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| author | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-02-10 18:45:24 +1100 |
|---|---|---|
| committer | Benjamin Herrenschmidt <benh@kernel.crashing.org> | 2011-04-01 15:37:09 +1100 |
| commit | fa3f82c8bb7acbe049ea71f258b3ae0a33d9d40b (patch) | |
| tree | 9c5e71195c7948c139ea37d8d0e0287f062910f9 /arch/powerpc/kernel/head_32.S | |
| parent | 963e5d3b76d657f1ebcf3561446d2ba1872bbfa2 (diff) | |
| download | lwn-fa3f82c8bb7acbe049ea71f258b3ae0a33d9d40b.tar.gz lwn-fa3f82c8bb7acbe049ea71f258b3ae0a33d9d40b.zip | |
powerpc/smp: soft-replugged CPUs must go back to start_secondary
Various thing are torn down when a CPU is hot-unplugged. That CPU
is expected to go back to start_secondary when re-plugged to re
initialize everything, such as clock sources, maps, ...
Some implementations just return from cpu_die() callback
in the idle loop when the CPU is "re-plugged". This is not enough.
We fix it using a little asm trampoline which resets the stack
and calls back into start_secondary as if we were all fresh from
boot. The trampoline already existed on ppc64, but we add it for
ppc32
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Diffstat (limited to 'arch/powerpc/kernel/head_32.S')
| -rw-r--r-- | arch/powerpc/kernel/head_32.S | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/head_32.S b/arch/powerpc/kernel/head_32.S index 98c4b29a56f4..c5c24beb8387 100644 --- a/arch/powerpc/kernel/head_32.S +++ b/arch/powerpc/kernel/head_32.S @@ -890,6 +890,15 @@ __secondary_start: mtspr SPRN_SRR1,r4 SYNC RFI + +_GLOBAL(start_secondary_resume) + /* Reset stack */ + rlwinm r1,r1,0,0,(31-THREAD_SHIFT) /* current_thread_info() */ + addi r1,r1,THREAD_SIZE-STACK_FRAME_OVERHEAD + li r3,0 + std r3,0(r1) /* Zero the stack frame pointer */ + bl start_secondary + b . #endif /* CONFIG_SMP */ #ifdef CONFIG_KVM_BOOK3S_HANDLER |