Commit Graph

501 Commits

Author SHA1 Message Date
Linus Torvalds 9b76d71fa8 RISC-V Patches for the 5.14 Merge Window, Part 1
In addition to We have a handful of new features for 5.14:
 
 * Support for transparent huge pages.
 * Support for generic PCI resources mapping.
 * Support for the mem= kernel parameter.
 * Support for KFENCE.
 * A handful of fixes to avoid W+X mappings in the kernel.
 * Support for VMAP_STACK based overflow detection.
 * An optimized copy_{to,from}_user.
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Merge tag 'riscv-for-linus-5.14-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:
 "We have a handful of new features for 5.14:

   - Support for transparent huge pages.

   - Support for generic PCI resources mapping.

   - Support for the mem= kernel parameter.

   - Support for KFENCE.

   - A handful of fixes to avoid W+X mappings in the kernel.

   - Support for VMAP_STACK based overflow detection.

   - An optimized copy_{to,from}_user"

* tag 'riscv-for-linus-5.14-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (37 commits)
  riscv: xip: Fix duplicate included asm/pgtable.h
  riscv: Fix PTDUMP output now BPF region moved back to module region
  riscv: __asm_copy_to-from_user: Optimize unaligned memory access and pipeline stall
  riscv: add VMAP_STACK overflow detection
  riscv: ptrace: add argn syntax
  riscv: mm: fix build errors caused by mk_pmd()
  riscv: Introduce structure that group all variables regarding kernel mapping
  riscv: Map the kernel with correct permissions the first time
  riscv: Introduce set_kernel_memory helper
  riscv: Enable KFENCE for riscv64
  RISC-V: Use asm-generic for {in,out}{bwlq}
  riscv: add ASID-based tlbflushing methods
  riscv: pass the mm_struct to __sbi_tlb_flush_range
  riscv: Add mem kernel parameter support
  riscv: Simplify xip and !xip kernel address conversion macros
  riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED
  riscv: Only initialize swiotlb when necessary
  riscv: fix typo in init.c
  riscv: Cleanup unused functions
  riscv: mm: Use better bitmap_zalloc()
  ...
2021-07-09 10:36:29 -07:00
Kefeng Wang 723a42f4f6 riscv: convert to setup_initial_init_mm()
Use setup_initial_init_mm() helper to simplify code.

Link: https://lkml.kernel.org/r/20210608083418.137226-13-wangkefeng.wang@huawei.com
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Acked-by: Palmer Dabbelt <palmerdabbelt@google.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2021-07-08 11:48:21 -07:00
Jiapeng Chong 1958e5aef5
riscv: xip: Fix duplicate included asm/pgtable.h
Clean up the following includecheck warning:

./arch/riscv/kernel/vmlinux-xip.lds.S: asm/pgtable.h is included more
than once.

No functional change.

Reported-by: Abaci Robot <abaci@linux.alibaba.com>
Signed-off-by: Jiapeng Chong <jiapeng.chong@linux.alibaba.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-07-06 16:17:40 -07:00
Tong Tiangen 31da94c25a
riscv: add VMAP_STACK overflow detection
This patch adds stack overflow detection to riscv, usable when
CONFIG_VMAP_STACK=y.

Overflow is detected in kernel exception entry(kernel/entry.S), if the
kernel stack is overflow and been detected, the overflow handler is
invoked on a per-cpu overflow stack. This approach preserves GPRs and
the original exception information.

The overflow detect is performed before any attempt is made to access
the stack and the principle of stack overflow detection: kernel stacks
are aligned to double their size, enabling overflow to be detected with
a single bit test. For example, a 16K stack is aligned to 32K, ensuring
that bit 14 of the SP must be zero. On an overflow (or underflow), this
bit is flipped. Thus, overflow (of less than the size of the stack) can
be detected by testing whether this bit is set.

This gives us a useful error message on stack overflow, as can be
trigger with the LKDTM overflow test:

[  388.053267] lkdtm: Performing direct entry EXHAUST_STACK
[  388.053663] lkdtm: Calling function with 1024 frame size to depth 32 ...
[  388.054016] lkdtm: loop 32/32 ...
[  388.054186] lkdtm: loop 31/32 ...
[  388.054491] lkdtm: loop 30/32 ...
[  388.054672] lkdtm: loop 29/32 ...
[  388.054859] lkdtm: loop 28/32 ...
[  388.055010] lkdtm: loop 27/32 ...
[  388.055163] lkdtm: loop 26/32 ...
[  388.055309] lkdtm: loop 25/32 ...
[  388.055481] lkdtm: loop 24/32 ...
[  388.055653] lkdtm: loop 23/32 ...
[  388.055837] lkdtm: loop 22/32 ...
[  388.056015] lkdtm: loop 21/32 ...
[  388.056188] lkdtm: loop 20/32 ...
[  388.058145] Insufficient stack space to handle exception!
[  388.058153] Task stack:     [0xffffffd014260000..0xffffffd014264000]
[  388.058160] Overflow stack: [0xffffffe1f8d2c220..0xffffffe1f8d2d220]
[  388.058168] CPU: 0 PID: 89 Comm: bash Not tainted 5.12.0-rc8-dirty #90
[  388.058175] Hardware name: riscv-virtio,qemu (DT)
[  388.058187] epc : number+0x32/0x2c0
[  388.058247]  ra : vsnprintf+0x2ae/0x3f0
[  388.058255] epc : ffffffe0002d38f6 ra : ffffffe0002d814e sp : ffffffd01425ffc0
[  388.058263]  gp : ffffffe0012e4010 tp : ffffffe08014da00 t0 : ffffffd0142606e8
[  388.058271]  t1 : 0000000000000000 t2 : 0000000000000000 s0 : ffffffd014260070
[  388.058303]  s1 : ffffffd014260158 a0 : ffffffd01426015e a1 : ffffffd014260158
[  388.058311]  a2 : 0000000000000013 a3 : ffff0a01ffffff10 a4 : ffffffe000c398e0
[  388.058319]  a5 : 511b02ec65f3e300 a6 : 0000000000a1749a a7 : 0000000000000000
[  388.058327]  s2 : ffffffff000000ff s3 : 00000000ffff0a01 s4 : ffffffe0012e50a8
[  388.058335]  s5 : 0000000000ffff0a s6 : ffffffe0012e50a8 s7 : ffffffe000da1cc0
[  388.058343]  s8 : ffffffffffffffff s9 : ffffffd0142602b0 s10: ffffffd0142602a8
[  388.058351]  s11: ffffffd01426015e t3 : 00000000000f0000 t4 : ffffffffffffffff
[  388.058359]  t5 : 000000000000002f t6 : ffffffd014260158
[  388.058366] status: 0000000000000100 badaddr: ffffffd01425fff8 cause: 000000000000000f
[  388.058374] Kernel panic - not syncing: Kernel stack overflow
[  388.058381] CPU: 0 PID: 89 Comm: bash Not tainted 5.12.0-rc8-dirty #90
[  388.058387] Hardware name: riscv-virtio,qemu (DT)
[  388.058393] Call Trace:
[  388.058400] [<ffffffe000004944>] walk_stackframe+0x0/0xce
[  388.058406] [<ffffffe0006f0b28>] dump_backtrace+0x38/0x46
[  388.058412] [<ffffffe0006f0b46>] show_stack+0x10/0x18
[  388.058418] [<ffffffe0006f3690>] dump_stack+0x74/0x8e
[  388.058424] [<ffffffe0006f0d52>] panic+0xfc/0x2b2
[  388.058430] [<ffffffe0006f0acc>] print_trace_address+0x0/0x24
[  388.058436] [<ffffffe0002d814e>] vsnprintf+0x2ae/0x3f0
[  388.058956] SMP: stopping secondary CPUs

