1. 20 Jun, 2017 7 commits
  2. 19 Jun, 2017 9 commits
  3. 15 Jun, 2017 9 commits
    • Murilo Opsfelder Araujo's avatar
      drivers/watchdog/Kconfig: Update CONFIG_WATCHDOG_RTAS dependencies · 42bed042
      Murilo Opsfelder Araujo authored
      drivers/watchdog/wdrtas.c uses symbols defined in arch/powerpc/kernel/rtas.c,
      which are exported iff CONFIG_PPC_RTAS is selected. Building wdrtas.c without
      setting CONFIG_PPC_RTAS throws the following errors:
      
          ERROR: ".rtas_token" [drivers/watchdog/wdrtas.ko] undefined!
          ERROR: "rtas_data_buf" [drivers/watchdog/wdrtas.ko] undefined!
          ERROR: "rtas_data_buf_lock" [drivers/watchdog/wdrtas.ko] undefined!
          ERROR: ".rtas_get_sensor" [drivers/watchdog/wdrtas.ko] undefined!
          ERROR: ".rtas_call" [drivers/watchdog/wdrtas.ko] undefined!
      
      This was identified during a randconfig build where CONFIG_WATCHDOG_RTAS=m and
      CONFIG_PPC_RTAS was not set. Logs are here:
      
          http://kisskb.ellerman.id.au/kisskb/buildresult/12982152/
      
      This patch fixes the issue by updating CONFIG_WATCHDOG_RTAS to depend on just
      CONFIG_PPC_RTAS, removing COMPILE_TEST entirely.
      Signed-off-by: default avatarMurilo Opsfelder Araujo <mopsfelder@gmail.com>
      Reviewed-by: default avatarGuenter Roeck <linux@roeck-us.net>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      42bed042
    • Nicholas Piggin's avatar
      powerpc/64s: Avoid cpabort in context switch when possible · 07d2a628
      Nicholas Piggin authored
      The ISA v3.0B copy-paste facility only requires cpabort when switching
      to a process that has foreign real addresses mapped (direct access to
      accelerators), to clear a potential copy buffer filled by a previous
      thread. There is no accelerator driver implemented yet, so cpabort can
      be removed. It can be be re-added when a driver is implemented.
      
      POWER9 DD1 requires the copy buffer to always be cleared on context
      switch, but if accelerators are not in use, then an unpaired copy from
      a dummy region is sufficient to clear data out of the copy buffer.
      
      This increases context switch performance by about 5% on POWER9.
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      07d2a628
    • Nicholas Piggin's avatar
      powerpc/64: Drop explicit hwsync in context switch · 9145effd
      Nicholas Piggin authored
      The sync (aka. hwsync, aka. heavyweight sync) in the context switch
      code to prevent MMIO access being reordered from the point of view of
      a single process if it gets migrated to a different CPU is not
      required because there is an hwsync performed earlier in the context
      switch path.
      
      Comment this so it's clear enough if anything changes on the scheduler
      or the powerpc sides. Remove the hwsync from _switch.
      
      This improves context switch performance by 2-3% on POWER8.
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      9145effd
    • Nicholas Piggin's avatar
      powerpc/64: Drop reservation-clearing ldarx in context switch · 837e72f7
      Nicholas Piggin authored
      There is no need to explicitly break the reservation in _switch,
      because we are guaranteed that the context switch path will include a
      larx/stcx.
      
      Comment the guarantee and remove the reservation clear from _switch.
      
      This is worth 1-2% in context switch performance.
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      837e72f7
    • Nicholas Piggin's avatar
      powerpc/64s: Leave interrupts hard enabled in context switch for radix · e4c0fc5f
      Nicholas Piggin authored
      Commit 4387e9ff25 ("[POWERPC] Fix PMU + soft interrupt disable bug")
      hard disabled interrupts over the low level context switch, because
      the SLB management can't cope with a PMU interrupt accesing the stack
      in that window.
      
      Radix based kernel mapping does not use the SLB so it does not require
      interrupts hard disabled here.
      
