| Message ID | 20210916231325.125533-6-pasha.tatashin@soleen.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | arm64: MMU enabled kexec relocation | expand |
On Thu, Sep 16, 2021 at 07:13:15PM -0400, Pasha Tatashin wrote: > In case of kdump or when segments are already in place the relocation > is not needed, therefore the setup of relocation function and call to > it can be skipped. > > Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> > Suggested-by: James Morse <james.morse@arm.com> > --- > arch/arm64/kernel/machine_kexec.c | 34 ++++++++++++++++++----------- > arch/arm64/kernel/relocate_kernel.S | 3 --- > 2 files changed, 21 insertions(+), 16 deletions(-) [...] > @@ -188,19 +190,25 @@ void machine_kexec(struct kimage *kimage) > local_daif_mask(); > > /* > - * cpu_soft_restart will shutdown the MMU, disable data caches, then > - * transfer control to the kern_reloc which contains a copy of > - * the arm64_relocate_new_kernel routine. arm64_relocate_new_kernel > - * uses physical addressing to relocate the new image to its final > - * position and transfers control to the image entry point when the > - * relocation is complete. > + * Both restart and cpu_soft_restart will shutdown the MMU, disable data > + * caches. However, restart will start new kernel or purgatory directly, > + * cpu_soft_restart will transfer control to arm64_relocate_new_kernel > * In kexec case, kimage->start points to purgatory assuming that > * kernel entry and dtb address are embedded in purgatory by > * userspace (kexec-tools). > * In kexec_file case, the kernel starts directly without purgatory. > */ > - cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start, > - kimage->arch.dtb_mem); > + if (kimage->head & IND_DONE) { > + typeof(__cpu_soft_restart) *restart; > + > + cpu_install_idmap(); > + restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart)); > + restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem, > + 0, 0); Why can't you call: cpu_soft_restart(kimage->start, kimage->arch.dtb_mem, 0, 0); here instead of open-coding it? Will
Hi Will, > > + cpu_install_idmap(); > > + restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart)); > > + restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem, > > + 0, 0); > > Why can't you call: > > cpu_soft_restart(kimage->start, kimage->arch.dtb_mem, 0, 0); > > here instead of open-coding it? This is part of a cleanup to remove cpu_soft_restart() wrapper and the header file that contains it. The wrapper is simple enough and has only one call site. It makes more sense to do what is needed directly from machine_kexec(). Pasha
diff --git a/arch/arm64/kernel/machine_kexec.c b/arch/arm64/kernel/machine_kexec.c index b6d5a02cba2e..7f1cb5a2a463 100644 --- a/arch/arm64/kernel/machine_kexec.c +++ b/arch/arm64/kernel/machine_kexec.c @@ -144,16 +144,16 @@ int machine_kexec_post_load(struct kimage *kimage) { void *reloc_code = page_to_virt(kimage->control_code_page); - /* If in place flush new kernel image, else flush lists and buffers */ - if (kimage->head & IND_DONE) + /* If in place, relocation is not used, only flush next kernel */ + if (kimage->head & IND_DONE) { kexec_segment_flush(kimage); - else - kexec_list_flush(kimage); + kexec_image_info(kimage); + return 0; + } memcpy(reloc_code, arm64_relocate_new_kernel, arm64_relocate_new_kernel_size); kimage->arch.kern_reloc = __pa(reloc_code); - kexec_image_info(kimage); /* Flush the reloc_code in preparation for its execution. */ dcache_clean_inval_poc((unsigned long)reloc_code, @@ -162,6 +162,8 @@ int machine_kexec_post_load(struct kimage *kimage) icache_inval_pou((uintptr_t)reloc_code, (uintptr_t)reloc_code + arm64_relocate_new_kernel_size); + kexec_list_flush(kimage); + kexec_image_info(kimage); return 0; } @@ -188,19 +190,25 @@ void machine_kexec(struct kimage *kimage) local_daif_mask(); /* - * cpu_soft_restart will shutdown the MMU, disable data caches, then - * transfer control to the kern_reloc which contains a copy of - * the arm64_relocate_new_kernel routine. arm64_relocate_new_kernel - * uses physical addressing to relocate the new image to its final - * position and transfers control to the image entry point when the - * relocation is complete. + * Both restart and cpu_soft_restart will shutdown the MMU, disable data + * caches. However, restart will start new kernel or purgatory directly, + * cpu_soft_restart will transfer control to arm64_relocate_new_kernel * In kexec case, kimage->start points to purgatory assuming that * kernel entry and dtb address are embedded in purgatory by * userspace (kexec-tools). * In kexec_file case, the kernel starts directly without purgatory. */ - cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, kimage->start, - kimage->arch.dtb_mem); + if (kimage->head & IND_DONE) { + typeof(__cpu_soft_restart) *restart; + + cpu_install_idmap(); + restart = (void *)__pa_symbol(function_nocfi(__cpu_soft_restart)); + restart(is_hyp_nvhe(), kimage->start, kimage->arch.dtb_mem, + 0, 0); + } else { + cpu_soft_restart(kimage->arch.kern_reloc, kimage->head, + kimage->start, kimage->arch.dtb_mem); + } BUG(); /* Should never get here. */ } diff --git a/arch/arm64/kernel/relocate_kernel.S b/arch/arm64/kernel/relocate_kernel.S index b78ea5de97a4..8058fabe0a76 100644 --- a/arch/arm64/kernel/relocate_kernel.S +++ b/arch/arm64/kernel/relocate_kernel.S @@ -32,8 +32,6 @@ SYM_CODE_START(arm64_relocate_new_kernel) mov x16, x0 /* x16 = kimage_head */ mov x14, xzr /* x14 = entry ptr */ mov x13, xzr /* x13 = copy dest */ - /* Check if the new image needs relocation. */ - tbnz x16, IND_DONE_BIT, .Ldone raw_dcache_line_size x15, x1 /* x15 = dcache line size */ .Lloop: and x12, x16, PAGE_MASK /* x12 = addr */ @@ -65,7 +63,6 @@ SYM_CODE_START(arm64_relocate_new_kernel) .Lnext: ldr x16, [x14], #8 /* entry = *ptr++ */ tbz x16, IND_DONE_BIT, .Lloop /* while (!(entry & DONE)) */ -.Ldone: /* wait for writes from copy_page to finish */ dsb nsh ic iallu
In case of kdump or when segments are already in place the relocation is not needed, therefore the setup of relocation function and call to it can be skipped. Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Suggested-by: James Morse <james.morse@arm.com> --- arch/arm64/kernel/machine_kexec.c | 34 ++++++++++++++++++----------- arch/arm64/kernel/relocate_kernel.S | 3 --- 2 files changed, 21 insertions(+), 16 deletions(-)