path: root/arch/sh/kernel
diff options
authorPaul Mundt <lethal@linux-sh.org>2010-02-18 18:13:51 +0900
committerPaul Mundt <lethal@linux-sh.org>2010-02-18 18:13:51 +0900
commitd01447b3197c2c470a14666be2c640407bbbfec7 (patch)
tree06d1b83868e4d3971b781b45607b124718ee2ec0 /arch/sh/kernel
parentsh: Use uncached I/O helpers in PMB setup. (diff)
sh: Merge legacy and dynamic PMB modes.
This implements a bit of rework for the PMB code, which permits us to kill off the legacy PMB mode completely. Rather than trusting the boot loader to do the right thing, we do a quick verification of the PMB contents to determine whether to have the kernel setup the initial mappings or whether it needs to mangle them later on instead. If we're booting from legacy mappings, the kernel will now take control of them and make them match the kernel's initial mapping configuration. This is accomplished by breaking the initialization phase out in to multiple steps: synchronization, merging, and resizing. With the recent rework, the synchronization code establishes page links for compound mappings already, so we build on top of this for promoting mappings and reclaiming unused slots. At the same time, the changes introduced for the uncached helpers also permit us to dynamically resize the uncached mapping without any particular headaches. The smallest page size is more than sufficient for mapping all of kernel text, and as we're careful not to jump to any far off locations in the setup code the mapping can safely be resized regardless of whether we are executing from it or not. Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Diffstat (limited to 'arch/sh/kernel')
2 files changed, 40 insertions, 4 deletions
diff --git a/arch/sh/kernel/head_32.S b/arch/sh/kernel/head_32.S
index 79ff39517f8e..fe0b743881b0 100644
--- a/arch/sh/kernel/head_32.S
+++ b/arch/sh/kernel/head_32.S
@@ -85,7 +85,7 @@ ENTRY(_stext)
ldc r0, r7_bank ! ... and initial thread_info
-#if defined(CONFIG_PMB) && !defined(CONFIG_PMB_LEGACY)
+#ifdef CONFIG_PMB
* Reconfigure the initial PMB mappings setup by the hardware.
@@ -139,7 +139,6 @@ ENTRY(_stext)
mov.l r0, @r1
mov.l .LMEMORY_SIZE, r5
- mov r5, r7
mov #PMB_E_SHIFT, r0
mov #0x1, r4
@@ -150,6 +149,40 @@ ENTRY(_stext)
mov.l .LPMB_ADDR, r3
+ /*
+ * First we need to walk the PMB and figure out if there are any
+ * existing mappings that match the initial mappings VPN/PPN.
+ * If these have already been established by the bootloader, we
+ * don't bother setting up new entries here, and let the late PMB
+ * initialization take care of things instead.
+ *
+ * Note that we may need to coalesce and merge entries in order
+ * to reclaim more available PMB slots, which is much more than
+ * we want to do at this early stage.
+ */
+ mov #0, r10
+ mov #NR_PMB_ENTRIES, r9
+ mov r1, r7 /* temporary PMB_DATA iter */
+ mov.l @r7, r8
+ and r0, r8
+ cmp/eq r0, r8 /* Check for valid __MEMORY_START mappings */
+ bt .Lpmb_done
+ add #1, r10 /* Increment the loop counter */
+ cmp/eq r9, r10
+ bf/s .Lvalidate_existing_mappings
+ add r4, r7 /* Increment to the next PMB_DATA entry */
+ /*
+ * If we've fallen through, continue with setting up the initial
+ * mappings.
+ */
+ mov r5, r7 /* cached_to_uncached */
mov #0, r10
@@ -252,7 +285,8 @@ ENTRY(_stext)
mov.l 6f, r0
icbi @r0
-#endif /* !CONFIG_PMB_LEGACY */
+#endif /* CONFIG_PMB */
@@ -304,7 +338,7 @@ ENTRY(stack_start)
6: .long sh_cpu_init
7: .long init_thread_union
-#if defined(CONFIG_PMB) && !defined(CONFIG_PMB_LEGACY)
+#ifdef CONFIG_PMB
diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index e187750dd319..3459e70eed72 100644
--- a/arch/sh/kernel/setup.c
+++ b/arch/sh/kernel/setup.c
@@ -421,6 +421,8 @@ void __init setup_arch(char **cmdline_p)
+ uncached_init();
/* Let earlyprintk output early console messages */