      This is worth 1-2% in context switch performance on POWER9.
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      e4c0fc5f
    • Nicholas Piggin's avatar
      powerpc/64: Avoid restore_math call if possible in syscall exit · bc4f65e4
      Nicholas Piggin authored
      The syscall exit code that branches to restore_math is quite heavy on
      Book3S, consisting of 2 mtmsr instructions. Threads that don't use both
      FP and vector can get caught here if the kernel ever uses FP or vector.
      Lazy-FP/vec context switching also trips this case.
      
      So check for lazy FP and vector before switching RI for restore_math.
      Move most of this case out of line.
      
      For threads that do want to restore math registers, the MSR switches are
      still suboptimal. Future direction may be to use a soft-RI bit to avoid
      MSR switches in kernel (similar to soft-EE), but for now at least the
      no-restore
      
      POWER9 context switch rate increases by about 5% due to sched_yield(2)
      return performance. I haven't constructed a test to measure the syscall
      cost.
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      bc4f65e4
    • Nicholas Piggin's avatar
      powerpc/64s: Optimize hypercall/syscall entry · acd7d8ce
      Nicholas Piggin authored
      After bc355125 ("powerpc/64: Allow for relocation-on interrupts from
      guest to host"), a getppid() system call goes from 307 cycles to 358
      cycles (+17%) on POWER8. This is due significantly to the scratch SPR
      used by the hypercall check.
      
      It turns out there are a some volatile registers common to both system
      call and hypercall (in particular, r12, cr0, ctr), which can be used to
      avoid the SPR and some other overheads. This brings getppid to 320 cycles
      (+4%).
      
      Testing hcall entry performance by running "sc 1" in guest userspace
      before this patch is 854 cycles, afterwards is 826. Also a small win
      there.
      
      POWER9 syscall is improved by about the same amount, hcall not tested.
      Signed-off-by: default avatarNicholas Piggin <npiggin@gmail.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      acd7d8ce
    • Michael Ellerman's avatar
      powerpc/mm/radix: Only add X for pages overlapping kernel text · 9abcc981
      Michael Ellerman authored
      Currently we map the whole linear mapping with PAGE_KERNEL_X. Instead we
      should check if the page overlaps the kernel text and only then add
      PAGE_KERNEL_X.
      
      Note that we still use 1G pages if they're available, so this will
      typically still result in a 1G executable page at KERNELBASE. So this fix is
      primarily useful for catching stray branches to high linear mapping addresses.
      
      Without this patch, we can execute at 1G in xmon using:
      
        0:mon> m c000000040000000
        c000000040000000  00 l
        c000000040000000  00000000 01006038
        c000000040000004  00000000 2000804e
        c000000040000008  00000000 x
        0:mon> di c000000040000000
        c000000040000000  38600001      li      r3,1
        c000000040000004  4e800020      blr
        0:mon> p c000000040000000
        return value is 0x1
      
      After we get a 400 as expected:
      
        0:mon> p c000000040000000
        *** 400 exception occurred
      
      Fixes: 2bfd65e4 ("powerpc/mm/radix: Add radix callbacks for early init routines")
      Cc: stable@vger.kernel.org # v4.7+
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      Reviewed-by: default avatarAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
      Acked-by: default avatarBalbir Singh <bsingharora@gmail.com>
      9abcc981
    • Michael Ellerman's avatar
      Revert "powerpc: Handle simultaneous interrupts at once" · 0edc2ca9
      Michael Ellerman authored
      This reverts commit 45cb08f4.
      
