<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux.git/arch/riscv/kernel/entry.S, branch v5.19</title>
<subtitle>Linux kernel source tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/'/>
<entry>
<title>riscv: compat: syscall: Add entry.S implementation</title>
<updated>2022-04-26T20:36:31+00:00</updated>
<author>
<name>Guo Ren</name>
<email>guoren@linux.alibaba.com</email>
</author>
<published>2022-04-05T07:13:06+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=dfb0bfa738f5c58b5c6e81262a0ee4ba154c3f28'/>
<id>dfb0bfa738f5c58b5c6e81262a0ee4ba154c3f28</id>
<content type='text'>
Implement the entry of compat_sys_call_table[] in asm. Ref to
riscv-privileged spec 4.1.1 Supervisor Status Register (sstatus):

 BIT[32:33] = UXL[1:0]:
 - 1:32
 - 2:64
 - 3:128

Signed-off-by: Guo Ren &lt;guoren@linux.alibaba.com&gt;
Signed-off-by: Guo Ren &lt;guoren@kernel.org&gt;
Reviewed-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
Tested-by: Heiko Stuebner &lt;heiko@sntech.de&gt;
Link: https://lore.kernel.org/r/20220405071314.3225832-13-guoren@kernel.org
Signed-off-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Implement the entry of compat_sys_call_table[] in asm. Ref to
riscv-privileged spec 4.1.1 Supervisor Status Register (sstatus):

 BIT[32:33] = UXL[1:0]:
 - 1:32
 - 2:64
 - 3:128

Signed-off-by: Guo Ren &lt;guoren@linux.alibaba.com&gt;
Signed-off-by: Guo Ren &lt;guoren@kernel.org&gt;
Reviewed-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
Tested-by: Heiko Stuebner &lt;heiko@sntech.de&gt;
Link: https://lore.kernel.org/r/20220405071314.3225832-13-guoren@kernel.org
Signed-off-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'riscv-for-linus-5.18-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux</title>
<updated>2022-03-25T17:11:38+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2022-03-25T17:11:38+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=aa5b537b0ecc16992577b013f11112d54c7ce869'/>
<id>aa5b537b0ecc16992577b013f11112d54c7ce869</id>
<content type='text'>
Pull RISC-V updates from Palmer Dabbelt:

 - Support for Sv57-based virtual memory.

 - Various improvements for the MicroChip PolarFire SOC and the
   associated Icicle dev board, which should allow upstream kernels to
   boot without any additional modifications.

 - An improved memmove() implementation.

 - Support for the new Ssconfpmf and SBI PMU extensions, which allows
   for a much more useful perf implementation on RISC-V systems.

 - Support for restartable sequences.

* tag 'riscv-for-linus-5.18-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (36 commits)
  rseq/selftests: Add support for RISC-V
  RISC-V: Add support for restartable sequence
  MAINTAINERS: Add entry for RISC-V PMU drivers
  Documentation: riscv: Remove the old documentation
  RISC-V: Add sscofpmf extension support
  RISC-V: Add perf platform driver based on SBI PMU extension
  RISC-V: Add RISC-V SBI PMU extension definitions
  RISC-V: Add a simple platform driver for RISC-V legacy perf
  RISC-V: Add a perf core library for pmu drivers
  RISC-V: Add CSR encodings for all HPMCOUNTERS
  RISC-V: Remove the current perf implementation
  RISC-V: Improve /proc/cpuinfo output for ISA extensions
  RISC-V: Do no continue isa string parsing without correct XLEN
  RISC-V: Implement multi-letter ISA extension probing framework
  RISC-V: Extract multi-letter extension names from "riscv, isa"
  RISC-V: Minimal parser for "riscv, isa" strings
  RISC-V: Correctly print supported extensions
  riscv: Fixed misaligned memory access. Fixed pointer comparison.
  MAINTAINERS: update riscv/microchip entry
  riscv: dts: microchip: add new peripherals to icicle kit device tree
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull RISC-V updates from Palmer Dabbelt:

 - Support for Sv57-based virtual memory.

