linux-stable.git/arch/powerpc/kernel/process.c, branch v6.2 Linux kernel stable tree Merge tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux 2022-12-19T13:13:33+00:00 Linus Torvalds torvalds@linux-foundation.org 2022-12-19T13:13:33+00:00 5f6e430f931d245da838db3e10e918681207029b Pull powerpc updates from Michael Ellerman: - Add powerpc qspinlock implementation optimised for large system scalability and paravirt. See the merge message for more details - Enable objtool to be built on powerpc to generate mcount locations - Use a temporary mm for code patching with the Radix MMU, so the writable mapping is restricted to the patching CPU - Add an option to build the 64-bit big-endian kernel with the ELFv2 ABI - Sanitise user registers on interrupt entry on 64-bit Book3S - Many other small features and fixes Thanks to Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn Helgaas, Bo Liu, Chen Lifu, Christoph Hellwig, Christophe JAILLET, Christophe Leroy, Christopher M. Riedl, Colin Ian King, Deming Wang, Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven, Gustavo A. R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol Jain, Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan Lynch, Naveen N. Rao, Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin, Pali Rohár, Randy Dunlap, Rohan McLure, Russell Currey, Sathvika Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng, XueBing Chen, Yang Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu, and Wolfram Sang. * tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (181 commits) powerpc/code-patching: Fix oops with DEBUG_VM enabled powerpc/qspinlock: Fix 32-bit build powerpc/prom: Fix 32-bit build powerpc/rtas: mandate RTAS syscall filtering powerpc/rtas: define pr_fmt and convert printk call sites powerpc/rtas: clean up includes powerpc/rtas: clean up rtas_error_log_max initialization powerpc/pseries/eeh: use correct API for error log size powerpc/rtas: avoid scheduling in rtas_os_term() powerpc/rtas: avoid device tree lookups in rtas_os_term() powerpc/rtasd: use correct OF API for event scan rate powerpc/rtas: document rtas_call() powerpc/pseries: unregister VPA when hot unplugging a CPU powerpc/pseries: reset the RCU watchdogs after a LPM powerpc: Take in account addition CPU node when building kexec FDT powerpc: export the CPU node count powerpc/cpuidle: Set CPUIDLE_FLAG_POLLING for snooze state powerpc/dts/fsl: Fix pca954x i2c-mux node names cxl: Remove unnecessary cxl_pci_window_alignment() selftests/powerpc: Fix resource leaks ... 
Pull powerpc updates from Michael Ellerman:

 - Add powerpc qspinlock implementation optimised for large system
   scalability and paravirt. See the merge message for more details

 - Enable objtool to be built on powerpc to generate mcount locations

 - Use a temporary mm for code patching with the Radix MMU, so the
   writable mapping is restricted to the patching CPU

 - Add an option to build the 64-bit big-endian kernel with the ELFv2
   ABI

 - Sanitise user registers on interrupt entry on 64-bit Book3S

 - Many other small features and fixes

Thanks to Aboorva Devarajan, Angel Iglesias, Benjamin Gray, Bjorn
Helgaas, Bo Liu, Chen Lifu, Christoph Hellwig, Christophe JAILLET,
Christophe Leroy, Christopher M. Riedl, Colin Ian King, Deming Wang,
Disha Goel, Dmitry Torokhov, Finn Thain, Geert Uytterhoeven, Gustavo A.
R. Silva, Haowen Bai, Joel Stanley, Jordan Niethe, Julia Lawall, Kajol
Jain, Laurent Dufour, Li zeming, Miaoqian Lin, Michael Jeanson, Nathan
Lynch, Naveen N. Rao, Nayna Jain, Nicholas Miehlbradt, Nicholas Piggin,
Pali Rohár, Randy Dunlap, Rohan McLure, Russell Currey, Sathvika
Vasireddy, Shaomin Deng, Stephen Kitt, Stephen Rothwell, Thomas
Weißschuh, Tiezhu Yang, Uwe Kleine-König, Xie Shaowen, Xiu Jianfeng,
XueBing Chen, Yang Yingliang, Zhang Jiaming, ruanjinjie, Jessica Yu,
and Wolfram Sang.