      For some reason this is causing IRQ problems on Freescale Book3E
      machines, eg on my p5020ds:
      
        irq 25: nobody cared (try booting with the "irqpoll" option)
        CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.12.0-rc3-gcc-6.3.1-00037-g45cb08f4 #624
        Call Trace:
        [c0000000fffdbb10] [c00000000049962c] .dump_stack+0xa8/0xe8 (unreliable)
        [c0000000fffdbba0] [c0000000000babf4] .__report_bad_irq+0x54/0x140
        [c0000000fffdbc40] [c0000000000bb11c] .note_interrupt+0x324/0x380
        [c0000000fffdbd00] [c0000000000b7110] .handle_irq_event_percpu+0x68/0x88
        [c0000000fffdbd90] [c0000000000b718c] .handle_irq_event+0x5c/0xa8
        [c0000000fffdbe10] [c0000000000bc01c] .handle_fasteoi_irq+0xe4/0x298
        [c0000000fffdbe90] [c0000000000b59c4] .generic_handle_irq+0x50/0x74
        [c0000000fffdbf10] [c0000000000075d8] .__do_irq+0x74/0x1f0
        [c0000000fffdbf90] [c0000000000189f8] .call_do_irq+0x14/0x24
        [c0000000f7173060] [c0000000000077e4] .do_IRQ+0x90/0x120
        [c0000000f7173100] [c00000000001d93c] exc_0x500_common+0xfc/0x100
        --- interrupt: 501 at .prepare_to_wait_event+0xc/0x14c
            LR = .fsl_elbc_run_command+0xc8/0x23c
        [c0000000f71734d0] [c00000000065f418] .nand_reset+0xb8/0x168
        [c0000000f7173560] [c00000000065fec4] .nand_scan_ident+0x2b0/0x1638
        [c0000000f7173650] [c000000000666cd8] .fsl_elbc_nand_probe+0x34c/0x5f0
        ata2: SATA link up 1.5 Gbps (SStatus 113 SControl 300)
        [c0000000f7173750] [c0000000005a3c60] .platform_drv_probe+0x64/0xb0
        [c0000000f71737d0] [c0000000005a12e0] .really_probe+0x290/0x334
        [c0000000f7173870] [c0000000005a14a0] .__driver_attach+0x11c/0x120
        [c0000000f7173900] [c00000000059e6a0] .bus_for_each_dev+0x98/0xfc
        [c0000000f71739a0] [c0000000005a0b3c] .driver_attach+0x34/0x4c
        [c0000000f7173a20] [c0000000005a04b0] .bus_add_driver+0x1ac/0x2e0
        [c0000000f7173ac0] [c0000000005a2170] .driver_register+0x94/0x160
        [c0000000f7173b40] [c0000000005a3be0] .__platform_driver_register+0x60/0x7c
        [c0000000f7173bc0] [c000000000d6aab4] .fsl_elbc_nand_driver_init+0x24/0x38
        [c0000000f7173c30] [c000000000001934] .do_one_initcall+0x68/0x1b8
        [c0000000f7173d00] [c000000000d210f8] .kernel_init_freeable+0x260/0x338
        [c0000000f7173db0] [c0000000000021b0] .kernel_init+0x20/0xe70
        [c0000000f7173e30] [c0000000000009bc] .ret_from_kernel_thread+0x58/0x9c
        handlers:
        [<c000000000ed85c8>] .fsl_lbc_ctrl_irq
        Disabling IRQ #25
      
      Ben also had concerns with the implementation being potentially slow on
      some PICs, so revert it for now.
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      0edc2ca9
  4. 06 Jun, 2017 2 commits
  5. 05 Jun, 2017 9 commits
  6. 02 Jun, 2017 4 commits
    • Matt Brown's avatar
      powerpc/lib/xor_vmx: Ensure no altivec code executes before enable_kernel_altivec() · f718d426
      Matt Brown authored
      The xor_vmx.c file is used for the RAID5 xor operations. In these functions
      altivec is enabled to run the operation and then disabled.
      
      The code uses enable_kernel_altivec() around the core of the algorithm, however
      the whole file is built with -maltivec, so the compiler is within its rights to
      generate altivec code anywhere. This has been seen at least once in the wild:
      