 - Various improvements for the MicroChip PolarFire SOC and the
   associated Icicle dev board, which should allow upstream kernels to
   boot without any additional modifications.

 - An improved memmove() implementation.

 - Support for the new Ssconfpmf and SBI PMU extensions, which allows
   for a much more useful perf implementation on RISC-V systems.

 - Support for restartable sequences.

* tag 'riscv-for-linus-5.18-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux: (36 commits)
  rseq/selftests: Add support for RISC-V
  RISC-V: Add support for restartable sequence
  MAINTAINERS: Add entry for RISC-V PMU drivers
  Documentation: riscv: Remove the old documentation
  RISC-V: Add sscofpmf extension support
  RISC-V: Add perf platform driver based on SBI PMU extension
  RISC-V: Add RISC-V SBI PMU extension definitions
  RISC-V: Add a simple platform driver for RISC-V legacy perf
  RISC-V: Add a perf core library for pmu drivers
  RISC-V: Add CSR encodings for all HPMCOUNTERS
  RISC-V: Remove the current perf implementation
  RISC-V: Improve /proc/cpuinfo output for ISA extensions
  RISC-V: Do no continue isa string parsing without correct XLEN
  RISC-V: Implement multi-letter ISA extension probing framework
  RISC-V: Extract multi-letter extension names from "riscv, isa"
  RISC-V: Minimal parser for "riscv, isa" strings
  RISC-V: Correctly print supported extensions
  riscv: Fixed misaligned memory access. Fixed pointer comparison.
  MAINTAINERS: update riscv/microchip entry
  riscv: dts: microchip: add new peripherals to icicle kit device tree
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>RISC-V: Add support for restartable sequence</title>
<updated>2022-03-22T21:45:14+00:00</updated>
<author>
<name>Vincent Chen</name>
<email>vincent.chen@sifive.com</email>
</author>
<published>2022-03-08T08:32:52+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=93917ad50972e6298885d81b37b6a8602eb0b188'/>
<id>93917ad50972e6298885d81b37b6a8602eb0b188</id>
<content type='text'>
Add calls to rseq_signal_deliver() and rseq_syscall() to introduce RSEQ
support.

1. Call the rseq_signal_deliver() function to fixup on the pre-signal
   frame when a signal is delivered on top of a restartable sequence
   critical section.

2. Check that system calls are not invoked from within rseq critical
   sections by invoking rseq_signal() from ret_from_syscall(). With
   CONFIG_DEBUG_RSEQ, such behavior results in termination of the
   process with SIGSEGV.

Signed-off-by: Vincent Chen &lt;vincent.chen@sifive.com&gt;
Reviewed-by: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Signed-off-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Add calls to rseq_signal_deliver() and rseq_syscall() to introduce RSEQ
support.

1. Call the rseq_signal_deliver() function to fixup on the pre-signal
   frame when a signal is delivered on top of a restartable sequence
   critical section.

2. Check that system calls are not invoked from within rseq critical
   sections by invoking rseq_signal() from ret_from_syscall(). With
   CONFIG_DEBUG_RSEQ, such behavior results in termination of the
   process with SIGSEGV.

Signed-off-by: Vincent Chen &lt;vincent.chen@sifive.com&gt;
Reviewed-by: Mathieu Desnoyers &lt;mathieu.desnoyers@efficios.com&gt;
Signed-off-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>riscv: fix oops caused by irqsoff latency tracer</title>
<updated>2022-02-25T04:30:30+00:00</updated>
<author>
<name>Changbin Du</name>
<email>changbin.du@gmail.com</email>
</author>
<published>2022-02-13T08:18:45+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=22e2100b1b07d6f5acc71cc1acb53f680c677d77'/>
<id>22e2100b1b07d6f5acc71cc1acb53f680c677d77</id>
<content type='text'>
The trace_hardirqs_{on,off}() require the caller to setup frame pointer
properly. This because these two functions use macro 'CALLER_ADDR1' (aka.
__builtin_return_address(1)) to acquire caller info. If the $fp is used
for other purpose, the code generated this macro (as below) could trigger
memory access fault.

