Le 10/12/2013 23:24, Scott Wood a écrit :
On Tue, 2013-12-10 at 12:29 +0100, Christophe Leroy wrote:
Today, the only way to load kernels whose size is greater than 8Mbytes is to
activate CONFIG_PIN_TLB. Otherwise, the physical memory initially mapped is
limited to 8Mbytes. This patch adds the capability to select the size of initial
memory between 8/16/24 Mbytes and this is regardless of whether CONFIG_PIN_TLB
is active or not. It allows to load "big" kernels (for instance when activating
CONFIG_LOCKDEP_SUPPORT) without having to activate CONFIG_PIN_TLB.
Signed-off-by: Christophe Leroy <christophe.le...@c-s.fr>
diff -ur a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -980,6 +980,29 @@
config PIN_TLB
bool "Pinned Kernel TLBs (860 ONLY)"
depends on ADVANCED_OPTIONS && 8xx
+
+choice
+ prompt "Initial Data Memory Mapped on 8xx"
+ default 8xx_MAP_8M
+ depends on ADVANCED_OPTIONS && 8xx
+
+config 8xx_INIT_MAP_8M
+ bool "8 Mbytes"
+
+config 8xx_INIT_MAP_16M
+ bool "16 Mbytes"
+
+config 8xx_INIT_MAP_24M
+ bool "24 Mbytes"
Are you working with a loader that passes initial-mapped-area size in r7
as per ePAPR? If so, we could rely on that at runtime. If you're using
a non-ancient U-Boot, it should qualify here even if it's not fully
ePAPR compliant (it passes the value of the bootm_mapsize variable in
r7).
Ok, let me check that. But it means that the size of the kernel I can
boot will depend on the initial memory mapped by uboot ? Isn't it
limitating ?
Even if uboot only maps 8Mbytes, why couldn't I be allowed to boot a
kernel having 10 Mbytes data if I have 32 Mbytes mem on the board ?
I don't like the idea of having to change the bootloader just because I
want to activate CONFIG_LOCKDEP to debug my kernel.
-#ifdef CONFIG_PIN_TLB
+#if defined (CONFIG_8xx_INIT_MAP_16M) || defined (CONFIG_8xx_INIT_MAP_24M)
/* Map two more 8M kernel data pages.
*/
+#ifdef CONFIG_PIN_TLB
addi r10, r10, 0x0100
mtspr SPRN_MD_CTR, r10
+#endif
lis r8, KERNELBASE@h /* Create vaddr for TLB */
addis r8, r8, 0x0080 /* Add 8M */
@@ -858,15 +860,19 @@
addis r11, r11, 0x0080 /* Add 8M */
mtspr SPRN_MD_RPN, r11
+#ifdef CONFIG_8xx_INIT_MAP_24M
+#ifdef CONFIG_PIN_TLB
addi r10, r10, 0x0100
mtspr SPRN_MD_CTR, r10
+#endif
Are these ifdefs for CONFIG_PIN_TLB really needed? It shouldn't harm
anything to use those entries even if they're not being pinned.
I'm not sure I understand your comment.
ifdef for CONFIG_PIN_TLB was already there before, but was enclosing the
whole block, so 24 Mbytes were automatically mapped when you selected
CONFIG_PIN_TLB and only 8 Mbytes were mapped when you didn't select
CONFIG_PIN_TLB.
I reduced the scope of those ifdefs so that they now apply on the
pinning only.
Christophe
_______________________________________________
Linuxppc-dev mailing list
Linuxppc-dev@lists.ozlabs.org
https://lists.ozlabs.org/listinfo/linuxppc-dev