* tag 'powerpc-6.2-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (181 commits)
  powerpc/code-patching: Fix oops with DEBUG_VM enabled
  powerpc/qspinlock: Fix 32-bit build
  powerpc/prom: Fix 32-bit build
  powerpc/rtas: mandate RTAS syscall filtering
  powerpc/rtas: define pr_fmt and convert printk call sites
  powerpc/rtas: clean up includes
  powerpc/rtas: clean up rtas_error_log_max initialization
  powerpc/pseries/eeh: use correct API for error log size
  powerpc/rtas: avoid scheduling in rtas_os_term()
  powerpc/rtas: avoid device tree lookups in rtas_os_term()
  powerpc/rtasd: use correct OF API for event scan rate
  powerpc/rtas: document rtas_call()
  powerpc/pseries: unregister VPA when hot unplugging a CPU
  powerpc/pseries: reset the RCU watchdogs after a LPM
  powerpc: Take in account addition CPU node when building kexec FDT
  powerpc: export the CPU node count
  powerpc/cpuidle: Set CPUIDLE_FLAG_POLLING for snooze state
  powerpc/dts/fsl: Fix pca954x i2c-mux node names
  cxl: Remove unnecessary cxl_pci_window_alignment()
  selftests/powerpc: Fix resource leaks
  ...
powerpc: allow minimum sized kernel stack frames 2022-12-02T06:54:09+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:40+00:00 90f1b43196c5e79f6c986a359011a19857984c27 This affects only 64-bit ELFv2 kernels, and reduces the minimum asm-created stack frame size from 112 to 32 byte on those kernels. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-16-npiggin@gmail.com 
This affects only 64-bit ELFv2 kernels, and reduces the minimum
asm-created stack frame size from 112 to 32 byte on those kernels.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-16-npiggin@gmail.com
powerpc: split validate_sp into two functions 2022-12-02T06:54:09+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:39+00:00 4cefb0f6c555971b3e6544a9b15470f9d1f12089 Most callers just want to validate an arbitrary kernel stack pointer, some need a particular size. Make the size case the exceptional one with an extra function. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-15-npiggin@gmail.com 
Most callers just want to validate an arbitrary kernel stack pointer,
some need a particular size. Make the size case the exceptional one
with an extra function.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-15-npiggin@gmail.com
powerpc: copy_thread add a back chain to the switch stack frame 2022-12-02T06:54:08+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:38+00:00 edbd0387f3249cc7e102f86d4852a9a9f3bb1305 Stack unwinders need LR and the back chain as a minimum. The switch stack uses regs->nip for its return pointer rather than lrsave, so that was not set in the fork frame, and neither was the back chain. This change sets those fields in the stack. With this and the previous change, a stack trace in the switch or interrupt stack goes from looking like this: Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries Modules linked in: CPU: 3 PID: 90 Comm: systemd Not tainted NIP: c000000000011060 LR: c000000000010f68 CTR: 0000000000007fff [ ... regs ... ] NIP [c000000000011060] _switch+0x160/0x17c LR [c000000000010f68] _switch+0x68/0x17c Call Trace: To this: Oops: Exception in kernel mode, sig: 5 [#1] LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries CPU: 0 PID: 93 Comm: systemd Not tainted NIP: c000000000011060 LR: c000000000010f68 CTR: 0000000000007fff [ ... regs ... ] NIP [c000000000011060] _switch+0x160/0x17c LR [c000000000010f68] _switch+0x68/0x17c Call Trace: [c000000005a93e10] [c00000000000cdbc] ret_from_fork_scv+0x0/0x54 --- interrupt: 3000 at 0x7fffa72f56d8 NIP: 00007fffa72f56d8 LR: 0000000000000000 CTR: 0000000000000000 [ ... regs ... ] NIP [00007fffa72f56d8] 0x7fffa72f56d8 LR [0000000000000000] 0x0 --- interrupt: 3000 Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-14-npiggin@gmail.com 
Stack unwinders need LR and the back chain as a minimum. The switch
stack uses regs->nip for its return pointer rather than lrsave, so
that was not set in the fork frame, and neither was the back chain.
This change sets those fields in the stack.

