Merge tag 'parisc-for-7.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux

Pull parisc fixes from Helge Deller:
 "While testing Sasha Levin's 'kallsyms: embed source file:line info in
  kernel stack traces' patch series, which increases the typical kernel
  image size, I found some issues with the parisc initial kernel mapping
  which may prevent the kernel to boot.

  The three small patches here fix this"

* tag 'parisc-for-7.0-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux:
  parisc: Fix initial page table creation for boot
  parisc: Check kernel mapping earlier at bootup
  parisc: Increase initial mapping to 64 MB with KALLSYMS

3 files changed, 19 insertions, 10 deletions

diff --git a/arch/parisc/include/asm/pgtable.h b/arch/parisc/include/asm/pgtable.h
index 2c139a4dbf4b..17afe7a59edf 100644
--- a/arch/parisc/include/asm/pgtable.h
+++ b/arch/parisc/include/asm/pgtable.h
@@ -85,7 +85,7 @@ extern void __update_cache(pte_t pte);
 	printk("%s:%d: bad pgd %08lx.\n", __FILE__, __LINE__, (unsigned long)pgd_val(e))
 
 /* This is the size of the initially mapped kernel memory */
-#if defined(CONFIG_64BIT)
+#if defined(CONFIG_64BIT) || defined(CONFIG_KALLSYMS)
 #define KERNEL_INITIAL_ORDER	26	/* 1<<26 = 64MB */
 #else
 #define KERNEL_INITIAL_ORDER	25	/* 1<<25 = 32MB */
diff --git a/arch/parisc/kernel/head.S b/arch/parisc/kernel/head.S
index 96e0264ac961..9188c8d87437 100644
--- a/arch/parisc/kernel/head.S
+++ b/arch/parisc/kernel/head.S
@@ -56,6 +56,7 @@ ENTRY(parisc_kernel_start)
 
 	.import __bss_start,data
 	.import __bss_stop,data
+	.import __end,data
 
 	load32		PA(__bss_start),%r3
 	load32		PA(__bss_stop),%r4
@@ -149,7 +150,11 @@ $cpu_ok:
 	 * everything ... it will get remapped correctly later */
 	ldo		0+_PAGE_KERNEL_RWX(%r0),%r3 /* Hardwired 0 phys addr start */
 	load32		(1<<(KERNEL_INITIAL_ORDER-PAGE_SHIFT)),%r11 /* PFN count */
-	load32		PA(pg0),%r1
+	load32		PA(_end),%r1
+	SHRREG		%r1,PAGE_SHIFT,%r1  /* %r1 is PFN count for _end symbol */
+	cmpb,<<,n	%r11,%r1,1f
+	copy		%r1,%r11	/* %r1 PFN count smaller than %r11 */
+1:	load32		PA(pg0),%r1
 
 $pgt_fill_loop:
 	STREGM          %r3,ASM_PTE_ENTRY_SIZE(%r1)
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);