Signed-off-by: Tong Tiangen <tongtiangen@huawei.com>
Reviewed-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-07-06 12:11:38 -07:00
Alexandre Ghiti 658e2c5125
riscv: Introduce structure that group all variables regarding kernel mapping
We have a lot of variables that are used to hold kernel mapping addresses,
offsets between physical and virtual mappings and some others used for XIP
kernels: they are all defined at different places in mm/init.c, so group
them into a single structure with, for some of them, more explicit and concise
names.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-07-05 18:04:00 -07:00
Palmer Dabbelt 01112e5e20
Merge branch 'riscv-wx-mappings' into for-next
This contains both the short-term fix for the W+X boot mappings and the
larger cleanup.

* riscv-wx-mappings:
  riscv: Map the kernel with correct permissions the first time
  riscv: Introduce set_kernel_memory helper
  riscv: Simplify xip and !xip kernel address conversion macros
  riscv: Remove CONFIG_PHYS_RAM_BASE_FIXED
  riscv: mm: Fix W+X mappings at boot
2021-06-30 21:50:32 -07:00
Alexandre Ghiti e5c35fa040
riscv: Map the kernel with correct permissions the first time
For 64-bit kernels, we map all the kernel with write and execute
permissions and afterwards remove writability from text and executability
from data.

For 32-bit kernels, the kernel mapping resides in the linear mapping, so we
map all the linear mapping as writable and executable and afterwards we
remove those properties for unused memory and kernel mapping as
described above.

Change this behavior to directly map the kernel with correct permissions
and avoid going through the whole mapping to fix the permissions.

At the same time, this fixes an issue introduced by commit 2bfc6cd81b
("riscv: Move kernel mapping outside of linear mapping") as reported
here https://github.com/starfive-tech/linux/issues/17.

Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-06-30 21:18:58 -07:00
Linus Torvalds 54a728dc5e Scheduler udpates for this cycle:
- Changes to core scheduling facilities:
 
     - Add "Core Scheduling" via CONFIG_SCHED_CORE=y, which enables
       coordinated scheduling across SMT siblings. This is a much
       requested feature for cloud computing platforms, to allow
       the flexible utilization of SMT siblings, without exposing
       untrusted domains to information leaks & side channels, plus
       to ensure more deterministic computing performance on SMT
       systems used by heterogenous workloads.
 
       There's new prctls to set core scheduling groups, which
       allows more flexible management of workloads that can share
       siblings.
 
     - Fix task->state access anti-patterns that may result in missed
       wakeups and rename it to ->__state in the process to catch new
       abuses.
 
  - Load-balancing changes:
 
      - Tweak newidle_balance for fair-sched, to improve
        'memcache'-like workloads.
 
      - "Age" (decay) average idle time, to better track & improve workloads
        such as 'tbench'.
 
      - Fix & improve energy-aware (EAS) balancing logic & metrics.
 
      - Fix & improve the uclamp metrics.
 
      - Fix task migration (taskset) corner case on !CONFIG_CPUSET.
 
      - Fix RT and deadline utilization tracking across policy changes
 
      - Introduce a "burstable" CFS controller via cgroups, which allows
        bursty CPU-bound workloads to borrow a bit against their future
        quota to improve overall latencies & batching. Can be tweaked
        via /sys/fs/cgroup/cpu/<X>/cpu.cfs_burst_us.
 
      - Rework assymetric topology/capacity detection & handling.
 
  - Scheduler statistics & tooling:
 
      - Disable delayacct by default, but add a sysctl to enable
        it at runtime if tooling needs it. Use static keys and
        other optimizations to make it more palatable.
 
      - Use sched_clock() in delayacct, instead of ktime_get_ns().
 
  - Misc cleanups and fixes.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'sched-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull scheduler udpates from Ingo Molnar:

 - Changes to core scheduling facilities:

    - Add "Core Scheduling" via CONFIG_SCHED_CORE=y, which enables
      coordinated scheduling across SMT siblings. This is a much
      requested feature for cloud computing platforms, to allow the
      flexible utilization of SMT siblings, without exposing untrusted
      domains to information leaks & side channels, plus to ensure more
      deterministic computing performance on SMT systems used by
      heterogenous workloads.

      There are new prctls to set core scheduling groups, which allows
      more flexible management of workloads that can share siblings.

    - Fix task->state access anti-patterns that may result in missed
      wakeups and rename it to ->__state in the process to catch new
      abuses.

 - Load-balancing changes:

    - Tweak newidle_balance for fair-sched, to improve 'memcache'-like
      workloads.

    - "Age" (decay) average idle time, to better track & improve
      workloads such as 'tbench'.

    - Fix & improve energy-aware (EAS) balancing logic & metrics.

    - Fix & improve the uclamp metrics.

    - Fix task migration (taskset) corner case on !CONFIG_CPUSET.

    - Fix RT and deadline utilization tracking across policy changes

    - Introduce a "burstable" CFS controller via cgroups, which allows
      bursty CPU-bound workloads to borrow a bit against their future
      quota to improve overall latencies & batching. Can be tweaked via
      /sys/fs/cgroup/cpu/<X>/cpu.cfs_burst_us.

    - Rework assymetric topology/capacity detection & handling.

