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Message-Id: <20221124-kexec-noalloc-v1-0-d78361e99aec@chromium.org> Date: Thu, 24 Nov 2022 23:23:36 +0100 From: Ricardo Ribalda <ribalda@...omium.org> To: Eric Biederman <ebiederm@...ssion.com> Cc: Baoquan He <bhe@...hat.com>, Philipp Rudo <prudo@...hat.com>, Sergey Senozhatsky <senozhatsky@...omium.org>, Ross Zwisler <zwisler@...nel.org>, kexec@...ts.infradead.org, linux-kernel@...r.kernel.org, Ricardo Ribalda <ribalda@...omium.org> Subject: [PATCH] kexec: Enable runtime allocation of crash_image Usually crash_image is defined statically via the crashkernel parameter or DT. But if the crash kernel is not used, or is smaller than then area pre-allocated that memory is wasted. Also, if the crash kernel was not defined at bootime, there is no way to use the crash kernel. Enable runtime allocation of the crash_image if the crash_image is not defined statically. Following the same memory allocation/validation path that for the reboot kexec kernel. Signed-off-by: Ricardo Ribalda <ribalda@...omium.org> --- kexec: Enable runtime allocation of crash_image To: Eric Biederman <ebiederm@...ssion.com> Cc: kexec@...ts.infradead.org Cc: linux-kernel@...r.kernel.org Cc: Sergey Senozhatsky <senozhatsky@...omium.org> Cc: linux-kernel@...r.kernel.org Cc: Ross Zwisler <zwisler@...nel.org> Cc: Philipp Rudo <prudo@...hat.com> Cc: Baoquan He <bhe@...hat.com> --- include/linux/kexec.h | 1 + kernel/kexec.c | 9 +++++---- kernel/kexec_core.c | 5 +++++ kernel/kexec_file.c | 7 ++++--- 4 files changed, 15 insertions(+), 7 deletions(-) diff --git a/include/linux/kexec.h b/include/linux/kexec.h index 41a686996aaa..98ca9a32bc8e 100644 --- a/include/linux/kexec.h +++ b/include/linux/kexec.h @@ -427,6 +427,7 @@ extern int kexec_load_disabled; extern bool kexec_in_progress; int crash_shrink_memory(unsigned long new_size); +bool __crash_memory_valid(void); ssize_t crash_get_memory_size(void); #ifndef arch_kexec_protect_crashkres diff --git a/kernel/kexec.c b/kernel/kexec.c index cb8e6e6f983c..b5c17db25e88 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -28,7 +28,7 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry, struct kimage *image; bool kexec_on_panic = flags & KEXEC_ON_CRASH; - if (kexec_on_panic) { + if (kexec_on_panic && __crash_memory_valid()) { /* Verify we have a valid entry point */ if ((entry < phys_to_boot_phys(crashk_res.start)) || (entry > phys_to_boot_phys(crashk_res.end))) @@ -44,7 +44,7 @@ static int kimage_alloc_init(struct kimage **rimage, unsigned long entry, image->nr_segments = nr_segments; memcpy(image->segment, segments, nr_segments * sizeof(*segments)); - if (kexec_on_panic) { + if (kexec_on_panic && __crash_memory_valid()) { /* Enable special crash kernel control page alloc policy. */ image->control_page = crashk_res.start; image->type = KEXEC_TYPE_CRASH; @@ -101,7 +101,7 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, if (flags & KEXEC_ON_CRASH) { dest_image = &kexec_crash_image; - if (kexec_crash_image) + if (kexec_crash_image && __crash_memory_valid()) arch_kexec_unprotect_crashkres(); } else { dest_image = &kexec_image; @@ -157,7 +157,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, image = xchg(dest_image, image); out: - if ((flags & KEXEC_ON_CRASH) && kexec_crash_image) + if ((flags & KEXEC_ON_CRASH) && kexec_crash_image && + __crash_memory_valid()) arch_kexec_protect_crashkres(); kimage_free(image); diff --git a/kernel/kexec_core.c b/kernel/kexec_core.c index ca2743f9c634..77083c9760fb 100644 --- a/kernel/kexec_core.c +++ b/kernel/kexec_core.c @@ -1004,6 +1004,11 @@ void crash_kexec(struct pt_regs *regs) } } +bool __crash_memory_valid(void) +{ + return crashk_res.end != crashk_res.start; +} + ssize_t crash_get_memory_size(void) { ssize_t size = 0; diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 45637511e0de..0671f4f370ff 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -280,7 +280,7 @@ kimage_file_alloc_init(struct kimage **rimage, int kernel_fd, image->file_mode = 1; - if (kexec_on_panic) { + if (kexec_on_panic && __crash_memory_valid()) { /* Enable special crash kernel control page alloc policy. */ image->control_page = crashk_res.start; image->type = KEXEC_TYPE_CRASH; @@ -345,7 +345,7 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, dest_image = &kexec_image; if (flags & KEXEC_FILE_ON_CRASH) { dest_image = &kexec_crash_image; - if (kexec_crash_image) + if (kexec_crash_image && __crash_memory_valid()) arch_kexec_unprotect_crashkres(); } @@ -408,7 +408,8 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, exchange: image = xchg(dest_image, image); out: - if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image) + if ((flags & KEXEC_FILE_ON_CRASH) && kexec_crash_image && + __crash_memory_valid()) arch_kexec_protect_crashkres(); kexec_unlock(); --- base-commit: 4312098baf37ee17a8350725e6e0d0e8590252d4 change-id: 20221124-kexec-noalloc-3cab3cbe000f Best regards, -- Ricardo Ribalda <ribalda@...omium.org>
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