kernel/arch/powerpc/include/asm/rtas.h, branch linux-4.16.y

powerpc/pseries: Implement indexed-count hotplug memory add

2017-02-17T06:57:30Z

Indexed-count add for memory hotplug guarantees that a contiguous block of lmbs beginning at a specified will be assigned, any LMBs in this range that are not already assigned will be DLPAR added. Because of Qemu's per-DIMM memory management, the addition of a contiguous block of memory currently requires a series of individual calls to add each LMB in the block. Indexed-count add reduces this series of calls to a single call for the entire block. Signed-off-by: Sahil Mehta Signed-off-by: Nathan Fontenot Signed-off-by: Michael Ellerman

powerpc/pseries: Introduce memory hotplug READD operation

2017-02-02T05:57:39Z

Currently, memory must be hot removed and subsequently re-added in order to dynamically update the affinity of LMBs specified by a PRRN event. Earlier implementations of the PRRN event handler ran into issues in which the hot remove would occur successfully, but a hotplug event would be initiated from another source and grab the hotplug lock preventing the hot add from occurring. To prevent this situation, this patch introduces the notion of a hot "readd" action for memory which atomizes a hot remove and a hot add into a single, serialized operation on the hotplug queue. Signed-off-by: John Allen Reviewed-by: Nathan Fontenot Signed-off-by: Michael Ellerman

powerpc: Merge 32-bit and 64-bit setup_arch()

2016-07-21T09:17:46Z

There is little enough differences now. mpe: Add a/p/k/setup.h to contain the prototypes and empty versions of functions we need, rather than using weak functions. Add a few other empty versions to avoid as many #ifdefs as possible in the code. Signed-off-by: Benjamin Herrenschmidt Signed-off-by: Michael Ellerman

powerpc: Make ppc_md.{halt, restart} __noreturn

2016-07-14T11:12:06Z

powernv marks it's halt and restart calls as __noreturn. However, ppc_md does not have this annotation. Add the annotation to ppc_md, and then to every halt/restart function that is missing it. Additionally, I have verified that all of these functions do not return. Occasionally I have added a spin loop to be sure. Signed-off-by: Daniel Axtens Signed-off-by: Michael Ellerman

powerpc/rtas: Make enter_rtas() private

2015-12-17T11:40:56Z

There are no longer any users of enter_rtas() outside of rtas.c, so make it "private", by moving the declaration inside rtas.c. Hopefully this will encourage people to use one of the wrappers which takes the sharp edges off the RTAS calling sequence. Signed-off-by: Michael Ellerman

powerpc/rtas: Add rtas_call_unlocked()

2015-12-17T11:40:55Z

Most users of RTAS (Run-Time Abstraction Services) use rtas_call(), which deals with locking as well as endian handling. However we have two users outside of rtas.c that can't use rtas_call() because they have different locking requirements. The hotplug CPU code can't take the RTAS lock because the CPU would go offline with the lock held and no other CPUs would be able to call RTAS until the CPU came back online. The xmon code doesn't want to take the lock because it would risk dead locking when we are trying to recover from a crash. Both sites required multiple patches when we added little endian support, proving that programmers can't do endian right. Although that ship has sailed, we can still clean the code up by providing an unlocked version of rtas_call() which avoids the need to open code the logic elsewhere. Signed-off-by: Michael Ellerman

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