diff options
| -rw-r--r-- | arch/i386/Kconfig | 33 | ||||
| -rw-r--r-- | arch/i386/boot/compressed/head.S | 26 | ||||
| -rw-r--r-- | arch/i386/boot/compressed/misc.c | 7 | ||||
| -rw-r--r-- | arch/i386/kernel/vmlinux.lds.S | 3 | ||||
| -rw-r--r-- | include/asm-i386/boot.h | 6 |
5 files changed, 43 insertions, 32 deletions
diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index d588ca8..fd2fa7a 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -785,23 +785,26 @@ config RELOCATABLE must live at a different physical address than the primary kernel. -config PHYSICAL_START - hex "Physical address where the kernel is loaded" if (EMBEDDED || CRASH_DUMP) - - default "0x1000000" if CRASH_DUMP +config PHYSICAL_ALIGN + hex "Alignment value to which kernel should be aligned" default "0x100000" + range 0x2000 0x400000 help - This gives the physical address where the kernel is loaded. Normally - for regular kernels this value is 0x100000 (1MB). But in the case - of kexec on panic the fail safe kernel needs to run at a different - address than the panic-ed kernel. This option is used to set the load - address for kernels used to capture crash dump on being kexec'ed - after panic. The default value for crash dump kernels is - 0x1000000 (16MB). This can also be set based on the "X" value as - specified in the "crashkernel=YM@XM" command line boot parameter - passed to the panic-ed kernel. Typically this parameter is set as - crashkernel=64M@16M. Please take a look at - Documentation/kdump/kdump.txt for more details about crash dumps. + This value puts the alignment restrictions on physical address + where kernel is loaded and run from. Kernel is compiled for an + address which meets above alignment restriction. + + If bootloader loads the kernel at a non-aligned address and + CONFIG_RELOCATABLE is set, kernel will move itself to nearest + address aligned to above value and run from there. + + If bootloader loads the kernel at a non-aligned address and + CONFIG_RELOCATABLE is not set, kernel will ignore the run time + load address and decompress itself to the address it has been + compiled for and run from there. The address for which kernel is + compiled already meets above alignment restrictions. Hence the + end result is that kernel runs from a physical address meeting + above alignment restrictions. Don't change this unless you know what you are doing. diff --git a/arch/i386/boot/compressed/head.S b/arch/i386/boot/compressed/head.S index e4dd7a6..f395a4b 100644 --- a/arch/i386/boot/compressed/head.S +++ b/arch/i386/boot/compressed/head.S @@ -26,6 +26,7 @@ #include <linux/linkage.h> #include <asm/segment.h> #include <asm/page.h> +#include <asm/boot.h> .section ".text.head" .globl startup_32 @@ -52,17 +53,17 @@ startup_32: 1: popl %ebp subl $1b, %ebp -/* Compute the delta between where we were compiled to run at - * and where the code will actually run at. +/* %ebp contains the address we are loaded at by the boot loader and %ebx + * contains the address where we should move the kernel image temporarily + * for safe in-place decompression. */ - /* Start with the delta to where the kernel will run at. If we are - * a relocatable kernel this is the delta to our load address otherwise - * this is the delta to CONFIG_PHYSICAL start. - */ + #ifdef CONFIG_RELOCATABLE - movl %ebp, %ebx + movl %ebp, %ebx + addl $(CONFIG_PHYSICAL_ALIGN - 1), %ebx + andl $(~(CONFIG_PHYSICAL_ALIGN - 1)), %ebx #else - movl $(CONFIG_PHYSICAL_START - startup_32), %ebx + movl $LOAD_PHYSICAL_ADDR, %ebx #endif /* Replace the compressed data size with the uncompressed size */ @@ -94,9 +95,10 @@ startup_32: /* Compute the kernel start address. */ #ifdef CONFIG_RELOCATABLE - leal startup_32(%ebp), %ebp + addl $(CONFIG_PHYSICAL_ALIGN - 1), %ebp + andl $(~(CONFIG_PHYSICAL_ALIGN - 1)), %ebp #else - movl $CONFIG_PHYSICAL_START, %ebp + movl $LOAD_PHYSICAL_ADDR, %ebp #endif /* @@ -150,8 +152,8 @@ relocated: * and where it was actually loaded. */ movl %ebp, %ebx - subl $CONFIG_PHYSICAL_START, %ebx - + subl $LOAD_PHYSICAL_ADDR, %ebx + jz 2f /* Nothing to be done if loaded at compiled addr. */ /* * Process relocations. */ diff --git a/arch/i386/boot/compressed/misc.c b/arch/i386/boot/compressed/misc.c index 4eac24e..dc15389 100644 --- a/arch/i386/boot/compressed/misc.c +++ b/arch/i386/boot/compressed/misc.c @@ -14,6 +14,7 @@ #include <linux/screen_info.h> #include <asm/io.h> #include <asm/page.h> +#include <asm/boot.h> /* WARNING!! * This code is compiled with -fPIC and it is relocated dynamically @@ -360,12 +361,12 @@ asmlinkage void decompress_kernel(void *rmode, unsigned long end, insize = input_len; inptr = 0; - if (((u32)output - CONFIG_PHYSICAL_START) & 0x3fffff) - error("Destination address not 4M aligned"); + if ((u32)output & (CONFIG_PHYSICAL_ALIGN -1)) + error("Destination address not CONFIG_PHYSICAL_ALIGN aligned"); if (end > ((-__PAGE_OFFSET-(512 <<20)-1) & 0x7fffffff)) error("Destination address too large"); #ifndef CONFIG_RELOCATABLE - if ((u32)output != CONFIG_PHYSICAL_START) + if ((u32)output != LOAD_PHYSICAL_ADDR) error("Wrong destination address"); #endif diff --git a/arch/i386/kernel/vmlinux.lds.S b/arch/i386/kernel/vmlinux.lds.S index f8d61ec..6860f20 100644 --- a/arch/i386/kernel/vmlinux.lds.S +++ b/arch/i386/kernel/vmlinux.lds.S @@ -14,6 +14,7 @@ #include <asm/thread_info.h> #include <asm/page.h> #include <asm/cache.h> +#include <asm/boot.h> OUTPUT_FORMAT("elf32-i386", "elf32-i386", "elf32-i386") OUTPUT_ARCH(i386) @@ -27,7 +28,7 @@ PHDRS { } SECTIONS { - . = LOAD_OFFSET + CONFIG_PHYSICAL_START; + . = LOAD_OFFSET + LOAD_PHYSICAL_ADDR; phys_startup_32 = startup_32 - LOAD_OFFSET; /* read-only */ .text : AT(ADDR(.text) - LOAD_OFFSET) { diff --git a/include/asm-i386/boot.h b/include/asm-i386/boot.h index 96b228e..8ce79a6 100644 --- a/include/asm-i386/boot.h +++ b/include/asm-i386/boot.h @@ -12,4 +12,8 @@ #define EXTENDED_VGA 0xfffe /* 80x50 mode */ #define ASK_VGA 0xfffd /* ask for it at bootup */ -#endif +/* Physical address where kenrel should be loaded. */ +#define LOAD_PHYSICAL_ADDR ((0x100000 + CONFIG_PHYSICAL_ALIGN - 1) \ + & ~(CONFIG_PHYSICAL_ALIGN - 1)) + +#endif /* _LINUX_BOOT_H */ |
