[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 <ebiederm@xmission.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
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@ -369,6 +369,17 @@ config X86_MCE_INTEL
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Additional support for intel specific MCE features such as
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the thermal monitor.
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config PHYSICAL_START
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hex "Physical address where the kernel is loaded" if EMBEDDED
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default "0x100000"
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help
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This gives the physical address where the kernel is loaded.
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Primarily used in the case of kexec on panic where the
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fail safe kernel needs to run at a different address than
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the panic-ed kernel.
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Don't change this unless you know what you are doing.
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config SECCOMP
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bool "Enable seccomp to safely compute untrusted bytecode"
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depends on PROC_FS
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@ -28,6 +28,7 @@
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#include <linux/linkage.h>
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#include <asm/segment.h>
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#include <asm/page.h>
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.code32
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.globl startup_32
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@ -77,7 +78,7 @@ startup_32:
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jnz 3f
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addl $8,%esp
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xorl %ebx,%ebx
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ljmp $(__KERNEL_CS), $0x100000
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ljmp $(__KERNEL_CS), $__PHYSICAL_START
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/*
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* We come here, if we were loaded high.
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@ -103,7 +104,7 @@ startup_32:
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popl %ecx # lcount
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popl %edx # high_buffer_start
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popl %eax # hcount
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movl $0x100000,%edi
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movl $__PHYSICAL_START,%edi
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cli # make sure we don't get interrupted
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ljmp $(__KERNEL_CS), $0x1000 # and jump to the move routine
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@ -128,7 +129,7 @@ move_routine_start:
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movsl
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movl %ebx,%esi # Restore setup pointer
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xorl %ebx,%ebx
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ljmp $(__KERNEL_CS), $0x100000
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ljmp $(__KERNEL_CS), $__PHYSICAL_START
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move_routine_end:
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@ -11,6 +11,7 @@
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#include "miscsetup.h"
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#include <asm/io.h>
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#include <asm/page.h>
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/*
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* gzip declarations
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@ -284,7 +285,7 @@ void setup_normal_output_buffer(void)
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#else
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if ((ALT_MEM_K > EXT_MEM_K ? ALT_MEM_K : EXT_MEM_K) < 1024) error("Less than 2MB of memory");
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#endif
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output_data = (char *)0x100000; /* Points to 1M */
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output_data = (char *)__PHYSICAL_START; /* Normally Points to 1M */
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free_mem_end_ptr = (long)real_mode;
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}
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@ -307,8 +308,8 @@ void setup_output_buffer_if_we_run_high(struct moveparams *mv)
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low_buffer_size = low_buffer_end - LOW_BUFFER_START;
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high_loaded = 1;
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free_mem_end_ptr = (long)high_buffer_start;
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if ( (0x100000 + low_buffer_size) > ((ulg)high_buffer_start)) {
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high_buffer_start = (uch *)(0x100000 + low_buffer_size);
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if ( (__PHYSICAL_START + low_buffer_size) > ((ulg)high_buffer_start)) {
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high_buffer_start = (uch *)(__PHYSICAL_START + low_buffer_size);
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mv->hcount = 0; /* say: we need not to move high_buffer */
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}
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else mv->hcount = -1;
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@ -248,23 +248,23 @@ ENTRY(_stext)
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*/
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.org 0x1000
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ENTRY(init_level4_pgt)
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.quad 0x0000000000102007 /* -> level3_ident_pgt */
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.quad 0x0000000000002007 + __PHYSICAL_START /* -> level3_ident_pgt */
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.fill 255,8,0
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.quad 0x000000000010a007
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.quad 0x000000000000a007 + __PHYSICAL_START
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.fill 254,8,0
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/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
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.quad 0x0000000000103007 /* -> level3_kernel_pgt */
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.quad 0x0000000000003007 + __PHYSICAL_START /* -> level3_kernel_pgt */
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.org 0x2000
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ENTRY(level3_ident_pgt)
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.quad 0x0000000000104007
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.quad 0x0000000000004007 + __PHYSICAL_START
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.fill 511,8,0
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.org 0x3000
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ENTRY(level3_kernel_pgt)
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.fill 510,8,0
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/* (2^48-(2*1024*1024*1024)-((2^39)*511))/(2^30) = 510 */
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.quad 0x0000000000105007 /* -> level2_kernel_pgt */
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.quad 0x0000000000005007 + __PHYSICAL_START /* -> level2_kernel_pgt */
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.fill 1,8,0
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.org 0x4000
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@ -337,17 +337,17 @@ ENTRY(empty_bad_pmd_table)
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.org 0xa000
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ENTRY(level3_physmem_pgt)
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.quad 0x0000000000105007 /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */
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.quad 0x0000000000005007 + __PHYSICAL_START /* -> level2_kernel_pgt (so that __va works even before pagetable_init) */
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.org 0xb000
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#ifdef CONFIG_ACPI_SLEEP
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ENTRY(wakeup_level4_pgt)
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.quad 0x0000000000102007 /* -> level3_ident_pgt */
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.quad 0x0000000000002007 + __PHYSICAL_START /* -> level3_ident_pgt */
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.fill 255,8,0
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.quad 0x000000000010a007
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.quad 0x000000000000a007 + __PHYSICAL_START
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.fill 254,8,0
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/* (2^48-(2*1024*1024*1024))/(2^39) = 511 */
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.quad 0x0000000000103007 /* -> level3_kernel_pgt */
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.quad 0x0000000000003007 + __PHYSICAL_START /* -> level3_kernel_pgt */
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#endif
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.data
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@ -64,12 +64,14 @@ typedef struct { unsigned long pgprot; } pgprot_t;
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#define __pgd(x) ((pgd_t) { (x) } )
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#define __pgprot(x) ((pgprot_t) { (x) } )
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#define __START_KERNEL 0xffffffff80100000UL
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#define __PHYSICAL_START ((unsigned long)CONFIG_PHYSICAL_START)
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#define __START_KERNEL (__START_KERNEL_map + __PHYSICAL_START)
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#define __START_KERNEL_map 0xffffffff80000000UL
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#define __PAGE_OFFSET 0xffff810000000000UL
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#else
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#define __START_KERNEL 0xffffffff80100000
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#define __PHYSICAL_START CONFIG_PHYSICAL_START
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#define __START_KERNEL (__START_KERNEL_map + __PHYSICAL_START)
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#define __START_KERNEL_map 0xffffffff80000000
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#define __PAGE_OFFSET 0xffff810000000000
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#endif /* !__ASSEMBLY__ */
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