 - Scheduler statistics & tooling:

    - Disable delayacct by default, but add a sysctl to enable it at
      runtime if tooling needs it. Use static keys and other
      optimizations to make it more palatable.

    - Use sched_clock() in delayacct, instead of ktime_get_ns().

 - Misc cleanups and fixes.

* tag 'sched-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
  sched/doc: Update the CPU capacity asymmetry bits
  sched/topology: Rework CPU capacity asymmetry detection
  sched/core: Introduce SD_ASYM_CPUCAPACITY_FULL sched_domain flag
  psi: Fix race between psi_trigger_create/destroy
  sched/fair: Introduce the burstable CFS controller
  sched/uclamp: Fix uclamp_tg_restrict()
  sched/rt: Fix Deadline utilization tracking during policy change
  sched/rt: Fix RT utilization tracking during policy change
  sched: Change task_struct::state
  sched,arch: Remove unused TASK_STATE offsets
  sched,timer: Use __set_current_state()
  sched: Add get_current_state()
  sched,perf,kvm: Fix preemption condition
  sched: Introduce task_is_running()
  sched: Unbreak wakeups
  sched/fair: Age the average idle time
  sched/cpufreq: Consider reduced CPU capacity in energy calculation
  sched/fair: Take thermal pressure into account while estimating energy
  thermal/cpufreq_cooling: Update offline CPUs per-cpu thermal_pressure
  sched/fair: Return early from update_tg_cfs_load() if delta == 0
  ...
2021-06-28 12:14:19 -07:00
Linus Torvalds 28a27cbd86 Perf events updates for this cycle:
- Platform PMU driver updates:
 
      - x86 Intel uncore driver updates for Skylake (SNR) and Icelake (ICX) servers
      - Fix RDPMC support
      - Fix [extended-]PEBS-via-PT support
      - Fix Sapphire Rapids event constraints
      - Fix :ppp support on Sapphire Rapids
      - Fix fixed counter sanity check on Alder Lake & X86_FEATURE_HYBRID_CPU
      - Other heterogenous-PMU fixes
 
  - Kprobes:
 
      - Remove the unused and misguided kprobe::fault_handler callbacks.
      - Warn about kprobes taking a page fault.
      - Fix the 'nmissed' stat counter.
 
  - Misc cleanups and fixes.
 
 Signed-off-by: Ingo Molnar <mingo@kernel.org>
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Merge tag 'perf-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf events updates from Ingo Molnar:

 - Platform PMU driver updates:

     - x86 Intel uncore driver updates for Skylake (SNR) and Icelake (ICX) servers
     - Fix RDPMC support
     - Fix [extended-]PEBS-via-PT support
     - Fix Sapphire Rapids event constraints
     - Fix :ppp support on Sapphire Rapids
     - Fix fixed counter sanity check on Alder Lake & X86_FEATURE_HYBRID_CPU
     - Other heterogenous-PMU fixes

 - Kprobes:

     - Remove the unused and misguided kprobe::fault_handler callbacks.
     - Warn about kprobes taking a page fault.
     - Fix the 'nmissed' stat counter.

 - Misc cleanups and fixes.

* tag 'perf-core-2021-06-28' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix task context PMU for Hetero
  perf/x86/intel: Fix instructions:ppp support in Sapphire Rapids
  perf/x86/intel: Add more events requires FRONTEND MSR on Sapphire Rapids
  perf/x86/intel: Fix fixed counter check warning for some Alder Lake
  perf/x86/intel: Fix PEBS-via-PT reload base value for Extended PEBS
  perf/x86: Reset the dirty counter to prevent the leak for an RDPMC task
  kprobes: Do not increment probe miss count in the fault handler
  x86,kprobes: WARN if kprobes tries to handle a fault
  kprobes: Remove kprobe::fault_handler
  uprobes: Update uprobe_write_opcode() kernel-doc comment
  perf/hw_breakpoint: Fix DocBook warnings in perf hw_breakpoint
  perf/core: Fix DocBook warnings
  perf/core: Make local function perf_pmu_snapshot_aux() static
  perf/x86/intel/uncore: Enable I/O stacks to IIO PMON mapping on ICX
  perf/x86/intel/uncore: Enable I/O stacks to IIO PMON mapping on SNR
  perf/x86/intel/uncore: Generalize I/O stacks to PMON mapping procedure
  perf/x86/intel/uncore: Drop unnecessary NULL checks after container_of()
2021-06-28 12:03:20 -07:00
Peter Zijlstra b03fbd4ff2 sched: Introduce task_is_running()
Replace a bunch of 'p->state == TASK_RUNNING' with a new helper:
task_is_running(p).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210611082838.222401495@infradead.org
2021-06-18 11:43:07 +02:00
Ingo Molnar b2c0931a07 Merge branch 'sched/urgent' into sched/core, to resolve conflicts
This commit in sched/urgent moved the cfs_rq_is_decayed() function:

  a7b359fc6a37: ("sched/fair: Correctly insert cfs_rq's to list on unthrottle")

and this fresh commit in sched/core modified it in the old location:

  9e077b52d86a: ("sched/pelt: Check that *_avg are null when *_sum are")

Merge the two variants.

Conflicts:
	kernel/sched/fair.c

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-06-18 11:31:25 +02:00
Kefeng Wang ce3aca0465
riscv: Only initialize swiotlb when necessary
The SWIOTLB buffer is not needed unless the physical address space
is beyond the limit of dma, only initialize swiotlb when swiotlb_force
is true or not all system memory is DMA-able.

Also move the swiotlb_init() into mem_init().

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-06-11 13:42:26 -07:00
Vitaly Wool 5e63215c2f
riscv: xip: support runtime trap patching
RISCV_ERRATA_ALTERNATIVE patches text at runtime which is currently
not possible when the kernel is executed from the flash in XIP mode.
Since runtime patching concerns only traps at the moment, let's just
have all the traps reside in RAM anyway if RISCV_ERRATA_ALTERNATIVE
is set. Thus, these functions will be patch-able even when the .text
section is in flash.

Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-06-10 16:16:06 -07:00
Ingo Molnar a9e906b71f Merge branch 'sched/urgent' into sched/core, to pick up fixes
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2021-06-03 19:00:49 +02:00
Naveen N. Rao 2e38eb04c9 kprobes: Do not increment probe miss count in the fault handler
Kprobes has a counter 'nmissed', that is used to count the number of
times a probe handler was not called. This generally happens when we hit
a kprobe while handling another kprobe.

