kernel.git/arch/powerpc/kernel/process.c, branch linux-5.7.y

powerpc: Fix kernel crash in show_instructions() w/DEBUG_VIRTUAL

2020-06-24T15:49:13Z

[ Upstream commit a6e2c226c3d51fd93636320e47cabc8a8f0824c5 ] With CONFIG_DEBUG_VIRTUAL=y, we can hit a BUG() if we take a hard lockup watchdog interrupt when in OPAL mode. This happens in show_instructions() if the kernel takes the watchdog NMI IPI, or any other interrupt, with MSR_IR == 0. show_instructions() updates the variable pc in the loop and the second iteration will result in BUG(). We hit the BUG_ON due the below check in __va() #define __va(x) ({ VIRTUAL_BUG_ON((unsigned long)(x) >= PAGE_OFFSET); (void *)(unsigned long)((phys_addr_t)(x) | PAGE_OFFSET); }) Fix it by moving the check out of the loop. Also update nip so that the nip == pc check still matches. Fixes: 4dd7554a6456 ("powerpc/64: Add VIRTUAL_BUG_ON checks for __va and __pa addresses") Signed-off-by: Aneesh Kumar K.V [mpe: Use IS_ENABLED(), massage change log] Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200524093822.423487-1-aneesh.kumar@linux.ibm.com Signed-off-by: Sasha Levin

powerpc/64s: Implement interrupt exit logic in C

2020-04-01T02:42:14Z

Implement the bulk of interrupt return logic in C. The asm return code must handle a few cases: restoring full GPRs, and emulating stack store. The stack store emulation is significantly simplfied, rather than creating a new return frame and switching to that before performing the store, it uses the PACA to keep a scratch register around to perform the store. The asm return code is moved into 64e for now. The new logic has made allowance for 64e, but I don't have a full environment that works well to test it, and even booting in emulated qemu is not great for stress testing. 64e shouldn't be too far off working with this, given a bit more testing and auditing of the logic. This is slightly faster on a POWER9 (page fault speed increases about 1.1%), probably due to reduced mtmsrd. mpe: Includes fixes from Nick for _TIF_EMULATE_STACK_STORE handling (including the fast_interrupt_return path), to remove trace_hardirqs_on(), and fixes the interrupt-return part of the MSR_VSX restore bug caught by tm-unavailable selftest. mpe: Incorporate fix from Nick: The return-to-kernel path has to replay any soft-pending interrupts if it is returning to a context that had interrupts soft-enabled. It has to do this carefully and avoid plain enabling interrupts if this is an irq context, which can cause multiple nesting of interrupts on the stack, and other unexpected issues. The code which avoided this case got the soft-mask state wrong, and marked interrupts as enabled before going around again to retry. This seems to be mostly harmless except when PREEMPT=y, this calls preempt_schedule_irq with irqs apparently enabled and runs into a BUG in kernel/sched/core.c Signed-off-by: Nicholas Piggin Signed-off-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200225173541.1549955-29-npiggin@gmail.com

