0] rtas_busy_delay+0x30/0xd0 [c00000007ffe7c50] [c00000000002bde4] rtas_get_sensor+0x74/0xe0 [c00000007ffe7ce0] [c000000000083264] ras_epow_interrupt+0x44/0x450 [c00000007ffe7d90] [c000000000120260] handle_irq_event_percpu+0xa0/0x300 [c00000007ffe7e70] [c000000000120524] handle_irq_event+0x64/0xc0 [c00000007ffe7eb0] [c000000000124dbc] handle_fasteoi_irq+0xec/0x260 [c00000007ffe7ef0] [c00000000011f4f0] generic_handle_irq+0x50/0x80 [c00000007ffe7f20] [c000000000010f3c] __do_irq+0x8c/0x200 [c00000007ffe7f90] [c0000000000236cc] call_do_irq+0x14/0x24 [c00000007e6f39e0] [c000000000011144] do_IRQ+0x94/0x110 [c00000007e6f3a30] [c000000000002594] hardware_interrupt_common+0x114/0x180 Fix this issue by introducing a new rtas_get_sensor_fast() function that does not use rtas_busy_delay() - and thus can only be used for sensors that do not cause a BUSY condition - known as "fast" sensors. The EPOW sensor is defined to be "fast" in sPAPR - mpe. Fixes: 587f83e8dd50 ("powerpc/pseries: Use rtas_get_sensor in RAS code") Signed-off-by: Thomas Huth Reviewed-by: Nathan Fontenot Signed-off-by: Michael Ellerman

Merge branch 'next-dlpar' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc into next

2015-04-13T05:30:21Z

Merge series from Nathan Fontenot to do memory hotplug in the kernel.

powerpc/pseries: Simplify check for suspendability during suspend/migration

2015-03-28T01:20:39Z

During suspend/migration operation we must wait for the VASI state reported by the hypervisor to become Suspending prior to making the ibm,suspend-me RTAS call. Calling routines to rtas_ibm_supend_me() pass a vasi_state variable that exposes the VASI state to the caller. This is unnecessary as the caller only really cares about the following three conditions; if there is an error we should bailout, success indicating we have suspended and woken back up so proceed to device tree update, or we are not suspendable yet so try calling rtas_ibm_suspend_me again shortly. This patch removes the extraneous vasi_state variable and simply uses the return code to communicate how to proceed. We either succeed, fail, or get -EAGAIN in which case we sleep for a second before trying to call rtas_ibm_suspend_me again. The behaviour of ppc_rtas() remains the same, but migrate_store() now returns the propogated error code on failure. Previously -1 was returned from migrate_store() in the failure case which equates to -EPERM and was clearly wrong. Signed-off-by: Tyrel Datwyler Cc: Nathan Fontenont Cc: Cyril Bur Signed-off-by: Michael Ellerman

powerpc/rtas: Make timestamp related code y2038-safe

2015-03-23T03:06:11Z

While we are here, let us make timestamp related code y2038-safe. Suggested-by: Arnd Bergmann Signed-off-by: Hari Bathini Signed-off-by: Michael Ellerman

powerpc/nvram: Move generic code for nvram and pstore

2015-03-23T03:05:49Z

With minor checks, we can move most of the code for nvram under pseries to a common place to be re-used by other powerpc platforms like powernv. This patch moves such common code to arch/powerpc/kernel/nvram_64.c file. Signed-off-by: Hari Bathini [mpe: Move select of ZLIB_DEFLATE to PPC64 to fix the build] Signed-off-by: Michael Ellerman

powerpc/pseries: Define rtas hotplug event sections

2015-03-16T23:57:44Z

In order to handle device hotplug in the kernel on pseries the hotplug request will be communicated in the kernel in the form of a rtas hotplug event. This patch adds the definition of rtas hotplug event sections. Signed-off-by: Nathan Fontenot Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Fix endian problems with LE migration

2015-01-27T03:03:53Z

RTAS events require arguments be passed in big endian while hypercalls have their arguments passed in registers and the values should therefore be in CPU endian. The "ibm,suspend_me" 'RTAS' call makes a sequence of hypercalls to setup one true RTAS call. This means that "ibm,suspend_me" is handled specially in the ppc_rtas() syscall. The ppc_rtas() syscall has its arguments in big endian and can therefore pass these arguments directly to the RTAS call. "ibm,suspend_me" is handled specially from within ppc_rtas() (by calling rtas_ibm_suspend_me()) which has left an endian bug on little endian systems due to the requirement of hypercalls. The return value from rtas_ibm_suspend_me() gets returned in cpu endian, and is left unconverted, also a bug on little endian systems. rtas_ibm_suspend_me() does not actually make use of the rtas_args that it is passed. This patch removes the convoluted use of the rtas_args struct to pass params to rtas_ibm_suspend_me() in favour of passing what it needs as actual arguments. This patch also ensures the two callers of rtas_ibm_suspend_me() pass function parameters in cpu endian and in the case of ppc_rtas(), converts the return value. migrate_store() (the other caller of rtas_ibm_suspend_me()) is from a sysfs file which deals with everything in cpu endian so this function only underwent cleanup. This patch has been tested with KVM both LE and BE and on PowerVM both LE and BE. Under QEMU/KVM the migration happens without touching these code pathes. For PowerVM there is no obvious regression on BE and the LE code path now provides the correct parameters to the hypervisor. Signed-off-by: Cyril Bur Signed-off-by: Michael Ellerman

powerpc/le: Enable RTAS events support

2014-04-07T00:33:12Z

The current kernel code assumes big endian and parses RTAS events all wrong. The most visible effect is that we cannot honor EPOW events, meaning, for example, we cannot shut down a guest properly from the hypervisor. This new patch is largely inspired by Nathan's work: we get rid of all the bit fields in the RTAS event structures (even the unused ones, for consistency). We also introduce endian safe accessors for the fields used by the kernel (trivial rtas_error_type() accessor added for consistency). Cc: Nathan Fontenot Signed-off-by: Greg Kurz Signed-off-by: Benjamin Herrenschmidt

powerpc/pseries: Update dynamic cache nodes for suspend/resume operation

2014-03-07T04:54:49Z

pHyp can change cache nodes for suspend/resume operation. Currently the device tree is updated by drmgr in userspace after all non boot CPUs are enabled. Hence, we do not modify the cache list based on the latest cache nodes. Also we do not remove cache entries for the primary CPU. This patch removes the cache list for the boot CPU, updates the device tree before enabling nonboot CPUs and adds cache list for the boot cpu. This patch also has the side effect that older versions of drmgr will perform a second device tree update from userspace. While this is a redundant waste of a couple cycles it is harmless since firmware returns the same data for the subsequent update-nodes/properties rtas calls. Signed-off-by: Haren Myneni Signed-off-by: Tyrel Datwyler Signed-off-by: Benjamin Herrenschmidt

powerpc: Make RTAS calls endian safe

2013-08-14T05:33:22Z

RTAS expects arguments in the call buffer to be big endian so we need to byteswap on little endian builds Signed-off-by: Anton Blanchard Signed-off-by: Benjamin Herrenschmidt