However, if one of the probe handlers causes a fault, we are currently
incrementing 'nmissed'. The comment in fault handler indicates that this
can be used to account faults taken by the probe handlers. But, this has
never been the intention as is evident from the comment above 'nmissed'
in 'struct kprobe':

	/*count the number of times this probe was temporarily disarmed */
	unsigned long nmissed;

Signed-off-by: Naveen N. Rao <naveen.n.rao@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lkml.kernel.org/r/20210601120150.672652-1-naveen.n.rao@linux.vnet.ibm.com
2021-06-03 15:47:26 +02:00
Wende Tan da2d48808f
RISC-V: Fix memblock_free() usages in init_resources()
`memblock_free()` takes a physical address as its first argument.
Fix the wrong usages in `init_resources()`.

Fixes: ffe0e52612 ("RISC-V: Improve init_resources()")
Fixes: 797f0375dd ("RISC-V: Do not allocate memblock while iterating reserved memblocks")
Signed-off-by: Wende Tan <twd2.me@gmail.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-06-01 21:16:42 -07:00
Peter Zijlstra ec6aba3d2b kprobes: Remove kprobe::fault_handler
The reason for kprobe::fault_handler(), as given by their comment:

 * We come here because instructions in the pre/post
 * handler caused the page_fault, this could happen
 * if handler tries to access user space by
 * copy_from_user(), get_user() etc. Let the
 * user-specified handler try to fix it first.

Is just plain bad. Those other handlers are ran from non-preemptible
context and had better use _nofault() functions. Also, there is no
upstream usage of this.

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Masami Hiramatsu <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20210525073213.561116662@infradead.org
2021-06-01 16:00:08 +02:00
Jisheng Zhang 3df952ae2a
riscv: Add __init section marker to some functions again
These functions are not needed after booting, so mark them as __init
to move them to the __init section.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-29 13:39:27 -07:00
Jisheng Zhang 8c9f4940c2
riscv: kprobes: Remove redundant kprobe_step_ctx
Inspired by commit ba090f9caf ("arm64: kprobes: Remove redundant
kprobe_step_ctx"), the ss_pending and match_addr of kprobe_step_ctx
are redundant because those can be replaced by KPROBE_HIT_SS and
&cur_kprobe->ainsn.api.insn[0] + GET_INSN_LENGTH(cur->opcode)
respectively.

Remove the kprobe_step_ctx to simplify the code.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-29 11:17:08 -07:00
Jisheng Zhang 37a7a2a10e
riscv: Turn has_fpu into a static key if FPU=y
The has_fpu check sits at hot code path: switch_to(). Currently, has_fpu
is a bool variable if FPU=y, switch_to() checks it each time, we can
optimize out this check by turning the has_fpu into a static key.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-25 22:56:57 -07:00
Kefeng Wang f842f5ff6a
riscv: Move setup_bootmem into paging_init
Make setup_bootmem() static.

Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-25 22:50:50 -07:00
Jisheng Zhang bab0d47c0e
riscv: kexec: Fix W=1 build warnings
Fixes the following W=1 build warning(s):

In file included from include/linux/kexec.h:28,
                 from arch/riscv/kernel/machine_kexec.c:7:
arch/riscv/include/asm/kexec.h:45:1: warning: ‘extern’ is not at beginning of declaration [-Wold-style-declaration]
   45 | const extern unsigned char riscv_kexec_relocate[];
      | ^~~~~
arch/riscv/include/asm/kexec.h:46:1: warning: ‘extern’ is not at beginning of declaration [-Wold-style-declaration]
   46 | const extern unsigned int riscv_kexec_relocate_size;
      | ^~~~~
arch/riscv/kernel/machine_kexec.c:125:6: warning: no previous prototype for ‘machine_shutdown’ [-Wmissing-prototypes]
  125 | void machine_shutdown(void)
      |      ^~~~~~~~~~~~~~~~
arch/riscv/kernel/machine_kexec.c:147:1: warning: no previous prototype for ‘machine_crash_shutdown’ [-Wmissing-prototypes]
  147 | machine_crash_shutdown(struct pt_regs *regs)
      | ^~~~~~~~~~~~~~~~~~~~~~
arch/riscv/kernel/machine_kexec.c:23: warning: Function parameter or member 'image' not described in 'kexec_image_info'
arch/riscv/kernel/machine_kexec.c:53: warning: Function parameter or member 'image' not described in 'machine_kexec_prepare'
arch/riscv/kernel/machine_kexec.c:114: warning: Function parameter or member 'image' not described in 'machine_kexec_cleanup'
arch/riscv/kernel/machine_kexec.c:148: warning: Function parameter or member 'regs' not described in 'machine_crash_shutdown'
arch/riscv/kernel/machine_kexec.c:167: warning: Function parameter or member 'image' not described in 'machine_kexec'

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-22 22:05:30 -07:00
Jisheng Zhang 02ccdeed18
riscv: kprobes: Fix build error when MMU=n
lkp reported a randconfig failure:

arch/riscv/kernel/probes/kprobes.c:90:22: error: use of undeclared identifier 'PAGE_KERNEL_READ_EXEC'

We implemented the alloc_insn_page() to allocate PAGE_KERNEL_READ_EXEC
page for kprobes insn page for STRICT_MODULE_RWX. But if MMU=n, we
should fall back to the generic weak alloc_insn_page() by generic
kprobe subsystem.

Fixes: cdd1b2bd35 ("riscv: kprobes: Implement alloc_insn_page()")
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reported-by: kernel test robot <lkp@intel.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-22 22:04:58 -07:00
Chen Huang eac2f3059e
riscv: stacktrace: fix the riscv stacktrace when CONFIG_FRAME_POINTER enabled
As [1] and [2] said, the arch_stack_walk should not to trace itself, or it will
leave the trace unexpectedly when called. The example is when we do "cat
/sys/kernel/debug/page_owner", all pages' stack is the same.

arch_stack_walk+0x18/0x20
stack_trace_save+0x40/0x60
register_dummy_stack+0x24/0x5e
init_page_owner+0x2e

So we use __builtin_frame_address(1) as the first frame to be walked. And mark
the arch_stack_walk() noinline.

We found that pr_cont will affact pages' stack whose task state is RUNNING when
testing "echo t > /proc/sysrq-trigger". So move the place of pr_cont and mark
the function dump_backtrace() noinline.

Also we move the case when task == NULL into else branch, and test for it in
"echo c > /proc/sysrq-trigger".

