From d0537508a9921efced238b20967e50e519ac34af Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Sat, 25 Jun 2005 14:57:52 -0700 Subject: [PATCH] [PATCH] kexec: x86_64: add CONFIG_PHYSICAL_START For one kernel to report a crash another kernel has created we need to have 2 kernels loaded simultaneously in memory. To accomplish this the two kernels need to built to run at different physical addresses. This patch adds the CONFIG_PHYSICAL_START option to the x86_64 kernel so we can do just that. You need to know what you are doing and the ramifications are before changing this value, and most users won't care so I have made it depend on CONFIG_EMBEDDED bzImage kernels will work and run at a different address when compiled with this option but they will still load at 1MB. If you need a kernel loaded at a different address as well you need to boot a vmlinux. Signed-off-by: Eric Biederman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- arch/x86_64/Kconfig | 11 +++++++++++ arch/x86_64/boot/compressed/head.S | 7 ++++--- arch/x86_64/boot/compressed/misc.c | 7 ++++--- arch/x86_64/kernel/head.S | 18 +++++++++--------- include/asm-x86_64/page.h | 6 ++++-- 5 files changed, 32 insertions(+), 17 deletions(-) diff --git a/arch/x86_64/Kconfig b/arch/x86_64/Kconfig index a853d87ff7e..56c02cf6397 100644 --- a/arch/x86_64/Kconfig +++ b/arch/x86_64/Kconfig @@ -369,6 +369,17 @@ config X86_MCE_INTEL Additional support for intel specific MCE features such as the thermal monitor. +config PHYSICAL_START + hex "Physical address where the kernel is loaded" if EMBEDDED + default "0x100000" + help + This gives the physical address where the kernel is loaded. + Primarily used in the case of kexec on panic where the + fail safe kernel needs to run at a different address than + the panic-ed kernel. + + Don't change this unless you know what you are doing. + config SECCOMP bool "Enable seccomp to safely compute untrusted bytecode" depends on PROC_FS diff --git a/arch/x86_64/boot/compressed/head.S b/arch/x86_64/boot/compressed/head.S index 27264dbd575..b0df2aeff5d 100644 --- a/arch/x86_64/boot/compressed/head.S +++ b/arch/x86_64/boot/compressed/head.S @@ -28,6 +28,7 @@ #include #include +#include .code32 .globl startup_32 @@ -77,7 +78,7 @@ startup_32: jnz 3f addl $8,%esp xorl %ebx,%ebx - ljmp $(__KERNEL_CS), $0x100000 + ljmp $(__KERNEL_CS), $__PHYSICAL_START /* * We come here, if we were loaded high. @@ -103,7 +104,7 @@ startup_32: popl %ecx # lcount popl %edx # high_buffer_start popl %eax # hcount - movl $0x100000,%edi + movl $__PHYSICAL_START,%edi cli # make sure we don't get interrupted ljmp $(__KERNEL_CS), $0x1000 # and jump to the move routine @@ -128,7 +129,7 @@ move_routine_start: movsl movl %ebx,%esi # Restore setup pointer xorl %ebx,%ebx - ljmp $(__KERNEL_CS), $0x100000 + ljmp $(__KERNEL_CS), $__PHYSICAL_START move_routine_end: diff --git a/arch/x86_64/boot/compressed/misc.c b/arch/x86_64/boot/compressed/misc.c index c8b9216f9e6..c43cedb5c1d 100644 --- a/arch/x86_64/boot/compressed/misc.c +++ b/arch/x86_64/boot/compressed/misc.c @@ -11,6 +11,7 @@ #include "miscsetup.h" #include +#include /* * gzip declarations @@ -284,7 +285,7 @@ void setup_normal_output_buffer(void) #else if ((ALT_MEM_K > EXT_MEM_K ? ALT_MEM_K : EXT_MEM_K) < 1024) error("Less than 2MB of memory"); #endif - output_data = (char *)0x100000; /* Points to 1M */ + output_data = (char *)__PHYSICAL_START; /* Normally Points to 1M */ free_mem_end_ptr = (long)real_mode; } @@ -307,8 +308,8 @@ void setup_output_buffer_if_we_run_high(struct moveparams *mv) low_buffer_size = low_buffer_end - LOW_BUFFER_START; high_loaded = 1; free_mem_end_ptr = (long)high_buffer_start; - if ( (0x100000 + low_buffer_size) > ((ulg)high_buffer_start)) { - high_buffer_start = (uch *)(0x100000 + low_buffer_size); + if ( (__PHYSICAL_START + low_buffer_size) > ((ulg)high_buffer_start)) { + high_buffer_start = (uch *)(__PHYSICAL_START + low_buffer_size); mv->hcount = 0; /* say: we need not to move high_buffer */ } else mv->hcount = -1; diff --git a/arch/x86_64/kernel/head.S b/arch/x86_64/kernel/head.S index 9bd2e7a4b81..8d765aa77a2 100644 --- a/arch/x86_64/kernel/head.S +++ b/arch/x86_64/kernel/head.S @@ -248,23 +248,23 @@ ENTRY(_stext) */ .org 0x1000 ENTRY(init_level4_pgt) - .quad 0x0000000000102007 /* -> level3_ident_pgt */ + .quad 0x0000000000002007 + __PHYSICAL_START /* -> level3_ident_pgt */ .fill 255,8,0 - .quad 0x000000000010a007 + .quad 0x000000000000a007 + __PHYSICAL_START .fill 254,8,0 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ - .quad 0x0000000000103007 /* -> level3_kernel_pgt */ + .quad 0x0000000000003007 + __PHYSICAL_START /* -> level3_kernel_pgt */ .org 0x2000 ENTRY(level3_ident_pgt) - .quad 0x0000000000104007 + .quad 0x0000000000004007 + __PHYSICAL_START .fill 511,8,0 .org 0x3000 ENTRY(level3_kernel_pgt) .fill 510,8,0 /* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */ - .quad 0x0000000000105007 /* -> level2_kernel_pgt */ + .quad 0x0000000000005007 + __PHYSICAL_START /* -> level2_kernel_pgt */ .fill 1,8,0 .org 0x4000 @@ -337,17 +337,17 @@ ENTRY(empty_bad_pmd_table) .org 0xa000 ENTRY(level3_physmem_pgt) - .quad 0x0000000000105007 /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */ + .quad 0x0000000000005007 + __PHYSICAL_START /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */ .org 0xb000 #ifdef CONFIG_ACPI_SLEEP ENTRY(wakeup_level4_pgt) - .quad 0x0000000000102007 /* -> level3_ident_pgt */ + .quad 0x0000000000002007 + __PHYSICAL_START /* -> level3_ident_pgt */ .fill 255,8,0 - .quad 0x000000000010a007 + .quad 0x000000000000a007 + __PHYSICAL_START .fill 254,8,0 /* (2^48-(2*1024*1024*1024))/(2^39) = 511 */ - .quad 0x0000000000103007 /* -> level3_kernel_pgt */ + .quad 0x0000000000003007 + __PHYSICAL_START /* -> level3_kernel_pgt */ #endif .data diff --git a/include/asm-x86_64/page.h b/include/asm-x86_64/page.h index 60130f4ca98..431318764af 100644 --- a/include/asm-x86_64/page.h +++ b/include/asm-x86_64/page.h @@ -64,12 +64,14 @@ typedef struct { unsigned long pgprot; } pgprot_t; #define __pgd(x) ((pgd_t) { (x) } ) #define __pgprot(x) ((pgprot_t) { (x) } ) -#define __START_KERNEL 0xffffffff80100000UL +#define __PHYSICAL_START ((unsigned long)CONFIG_PHYSICAL_START) +#define __START_KERNEL (__START_KERNEL_map + __PHYSICAL_START) #define __START_KERNEL_map 0xffffffff80000000UL #define __PAGE_OFFSET 0xffff810000000000UL #else -#define __START_KERNEL 0xffffffff80100000 +#define __PHYSICAL_START CONFIG_PHYSICAL_START +#define __START_KERNEL (__START_KERNEL_map + __PHYSICAL_START) #define __START_KERNEL_map 0xffffffff80000000 #define __PAGE_OFFSET 0xffff810000000000 #endif /* !__ASSEMBLY__ */ -- 2.41.1