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| author | Hari Bathini <hbathini@linux.ibm.com> | 2020-07-29 13:42:58 +0200 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2020-07-29 15:47:54 +0200 |
| commit | 1a1cf93c200581c72a3cd521e1e0a1a3b5d0077d (patch) | |
| tree | cb3c966e21b0bd1d04a7d33fa2199d5d1109a2ae /arch/powerpc/purgatory | |
| parent | powerpc/kexec_file: Restrict memory usage of kdump kernel (diff) | |
| download | linux-1a1cf93c200581c72a3cd521e1e0a1a3b5d0077d.tar.xz linux-1a1cf93c200581c72a3cd521e1e0a1a3b5d0077d.zip | |
powerpc/kexec_file: Setup backup region for kdump kernel
Though kdump kernel boots from loaded address, the first 64KB of it is
copied down to real 0. So, setup a backup region and let purgatory
copy the first 64KB of crashed kernel into this backup region before
booting into kdump kernel. Update reserve map with backup region and
crashed kernel's memory to avoid kdump kernel from accidentially using
that memory.
Signed-off-by: Hari Bathini <hbathini@linux.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159602294718.575379.16216507537038008623.stgit@hbathini
Diffstat (limited to 'arch/powerpc/purgatory')
| -rw-r--r-- | arch/powerpc/purgatory/trampoline_64.S | 38 |
1 files changed, 34 insertions, 4 deletions
diff --git a/arch/powerpc/purgatory/trampoline_64.S b/arch/powerpc/purgatory/trampoline_64.S index a5a83c3f53e6..b567da56dde1 100644 --- a/arch/powerpc/purgatory/trampoline_64.S +++ b/arch/powerpc/purgatory/trampoline_64.S @@ -10,6 +10,7 @@ */ #include <asm/asm-compat.h> +#include <asm/crashdump-ppc64.h> .machine ppc64 .balign 256 @@ -43,14 +44,39 @@ master: mr %r17,%r3 /* save cpu id to r17 */ mr %r15,%r4 /* save physical address in reg15 */ + /* Work out where we're running */ + bcl 20, 31, 0f +0: mflr %r18 + + /* + * Copy BACKUP_SRC_SIZE bytes from BACKUP_SRC_START to + * backup_start 8 bytes at a time. + * + * Use r3 = dest, r4 = src, r5 = size, r6 = count + */ + ld %r3, (backup_start - 0b)(%r18) + cmpdi %cr0, %r3, 0 + beq .Lskip_copy /* skip if there is no backup region */ + lis %r5, BACKUP_SRC_SIZE@h + ori %r5, %r5, BACKUP_SRC_SIZE@l + cmpdi %cr0, %r5, 0 + beq .Lskip_copy /* skip if copy size is zero */ + lis %r4, BACKUP_SRC_START@h + ori %r4, %r4, BACKUP_SRC_START@l + li %r6, 0 +.Lcopy_loop: + ldx %r0, %r6, %r4 + stdx %r0, %r6, %r3 + addi %r6, %r6, 8 + cmpld %cr0, %r6, %r5 + blt .Lcopy_loop + +.Lskip_copy: or %r3,%r3,%r3 /* ok now to high priority, lets boot */ lis %r6,0x1 mtctr %r6 /* delay a bit for slaves to catch up */ bdnz . /* before we overwrite 0-100 again */ - bl 0f /* Work out where we're running */ -0: mflr %r18 - /* load device-tree address */ ld %r3, (dt_offset - 0b)(%r18) mr %r16,%r3 /* save dt address in reg16 */ @@ -89,7 +115,6 @@ master: rfid /* update MSR and start kernel */ - .balign 8 .globl kernel kernel: @@ -102,6 +127,11 @@ dt_offset: .8byte 0x0 .size dt_offset, . - dt_offset + .balign 8 + .globl backup_start +backup_start: + .8byte 0x0 + .size backup_start, . - backup_start .data .balign 8 |