powerpc/64: mark emergency stacks valid to unwind

2020-04-01T02:42:09Z

Before: WARNING: CPU: 0 PID: 494 at arch/powerpc/kernel/irq.c:343 CPU: 0 PID: 494 Comm: a Tainted: G W NIP: c00000000001ed2c LR: c000000000d13190 CTR: c00000000003f910 REGS: c0000001fffd3870 TRAP: 0700 Tainted: G W MSR: 8000000000021003 CR: 28000488 XER: 00000000 CFAR: c00000000001ec90 IRQMASK: 0 GPR00: c000000000aeb12c c0000001fffd3b00 c0000000012ba300 0000000000000000 GPR04: 0000000000000000 0000000000000000 000000010bd207c8 6b00696e74657272 GPR08: 0000000000000000 0000000000000000 0000000000000000 efbeadde00000000 GPR12: 0000000000000000 c0000000014a0000 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR24: 0000000000000000 0000000000000000 0000000000000000 000000010bd207bc GPR28: 0000000000000000 c00000000148a898 0000000000000000 c0000001ffff3f50 NIP [c00000000001ed2c] arch_local_irq_restore.part.0+0xac/0x100 LR [c000000000d13190] _raw_spin_unlock_irqrestore+0x50/0xc0 Call Trace: Instruction dump: 60000000 7d2000a6 71298000 41820068 39200002 7d210164 4bffff9c 60000000 60000000 7d2000a6 71298000 4c820020 <0fe00000> 4e800020 60000000 60000000 After: WARNING: CPU: 0 PID: 499 at arch/powerpc/kernel/irq.c:343 CPU: 0 PID: 499 Comm: a Not tainted NIP: c00000000001ed2c LR: c000000000d13210 CTR: c00000000003f980 REGS: c0000001fffd3870 TRAP: 0700 Not tainted MSR: 8000000000021003 CR: 28000488 XER: 00000000 CFAR: c00000000001ec90 IRQMASK: 0 GPR00: c000000000aeb1ac c0000001fffd3b00 c0000000012ba300 0000000000000000 GPR04: 0000000000000000 0000000000000000 00000001347607c8 6b00696e74657272 GPR08: 0000000000000000 0000000000000000 0000000000000000 efbeadde00000000 GPR12: 0000000000000000 c0000000014a0000 0000000000000000 0000000000000000 GPR16: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR20: 0000000000000000 0000000000000000 0000000000000000 0000000000000000 GPR24: 0000000000000000 0000000000000000 0000000000000000 00000001347607bc GPR28: 0000000000000000 c00000000148a898 0000000000000000 c0000001ffff3f50 NIP [c00000000001ed2c] arch_local_irq_restore.part.0+0xac/0x100 LR [c000000000d13210] _raw_spin_unlock_irqrestore+0x50/0xc0 Call Trace: [c0000001fffd3b20] [c000000000aeb1ac] of_find_property+0x6c/0x90 [c0000001fffd3b70] [c000000000aeb1f0] of_get_property+0x20/0x40 [c0000001fffd3b90] [c000000000042cdc] rtas_token+0x3c/0x70 [c0000001fffd3bb0] [c0000000000dc318] fwnmi_release_errinfo+0x28/0x70 [c0000001fffd3c10] [c0000000000dcd8c] pseries_machine_check_realmode+0x1dc/0x540 [c0000001fffd3cd0] [c00000000003fe04] machine_check_early+0x54/0x70 [c0000001fffd3d00] [c000000000008384] machine_check_early_common+0x134/0x1f0 --- interrupt: 200 at 0x1347607c8 LR = 0x7fffafbd8328 Instruction dump: 60000000 7d2000a6 71298000 41820068 39200002 7d210164 4bffff9c 60000000 60000000 7d2000a6 71298000 4c820020 <0fe00000> 4e800020 60000000 60000000 Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20200325104144.158362-1-npiggin@gmail.com

powerpc: Rename current_stack_pointer() to current_stack_frame()

2020-03-04T11:44:28Z

current_stack_pointer(), which was called __get_SP(), used to just return the value in r1. But that caused problems in some cases, so it was turned into a function in commit bfe9a2cfe91a ("powerpc: Reimplement __get_SP() as a function not a define"). Because it's a function in a separate compilation unit to all its callers, it has the effect of causing a stack frame to be created, and then returns the address of that frame. This is good in some cases like those described in the above commit, but in other cases it's overkill, we just need to know what stack page we're on. On some other arches current_stack_pointer is just a register global giving the stack pointer, and we'd like to do that too. So rename our current_stack_pointer() to current_stack_frame() to make that possible. Signed-off-by: Michael Ellerman Reviewed-by: Christophe Leroy Link: https://lore.kernel.org/r/20200220115141.2707-1-mpe@ellerman.id.au

powerpc/process: Remove unneccessary #ifdef CONFIG_PPC64 in copy_thread_tls()

2020-02-19T10:07:09Z

is_32bit_task() exists on both PPC64 and PPC32, no need of an ifdefery. Signed-off-by: Christophe Leroy Reviewed-by: Michal Suchanek Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/6ecbda05b4119c40222dc8ec284604e1597c9bff.1580327381.git.christophe.leroy@c-s.fr

powerpc: use probe_user_read() and probe_user_write()

2020-01-25T13:11:35Z

Instead of opencoding, use probe_user_read() to failessly read a user location and probe_user_write() for writing to user. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/e041f5eedb23f09ab553be8a91c3de2087147320.1579800517.git.christophe.leroy@c-s.fr

powerpc/hw_breakpoints: Rewrite 8xx breakpoints to allow any address range size.