[1] https://lore.kernel.org/lkml/20210319184106.5688-1-mark.rutland@arm.com/
[2] https://lore.kernel.org/lkml/20210317142050.57712-1-chenjun102@huawei.com/

Signed-off-by: Chen Huang <chenhuang5@huawei.com>
Fixes: 5d8544e2d0 ("RISC-V: Generic library routines and assembly")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-22 18:59:20 -07:00
Valentin Schneider f1a0a376ca sched/core: Initialize the idle task with preemption disabled
As pointed out by commit

  de9b8f5dcb ("sched: Fix crash trying to dequeue/enqueue the idle thread")

init_idle() can and will be invoked more than once on the same idle
task. At boot time, it is invoked for the boot CPU thread by
sched_init(). Then smp_init() creates the threads for all the secondary
CPUs and invokes init_idle() on them.

As the hotplug machinery brings the secondaries to life, it will issue
calls to idle_thread_get(), which itself invokes init_idle() yet again.
In this case it's invoked twice more per secondary: at _cpu_up(), and at
bringup_cpu().

Given smp_init() already initializes the idle tasks for all *possible*
CPUs, no further initialization should be required. Now, removing
init_idle() from idle_thread_get() exposes some interesting expectations
with regards to the idle task's preempt_count: the secondary startup always
issues a preempt_disable(), requiring some reset of the preempt count to 0
between hot-unplug and hotplug, which is currently served by
idle_thread_get() -> idle_init().

Given the idle task is supposed to have preemption disabled once and never
see it re-enabled, it seems that what we actually want is to initialize its
preempt_count to PREEMPT_DISABLED and leave it there. Do that, and remove
init_idle() from idle_thread_get().

Secondary startups were patched via coccinelle:

  @begone@
  @@

  -preempt_disable();
  ...
  cpu_startup_entry(CPUHP_AP_ONLINE_IDLE);

Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/r/20210512094636.2958515-1-valentin.schneider@arm.com
2021-05-12 13:01:45 +02:00
Rouven Czerwinski beaf5ae15a
riscv: remove unused handle_exception symbol
Since commit 79b1feba54 ("RISC-V: Setup exception vector early")
exception vectors are setup early and the handle_exception symbol from
the asm files is no longer referenced in traps.c. Remove it.

Signed-off-by: Rouven Czerwinski <rouven@czerwinskis.de>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-06 09:40:16 -07:00
Geert Uytterhoeven 8d91b09733
riscv: Consistify protect_kernel_linear_mapping_text_rodata() use
The various uses of protect_kernel_linear_mapping_text_rodata() are
not consistent:
  - Its definition depends on "64BIT && !XIP_KERNEL",
  - Its forward declaration depends on MMU,
  - Its single caller depends on "STRICT_KERNEL_RWX && 64BIT && MMU &&
    !XIP_KERNEL".

Fix this by settling on the dependencies of the caller, which can be
simplified as STRICT_KERNEL_RWX depends on "MMU && !XIP_KERNEL".
Provide a dummy definition, as the caller is protected by
"IS_ENABLED(CONFIG_STRICT_KERNEL_RWX)" instead of "#ifdef
CONFIG_STRICT_KERNEL_RWX".

Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Tested-by: Alexandre Ghiti <alex@ghiti.fr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-06 09:40:15 -07:00
Linus Torvalds 939b7cbc00 RISC-V Patches for the 5.13 Merge Window, Part 1
* Support for the memtest= kernel command-line argument.
 * Support for building the kernel with FORTIFY_SOURCE.
 * Support for generic clockevent broadcasts.
 * Support for the buildtar build target.
 * Some build system cleanups to pass more LLVM-friendly arguments.
 * Support for kprobes.
 * A rearranged kernel memory map, the first part of supporting sv48
   systems.
 * Improvements to kexec, along with support for kdump and crash kernels.
 * An alternatives-based errata framework, along with support for
   handling a pair of errata that manifest on some SiFive designs
   (including the HiFive Unmatched).
 * Support for XIP.
 * A device tree for the Microchip PolarFire ICICLE SoC and associated
   dev board.
 
 Along with a bunch of cleanups.  There are already a handful of fixes
 on the list so there will likely be a part 2.
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Merge tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux

Pull RISC-V updates from Palmer Dabbelt:

 - Support for the memtest= kernel command-line argument.

 - Support for building the kernel with FORTIFY_SOURCE.

 - Support for generic clockevent broadcasts.

 - Support for the buildtar build target.

 - Some build system cleanups to pass more LLVM-friendly arguments.

 - Support for kprobes.

 - A rearranged kernel memory map, the first part of supporting sv48
   systems.

 - Improvements to kexec, along with support for kdump and crash
   kernels.

 - An alternatives-based errata framework, along with support for
   handling a pair of errata that manifest on some SiFive designs
   (including the HiFive Unmatched).

 - Support for XIP.

 - A device tree for the Microchip PolarFire ICICLE SoC and associated
   dev board.

... along with a bunch of cleanups.  There are already a handful of fixes
on the list so there will likely be a part 2.

* tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (45 commits)
  RISC-V: Always define XIP_FIXUP
  riscv: Remove 32b kernel mapping from page table dump
  riscv: Fix 32b kernel build with CONFIG_DEBUG_VIRTUAL=y
  RISC-V: Fix error code returned by riscv_hartid_to_cpuid()
  RISC-V: Enable Microchip PolarFire ICICLE SoC
  RISC-V: Initial DTS for Microchip ICICLE board
  dt-bindings: riscv: microchip: Add YAML documentation for the PolarFire SoC
  RISC-V: Add Microchip PolarFire SoC kconfig option
  RISC-V: enable XIP
  RISC-V: Add crash kernel support
  RISC-V: Add kdump support
  RISC-V: Improve init_resources()
  RISC-V: Add kexec support
  RISC-V: Add EM_RISCV to kexec UAPI header
  riscv: vdso: fix and clean-up Makefile
  riscv/mm: Use BUG_ON instead of if condition followed by BUG.
  riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe
  riscv: Set ARCH_HAS_STRICT_MODULE_RWX if MMU
  riscv: module: Create module allocations without exec permissions
  riscv: bpf: Avoid breaking W^X
  ...
2021-05-06 09:24:18 -07:00
Anup Patel 533b4f3a78
RISC-V: Fix error code returned by riscv_hartid_to_cpuid()
We should return a negative error code upon failure in
riscv_hartid_to_cpuid() instead of NR_CPUS. This is also
aligned with all uses of riscv_hartid_to_cpuid() which
expect negative error code upon failure.