With this and the previous change, a stack trace in the switch or
interrupt stack goes from looking like this:

  Oops: Exception in kernel mode, sig: 5 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  Modules linked in:
  CPU: 3 PID: 90 Comm: systemd Not tainted
  NIP:  c000000000011060 LR: c000000000010f68 CTR: 0000000000007fff
  [ ... regs ... ]
  NIP [c000000000011060] _switch+0x160/0x17c
  LR [c000000000010f68] _switch+0x68/0x17c
  Call Trace:

To this:

  Oops: Exception in kernel mode, sig: 5 [#1]
  LE PAGE_SIZE=64K MMU=Radix SMP NR_CPUS=2048 NUMA pSeries
  CPU: 0 PID: 93 Comm: systemd Not tainted
  NIP:  c000000000011060 LR: c000000000010f68 CTR: 0000000000007fff
  [ ... regs ... ]
  NIP [c000000000011060] _switch+0x160/0x17c
  LR [c000000000010f68] _switch+0x68/0x17c
  Call Trace:
  [c000000005a93e10] [c00000000000cdbc] ret_from_fork_scv+0x0/0x54
  --- interrupt: 3000 at 0x7fffa72f56d8
  NIP:  00007fffa72f56d8 LR: 0000000000000000 CTR: 0000000000000000
  [ ... regs ... ]
  NIP [00007fffa72f56d8] 0x7fffa72f56d8
  LR [0000000000000000] 0x0
  --- interrupt: 3000

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-14-npiggin@gmail.com
powerpc: copy_thread fill in interrupt frame marker and back chain 2022-12-02T06:54:08+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:37+00:00 6895dfc0474170c492191c126fcfc420f7771a09 Backtraces will not recognise the fork system call interrupt without the regs marker. And regular interrupt entry from userspace creates the back chain to the user stack, so do this for the initial fork frame too, to be consistent. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-13-npiggin@gmail.com 
Backtraces will not recognise the fork system call interrupt without
the regs marker. And regular interrupt entry from userspace creates
the back chain to the user stack, so do this for the initial fork
frame too, to be consistent.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-13-npiggin@gmail.com
powerpc: add a define for the switch frame size and regs offset 2022-12-02T06:54:08+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:36+00:00 6f291a03819e4051ebc870471d26915ef2e6ba31 This is open-coded in process.c, ppc32 uses a different define with the same value, and the C definition is name differently which makes it an extra indirection to grep for. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-12-npiggin@gmail.com 
This is open-coded in process.c, ppc32 uses a different define with the
same value, and the C definition is name differently which makes it an
extra indirection to grep for.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-12-npiggin@gmail.com
powerpc: add a define for the user interrupt frame size 2022-12-02T06:54:08+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:35+00:00 1223e5a20f7fb3c31c91a328d1a04ed26d5e889b The user interrupt frame is a different size from the kernel frame, so give it its own name. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-11-npiggin@gmail.com 
The user interrupt frame is a different size from the kernel frame, so
give it its own name.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-11-npiggin@gmail.com
powerpc: Rename STACK_FRAME_MARKER and derive it from frame offset 2022-12-02T06:54:08+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:34+00:00 e856e336924b0ecd0b7058e65e6b3e7266ee0b95 This is a count of longs from the stack pointer to the regs marker. Rename it to make it more distinct from the other byte offsets. It can be derived from the byte offset definitions just added. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-10-npiggin@gmail.com 
This is a count of longs from the stack pointer to the regs marker.
Rename it to make it more distinct from the other byte offsets. It
can be derived from the byte offset definitions just added.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-10-npiggin@gmail.com
powerpc: add definition for pt_regs offset within an interrupt frame 2022-12-02T06:54:08+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:32+00:00 c03be0a3f3cc656eab5c427b78959b8f1b169a11 This is a common offset that currently uses the overloaded STACK_FRAME_OVERHEAD constant. It's easier to read and more flexible to use a specific regs offset for this. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-8-npiggin@gmail.com 
This is a common offset that currently uses the overloaded
STACK_FRAME_OVERHEAD constant. It's easier to read and more
flexible to use a specific regs offset for this.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-8-npiggin@gmail.com
powerpc: Rearrange copy_thread child stack creation 2022-12-02T06:54:07+00:00 Nicholas Piggin npiggin@gmail.com 2022-11-27T12:49:29+00:00 bc0677363d0ffaec0c56685291e97b080116976c This makes it a bit clearer where the stack frame is created, and will allow easier use of some of the stack offset constants in a later change. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au> Link: https://lore.kernel.org/r/20221127124942.1665522-5-npiggin@gmail.com 
This makes it a bit clearer where the stack frame is created, and will
allow easier use of some of the stack offset constants in a later
change.

Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221127124942.1665522-5-npiggin@gmail.com