   0xffffffff8011510e &lt;+80&gt;:    ld      a1,-16(s0)
   0xffffffff80115112 &lt;+84&gt;:    ld      s2,-8(a1)  # &lt;-- paging fault here

The oops message during booting if compiled with 'irqoff' tracer enabled:
[    0.039615][    T0] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000f8
[    0.041925][    T0] Oops [#1]
[    0.042063][    T0] Modules linked in:
[    0.042864][    T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.17.0-rc1-00233-g9a20c48d1ed2 #29
[    0.043568][    T0] Hardware name: riscv-virtio,qemu (DT)
[    0.044343][    T0] epc : trace_hardirqs_on+0x56/0xe2
[    0.044601][    T0]  ra : restore_all+0x12/0x6e
[    0.044721][    T0] epc : ffffffff80126a5c ra : ffffffff80003b94 sp : ffffffff81403db0
[    0.044801][    T0]  gp : ffffffff8163acd8 tp : ffffffff81414880 t0 : 0000000000000020
[    0.044882][    T0]  t1 : 0098968000000000 t2 : 0000000000000000 s0 : ffffffff81403de0
[    0.044967][    T0]  s1 : 0000000000000000 a0 : 0000000000000001 a1 : 0000000000000100
[    0.045046][    T0]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.045124][    T0]  a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000054494d45
[    0.045210][    T0]  s2 : ffffffff80003b94 s3 : ffffffff81a8f1b0 s4 : ffffffff80e27b50
[    0.045289][    T0]  s5 : ffffffff81414880 s6 : ffffffff8160fa00 s7 : 00000000800120e8
[    0.045389][    T0]  s8 : 0000000080013100 s9 : 000000000000007f s10: 0000000000000000
[    0.045474][    T0]  s11: 0000000000000000 t3 : 7fffffffffffffff t4 : 0000000000000000
[    0.045548][    T0]  t5 : 0000000000000000 t6 : ffffffff814aa368
[    0.045620][    T0] status: 0000000200000100 badaddr: 00000000000000f8 cause: 000000000000000d
[    0.046402][    T0] [&lt;ffffffff80003b94&gt;] restore_all+0x12/0x6e

This because the $fp(aka. $s0) register is not used as frame pointer in the
assembly entry code.

	resume_kernel:
		REG_L s0, TASK_TI_PREEMPT_COUNT(tp)
		bnez s0, restore_all
		REG_L s0, TASK_TI_FLAGS(tp)
                andi s0, s0, _TIF_NEED_RESCHED
                beqz s0, restore_all
                call preempt_schedule_irq
                j restore_all

To fix above issue, here we add one extra level wrapper for function
trace_hardirqs_{on,off}() so they can be safely called by low level entry
code.

Signed-off-by: Changbin Du &lt;changbin.du@gmail.com&gt;
Fixes: 3c4697982982 ("riscv: Enable LOCKDEP_SUPPORT &amp; fixup TRACE_IRQFLAGS_SUPPORT")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
The trace_hardirqs_{on,off}() require the caller to setup frame pointer
properly. This because these two functions use macro 'CALLER_ADDR1' (aka.
__builtin_return_address(1)) to acquire caller info. If the $fp is used
for other purpose, the code generated this macro (as below) could trigger
memory access fault.

   0xffffffff8011510e &lt;+80&gt;:    ld      a1,-16(s0)
   0xffffffff80115112 &lt;+84&gt;:    ld      s2,-8(a1)  # &lt;-- paging fault here

