linux/arch
Russell Currey eac030b22e powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT
lppaca_shared_proc() takes a pointer to the lppaca which is typically
accessed through get_lppaca().  With DEBUG_PREEMPT enabled, this leads
to checking if preemption is enabled, for example:

  BUG: using smp_processor_id() in preemptible [00000000] code: grep/10693
  caller is lparcfg_data+0x408/0x19a0
  CPU: 4 PID: 10693 Comm: grep Not tainted 6.5.0-rc3 #2
  Call Trace:
    dump_stack_lvl+0x154/0x200 (unreliable)
    check_preemption_disabled+0x214/0x220
    lparcfg_data+0x408/0x19a0
    ...

This isn't actually a problem however, as it does not matter which
lppaca is accessed, the shared proc state will be the same.
vcpudispatch_stats_procfs_init() already works around this by disabling
preemption, but the lparcfg code does not, erroring any time
/proc/powerpc/lparcfg is accessed with DEBUG_PREEMPT enabled.

Instead of disabling preemption on the caller side, rework
lppaca_shared_proc() to not take a pointer and instead directly access
the lppaca, bypassing any potential preemption checks.

Fixes: f13c13a005 ("powerpc: Stop using non-architected shared_proc field in lppaca")
Signed-off-by: Russell Currey <ruscur@russell.cc>
[mpe: Rework to avoid needing a definition in paca.h and lppaca.h]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://msgid.link/20230823055317.751786-4-mpe@ellerman.id.au
2023-08-24 22:33:17 +10:00
..
alpha Merge branch 'expand-stack' 2023-06-28 20:35:21 -07:00
arc asm-generic updates for 6.5 2023-07-06 10:06:04 -07:00
arm asm-generic updates for 6.5 2023-07-06 10:06:04 -07:00
arm64 ARM: 2023-07-23 10:44:38 -07:00
csky arch/csky patches for 6.5 2023-07-01 21:12:32 -07:00
hexagon Merge branch 'expand-stack' 2023-06-28 20:35:21 -07:00
ia64 io_uring-6.5-2023-07-21 2023-07-22 10:46:30 -07:00
loongarch asm-generic updates for 6.5 2023-07-06 10:06:04 -07:00
m68k asm-generic updates for 6.5 2023-07-06 10:06:04 -07:00
microblaze slab updates for 6.5 2023-06-29 16:34:12 -07:00
mips - fixes for KVM 2023-07-09 10:02:49 -07:00
nios2 slab updates for 6.5 2023-06-29 16:34:12 -07:00
openrisc OpenRISC fix for 6.5 2023-07-12 16:28:53 -07:00
parisc io_uring-6.5-2023-07-21 2023-07-22 10:46:30 -07:00
powerpc powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT 2023-08-24 22:33:17 +10:00
riscv RISC-V Fixes for 6.5-rc2 2023-07-14 11:14:07 -07:00
s390 ARM: 2023-07-23 10:44:38 -07:00
sh sh fixes for v6.5 2023-07-13 13:34:00 -07:00
sparc sparc: mark __arch_xchg() as __always_inline 2023-07-13 09:54:32 -07:00
um x86/alternative: Rename apply_ibt_endbr() 2023-07-10 09:52:23 +02:00
x86 cpu/SMT: Remove topology_smt_supported() 2023-07-28 09:53:37 +02:00
xtensa xtensa: fix unaligned and load/store configuration interaction 2023-07-10 21:41:04 -07:00
.gitignore
Kconfig cpu/SMT: Create topology_smt_thread_allowed() 2023-07-28 09:53:37 +02:00