When SPARSEMEM and CRASH_DUMP both selected, simple pfn_valid prevents the second kernel ioremap first kernel's memory if the address falls into second kernel section. This limitation requires the second kernel occupies a full section, and elfcorehdr must resides in another section. This patch makes crash dump kernel use strict pfn_valid, removes such limitation. For example: For a platform with SECTION_SIZE_BITS == 28 (256MiB) and crashkernel=128M at 0x28000000 in kernel cmdline, the second kernel is loaded at 0x28000000. Kexec puts elfcorehdr at 0x2ff00000, and passes 'elfcorehdr=0x2ff00000 mem=130048K' to second kernel. When second kernel start, it tries to use ioremap to retrive its elfcorehrd. In this case, elfcodehdr is at the same section of the second kernel, pfn_valid will recongnize the page as valid, so ioremap will refuse to map it. Signed-off-by: Wang Nan <wangnan0 at huawei.com> Cc: Geng Hui <hui.geng at huawei.com> --- I have sent this patch once, but get no response. Resend with commit message update. --- arch/arm/Kconfig | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig index db3c541..795b1d4 100644 --- a/arch/arm/Kconfig +++ b/arch/arm/Kconfig @@ -1800,7 +1800,7 @@ config ARCH_SELECT_MEMORY_MODEL def_bool ARCH_SPARSEMEM_ENABLE config HAVE_ARCH_PFN_VALID - def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM + def_bool ARCH_HAS_HOLES_MEMORYMODEL || !SPARSEMEM || CRASH_DUMP config HIGHMEM bool "High Memory Support" -- 1.8.4