2020-01-23T10:31:14Z

Unlike standard powerpc, Powerpc 8xx doesn't have SPRN_DABR, but it has a breakpoint support based on a set of comparators which allow more flexibility. Commit 4ad8622dc548 ("powerpc/8xx: Implement hw_breakpoint") implemented breakpoints by emulating the DABR behaviour. It did this by setting one comparator the match 4 bytes at breakpoint address and the other comparator to match 4 bytes at breakpoint address + 4. Rewrite 8xx hw_breakpoint to make breakpoints match all addresses defined by the breakpoint address and length by making full use of comparators. Now, comparator E is set to match any address greater than breakpoint address minus one. Comparator F is set to match any address lower than breakpoint address plus breakpoint length. Addresses are aligned to 32 bits. When the breakpoint range starts at address 0, the breakpoint is set to match comparator F only. When the breakpoint range end at address 0xffffffff, the breakpoint is set to match comparator E only. Otherwise the breakpoint is set to match comparator E and F. At the same time, use registers bit names instead of hardcoded values. Signed-off-by: Christophe Leroy Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/05105deeaf63bc02151aea2cdeaf525534e0e9d4.1574790198.git.christophe.leroy@c-s.fr

powerpc/watchpoint: Fix length calculation for unaligned target

2019-11-13T05:58:03Z

Watchpoint match range is always doubleword(8 bytes) aligned on powerpc. If the given range is crossing doubleword boundary, we need to increase the length such that next doubleword also get covered. Ex, address len = 6 bytes |=========. |------------v--|------v--------| | | | | | | | | | | | | | | | | | |---------------|---------------| <---8 bytes---> In such case, current code configures hw as: start_addr = address & ~HW_BREAKPOINT_ALIGN len = 8 bytes And thus read/write in last 4 bytes of the given range is ignored. Fix this by including next doubleword in the length. Signed-off-by: Ravi Bangoria Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/20191017093204.7511-3-ravi.bangoria@linux.ibm.com

Merge tag 'powerpc-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

2019-09-20T18:48:06Z

Pull powerpc updates from Michael Ellerman: "This is a bit late, partly due to me travelling, and partly due to a power outage knocking out some of my test systems *while* I was travelling. - Initial support for running on a system with an Ultravisor, which is software that runs below the hypervisor and protects guests against some attacks by the hypervisor. - Support for building the kernel to run as a "Secure Virtual Machine", ie. as a guest capable of running on a system with an Ultravisor. - Some changes to our DMA code on bare metal, to allow devices with medium sized DMA masks (> 32 && < 59 bits) to use more than 2GB of DMA space. - Support for firmware assisted crash dumps on bare metal (powernv). - Two series fixing bugs in and refactoring our PCI EEH code. - A large series refactoring our exception entry code to use gas macros, both to make it more readable and also enable some future optimisations. As well as many cleanups and other minor features & fixups. Thanks to: Adam Zerella, Alexey Kardashevskiy, Alistair Popple, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Anshuman Khandual, Balbir Singh, Benjamin Herrenschmidt, Cédric Le Goater, Christophe JAILLET, Christophe Leroy, Christopher M. Riedl, Christoph Hellwig, Claudio Carvalho, Daniel Axtens, David Gibson, David Hildenbrand, Desnes A. Nunes do Rosario, Ganesh Goudar, Gautham R. Shenoy, Greg Kurz, Guerney Hunt, Gustavo Romero, Halil Pasic, Hari Bathini, Joakim Tjernlund, Jonathan Neuschafer, Jordan Niethe, Leonardo Bras, Lianbo Jiang, Madhavan Srinivasan, Mahesh Salgaonkar, Mahesh Salgaonkar, Masahiro Yamada, Maxiwell S. Garcia, Michael Anderson, Nathan Chancellor, Nathan Lynch, Naveen N. Rao, Nicholas Piggin, Oliver O'Halloran, Qian Cai, Ram Pai, Ravi Bangoria, Reza Arbab, Ryan Grimm, Sam Bobroff, Santosh Sivaraj, Segher Boessenkool, Sukadev Bhattiprolu, Thiago Bauermann, Thiago Jung Bauermann, Thomas Gleixner, Tom Lendacky, Vasant Hegde" * tag 'powerpc-5.4-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (264 commits) powerpc/mm/mce: Keep irqs disabled during lockless page table walk powerpc: Use ftrace_graph_ret_addr() when unwinding powerpc/ftrace: Enable HAVE_FUNCTION_GRAPH_RET_ADDR_PTR ftrace: Look up the address of return_to_handler() using helpers powerpc: dump kernel log before carrying out fadump or kdump docs: powerpc: Add missing documentation reference powerpc/xmon: Fix output of XIVE IPI powerpc/xmon: Improve output of XIVE interrupts powerpc/mm/radix: remove useless kernel messages powerpc/fadump: support holes in kernel boot memory area powerpc/fadump: remove RMA_START and RMA_END macros powerpc/fadump: update documentation about option to release opalcore powerpc/fadump: consider f/w load area powerpc/opalcore: provide an option to invalidate /sys/firmware/opal/core file powerpc/opalcore: export /sys/firmware/opal/core for analysing opal crashes powerpc/fadump: update documentation about CONFIG_PRESERVE_FA_DUMP powerpc/fadump: add support to preserve crash data on FADUMP disabled kernel powerpc/fadump: improve how crashed kernel's memory is reserved powerpc/fadump: consider reserved ranges while releasing memory powerpc/fadump: make crash memory ranges array allocation generic ...

