From 8c530ea35caef8bc293b56580ab55352f7d86bfc Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Thu, 31 Mar 2016 10:05:39 +0100 Subject: [PATCH] MIPS: Add CONFIG_RELOCATABLE Kconfig option Add option to KConfig to enable the kernel to relocate itself at runtime. Relocation is supported R2 and later of the MIPS architecture, 32bit and 64bit. The platform is also required to provide support through plat_get_fdt() added in a later patch. Signed-off-by: Matt Redfearn Cc: linux-mips@linux-mips.org Cc: kernel-hardening@lists.openwall.com Cc: linux-kernel@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12987/ Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 18 ++++++++++++++++++ 1 file changed, 18 insertions(+) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index 99ec21f35433..7040a6bcc74f 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -475,6 +475,7 @@ config MIPS_MALTA select SYS_SUPPORTS_MULTITHREADING select SYS_SUPPORTS_SMARTMIPS select SYS_SUPPORTS_ZBOOT + select SYS_SUPPORTS_RELOCATABLE select USE_OF select ZONE_DMA32 if 64BIT select BUILTIN_DTB @@ -519,6 +520,7 @@ config MIPS_SEAD3 select SYS_SUPPORTS_SMARTMIPS select SYS_SUPPORTS_MICROMIPS select SYS_SUPPORTS_MIPS16 + select SYS_SUPPORTS_RELOCATABLE select USB_EHCI_BIG_ENDIAN_DESC select USB_EHCI_BIG_ENDIAN_MMIO select USE_OF @@ -1158,6 +1160,13 @@ config ISA_DMA_API config HOLES_IN_ZONE bool +config SYS_SUPPORTS_RELOCATABLE + bool + help + Selected if the platform supports relocating the kernel. + The platform must provide plat_get_fdt() if it selects CONFIG_USE_OF + to allow access to command line and entropy sources. + # # Endianness selection. Sufficiently obscure so many users don't know what to # answer,so we try hard to limit the available choices. Also the use of a @@ -2473,6 +2482,15 @@ config NUMA config SYS_SUPPORTS_NUMA bool +config RELOCATABLE + bool "Relocatable kernel" + depends on SYS_SUPPORTS_RELOCATABLE && (CPU_MIPS32_R2 || CPU_MIPS64_R2 || CPU_MIPS32_R6 || CPU_MIPS64_R6) + help + This builds a kernel image that retains relocation information + so it can be loaded someplace besides the default 1MB. + The relocations make the kernel binary about 15% larger, + but are discarded at runtime + config RELOCATION_TABLE_SIZE hex "Relocation table size" depends on RELOCATABLE -- 2.20.1