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| author |  Nicholas Piggin <npiggin@gmail.com>
| 2022-12-16 21:59:29 +1000 |
|---|---|---|
| committer |  Michael Ellerman <mpe@ellerman.id.au>
| 2023-02-10 22:19:56 +1100 |
| commit | dc222fa7737212fe0da513e5b8937c156d02225d (patch) | |
| tree | ce96a3b2c8b5449e434ff5f69e6a5abfd5396e87 /arch/powerpc/include | |
| parent | powerpc/64: Fix task_cpu in early boot when booting non-zero cpuid (diff) | |
| download | linux-dc222fa7737212fe0da513e5b8937c156d02225d.tar.gz linux-dc222fa7737212fe0da513e5b8937c156d02225d.tar.bz2 linux-dc222fa7737212fe0da513e5b8937c156d02225d.zip | |
powerpc/64: Move paca allocation to early_setup()
The early paca and boot cpuid dance is complicated and currently does
not quite work as expected for boot cpuid != 0 cases.
early_init_devtree() currently allocates the paca_ptrs and boot cpuid
paca, but until that returns and early_setup() calls setup_paca(), this
thread is currently still executing with smp_processor_id() == 0.
One problem this causes is the paca_ptrs[smp_processor_id()] pointer is
poisoned, so valid_emergency_stack() (any backtrace) and any similar
users will crash.
Another is that the hardware id which is set here will not be returned
by get_hard_smp_processor_id(smp_processor_id()), but it would work
correctly for boot_cpuid == 0, which could lead to difficult to
reproduce or find bugs. The hard id does not seem to be used by the rest
of early_init_devtree(), it just looks like all this code might have
been put here to allocate somewhere to store boot CPU hardware id while
scanning the devtree.
Rearrange things so the hwid is put in a global variable like
boot_cpuid, and do all the paca allocation and boot paca setup in the
64-bit early_setup() after we have everything ready to go.
The paca_ptrs[0] re-poisoning code in early_setup does not seem to have
ever worked, because paca_ptrs[0] was never not-poisoned when boot_cpuid
is not 0.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
[mpe: Fix build error on 32-bit]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20221216115930.2667772-4-npiggin@gmail.com
Diffstat (limited to 'arch/powerpc/include')
| -rw-r--r-- | arch/powerpc/include/asm/paca.h | 1 | ||||
| -rw-r--r-- | arch/powerpc/include/asm/smp.h | 1 |
2 files changed, 1 insertions, 1 deletions
diff --git a/arch/powerpc/include/asm/paca.h b/arch/powerpc/include/asm/paca.h index 09f1790d0ae1..0ab3511a47d7 100644 --- a/arch/powerpc/include/asm/paca.h +++ b/arch/powerpc/include/asm/paca.h @@ -295,7 +295,6 @@ extern void free_unused_pacas(void); #else /* CONFIG_PPC64 */ -static inline void allocate_paca_ptrs(void) { } static inline void allocate_paca(int cpu) { } static inline void free_unused_pacas(void) { } diff --git a/arch/powerpc/include/asm/smp.h b/arch/powerpc/include/asm/smp.h index f63505d74932..6c6cb53d7045 100644 --- a/arch/powerpc/include/asm/smp.h +++ b/arch/powerpc/include/asm/smp.h @@ -26,6 +26,7 @@ #include <asm/percpu.h> extern int boot_cpuid; +extern int boot_cpu_hwid; /* PPC64 only */ extern int spinning_secondaries; extern u32 *cpu_to_phys_id; extern bool coregroup_enabled; |