The oops message during booting if compiled with 'irqoff' tracer enabled:
[    0.039615][    T0] Unable to handle kernel NULL pointer dereference at virtual address 00000000000000f8
[    0.041925][    T0] Oops [#1]
[    0.042063][    T0] Modules linked in:
[    0.042864][    T0] CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.17.0-rc1-00233-g9a20c48d1ed2 #29
[    0.043568][    T0] Hardware name: riscv-virtio,qemu (DT)
[    0.044343][    T0] epc : trace_hardirqs_on+0x56/0xe2
[    0.044601][    T0]  ra : restore_all+0x12/0x6e
[    0.044721][    T0] epc : ffffffff80126a5c ra : ffffffff80003b94 sp : ffffffff81403db0
[    0.044801][    T0]  gp : ffffffff8163acd8 tp : ffffffff81414880 t0 : 0000000000000020
[    0.044882][    T0]  t1 : 0098968000000000 t2 : 0000000000000000 s0 : ffffffff81403de0
[    0.044967][    T0]  s1 : 0000000000000000 a0 : 0000000000000001 a1 : 0000000000000100
[    0.045046][    T0]  a2 : 0000000000000000 a3 : 0000000000000000 a4 : 0000000000000000
[    0.045124][    T0]  a5 : 0000000000000000 a6 : 0000000000000000 a7 : 0000000054494d45
[    0.045210][    T0]  s2 : ffffffff80003b94 s3 : ffffffff81a8f1b0 s4 : ffffffff80e27b50
[    0.045289][    T0]  s5 : ffffffff81414880 s6 : ffffffff8160fa00 s7 : 00000000800120e8
[    0.045389][    T0]  s8 : 0000000080013100 s9 : 000000000000007f s10: 0000000000000000
[    0.045474][    T0]  s11: 0000000000000000 t3 : 7fffffffffffffff t4 : 0000000000000000
[    0.045548][    T0]  t5 : 0000000000000000 t6 : ffffffff814aa368
[    0.045620][    T0] status: 0000000200000100 badaddr: 00000000000000f8 cause: 000000000000000d
[    0.046402][    T0] [&lt;ffffffff80003b94&gt;] restore_all+0x12/0x6e

This because the $fp(aka. $s0) register is not used as frame pointer in the
assembly entry code.

	resume_kernel:
		REG_L s0, TASK_TI_PREEMPT_COUNT(tp)
		bnez s0, restore_all
		REG_L s0, TASK_TI_FLAGS(tp)
                andi s0, s0, _TIF_NEED_RESCHED
                beqz s0, restore_all
                call preempt_schedule_irq
                j restore_all

To fix above issue, here we add one extra level wrapper for function
trace_hardirqs_{on,off}() so they can be safely called by low level entry
code.

Signed-off-by: Changbin Du &lt;changbin.du@gmail.com&gt;
Fixes: 3c4697982982 ("riscv: Enable LOCKDEP_SUPPORT &amp; fixup TRACE_IRQFLAGS_SUPPORT")
Cc: stable@vger.kernel.org
Signed-off-by: Palmer Dabbelt &lt;palmer@rivosinc.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux</title>
<updated>2021-11-02T00:00:05+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-11-02T00:00:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=01463374c50e4fe75abec927fa231f8f5d701852'/>
<id>01463374c50e4fe75abec927fa231f8f5d701852</id>
<content type='text'>
Pull thread_info update to move 'cpu' back from task_struct from Kees Cook:
 "Cross-architecture update to move task_struct::cpu back into
  thread_info on arm64, x86, s390, powerpc, and riscv. All Acked by arch
  maintainers.

  Quoting Ard Biesheuvel:

     'Move task_struct::cpu back into thread_info

      Keeping CPU in task_struct is problematic for architectures that
      define raw_smp_processor_id() in terms of this field, as it
      requires linux/sched.h to be included, which causes a lot of pain
      in terms of circular dependencies (aka 'header soup')

      This series moves it back into thread_info (where it came from)
      for all architectures that enable THREAD_INFO_IN_TASK, addressing
      the header soup issue as well as some pointless differences in the
      implementations of task_cpu() and set_task_cpu()'"

* tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  riscv: rely on core code to keep thread_info::cpu updated
  powerpc: smp: remove hack to obtain offset of task_struct::cpu
  sched: move CPU field back into thread_info if THREAD_INFO_IN_TASK=y
  powerpc: add CPU field to struct thread_info
  s390: add CPU field to struct thread_info
  x86: add CPU field to struct thread_info
  arm64: add CPU field to struct thread_info
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Pull thread_info update to move 'cpu' back from task_struct from Kees Cook:
 "Cross-architecture update to move task_struct::cpu back into
  thread_info on arm64, x86, s390, powerpc, and riscv. All Acked by arch
  maintainers.

