Messages in this thread Patch in this message | | | Subject | Re: kexec, x86/purgatory: Cleanup the unholy mess | From | Mike Galbraith <> | Date | Fri, 10 Mar 2017 15:31:48 +0100 |
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On Fri, 2017-03-10 at 14:57 +0100, Thomas Gleixner wrote: > On Fri, 10 Mar 2017, Mike Galbraith wrote: > > On Fri, 2017-03-10 at 13:17 +0100, Thomas Gleixner wrote: > > > The purgatory code defines global variables which are referenced via a > > > symbol lookup in the kexec code (core and arch). > > > > > > A recent commit addressing sparse warning made these static and thereby > > > broke kexec file. > > > > > > Why did this happen? Simply because the whole machinery is undocumented and > > > lacks any form of forward declarations. The variable names are unspecific > > > and lack a prefix, so adding forward declarations creates shadow variables > > > in the core code. Aside of that the code relies on magic constants and > > > duplicate struct definitions with no way to ensure that these things stay > > > in sync. > > > > > > Unbreak kexec and cleanup the mess by: > > > > > > - Adding proper forward declarations and document the usage > > > - Use the proper common defines instead of magic constants > > > - Add a purgatory_ prefix to have a proper name space > > > - Use ARRAY_SIZE() instead of a homebrewn reimplementation > > > > > > Fixes: 72042a8c7b01 ("x86/purgatory: Make functions and variables static") > > > > Well, almost fixes. > > > > [ 15.118820] kexec: symbol 'purgatory_sha_regions' in common section > > [ 15.119187] kexec-bzImage64: Loading purgatory failed > > Bah. /me goes to investigate.
Stuffing the lot into .kexec-purgatory worked.
--- arch/x86/purgatory/purgatory.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)
--- a/arch/x86/purgatory/purgatory.c +++ b/arch/x86/purgatory/purgatory.c @@ -16,13 +16,13 @@ #include "sha256.h" #include "../boot/string.h" -unsigned long purgatory_backup_dest; -unsigned long purgatory_backup_src; -unsigned long purgatory_backup_sz; +unsigned long purgatory_backup_dest __section(.kexec-purgatory); +unsigned long purgatory_backup_src __section(.kexec-purgatory); +unsigned long purgatory_backup_sz __section(.kexec-purgatory); -u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE]; +u8 purgatory_sha256_digest[SHA256_DIGEST_SIZE] __section(.kexec-purgatory); -struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX]; +struct kexec_sha_region purgatory_sha_regions[KEXEC_SEGMENT_MAX] __section(.kexec-purgatory); /* * On x86, second kernel requries first 640K of memory to boot. Copy
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