Support for relocatable kernel in kexec-tools This patch is based on the patch sent by Milton Miller with the subject [PATCH 1/2 kexec-tools] ppc64: new relocatble kernel activation ABI http://patchwork.ozlabs.org/patch/5378/ Even with the above patch, the relocatable kernel always move to physical address 0 (ie PHYSICAL_START). Following patch fixes this problem by marking a local variable to 1 in purgatory during kdump kernel load time (kexec -p). After a crash, purgatory sets __run_at_load variable location in the kernel to 1 if the local variable is set to 1. So that the kernel will be running as a relocatable kernel. Signed-off-by: M. Mohan Kumar <mohan at in.ibm.com> Signed-off-by: Milton Miller <miltonm at bga.com> --- kexec/arch/ppc64/crashdump-ppc64.h | 2 ++ kexec/arch/ppc64/kexec-elf-ppc64.c | 17 +++++++++++++++++ purgatory/arch/ppc64/v2wrap.S | 25 ++++++++++++------------- 3 files changed, 31 insertions(+), 13 deletions(-) diff --git a/kexec/arch/ppc64/crashdump-ppc64.h b/kexec/arch/ppc64/crashdump-ppc64.h index 9608782..be02213 100644 --- a/kexec/arch/ppc64/crashdump-ppc64.h +++ b/kexec/arch/ppc64/crashdump-ppc64.h @@ -23,6 +23,8 @@ void add_usable_mem_rgns(unsigned long long base, unsigned long long size); #define _ALIGN_UP(addr,size) (((addr)+((size)-1))&(~((size)-1))) #define _ALIGN_DOWN(addr,size) ((addr)&(~((size)-1))) +#define KERNEL_RUN_AT_ZERO_MAGIC 0x72756e30 /* "run0" */ + extern uint64_t crash_base; extern uint64_t crash_size; extern unsigned int rtas_base; diff --git a/kexec/arch/ppc64/kexec-elf-ppc64.c b/kexec/arch/ppc64/kexec-elf-ppc64.c index d72550d..870315e 100644 --- a/kexec/arch/ppc64/kexec-elf-ppc64.c +++ b/kexec/arch/ppc64/kexec-elf-ppc64.c @@ -93,6 +93,7 @@ int elf_ppc64_load(int argc, char **argv, const char *buf, off_t len, uint64_t my_stack, my_backup_start; uint64_t toc_addr; unsigned int slave_code[256/sizeof (unsigned int)], master_entry; + unsigned int run_at_load; #define OPT_APPEND (OPT_ARCH_MAX+0) #define OPT_RAMDISK (OPT_ARCH_MAX+1) @@ -307,6 +308,18 @@ int elf_ppc64_load(int argc, char **argv, const char *buf, off_t len, my_backup_start = info->backup_start; elf_rel_set_symbol(&info->rhdr, "backup_start", &my_backup_start, sizeof(my_backup_start)); + + /* Tell relocatable kernel to run at load address + * via word before slave code in purgatory + */ + + elf_rel_get_symbol(&info->rhdr, "run_at_load", &run_at_load, + sizeof(run_at_load)); + if (run_at_load == KERNEL_RUN_AT_ZERO_MAGIC) + run_at_load = 1; + /* else it should be a fixed offset image */ + elf_rel_set_symbol(&info->rhdr, "run_at_load", &run_at_load, + sizeof(run_at_load)); } /* Set stack address */ @@ -325,10 +338,13 @@ int elf_ppc64_load(int argc, char **argv, const char *buf, off_t len, my_backup_start = 0; my_stack = 0; toc_addr = 0; + run_at_load = 0; elf_rel_get_symbol(&info->rhdr, "kernel", &my_kernel, sizeof(my_kernel)); elf_rel_get_symbol(&info->rhdr, "dt_offset", &my_dt_offset, sizeof(my_dt_offset)); + elf_rel_get_symbol(&info->rhdr, "run_at_load", &run_at_load, + sizeof(run_at_load)); elf_rel_get_symbol(&info->rhdr, "panic_kernel", &my_panic_kernel, sizeof(my_panic_kernel)); elf_rel_get_symbol(&info->rhdr, "backup_start", &my_backup_start, @@ -341,6 +357,7 @@ int elf_ppc64_load(int argc, char **argv, const char *buf, off_t len, fprintf(stderr, "kernel is %llx\n", (unsigned long long)my_kernel); fprintf(stderr, "dt_offset is %llx\n", (unsigned long long)my_dt_offset); + fprintf(stderr, "run_at_load flag is %x\n", run_at_load); fprintf(stderr, "panic_kernel is %x\n", my_panic_kernel); fprintf(stderr, "backup_start is %llx\n", (unsigned long long)my_backup_start); diff --git a/purgatory/arch/ppc64/v2wrap.S b/purgatory/arch/ppc64/v2wrap.S index f69dad2..78b6eec 100644 --- a/purgatory/arch/ppc64/v2wrap.S +++ b/purgatory/arch/ppc64/v2wrap.S @@ -45,11 +45,14 @@ oris rn,rn,name##@h; \ ori rn,rn,name##@l -#define KDUMP_SIGNATURE 0xfeed1234 - .machine ppc64 .globl purgatory_start purgatory_start: b master + .org purgatory_start + 0x5c # ABI: possible run_at_load flag at 0x5c +run_at_load: + .globl run_at_load + .long 0 + .size run_at_load, . - run_at_load .org purgatory_start + 0x60 # ABI: slaves start at 60 with r3=phys slave: b $ .org purgatory_start + 0x100 # ABI: end of copied region @@ -65,7 +68,6 @@ master: isync mr 17,3 # save cpu id to r17 mr 15,4 # save physical address in reg15 - mr 18,6 # save kdump flag in reg18 LOADADDR(6,my_toc) ld 2,0(6) #setup toc @@ -96,14 +98,11 @@ master: mtctr 4 # prepare branch too mr 3,16 # restore dt address - LOADADDR(6,KDUMP_SIGNATURE) - cmpd 18,6 - bne regular - li 7,1 - std 7,24(4) # mark kdump flag at kernel -regular: - lwz 7,0(4) # get the first instruction that we stole - stw 7,0(0) # and put it in the slave loop at 0 - # skip cache flush, do we care? - + LOADADDR(6,run_at_load) # load the run_at_load address + lwz 18,0(6) # it will be 1 for kdump kernel + cmpwi 18,1 + bne skip + li 7,1 # if its kdump kernel, mark it + stw 7,92(4) # in kernel +skip: bctr # start kernel -- 1.6.0.6
