[PATCH 2/2] parisc: Fix initial kernel mapping sanity check

[deller@kernel.org]

From: Helge Deller <deller@gmx.de>

The check if the initial mapping is sufficient needs to happen much
earlier during bootup. Move this test directly to the start_parisc()
function and use native PDC iodc functions to print the warning, because
panic() and printk() are not functional yet.

This fixes boot when enabling various options of KALLSYSMS.

Signed-off-by: Helge Deller <deller@gmx.de>
---
 arch/parisc/kernel/setup.c | 20 ++++++++++++--------
 1 file changed, 12 insertions(+), 8 deletions(-)

diff --git a/arch/parisc/kernel/setup.c b/arch/parisc/kernel/setup.c
index ace483b6f19a..d3e17a7a8901 100644
--- a/arch/parisc/kernel/setup.c
+++ b/arch/parisc/kernel/setup.c
@@ -120,14 +120,6 @@ void __init setup_arch(char **cmdline_p)
 #endif
 	printk(KERN_CONT ".\n");
 
-	/*
-	 * Check if initial kernel page mappings are sufficient.
-	 * panic early if not, else we may access kernel functions
-	 * and variables which can't be reached.
-	 */
-	if (__pa((unsigned long) &_end) >= KERNEL_INITIAL_SIZE)
-		panic("KERNEL_INITIAL_ORDER too small!");
-
 #ifdef CONFIG_64BIT
 	if(parisc_narrow_firmware) {
 		printk(KERN_INFO "Kernel is using PDC in 32-bit mode.\n");
@@ -279,6 +271,18 @@ void __init start_parisc(void)
 	int ret, cpunum;
 	struct pdc_coproc_cfg coproc_cfg;
 
+	/*
+	 * Check if initial kernel page mapping is sufficient.
+	 * Print warning if not, because we may access kernel functions and
+	 * variables which can't be reached yet through the initial mappings.
+	 * Note that the panic() and printk() functions are not functional
+	 * yet, so we need to use direct iodc() firmware calls instead.
+	 */
+	const char warn1[] = "CRITICAL: Kernel may crash because "
+			     "KERNEL_INITIAL_ORDER is too small.\n";
+	if (__pa((unsigned long) &_end) >= KERNEL_INITIAL_SIZE)
+		pdc_iodc_print(warn1, sizeof(warn1) - 1);
+
 	/* check QEMU/SeaBIOS marker in PAGE0 */
 	running_on_qemu = (memcmp(&PAGE0->pad0, "SeaBIOS", 8) == 0);
 
-- 
2.53.0