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-rw-r--r--arch/powerpc/kernel/setup_64.c32
1 files changed, 25 insertions, 7 deletions
diff --git a/arch/powerpc/kernel/setup_64.c b/arch/powerpc/kernel/setup_64.c
index e05e6dd67ae6..438a9befce41 100644
--- a/arch/powerpc/kernel/setup_64.c
+++ b/arch/powerpc/kernel/setup_64.c
@@ -279,24 +279,42 @@ void __init record_spr_defaults(void)
* device-tree is not accessible via normal means at this point.
*/
-void __init early_setup(unsigned long dt_ptr)
+void __init __nostackprotector early_setup(unsigned long dt_ptr)
{
static __initdata struct paca_struct boot_paca;
/* -------- printk is _NOT_ safe to use here ! ------- */
- /* Try new device tree based feature discovery ... */
- if (!dt_cpu_ftrs_init(__va(dt_ptr)))
- /* Otherwise use the old style CPU table */
- identify_cpu(0, mfspr(SPRN_PVR));
-
- /* Assume we're on cpu 0 for now. Don't write to the paca yet! */
+ /*
+ * Assume we're on cpu 0 for now.
+ *
+ * We need to load a PACA very early for a few reasons.
+ *
+ * The stack protector canary is stored in the paca, so as soon as we
+ * call any stack protected code we need r13 pointing somewhere valid.
+ *
+ * If we are using kcov it will call in_task() in its instrumentation,
+ * which relies on the current task from the PACA.
+ *
+ * dt_cpu_ftrs_init() calls into generic OF/fdt code, as well as
+ * printk(), which can trigger both stack protector and kcov.
+ *
+ * percpu variables and spin locks also use the paca.
+ *
+ * So set up a temporary paca. It will be replaced below once we know
+ * what CPU we are on.
+ */
initialise_paca(&boot_paca, 0);
setup_paca(&boot_paca);
fixup_boot_paca();
/* -------- printk is now safe to use ------- */
+ /* Try new device tree based feature discovery ... */
+ if (!dt_cpu_ftrs_init(__va(dt_ptr)))
+ /* Otherwise use the old style CPU table */
+ identify_cpu(0, mfspr(SPRN_PVR));
+
/* Enable early debugging if any specified (see udbg.h) */
udbg_early_init();