| Message ID | 20200917020548.20386-1-jniethe5@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/2] powerpc/64: Set up a kernel stack for secondaries before cpu_restore() | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (27e2fbcd815a088d7d83c7158f76b6e95ab07c50) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 20 lines checked |
| snowpatch_ozlabs/needsstable | warning | Please consider tagging this patch for stable! |
diff --git a/arch/powerpc/kernel/head_64.S b/arch/powerpc/kernel/head_64.S index 0e05a9a47a4b..4b7f4c6c2600 100644 --- a/arch/powerpc/kernel/head_64.S +++ b/arch/powerpc/kernel/head_64.S @@ -420,6 +420,10 @@ generic_secondary_common_init: /* From now on, r24 is expected to be logical cpuid */ mr r24,r5 + /* Create a temp kernel stack for use before relocation is on. */ + ld r1,PACAEMERGSP(r13) + subi r1,r1,STACK_FRAME_OVERHEAD + /* See if we need to call a cpu state restore handler */ LOAD_REG_ADDR(r23, cur_cpu_spec) ld r23,0(r23) @@ -448,10 +452,6 @@ generic_secondary_common_init: sync /* order paca.run and cur_cpu_spec */ isync /* In case code patching happened */ - /* Create a temp kernel stack for use before relocation is on. */ - ld r1,PACAEMERGSP(r13) - subi r1,r1,STACK_FRAME_OVERHEAD - b __secondary_start #endif /* SMP */
Currently in generic_secondary_smp_init(), cur_cpu_spec->cpu_restore() is called before a stack has been set up in r1. This was previously fine as the cpu_restore() functions were implemented in assembly and did not use a stack. However commit 5a61ef74f269 ("powerpc/64s: Support new device tree binding for discovering CPU features") used __restore_cpu_cpufeatures() as the cpu_restore() function for a device-tree features based cputable entry. This is a nonleaf C function and hence requires a stack in r1. Create the temp kernel stack before calling cpu_restore(). Fixes: 5a61ef74f269 ("powerpc/64s: Support new device tree binding for discovering CPU features") Signed-off-by: Jordan Niethe <jniethe5@gmail.com> --- arch/powerpc/kernel/head_64.S | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)