[PATCH v2 01/18] powerpc/fsl-booke-64: Allow booting from the secondary thread
From: Scott Wood <hidden>
Date: 2015-10-07 03:48:37
Also in:
kexec
Subsystem:
linux for powerpc (32-bit and 64-bit), linux for powerpc embedded ppc85xx, the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Scott Wood, Linus Torvalds
This allows SMP kernels to work as kdump crash kernels. While crash kernels don't really need to be SMP, this prevents things from breaking if a user does it anyway (which is not something you want to only find out once the main kernel has crashed in the field, especially if whether it works or not depends on which cpu crashed). Signed-off-by: Scott Wood <redacted> --- arch/powerpc/platforms/85xx/smp.c | 27 ++++++++++++++++++++------- 1 file changed, 20 insertions(+), 7 deletions(-)
diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index b8b8216..c2ded03 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c@@ -173,15 +173,22 @@ static inline u32 read_spin_table_addr_l(void *spin_table) static void wake_hw_thread(void *info) { void fsl_secondary_thread_init(void); - unsigned long imsr1, inia1; + unsigned long imsr, inia; int nr = *(const int *)info; - imsr1 = MSR_KERNEL; - inia1 = *(unsigned long *)fsl_secondary_thread_init; - - mttmr(TMRN_IMSR1, imsr1); - mttmr(TMRN_INIA1, inia1); - mtspr(SPRN_TENS, TEN_THREAD(1)); + imsr = MSR_KERNEL; + inia = *(unsigned long *)fsl_secondary_thread_init; + + if (cpu_thread_in_core(nr) == 0) { + /* For when we boot on a secondary thread with kdump */ + mttmr(TMRN_IMSR0, imsr); + mttmr(TMRN_INIA0, inia); + mtspr(SPRN_TENS, TEN_THREAD(0)); + } else { + mttmr(TMRN_IMSR1, imsr); + mttmr(TMRN_INIA1, inia); + mtspr(SPRN_TENS, TEN_THREAD(1)); + } smp_generic_kick_cpu(nr); }
@@ -224,6 +231,12 @@ static int smp_85xx_kick_cpu(int nr) smp_call_function_single(primary, wake_hw_thread, &nr, 0); return 0; + } else if (cpu_thread_in_core(boot_cpuid) != 0 && + cpu_first_thread_sibling(boot_cpuid) == nr) { + if (WARN_ON_ONCE(!cpu_has_feature(CPU_FTR_SMT))) + return -ENOENT; + + smp_call_function_single(boot_cpuid, wake_hw_thread, &nr, 0); } #endif
--
2.1.4