[SPARC64]: Remove most limitations to kernel image size.

Currently kernel images are limited to 8MB in size, and this causes
problems especially when enabling features that take up a lot of
kernel image space such as lockdep.

The code now will align the kernel image size up to 4MB and map that
many locked TLB entries.  So, the only practical limitation is the
number of available locked TLB entries which is 16 on Cheetah and 64
on pre-Cheetah sparc64 cpus.  Niagara cpus don't actually have hw
locked TLB entry support.  Rather, the hypervisor transparently
provides support for "locked" TLB entries since it runs with physical
addressing and does the initial TLB miss processing.

Fully utilizing this change requires some help from SILO, a patch for
which will be submitted to the maintainer.  Essentially, SILO will
only currently map up to 8MB for the kernel image and that needs to be
increased.

Note that neither this patch nor the SILO bits will help with network
booting.  The openfirmware code will only map up to a certain amount
of kernel image during a network boot and there isn't much we can to
about that other than to implemented a layered network booting
facility.  Solaris has this, and calls it "wanboot" and we may
implement something similar at some point.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 9 insertions, 8 deletions

diff --git a/arch/sparc64/kernel/smp.c b/arch/sparc64/kernel/smp.c
index cc454731d879..5a1126b363a4 100644
--- a/arch/sparc64/kernel/smp.c
+++ b/arch/sparc64/kernel/smp.c
@@ -284,14 +284,17 @@ static void ldom_startcpu_cpuid(unsigned int cpu, unsigned long thread_reg)
 {
 	extern unsigned long sparc64_ttable_tl0;
 	extern unsigned long kern_locked_tte_data;
-	extern int bigkernel;
 	struct hvtramp_descr *hdesc;
 	unsigned long trampoline_ra;
 	struct trap_per_cpu *tb;
 	u64 tte_vaddr, tte_data;
 	unsigned long hv_err;
+	int i;
 
-	hdesc = kzalloc(sizeof(*hdesc), GFP_KERNEL);
+	hdesc = kzalloc(sizeof(*hdesc) +
+			(sizeof(struct hvtramp_mapping) *
+			 num_kernel_image_mappings - 1),
+			GFP_KERNEL);
 	if (!hdesc) {
 		printk(KERN_ERR "ldom_startcpu_cpuid: Cannot allocate "
 		       "hvtramp_descr.\n");
@@ -299,7 +302,7 @@ static void ldom_startcpu_cpuid(unsigned int cpu, unsigned long thread_reg)
 	}
 
 	hdesc->cpu = cpu;
-	hdesc->num_mappings = (bigkernel ? 2 : 1);
+	hdesc->num_mappings = num_kernel_image_mappings;
 
 	tb = &trap_block[cpu];
 	tb->hdesc = hdesc;
@@ -312,13 +315,11 @@ static void ldom_startcpu_cpuid(unsigned int cpu, unsigned long thread_reg)
 	tte_vaddr = (unsigned long) KERNBASE;
 	tte_data = kern_locked_tte_data;
 
-	hdesc->maps[0].vaddr = tte_vaddr;
-	hdesc->maps[0].tte   = tte_data;
-	if (bigkernel) {
+	for (i = 0; i < hdesc->num_mappings; i++) {
+		hdesc->maps[i].vaddr = tte_vaddr;
+		hdesc->maps[i].tte   = tte_data;
 		tte_vaddr += 0x400000;
 		tte_data  += 0x400000;
-		hdesc->maps[1].vaddr = tte_vaddr;
-		hdesc->maps[1].tte   = tte_data;
 	}
 
 	trampoline_ra = kimage_addr_to_ra(hv_cpu_startup);