powerpc: Use ftrace_graph_ret_addr() when unwinding

2019-09-18T02:24:55Z

With support for HAVE_FUNCTION_GRAPH_RET_ADDR_PTR, ftrace_graph_ret_addr() provides more robust unwinding when function graph is in use. Update show_stack() to use the same. With dump_stack() added to sysrq_sysctl_handler(), before this patch: root@(none):/sys/kernel/debug/tracing# cat /proc/sys/kernel/sysrq CPU: 0 PID: 218 Comm: cat Not tainted 5.3.0-rc7-00868-g8453ad4a078c-dirty #20 Call Trace: [c0000000d1e13c30] [c00000000006ab98] return_to_handler+0x0/0x40 (dump_stack+0xe8/0x164) (unreliable) [c0000000d1e13c80] [c000000000145680] sysrq_sysctl_handler+0x48/0xb8 [c0000000d1e13cd0] [c00000000006ab98] return_to_handler+0x0/0x40 (proc_sys_call_handler+0x274/0x2a0) [c0000000d1e13d60] [c00000000006ab98] return_to_handler+0x0/0x40 (return_to_handler+0x0/0x40) [c0000000d1e13d80] [c00000000006ab98] return_to_handler+0x0/0x40 (__vfs_read+0x3c/0x70) [c0000000d1e13dd0] [c00000000006ab98] return_to_handler+0x0/0x40 (vfs_read+0xb8/0x1b0) [c0000000d1e13e20] [c00000000006ab98] return_to_handler+0x0/0x40 (ksys_read+0x7c/0x140) After this patch: Call Trace: [c0000000d1e33c30] [c00000000006ab58] return_to_handler+0x0/0x40 (dump_stack+0xe8/0x164) (unreliable) [c0000000d1e33c80] [c000000000145680] sysrq_sysctl_handler+0x48/0xb8 [c0000000d1e33cd0] [c00000000006ab58] return_to_handler+0x0/0x40 (proc_sys_call_handler+0x274/0x2a0) [c0000000d1e33d60] [c00000000006ab58] return_to_handler+0x0/0x40 (__vfs_read+0x3c/0x70) [c0000000d1e33d80] [c00000000006ab58] return_to_handler+0x0/0x40 (vfs_read+0xb8/0x1b0) [c0000000d1e33dd0] [c00000000006ab58] return_to_handler+0x0/0x40 (ksys_read+0x7c/0x140) [c0000000d1e33e20] [c00000000006ab58] return_to_handler+0x0/0x40 (system_call+0x5c/0x68) Signed-off-by: Naveen N. Rao Signed-off-by: Michael Ellerman Link: https://lore.kernel.org/r/dc89c9a887121342d9c7819482c3dabdece2a323.1567707399.git.naveen.n.rao@linux.vnet.ibm.com