[PATCH 2/2] powerpc/fsl_booke: enable the relocatable for the kdump kernel
From: Kevin Hao <hidden>
Date: 2013-06-27 02:01:24
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Michael Ellerman, Linus Torvalds
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 <redacted> --- 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);
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1.8.1.4