  Quoting Ard Biesheuvel:

     'Move task_struct::cpu back into thread_info

      Keeping CPU in task_struct is problematic for architectures that
      define raw_smp_processor_id() in terms of this field, as it
      requires linux/sched.h to be included, which causes a lot of pain
      in terms of circular dependencies (aka 'header soup')

      This series moves it back into thread_info (where it came from)
      for all architectures that enable THREAD_INFO_IN_TASK, addressing
      the header soup issue as well as some pointless differences in the
      implementations of task_cpu() and set_task_cpu()'"

* tag 'cpu-to-thread_info-v5.16-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/kees/linux:
  riscv: rely on core code to keep thread_info::cpu updated
  powerpc: smp: remove hack to obtain offset of task_struct::cpu
  sched: move CPU field back into thread_info if THREAD_INFO_IN_TASK=y
  powerpc: add CPU field to struct thread_info
  s390: add CPU field to struct thread_info
  x86: add CPU field to struct thread_info
  arm64: add CPU field to struct thread_info
</pre>
</div>
</content>
</entry>
<entry>
<title>irq: riscv: perform irqentry in entry code</title>
<updated>2021-10-26T09:13:29+00:00</updated>
<author>
<name>Mark Rutland</name>
<email>mark.rutland@arm.com</email>
</author>
<published>2021-10-20T10:33:49+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=7ecbc648102f2fa80d2aefb75b7f8b482f1a4483'/>
<id>7ecbc648102f2fa80d2aefb75b7f8b482f1a4483</id>
<content type='text'>
In preparation for removing HANDLE_DOMAIN_IRQ_IRQENTRY, have arch/riscv
perform all the irqentry accounting in its entry code. As arch/riscv
uses GENERIC_IRQ_MULTI_HANDLER, we can use generic_handle_arch_irq() to
do so.

Since generic_handle_arch_irq() handles the irq entry and setting the
irq regs, and happens before the irqchip code calls handle_IPI(), we can
remove the redundant irq entry and irq regs manipulation from
handle_IPI().

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Guo Ren &lt;guoren@kernel.org&gt;
Reviewed-by: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Albert Ou &lt;aou@eecs.berkeley.edu&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
In preparation for removing HANDLE_DOMAIN_IRQ_IRQENTRY, have arch/riscv
perform all the irqentry accounting in its entry code. As arch/riscv
uses GENERIC_IRQ_MULTI_HANDLER, we can use generic_handle_arch_irq() to
do so.

Since generic_handle_arch_irq() handles the irq entry and setting the
irq regs, and happens before the irqchip code calls handle_IPI(), we can
remove the redundant irq entry and irq regs manipulation from
handle_IPI().

There should be no functional change as a result of this patch.

Signed-off-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
Reviewed-by: Guo Ren &lt;guoren@kernel.org&gt;
Reviewed-by: Marc Zyngier &lt;maz@kernel.org&gt;
Cc: Albert Ou &lt;aou@eecs.berkeley.edu&gt;
Cc: Palmer Dabbelt &lt;palmer@dabbelt.com&gt;
Cc: Paul Walmsley &lt;paul.walmsley@sifive.com&gt;
Cc: Thomas Gleixner &lt;tglx@linutronix.de&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>riscv: rely on core code to keep thread_info::cpu updated</title>
<updated>2021-09-30T14:13:11+00:00</updated>
<author>
<name>Ard Biesheuvel</name>
<email>ardb@kernel.org</email>
</author>
<published>2021-09-14T12:10:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=8aa0fb0fbb82a4d2395be7eaeb994653b2d869fc'/>
<id>8aa0fb0fbb82a4d2395be7eaeb994653b2d869fc</id>
<content type='text'>
Now that the core code switched back to using thread_info::cpu to keep
a task's CPU number, we no longer need to keep it in sync explicitly. So
just drop the code that does this.

Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Acked-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
Now that the core code switched back to using thread_info::cpu to keep
a task's CPU number, we no longer need to keep it in sync explicitly. So
just drop the code that does this.

Signed-off-by: Ard Biesheuvel &lt;ardb@kernel.org&gt;
Acked-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&gt;
Acked-by: Mark Rutland &lt;mark.rutland@arm.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>riscv: add VMAP_STACK overflow detection</title>
<updated>2021-07-06T19:11:38+00:00</updated>
<author>
<name>Tong Tiangen</name>
<email>tongtiangen@huawei.com</email>
</author>
<published>2021-06-21T03:28:55+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=31da94c25aea835ceac00575a9fd206c5a833fed'/>
<id>31da94c25aea835ceac00575a9fd206c5a833fed</id>
<content type='text'>
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] [&lt;ffffffe000004944&gt;] walk_stackframe+0x0/0xce
[  388.058406] [&lt;ffffffe0006f0b28&gt;] dump_backtrace+0x38/0x46
[  388.058412] [&lt;ffffffe0006f0b46&gt;] show_stack+0x10/0x18
[  388.058418] [&lt;ffffffe0006f3690&gt;] dump_stack+0x74/0x8e
[  388.058424] [&lt;ffffffe0006f0d52&gt;] panic+0xfc/0x2b2
[  388.058430] [&lt;ffffffe0006f0acc&gt;] print_trace_address+0x0/0x24
[  388.058436] [&lt;ffffffe0002d814e&gt;] vsnprintf+0x2ae/0x3f0
[  388.058956] SMP: stopping secondary CPUs

Signed-off-by: Tong Tiangen &lt;tongtiangen@huawei.com&gt;
Reviewed-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Signed-off-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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] [&lt;ffffffe000004944&gt;] walk_stackframe+0x0/0xce
[  388.058406] [&lt;ffffffe0006f0b28&gt;] dump_backtrace+0x38/0x46
[  388.058412] [&lt;ffffffe0006f0b46&gt;] show_stack+0x10/0x18
[  388.058418] [&lt;ffffffe0006f3690&gt;] dump_stack+0x74/0x8e
[  388.058424] [&lt;ffffffe0006f0d52&gt;] panic+0xfc/0x2b2
[  388.058430] [&lt;ffffffe0006f0acc&gt;] print_trace_address+0x0/0x24
[  388.058436] [&lt;ffffffe0002d814e&gt;] vsnprintf+0x2ae/0x3f0
[  388.058956] SMP: stopping secondary CPUs

Signed-off-by: Tong Tiangen &lt;tongtiangen@huawei.com&gt;
Reviewed-by: Kefeng Wang &lt;wangkefeng.wang@huawei.com&gt;
Signed-off-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>Merge tag 'riscv-for-linus-5.13-mw0' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux</title>
<updated>2021-05-06T16:24:18+00:00</updated>
<author>
<name>Linus Torvalds</name>
<email>torvalds@linux-foundation.org</email>
</author>
<published>2021-05-06T16:24:18+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=939b7cbc00906b02c6eae6a380ad6c24c7a1e043'/>
<id>939b7cbc00906b02c6eae6a380ad6c24c7a1e043</id>
<content type='text'>
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
  ...
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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
  ...
</pre>
</div>
</content>
</entry>
<entry>
<title>riscv: sifive: Apply errata "cip-453" patch</title>
<updated>2021-04-26T15:24:57+00:00</updated>
<author>
<name>Vincent Chen</name>
<email>vincent.chen@sifive.com</email>
</author>
<published>2021-03-22T14:26:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux.git/commit/?id=800149a77c2cb8746a94457939b1ba1e37d2c14e'/>
<id>800149a77c2cb8746a94457939b1ba1e37d2c14e</id>
<content type='text'>
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 &lt;vincent.chen@sifive.com&gt;
Signed-off-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
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 &lt;vincent.chen@sifive.com&gt;
Signed-off-by: Palmer Dabbelt &lt;palmerdabbelt@google.com&gt;
</pre>
</div>
</content>
</entry>
</feed>