Fixes: 6825c7a80f ("RISC-V: Add logical CPU indexing for RISC-V")
Fixes: f99fb607fb ("RISC-V: Use Linux logical CPU number instead of hartid")
Signed-off-by: Anup Patel <anup.patel@wdc.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-05-01 08:53:19 -07:00
Vitaly Wool 44c9225729
RISC-V: enable XIP
Introduce XIP (eXecute In Place) support for RISC-V platforms.
It allows code to be executed directly from non-volatile storage
directly addressable by the CPU, such as QSPI NOR flash which can
be found on many RISC-V platforms. This makes way for significant
optimization of RAM footprint. The XIP kernel is not compressed
since it has to run directly from flash, so it will occupy more
space on the non-volatile storage. The physical flash address used
to link the kernel object files and for storing it has to be known
at compile time and is represented by a Kconfig option.

XIP on RISC-V will for the time being only work on MMU-enabled
kernels.

Signed-off-by: Vitaly Wool <vitaly.wool@konsulko.com>
[Alex: Rebase on top of "Move kernel mapping outside the linear mapping" ]
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
[Palmer: disable XIP for allyesconfig]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:31:28 -07:00
Nick Kossifidis 5640975003
RISC-V: Add crash kernel support
This patch allows Linux to act as a crash kernel for use with
kdump. Userspace will let the crash kernel know about the
memory region it can use through linux,usable-memory property
on the /memory node (overriding its reg property), and about the
memory region where the elf core header of the previous kernel
is saved, through a reserved-memory node with a compatible string
of "linux,elfcorehdr". This approach is the least invasive and
re-uses functionality already present.

I tested this on riscv64 qemu and it works as expected, you
may test it by retrieving the dmesg of the previous kernel
through /proc/vmcore, using the vmcore-dmesg utility from
kexec-tools.

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:24 -07:00
Nick Kossifidis e53d28180d
RISC-V: Add kdump support
This patch adds support for kdump, the kernel will reserve a
region for the crash kernel and jump there on panic. In order
for userspace tools (kexec-tools) to prepare the crash kernel
kexec image, we also need to expose some information on
/proc/iomem for the memory regions used by the kernel and for
the region reserved for crash kernel. Note that on userspace
the device tree is used to determine the system's memory
layout so the "System RAM" on /proc/iomem is ignored.

I tested this on riscv64 qemu and works as expected, you may
test it by triggering a crash through /proc/sysrq_trigger:

echo c > /proc/sysrq_trigger

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:23 -07:00
Nick Kossifidis ffe0e52612
RISC-V: Improve init_resources()
The kernel region is always present and we know where it is, no need to
look for it inside the loop, just ignore it like the rest of the
reserved regions within system's memory.

Additionally, we don't need to call memblock_free inside the loop, as if
called it'll split the region of pre-allocated resources in two parts,
messing things up, just re-use the previous pre-allocated resource and
free any unused resources after both loops finish.

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
[Palmer: commit text]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:22 -07:00
Nick Kossifidis fba8a8674f
RISC-V: Add kexec support
This patch adds support for kexec on RISC-V. On SMP systems it depends
on HOTPLUG_CPU in order to be able to bring up all harts after kexec.
It also needs a recent OpenSBI version that supports the HSM extension.
I tested it on riscv64 QEMU on both an smp and a non-smp system.

Signed-off-by: Nick Kossifidis <mick@ics.forth.gr>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:21 -07:00
Jisheng Zhang 772d7891e8
riscv: vdso: fix and clean-up Makefile
Running "make" on an already compiled kernel tree will rebuild the
kernel even without any modifications:

  CALL    linux/scripts/checksyscalls.sh
  CALL    linux/scripts/atomic/check-atomics.sh
  CHK     include/generated/compile.h
  SO2S    arch/riscv/kernel/vdso/vdso-syms.S
  AS      arch/riscv/kernel/vdso/vdso-syms.o
  AR      arch/riscv/kernel/vdso/built-in.a
  AR      arch/riscv/kernel/built-in.a
  AR      arch/riscv/built-in.a
  GEN     .version
  CHK     include/generated/compile.h
  UPD     include/generated/compile.h
  CC      init/version.o
  AR      init/built-in.a
  LD      vmlinux.o

The reason is "Any target that utilizes if_changed must be listed in
$(targets), otherwise the command line check will fail, and the target
will always be built" as explained by Documentation/kbuild/makefiles.rst

Fix this build bug by adding vdso-syms.S to $(targets)

At the same time, there are two trivial clean up modifications:

- the vdso-dummy.o is not needed any more after so remove it.

- vdso.lds is a generated file, so it should be prefixed with
  $(obj)/ instead of $(src)/

Fixes: c2c81bb2f6 ("RISC-V: Fix the VDSO symbol generaton for binutils-2.35+")
Cc: stable@vger.kernel.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:19 -07:00
Liao Chang b1ebaa0e13
riscv/kprobe: fix kernel panic when invoking sys_read traced by kprobe
The execution of sys_read end up hitting a BUG_ON() in __find_get_block
after installing kprobe at sys_read, the BUG message like the following:

