For a relocatable kdump kernel, we may create a tlb map which is
beyond the real memory allocated to the kdump kernel. For example,
when the boot kernel reserve 32M memory for the kdump kernel by
using 'crashkernel=32M@64M', we will have to create a 256M tlb
entry in the kdump kernel. So define PPC_PIN_SIZE for fsl ppc32 bit,
this will make sure that we still get the right VMALLOC_START in
this case.
Signed-off-by: Kevin Hao <haoke...@gmail.com>
---
arch/powerpc/Kconfig | 3 +--
arch/powerpc/include/asm/mmu-book3e.h | 5 +++++
arch/powerpc/mm/fsl_booke_mmu.c | 30 +++++++++++++++++++++++++++---
3 files changed, 33 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 9eb97ac..ca237f5 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -382,8 +382,7 @@ config KEXEC
config CRASH_DUMP
bool "Build a kdump crash kernel"
depends on PPC64 || 6xx || FSL_BOOKE || (44x && !SMP)
- select RELOCATABLE if PPC64 || 44x
- select DYNAMIC_MEMSTART if FSL_BOOKE
+ select RELOCATABLE if PPC64 || 44x || FSL_BOOKE
help
Build a kernel suitable for use as a kdump capture kernel.
The same kernel binary can be used as production kernel and dump
diff --git a/arch/powerpc/include/asm/mmu-book3e.h
b/arch/powerpc/include/asm/mmu-book3e.h
index 936db36..bf422db 100644
--- a/arch/powerpc/include/asm/mmu-book3e.h
+++ b/arch/powerpc/include/asm/mmu-book3e.h
@@ -214,6 +214,11 @@
#define TLBILX_T_CLASS2 6
#define TLBILX_T_CLASS3 7
+#ifdef CONFIG_PPC32
+/* The max size that one tlb can map in a 32bit kernel. */
+#define PPC_PIN_SIZE (1 << 28) /* 256M */
+#endif
+
#ifndef __ASSEMBLY__
#include <asm/bug.h>
diff --git a/arch/powerpc/mm/fsl_booke_mmu.c b/arch/powerpc/mm/fsl_booke_mmu.c
index 07ba45b..59549b3 100644
--- a/arch/powerpc/mm/fsl_booke_mmu.c
+++ b/arch/powerpc/mm/fsl_booke_mmu.c
@@ -52,6 +52,7 @@
#include <asm/smp.h>
#include <asm/machdep.h>
#include <asm/setup.h>
+#include <asm/sections.h>
#include "mmu_decl.h"
@@ -177,11 +178,34 @@ unsigned long map_mem_in_cams(unsigned long ram, int
max_cam_idx)
unsigned long virt = PAGE_OFFSET;
phys_addr_t phys = memstart_addr;
unsigned long amount_mapped = 0;
-
+ unsigned long cam_sz;
+
+#if defined(CONFIG_RELOCATABLE) && defined(CONFIG_PPC32)
+ /*
+ * For a relocatable kernel, we would not map from memstart_addr.
+ * We first align to PPC_PIN_SIZE (256M), then map the PAGE_OFFSET
+ * from there.
+ */
+ phys &= ~(PPC_PIN_SIZE - 1);
+ ram += memstart_addr & (PPC_PIN_SIZE - 1);
+
+ /*
+ * For a kdump kernel, we may use a memory area reserved by the boot
+ * kernel by using a kernel option like this 'crashkernel=32M@64M'.
+ * In this case, the ram is 96M. The kernel will try to map the first
+ * 64M in the first tlb entry. The kernel will definitely get stuck,
+ * since the kernel is running above the 64M. So we have to make sure
+ * that the first tlb cover the current kernel running address at least.
+ */
+ while (1) {
+ cam_sz = calc_cam_sz(ram, virt, phys);
+ if (cam_sz + phys > PHYSICAL_START + _end - _stext)
+ break;
+ ram = 1 << (ilog2(ram) + 1);
+ }
+#endif
/* Calculate CAM values */
for (i = 0; ram && i < max_cam_idx; i++) {
- unsigned long cam_sz;
-
cam_sz = calc_cam_sz(ram, virt, phys);
settlbcam(i, virt, phys, cam_sz, PAGE_KERNEL_X, 0);
--
1.8.1.4
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