ARCv2: spinlock/rwlock/atomics: Delayed retry of failed SCOND with exponential backoff

[cascardo/linux.git] / arch / arc / kernel / setup.c

diff --git a/arch/arc/kernel/setup.c b/arch/arc/kernel/setup.c
index 18cc015..cabde9d 100644 (file)
--- a/arch/arc/kernel/setup.c
+++ b/arch/arc/kernel/setup.c
@@ -47,6 +47,7 @@ static void read_arc_build_cfg_regs(void)
        struct bcr_perip uncached_space;
        struct bcr_generic bcr;
        struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
+       unsigned long perip_space;
        FIX_PTR(cpu);
 
        READ_BCR(AUX_IDENTITY, cpu->core);
@@ -56,7 +57,12 @@ static void read_arc_build_cfg_regs(void)
        cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);
 
        READ_BCR(ARC_REG_D_UNCACH_BCR, uncached_space);
-       BUG_ON((uncached_space.start << 24) != ARC_UNCACHED_ADDR_SPACE);
+        if (uncached_space.ver < 3)
+               perip_space = uncached_space.start << 24;
+       else
+               perip_space = read_aux_reg(AUX_NON_VOL) & 0xF0000000;
+
+       BUG_ON(perip_space != ARC_UNCACHED_ADDR_SPACE);
 
        READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);
 
@@ -330,6 +336,10 @@ static void arc_chk_core_config(void)
                pr_warn("CONFIG_ARC_FPU_SAVE_RESTORE needed for working apps\n");
        else if (!cpu->extn.fpu_dp && fpu_enabled)
                panic("FPU non-existent, disable CONFIG_ARC_FPU_SAVE_RESTORE\n");
+
+       if (is_isa_arcv2() && IS_ENABLED(CONFIG_SMP) && cpu->isa.atomic &&
+           !IS_ENABLED(CONFIG_ARC_STAR_9000923308))
+               panic("llock/scond livelock workaround missing\n");
 }
 
 /*