| Message ID | 20220411084357.157308-6-sourabhjain@linux.ibm.com (mailing list archive) |
|---|---|
| State | RFC |
| Headers | show |
| Series | [RFC,v4,1/5] powerpc/kexec: make update_cpus_node non-static | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/github-powerpc_selftests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_ppctests | success | Successfully ran 8 jobs. |
| snowpatch_ozlabs/github-powerpc_kernel_qemu | success | Successfully ran 24 jobs. |
| snowpatch_ozlabs/github-powerpc_sparse | success | Successfully ran 4 jobs. |
| snowpatch_ozlabs/github-powerpc_clang | success | Successfully ran 7 jobs. |
On 11/04/2022, 10:43:57, Sourabh Jain wrote: > The kernel changes needed for crash hotplug support for kexec_load system > calls are similar to kexec_file_load (which has already been implemented > in earlier patches) except for finding the index of the FDT segment in the > kexec segment array. Since the kexec segment array is prepared by the > kexec tool in the userspace, the kernel is not aware of at which index FDT > segment is present. > > Now to enable crash hotplug support for the kexec_load case, the crash > hotplug handler is updated to identify the index at which the FDT segment > is present in the kexec segment array by comparing the first 32 bits of > every kexec segment with the FDT magic number. > > Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> > --- > arch/powerpc/kexec/core_64.c | 22 +++++++++++++++++++++- > 1 file changed, 21 insertions(+), 1 deletion(-) > > diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c > index 62f77cc86407..e3f224f8eb3a 100644 > --- a/arch/powerpc/kexec/core_64.c > +++ b/arch/powerpc/kexec/core_64.c > @@ -480,7 +480,9 @@ int update_cpus_node(void *fdt) > void arch_crash_hotplug_handler(struct kimage *image, unsigned int hp_action, > unsigned long a, unsigned long b) > { > - void *fdt; > + void *fdt, *ptr; > + unsigned int n; > + unsigned long mem, memsz; > > /* No action needed for CPU hot-unplug */ > if (hp_action == KEXEC_CRASH_HP_REMOVE_CPU) > @@ -492,6 +494,24 @@ void arch_crash_hotplug_handler(struct kimage *image, unsigned int hp_action, > return; > } > > + /* Sine kexec segments for kexec_load system call is prepred by Since FWIW, Reviewed-by: Laurent Dufour <ldufour@linux.ibm.com> > + * kexec tool in userspace we need loop through all the segments > + * to find out segment index corresponds FDT segment. In case of > + * kexec_file_load it is discovered during the load itself. > + */ > + if (!image->arch.fdt_index_valid) { > + for (n = 0; n < image->nr_segments; n++) { > + mem = image->segment[n].mem; > + memsz = image->segment[n].memsz; > + ptr = __va(mem); > + if (ptr && fdt_magic(ptr) == FDT_MAGIC) { > + image->arch.fdt_index = n; > + image->arch.fdt_index_valid = true; > + break; > + } > + } > + } > + > /* Must have valid FDT index */ > if (!image->arch.fdt_index_valid) { > pr_err("crash hp: unable to locate FDT segment");
diff --git a/arch/powerpc/kexec/core_64.c b/arch/powerpc/kexec/core_64.c index 62f77cc86407..e3f224f8eb3a 100644 --- a/arch/powerpc/kexec/core_64.c +++ b/arch/powerpc/kexec/core_64.c @@ -480,7 +480,9 @@ int update_cpus_node(void *fdt) void arch_crash_hotplug_handler(struct kimage *image, unsigned int hp_action, unsigned long a, unsigned long b) { - void *fdt; + void *fdt, *ptr; + unsigned int n; + unsigned long mem, memsz; /* No action needed for CPU hot-unplug */ if (hp_action == KEXEC_CRASH_HP_REMOVE_CPU) @@ -492,6 +494,24 @@ void arch_crash_hotplug_handler(struct kimage *image, unsigned int hp_action, return; } + /* Sine kexec segments for kexec_load system call is prepred by + * kexec tool in userspace we need loop through all the segments + * to find out segment index corresponds FDT segment. In case of + * kexec_file_load it is discovered during the load itself. + */ + if (!image->arch.fdt_index_valid) { + for (n = 0; n < image->nr_segments; n++) { + mem = image->segment[n].mem; + memsz = image->segment[n].memsz; + ptr = __va(mem); + if (ptr && fdt_magic(ptr) == FDT_MAGIC) { + image->arch.fdt_index = n; + image->arch.fdt_index_valid = true; + break; + } + } + } + /* Must have valid FDT index */ if (!image->arch.fdt_index_valid) { pr_err("crash hp: unable to locate FDT segment");
The kernel changes needed for crash hotplug support for kexec_load system calls are similar to kexec_file_load (which has already been implemented in earlier patches) except for finding the index of the FDT segment in the kexec segment array. Since the kexec segment array is prepared by the kexec tool in the userspace, the kernel is not aware of at which index FDT segment is present. Now to enable crash hotplug support for the kexec_load case, the crash hotplug handler is updated to identify the index at which the FDT segment is present in the kexec segment array by comparing the first 32 bits of every kexec segment with the FDT magic number. Signed-off-by: Sourabh Jain <sourabhjain@linux.ibm.com> --- arch/powerpc/kexec/core_64.c | 22 +++++++++++++++++++++- 1 file changed, 21 insertions(+), 1 deletion(-)