linux.git/arch/powerpc/kernel/rtas.c, branch v5.15

isystem: ship and use stdarg.h

2021-08-19T00:02:55+00:00

Ship minimal stdarg.h (1 type, 4 macros) as .
stdarg.h is the only userspace header commonly used in the kernel.

GPL 2 version of  can be extracted from
http://archive.debian.org/debian/pool/main/g/gcc-4.2/gcc-4.2_4.2.4.orig.tar.gz

Signed-off-by: Alexey Dobriyan 
Acked-by: Rafael J. Wysocki 
Acked-by: Ard Biesheuvel 
Signed-off-by: Masahiro Yamada

powerpc/64s: avoid reloading (H)SRR registers if they are still valid

2021-06-24T14:06:55+00:00

When an interrupt is taken, the SRR registers are set to return to where
it left off. Unless they are modified in the meantime, or the return
address or MSR are modified, there is no need to reload these registers
when returning from interrupt.

Introduce per-CPU flags that track the validity of SRR and HSRR
registers. These are cleared when returning from interrupt, when
using the registers for something else (e.g., OPAL calls), when
adjusting the return address or MSR of a context, and when context
switching (which changes the return address and MSR).

This improves the performance of interrupt returns.

Signed-off-by: Nicholas Piggin 
[mpe: Fold in fixup patch from Nick]
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210617155116.2167984-5-npiggin@gmail.com

powerpc/rtas: rename RTAS_RMOBUF_MAX to RTAS_USER_REGION_SIZE

2021-04-14T13:04:16+00:00

RTAS_RMOBUF_MAX doesn't actually describe a "maximum" value in any
sense. It represents the size of an area of memory set aside for user
space to use as work areas for certain RTAS calls.

Rename it to RTAS_USER_REGION_SIZE.

Signed-off-by: Nathan Lynch 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210408140630.205502-6-nathanl@linux.ibm.com

powerpc/rtas: move syscall filter setup into separate function

2021-04-14T13:04:16+00:00

Reduce conditionally compiled sections within rtas_initialize() by
moving the filter table initialization into its own function already
guarded by CONFIG_PPC_RTAS_FILTER. No behavior change intended.

Signed-off-by: Nathan Lynch 
Reviewed-by: Alexey Kardashevskiy 
Acked-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210408140630.205502-5-nathanl@linux.ibm.com

powerpc/rtas: remove ibm_suspend_me_token

2021-04-14T13:04:16+00:00

There's not a compelling reason to cache the value of the token for
the ibm,suspend-me function. Just look it up when needed in the RTAS
syscall's special case for it.

Signed-off-by: Nathan Lynch 
Reviewed-by: Alexey Kardashevskiy 
Reviewed-by: Andrew Donnellan 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20210408140630.205502-4-nathanl@linux.ibm.com

powerpc/rtas: Fix typo of ibm,open-errinjct in RTAS filter

2020-12-09T02:36:51+00:00

Commit bd59380c5ba4 ("powerpc/rtas: Restrict RTAS requests from userspace")
introduced the following error when invoking the errinjct userspace
tool:

  [root@ltcalpine2-lp5 librtas]# errinjct open
  [327884.071171] sys_rtas: RTAS call blocked - exploit attempt?
  [327884.071186] sys_rtas: token=0x26, nargs=0 (called by errinjct)
  errinjct: Could not open RTAS error injection facility
  errinjct: librtas: open: Unexpected I/O error

The entry for ibm,open-errinjct in rtas_filter array has a typo where
the "j" is omitted in the rtas call name. After fixing this typo the
errinjct tool functions again as expected.

  [root@ltcalpine2-lp5 linux]# errinjct open
  RTAS error injection facility open, token = 1

Fixes: bd59380c5ba4 ("powerpc/rtas: Restrict RTAS requests from userspace")
Cc: stable@vger.kernel.org
Signed-off-by: Tyrel Datwyler 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201208195434.8289-1-tyreld@linux.ibm.com

powerpc/rtas: remove unused rtas_suspend_last_cpu()

2020-12-08T10:41:01+00:00

rtas_suspend_last_cpu() is now unused, remove it and
__rtas_suspend_last_cpu() which also becomes unused.

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201207215200.1785968-24-nathanl@linux.ibm.com

powerpc/rtas: remove rtas_suspend_cpu()

2020-12-08T10:41:01+00:00

rtas_suspend_cpu() no longer has users; remove it and
__rtas_suspend_cpu() which now becomes unused as well.

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201207215200.1785968-22-nathanl@linux.ibm.com

powerpc/rtas: remove rtas_ibm_suspend_me_unsafe()

2020-12-08T10:40:59+00:00

rtas_ibm_suspend_me_unsafe() is now unused; remove it and
rtas_percpu_suspend_me() which becomes unused as a result.

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201207215200.1785968-17-nathanl@linux.ibm.com

powerpc/rtas: dispatch partition migration requests to pseries

2020-12-08T10:40:59+00:00

sys_rtas() cannot call ibm,suspend-me directly in the same way it
handles other inputs. Instead it must dispatch the request to code
that can first perform the H_JOIN sequence before any call to
ibm,suspend-me can succeed. Over time kernel/rtas.c has accreted a fair
amount of platform-specific code to implement this.

Since a different, more robust implementation of the suspend sequence
is now in the pseries platform code, we want to dispatch the request
there.

Note that invoking ibm,suspend-me via the RTAS syscall is all but
deprecated; this change preserves ABI compatibility for old programs
while providing to them the benefit of the new partition suspend
implementation. This is a behavior change in that the kernel performs
the device tree update and firmware activation before returning, but
experimentation indicates this is tolerated fine by legacy user space.

Signed-off-by: Nathan Lynch 
Signed-off-by: Michael Ellerman 
Link: https://lore.kernel.org/r/20201207215200.1785968-16-nathanl@linux.ibm.com