[   65.708663] ------------[ cut here ]------------
[   65.709987] kernel BUG at fs/buffer.c:1251!
[   65.711283] Kernel BUG [#1]
[   65.712032] Modules linked in:
[   65.712925] CPU: 0 PID: 51 Comm: sh Not tainted 5.12.0-rc4 #1
[   65.714407] Hardware name: riscv-virtio,qemu (DT)
[   65.715696] epc : __find_get_block+0x218/0x2c8
[   65.716835]  ra : __getblk_gfp+0x1c/0x4a
[   65.717831] epc : ffffffe00019f11e ra : ffffffe00019f56a sp : ffffffe002437930
[   65.719553]  gp : ffffffe000f06030 tp : ffffffe0015abc00 t0 : ffffffe00191e038
[   65.721290]  t1 : ffffffe00191e038 t2 : 000000000000000a s0 : ffffffe002437960
[   65.723051]  s1 : ffffffe00160ad00 a0 : ffffffe00160ad00 a1 : 000000000000012a
[   65.724772]  a2 : 0000000000000400 a3 : 0000000000000008 a4 : 0000000000000040
[   65.726545]  a5 : 0000000000000000 a6 : ffffffe00191e000 a7 : 0000000000000000
[   65.728308]  s2 : 000000000000012a s3 : 0000000000000400 s4 : 0000000000000008
[   65.730049]  s5 : 000000000000006c s6 : ffffffe00240f800 s7 : ffffffe000f080a8
[   65.731802]  s8 : 0000000000000001 s9 : 000000000000012a s10: 0000000000000008
[   65.733516]  s11: 0000000000000008 t3 : 00000000000003ff t4 : 000000000000000f
[   65.734434]  t5 : 00000000000003ff t6 : 0000000000040000
[   65.734613] status: 0000000000000100 badaddr: 0000000000000000 cause: 0000000000000003
[   65.734901] Call Trace:
[   65.735076] [<ffffffe00019f11e>] __find_get_block+0x218/0x2c8
[   65.735417] [<ffffffe00020017a>] __ext4_get_inode_loc+0xb2/0x2f6
[   65.735618] [<ffffffe000201b6c>] ext4_get_inode_loc+0x3a/0x8a
[   65.735802] [<ffffffe000203380>] ext4_reserve_inode_write+0x2e/0x8c
[   65.735999] [<ffffffe00020357a>] __ext4_mark_inode_dirty+0x4c/0x18e
[   65.736208] [<ffffffe000206bb0>] ext4_dirty_inode+0x46/0x66
[   65.736387] [<ffffffe000192914>] __mark_inode_dirty+0x12c/0x3da
[   65.736576] [<ffffffe000180dd2>] touch_atime+0x146/0x150
[   65.736748] [<ffffffe00010d762>] filemap_read+0x234/0x246
[   65.736920] [<ffffffe00010d834>] generic_file_read_iter+0xc0/0x114
[   65.737114] [<ffffffe0001f5d7a>] ext4_file_read_iter+0x42/0xea
[   65.737310] [<ffffffe000163f2c>] new_sync_read+0xe2/0x15a
[   65.737483] [<ffffffe000165814>] vfs_read+0xca/0xf2
[   65.737641] [<ffffffe000165bae>] ksys_read+0x5e/0xc8
[   65.737816] [<ffffffe000165c26>] sys_read+0xe/0x16
[   65.737973] [<ffffffe000003972>] ret_from_syscall+0x0/0x2
[   65.738858] ---[ end trace fe93f985456c935d ]---

A simple reproducer looks like:
	echo 'p:myprobe sys_read fd=%a0 buf=%a1 count=%a2' > /sys/kernel/debug/tracing/kprobe_events
	echo 1 > /sys/kernel/debug/tracing/events/kprobes/myprobe/enable
	cat /sys/kernel/debug/tracing/trace

Here's what happens to hit that BUG_ON():

1) After installing kprobe at entry of sys_read, the first instruction
   is replaced by 'ebreak' instruction on riscv64 platform.

2) Once kernel reach the 'ebreak' instruction at the entry of sys_read,
   it trap into the riscv breakpoint handler, where it do something to
   setup for coming single-step of origin instruction, including backup
   the 'sstatus' in pt_regs, followed by disable interrupt during single
   stepping via clear 'SIE' bit of 'sstatus' in pt_regs.

3) Then kernel restore to the instruction slot contains two instructions,
   one is original instruction at entry of sys_read, the other is 'ebreak'.
   Here it trigger a 'Instruction page fault' exception (value at 'scause'
   is '0xc'), if PF is not filled into PageTabe for that slot yet.

4) Again kernel trap into page fault exception handler, where it choose
   different policy according to the state of running kprobe. Because
   afte 2) the state is KPROBE_HIT_SS, so kernel reset the current kprobe
   and 'pc' points back to the probe address.

5) Because 'epc' point back to 'ebreak' instrution at sys_read probe,
   kernel trap into breakpoint handler again, and repeat the operations
   at 2), however 'sstatus' without 'SIE' is keep at 4), it cause the
   real 'sstatus' saved at 2) is overwritten by the one withou 'SIE'.

6) When kernel cross the probe the 'sstatus' CSR restore with value
   without 'SIE', and reach __find_get_block where it requires the
   interrupt must be enabled.

Fix this is very trivial, just restore the value of 'sstatus' in pt_regs
with backup one at 2) when the instruction being single stepped cause a
page fault.

Fixes: c22b0bcb1d ("riscv: Add kprobes supported")
Signed-off-by: Liao Chang <liaochang1@huawei.com>
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:17 -07:00
Jisheng Zhang 5387054b98
riscv: module: Create module allocations without exec permissions
The core code manages the executable permissions of code regions of
modules explicitly, it is not necessary to create the module vmalloc
regions with RWX permissions. Create them with RW- permissions instead.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:15 -07:00
Jisheng Zhang cdd1b2bd35
riscv: kprobes: Implement alloc_insn_page()
Allocate PAGE_KERNEL_READ_EXEC(read only, executable) page for kprobes
insn page. This is to prepare for STRICT_MODULE_RWX.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:11 -07:00
Jisheng Zhang 300f62c37d
riscv: Constify sbi_ipi_ops
Constify the sbi_ipi_ops so that it will be placed in the .rodata
section. This will cause attempts to modify it to fail when strict
page permissions are in place.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:10 -07:00
Jisheng Zhang e6a302248c
riscv: Constify sys_call_table
Constify the sys_call_table so that it will be placed in the .rodata
section. This will cause attempts to modify the table to fail when
strict page permissions are in place.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:09 -07:00
Jisheng Zhang de31ea4a11
riscv: Mark some global variables __ro_after_init
All of these are never modified after init, so they can be
__ro_after_init.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:08 -07:00
Jisheng Zhang 1987501b11
riscv: add __init section marker to some functions
They are not needed after booting, so mark them as __init to move them
to the __init section.

Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:07 -07:00
Alexandre Ghiti 2bfc6cd81b
riscv: Move kernel mapping outside of linear mapping
This is a preparatory patch for relocatable kernel and sv48 support.

The kernel used to be linked at PAGE_OFFSET address therefore we could use
the linear mapping for the kernel mapping. But the relocated kernel base
address will be different from PAGE_OFFSET and since in the linear mapping,
two different virtual addresses cannot point to the same physical address,
the kernel mapping needs to lie outside the linear mapping so that we don't
have to copy it at the same physical offset.

The kernel mapping is moved to the last 2GB of the address space, BPF
is now always after the kernel and modules use the 2GB memory range right
before the kernel, so BPF and modules regions do not overlap. KASLR
implementation will simply have to move the kernel in the last 2GB range
and just take care of leaving enough space for BPF.

In addition, by moving the kernel to the end of the address space, both
sv39 and sv48 kernels will be exactly the same without needing to be
relocated at runtime.

