kernel.git/arch/powerpc/kernel/exceptions-64s.S, branch linux-4.11.y

powerpc/64s: Handle data breakpoints in Radix mode

2017-06-29T11:02:50Z

commit d89ba5353f301971dd7d2f9fdf25c4432728f38e upstream. On Power9, trying to use data breakpoints throws the splat shown below. This is because the check for a data breakpoint in DSISR is in do_hash_page(), which is not called when in Radix mode. Unable to handle kernel paging request for data at address 0xc000000000e19218 Faulting instruction address: 0xc0000000001155e8 cpu 0x0: Vector: 300 (Data Access) at [c0000000ef1e7b20] pc: c0000000001155e8: find_pid_ns+0x48/0xe0 lr: c000000000116ac4: find_task_by_vpid+0x44/0x90 sp: c0000000ef1e7da0 msr: 9000000000009033 dar: c000000000e19218 dsisr: 400000 Move the check to handle_page_fault() so as to catch data breakpoints in both Hash and Radix MMU modes. We have to change the check in do_hash_page() against 0xa410 to use 0xa450, so as to include the value of (DSISR_DABRMATCH << 16). There are two sites that call handle_page_fault() when in Radix, both already pass DSISR in r4. Fixes: caca285e5ab4 ("powerpc/mm/radix: Use STD_MMU_64 to properly isolate hash related code") Reported-by: Shriya R. Kulkarni Signed-off-by: Naveen N. Rao [mpe: Fix the fall-through case on hash, we need to reload DSISR] Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman

powerpc/64: Fix HMI exception on LE with CONFIG_RELOCATABLE=y

2017-04-18T10:19:52Z

Prior to commit 2337d207288f ("powerpc/64: CONFIG_RELOCATABLE support for hmi interrupts"), the branch from hmi_exception_early() to hmi_exception_realmode() was just a bl hmi_exception_realmode, which the linker would turn into a bl to the local entry point of hmi_exception_realmode. This was broken when CONFIG_RELOCATABLE=y because hmi_exception_realmode() is not in the low part of the kernel text that is copied down to 0x0. But in fixing that, we added a new bug on little endian kernels. Because the branch is now a bctrl when CONFIG_RELOCATABLE=y, we branch to the global entry point of hmi_exception_realmode(). The global entry point must be called with r12 containing the address of hmi_exception_realmode(), because it uses that value to calculate the TOC value (r2). This may manifest as a checkstop, because we take a junk value from r12 which came from HSRR1, add a small constant to it and then use that as the TOC pointer. The HSRR1 value will have 0x9 as the top nibble, which puts it above RAM and somewhere in MMIO space. Fix it by changing the BRANCH_LINK_TO_FAR() macro to always use r12 to load the label we're branching to. This means r12 will be setup correctly on LE, fixing this bug, and r12 is also volatile across function calls on BE so it's a good choice anyway. Fixes: 2337d207288f ("powerpc/64: CONFIG_RELOCATABLE support for hmi interrupts") Reported-by: Mahesh Salgaonkar Acked-by: Nicholas Piggin Signed-off-by: Michael Ellerman

Merge branch 'topic/ppc-kvm' into next

2017-02-14T06:18:29Z

Merge the topic branch we're sharing with the kvm-ppc tree.

powerpc/64: CONFIG_RELOCATABLE support for hmi interrupts

2017-02-07T05:39:44Z

The branch from hmi_exception_early to hmi_exception_realmode must use a "relocatable-style" branch, because it is branching from unrelocated exception code to beyond __end_interrupts. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

powerpc/64s: Use (start, size) rather than (start, end) for exception handlers

2017-02-06T20:26:57Z

start,size has the benefit of being easier to search for (start,end usually gives you the preceeding vector from the one you want, as first result). Suggested-by: Benjamin Herrenschmidt Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

powerpc/64s: Tidy up after exception handler rework

2017-02-06T20:26:57Z

Somewhere along the line, search/replace left some naming garbled, and untidy alignment (aka. mpe stuffed it up). Might as well fix them all up now while git blame history doesn't extend too far. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman

powerpc/64: Allow for relocation-on interrupts from guest to host

2017-01-31T08:11:46Z

With host and guest both using radix translation, it is feasible for the host to take interrupts that come from the guest with relocation on, and that is in fact what the POWER9 hardware will do when LPCR[AIL] = 3. All such interrupts use HSRR0/1 not SRR0/1 except for system call with LEV=1 (hcall). Therefore this adds the KVM tests to the _HV variants of the relocation-on interrupt handlers, and adds the KVM test to the relocation-on system call entry point. We also instantiate the relocation-on versions of the hypervisor data storage and instruction interrupt handlers, since these can occur with relocation on in radix guests. Signed-off-by: Paul Mackerras Signed-off-by: Michael Ellerman

KVM: PPC: Book3S: 64-bit CONFIG_RELOCATABLE support for interrupts

2017-01-31T08:07:39Z

64-bit Book3S exception handlers must find the dynamic kernel base to add to the target address when branching beyond __end_interrupts, in order to support kernel running at non-0 physical address. Support this in KVM by branching with CTR, similarly to regular interrupt handlers. The guest CTR saved in HSTATE_SCRATCH1 and restored after the branch. Without this, the host kernel hangs and crashes randomly when it is running at a non-0 address and a KVM guest is started. Signed-off-by: Nicholas Piggin Acked-by: Paul Mackerras Signed-off-by: Michael Ellerman

powernv:idle: Add IDLE_STATE_ENTER_SEQ_NORET macro

2017-01-30T21:32:12Z

Currently all the low-power idle states are expected to wake up at reset vector 0x100. Which is why the macro IDLE_STATE_ENTER_SEQ that puts the CPU to an idle state and never returns. On ISA v3.0, when the ESL and EC bits in the PSSCR are zero, the CPU is expected to wake up at the next instruction of the idle instruction. This patch adds a new macro named IDLE_STATE_ENTER_SEQ_NORET for the no-return variant and reuses the name IDLE_STATE_ENTER_SEQ for a variant that allows resuming operation at the instruction next to the idle-instruction. Acked-by: Balbir Singh Signed-off-by: Gautham R. Shenoy Signed-off-by: Michael Ellerman

KVM: PPC: Book3S: Move 64-bit KVM interrupt handler out from alt section

2017-01-27T04:41:21Z

A subsequent patch to make KVM handlers relocation-safe makes them unusable from within alt section "else" cases (due to the way fixed addresses are taken from within fixed section head code). Stop open-coding the KVM handlers, and add them both as normal. A more optimal fix may be to allow some level of alternate feature patching in the exception macros themselves, but for now this will do. The TRAMP_KVM handlers must be moved to the "virt" fixed section area (name is arbitrary) in order to be closer to .text and avoid the dreaded "relocation truncated to fit" error. Signed-off-by: Nicholas Piggin Acked-by: Paul Mackerras Signed-off-by: Michael Ellerman