| Message ID | 20191209104909.14903-1-npiggin@gmail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/2] fast-reboot: don't back up old vectors upon fast reboot | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch master (d75e82dbfbb9443efeb3f9a5921ac23605aab469) |
| snowpatch_ozlabs/snowpatch_job_snowpatch-skiboot | success | Test snowpatch/job/snowpatch-skiboot on branch master |
| snowpatch_ozlabs/snowpatch_job_snowpatch-skiboot-dco | success | Signed-off-by present |
On Mon, Dec 9, 2019 at 9:50 PM Nicholas Piggin <npiggin@gmail.com> wrote: > > Initial boot already saved original exception vectors to old_vectors, > copying again upon fast reboot will overwrite old_vectors with some > arbitrary vectors set up by the current OS. What's this even needed for? Re-entering the previously booted kernel image seems fundamentally sketch and we re-load the kernel anyway. The only thing I can think of is fast-rebooting in mambo and I'm not sure it'll work there either. > Signed-off-by: Nicholas Piggin <npiggin@gmail.com> > --- > core/init.c | 10 +++++----- > 1 file changed, 5 insertions(+), 5 deletions(-) > > diff --git a/core/init.c b/core/init.c > index 339462e5d..1725639f8 100644 > --- a/core/init.c > +++ b/core/init.c > @@ -858,11 +858,6 @@ void copy_sreset_vector_fast_reboot(void) > > void copy_exception_vectors(void) > { > - /* Backup previous vectors as this could contain a kernel > - * image. > - */ > - memcpy_null(old_vectors, NULL, EXCEPTION_VECTORS_END); > - > /* Copy from 0x100 to EXCEPTION_VECTORS_END, avoid below 0x100 as > * this is the boot flag used by CPUs still potentially entering > * skiboot. > @@ -1020,6 +1015,11 @@ void __noreturn __nomcount main_cpu_entry(const void *fdt) > */ > clear_console(); > > + /* Backup previous vectors as this could contain a kernel > + * image. > + */ > + memcpy_null(old_vectors, NULL, EXCEPTION_VECTORS_END); > + > /* > * Some boot firmwares enter OPAL with MSR[ME]=1, as they presumably > * handle machine checks until we take over. As we overwrite the > -- > 2.23.0 > > _______________________________________________ > Skiboot mailing list > Skiboot@lists.ozlabs.org > https://lists.ozlabs.org/listinfo/skiboot
Oliver O'Halloran's on December 10, 2019 10:01 am: > On Mon, Dec 9, 2019 at 9:50 PM Nicholas Piggin <npiggin@gmail.com> wrote: >> >> Initial boot already saved original exception vectors to old_vectors, >> copying again upon fast reboot will overwrite old_vectors with some >> arbitrary vectors set up by the current OS. > > What's this even needed for? Re-entering the previously booted kernel > image seems fundamentally sketch and we re-load the kernel anyway. The > only thing I can think of is fast-rebooting in mambo and I'm not sure > it'll work there either. Yeah I'm not too sure. Whatever it was for is definitely broken with fast reboot. Fast reboot with a kernel at zero might still be broken for other reasons, but it won't be for this at least :P Thanks, Nick
diff --git a/core/init.c b/core/init.c index 339462e5d..1725639f8 100644 --- a/core/init.c +++ b/core/init.c @@ -858,11 +858,6 @@ void copy_sreset_vector_fast_reboot(void) void copy_exception_vectors(void) { - /* Backup previous vectors as this could contain a kernel - * image. - */ - memcpy_null(old_vectors, NULL, EXCEPTION_VECTORS_END); - /* Copy from 0x100 to EXCEPTION_VECTORS_END, avoid below 0x100 as * this is the boot flag used by CPUs still potentially entering * skiboot. @@ -1020,6 +1015,11 @@ void __noreturn __nomcount main_cpu_entry(const void *fdt) */ clear_console(); + /* Backup previous vectors as this could contain a kernel + * image. + */ + memcpy_null(old_vectors, NULL, EXCEPTION_VECTORS_END); + /* * Some boot firmwares enter OPAL with MSR[ME]=1, as they presumably * handle machine checks until we take over. As we overwrite the
Initial boot already saved original exception vectors to old_vectors, copying again upon fast reboot will overwrite old_vectors with some arbitrary vectors set up by the current OS. Signed-off-by: Nicholas Piggin <npiggin@gmail.com> --- core/init.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-)