Suggested-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alexandre Ghiti <alex@ghiti.fr>
[Palmer: Squash the STRICT_RWX fix, and a !MMU fix]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:04 -07:00
Nathan Chancellor 7ce0477150
riscv: Workaround mcount name prior to clang-13
Prior to clang 13.0.0, the RISC-V name for the mcount symbol was
"mcount", which differs from the GCC version of "_mcount", which results
in the following errors:

riscv64-linux-gnu-ld: init/main.o: in function `__traceiter_initcall_level':
main.c:(.text+0xe): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `__traceiter_initcall_start':
main.c:(.text+0x4e): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `__traceiter_initcall_finish':
main.c:(.text+0x92): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `.LBB32_28':
main.c:(.text+0x30c): undefined reference to `mcount'
riscv64-linux-gnu-ld: init/main.o: in function `free_initmem':
main.c:(.text+0x54c): undefined reference to `mcount'

This has been corrected in https://reviews.llvm.org/D98881 but the
minimum supported clang version is 10.0.1. To avoid build errors and to
gain a working function tracer, adjust the name of the mcount symbol for
older versions of clang in mount.S and recordmcount.pl.

Link: https://github.com/ClangBuiltLinux/linux/issues/1331
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Nick Desaulniers <ndesaulniers@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:25:01 -07:00
Nathan Chancellor 7f3d349065
riscv: Use $(LD) instead of $(CC) to link vDSO
Currently, the VDSO is being linked through $(CC). This does not match
how the rest of the kernel links objects, which is through the $(LD)
variable.

When linking with clang, there are a couple of warnings about flags that
will not be used during the link:

clang-12: warning: argument unused during compilation: '-no-pie' [-Wunused-command-line-argument]
clang-12: warning: argument unused during compilation: '-pg' [-Wunused-command-line-argument]

'-no-pie' was added in commit 85602bea29 ("RISC-V: build vdso-dummy.o
with -no-pie") to override '-pie' getting added to the ld command from
distribution versions of GCC that enable PIE by default. It is
technically no longer needed after commit c2c81bb2f6 ("RISC-V: Fix the
VDSO symbol generaton for binutils-2.35+"), which removed vdso-dummy.o
in favor of generating vdso-syms.S from vdso.so with $(NM) but this also
resolves the issue in case it ever comes back due to having full control
over the $(LD) command. '-pg' is for function tracing, it is not used
during linking as clang states.

These flags could be removed/filtered to fix the warnings but it is
easier to just match the rest of the kernel and use $(LD) directly for
linking. See commits

  fe00e50b2d ("ARM: 8858/1: vdso: use $(LD) instead of $(CC) to link VDSO")
  691efbedc6 ("arm64: vdso: use $(LD) instead of $(CC) to link VDSO")
  2ff906994b ("MIPS: VDSO: Use $(LD) instead of $(CC) to link VDSO")
  2b2a25845d ("s390/vdso: Use $(LD) instead of $(CC) to link vDSO")

for more information.

The flags are converted to linker flags and '--eh-frame-hdr' is added to
match what is added by GCC implicitly, which can be seen by adding '-v'
to GCC's invocation.

Additionally, since this area is being modified, use the $(OBJCOPY)
variable instead of an open coded $(CROSS_COMPILE)objcopy so that the
user's choice of objcopy binary is respected.

Link: https://github.com/ClangBuiltLinux/linux/issues/803
Link: https://github.com/ClangBuiltLinux/linux/issues/970
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Reviewed-by: Fangrui Song <maskray@google.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:24:59 -07:00
Vincent Chen 800149a77c
riscv: sifive: Apply errata "cip-453" patch
Add sign extension to the $badaddr before addressing the instruction page
fault and instruction access fault to workaround the issue "cip-453".

To avoid affecting the existing code sequence, this patch will creates two
trampolines to add sign extension to the $badaddr. By the "alternative"
mechanism, these two trampolines will replace the original exception
handler of instruction page fault and instruction access fault in the
excp_vect_table. In this case, only the specific SiFive CPU core jumps to
the do_page_fault and do_trap_insn_fault through these two trampolines.
Other CPUs are not affected.

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:24:57 -07:00
Vincent Chen 6f4eea9046
riscv: Introduce alternative mechanism to apply errata solution
Introduce the "alternative" mechanism from ARM64 and x86 to apply the CPU
vendors' errata solution at runtime. The main purpose of this patch is
to provide a framework. Therefore, the implementation is quite basic for
now so that some scenarios could not use this schemei, such as patching
code to a module, relocating the patching code and heterogeneous CPU
topology.

Users could use the macro ALTERNATIVE to apply an errata to the existing
code flow. In the macro ALTERNATIVE, users need to specify the manufacturer
information(vendorid, archid, and impid) for this errata. Therefore, kernel
will know this errata is suitable for which CPU core. During the booting
procedure, kernel will select the errata required by the CPU core and then
patch it. It means that the kernel only applies the errata to the specified
CPU core. In this case, the vendor's errata does not affect each other at
runtime. The above patching procedure only occurs during the booting phase,
so we only take the overhead of the "alternative" mechanism once.

This "alternative" mechanism is enabled by default to ensure that all
required errata will be applied. However, users can disable this feature by
the Kconfig "CONFIG_RISCV_ERRATA_ALTERNATIVE".

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:24:55 -07:00
Vincent Chen 183787c6fc
riscv: Add 3 SBI wrapper functions to get cpu manufacturer information
Add 3 wrapper functions to get vendor id, architecture id and implement id
from M-mode

Signed-off-by: Vincent Chen <vincent.chen@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-26 08:24:54 -07:00
Jisheng Zhang 7ae11635ec
riscv: keep interrupts disabled for BREAKPOINT exception
Current riscv's kprobe handlers are run with both preemption and
interrupt enabled, this violates kprobe requirements. Fix this issue
by keeping interrupts disabled for BREAKPOINT exception.

Fixes: c22b0bcb1d ("riscv: Add kprobes supported")
Cc: stable@vger.kernel.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Masami Hiramatsu <mhiramat@kernel.org>
[Palmer: add a comment]
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-15 21:32:40 -07:00
Jisheng Zhang e31be8d343
riscv: kprobes/ftrace: Add recursion protection to the ftrace callback
Currently, the riscv's kprobes(powerred by ftrace) handler is
preemptible. Futher check indicates we miss something similar as the
commit c536aa1c5b ("kprobes/ftrace: Add recursion protection to the
ftrace callback"), so do similar modifications as the commit does.

Fixes: 829adda597 ("riscv: Add KPROBES_ON_FTRACE supported")
Cc: stable@vger.kernel.org
Signed-off-by: Jisheng Zhang <jszhang@kernel.org>
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Palmer Dabbelt <palmerdabbelt@google.com>
2021-04-15 21:32:34 -07:00