        0:mon> di $xor_altivec_2
        c0000000000b97d0  3c4c01d9	addis   r2,r12,473
        c0000000000b97d4  3842db30	addi    r2,r2,-9424
        c0000000000b97d8  7c0802a6	mflr    r0
        c0000000000b97dc  f8010010	std     r0,16(r1)
        c0000000000b97e0  60000000	nop
        c0000000000b97e4  7c0802a6	mflr    r0
        c0000000000b97e8  faa1ffa8	std     r21,-88(r1)
        ...
        c0000000000b981c  f821ff41	stdu    r1,-192(r1)
        c0000000000b9820  7f8101ce	stvx    v28,r1,r0		<-- POP
        c0000000000b9824  38000030	li      r0,48
        c0000000000b9828  7fa101ce	stvx    v29,r1,r0
        ...
        c0000000000b984c  4bf6a06d	bl      c0000000000238b8 # enable_kernel_altivec
      
      This patch splits the non-altivec code into xor_vmx_glue.c which calls the
      altivec functions in xor_vmx.c. By compiling xor_vmx_glue.c without
      -maltivec we can guarantee that altivec instruction will not be executed
      outside of the enable/disable block.
      Signed-off-by: default avatarMatt Brown <matthew.brown.dev@gmail.com>
      [mpe: Rework change log and include disassembly]
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      f718d426
    • Hari Bathini's avatar
      powerpc/fadump: Set an upper limit for boot memory size · 48a316e3
      Hari Bathini authored
      By default, 5% of system RAM is reserved for preserving boot memory.
      Alternatively, a user can specify the amount of memory to reserve.
      See Documentation/powerpc/firmware-assisted-dump.txt for details. In
      addition to the memory reserved for preserving boot memory, some more
      memory is reserved, to save HPTE region, CPU state data and ELF core
      headers.
      
      Memory Reservation during first kernel looks like below:
      
        Low memory                                        Top of memory
        0      boot memory size                                       |
        |           |                       |<--Reserved dump area -->|
        V           V                       |   Permanent Reservation V
        +-----------+----------/ /----------+---+----+-----------+----+
        |           |                       |CPU|HPTE|  DUMP     |ELF |
        +-----------+----------/ /----------+---+----+-----------+----+
              |                                           ^
              |                                           |
              \                                           /
               -------------------------------------------
                Boot memory content gets transferred to
                reserved area by firmware at the time of
                crash
      
      This implicitly means that the sum of the sizes of boot memory, CPU
      state data, HPTE region, DUMP preserving area and ELF core headers
      can't be greater than the total memory size. But currently, a user is
      allowed to specify any value as boot memory size. So, the above rule
      is violated when a boot memory size around 50% of the total available
      memory is specified. As the kernel is not handling this currently, it
      may lead to undefined behavior. Fix it by setting an upper limit for
      boot memory size to 25% of the total available memory. Also, instead
      of using memblock_end_of_DRAM(), which doesn't take the holes, if any,
      in the memory layout into account, use memblock_phys_mem_size() to
      calculate the percentage of total available memory.
      Signed-off-by: default avatarHari Bathini <hbathini@linux.vnet.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      48a316e3
    • Hari Bathini's avatar
      powerpc/fadump: Update comment about offset where fadump is reserved · e7467dc6
      Hari Bathini authored
      With commit f6e6bedb ("powerpc/fadump: Reserve memory at an offset
      closer to bottom of RAM"), memory for fadump is no longer reserved at
      the top of RAM. But there are still a few places which say so. Change
      them appropriately.
      Signed-off-by: default avatarHari Bathini <hbathini@linux.vnet.ibm.com>
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      e7467dc6
    • Hari Bathini's avatar
      powerpc/fadump: Add a warning when 'fadump_reserve_mem=' is used · 81d9eca5
      Hari Bathini authored
      With commit 11550dc0 ("powerpc/fadump: reuse crashkernel parameter
      for fadump memory reservation"), 'fadump_reserve_mem=' parameter is
      deprecated in favor of 'crashkernel=' parameter. Add a warning if
      'fadump_reserve_mem=' is still used.
      
      Fixes: 11550dc0 ("powerpc/fadump: reuse crashkernel parameter for fadump memory reservation")
      Suggested-by: default avatarPrarit Bhargava <prarit@redhat.com>
      Signed-off-by: default avatarHari Bathini <hbathini@linux.vnet.ibm.com>
      [mpe: Unsplit long printk strings]
      Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
      81d9eca5