From 118005713e35a1893c6ee47ab2926cca277737de Mon Sep 17 00:00:00 2001 From: Sourabh Jain Date: Tue, 26 Mar 2024 11:24:08 +0530 Subject: crash: forward memory_notify arg to arch crash hotplug handler In the event of memory hotplug or online/offline events, the crash memory hotplug notifier `crash_memhp_notifier()` receives a `memory_notify` object but doesn't forward that object to the generic and architecture-specific crash hotplug handler. The `memory_notify` object contains the starting PFN (Page Frame Number) and the number of pages in the hot-removed memory. This information is necessary for architectures like PowerPC to update/recreate the kdump image, specifically `elfcorehdr`. So update the function signature of `crash_handle_hotplug_event()` and `arch_crash_handle_hotplug_event()` to accept the `memory_notify` object as an argument from crash memory hotplug notifier. Since no such object is available in the case of CPU hotplug event, the crash CPU hotplug notifier `crash_cpuhp_online()` passes NULL to the crash hotplug handler. Signed-off-by: Sourabh Jain Acked-by: Baoquan He Acked-by: Hari Bathini Signed-off-by: Michael Ellerman Link: https://msgid.link/20240326055413.186534-2-sourabhjain@linux.ibm.com --- kernel/crash_core.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-) (limited to 'kernel') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 78b5dc7cee3a..70fa8111a9d6 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -534,7 +534,7 @@ int crash_check_update_elfcorehdr(void) * list of segments it checks (since the elfcorehdr changes and thus * would require an update to purgatory itself to update the digest). */ -static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu) +static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, void *arg) { struct kimage *image; @@ -596,7 +596,7 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu) image->hp_action = hp_action; /* Now invoke arch-specific update handler */ - arch_crash_handle_hotplug_event(image); + arch_crash_handle_hotplug_event(image, arg); /* No longer handling a hotplug event */ image->hp_action = KEXEC_CRASH_HP_NONE; @@ -612,17 +612,17 @@ out: crash_hotplug_unlock(); } -static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *v) +static int crash_memhp_notifier(struct notifier_block *nb, unsigned long val, void *arg) { switch (val) { case MEM_ONLINE: crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_MEMORY, - KEXEC_CRASH_HP_INVALID_CPU); + KEXEC_CRASH_HP_INVALID_CPU, arg); break; case MEM_OFFLINE: crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_MEMORY, - KEXEC_CRASH_HP_INVALID_CPU); + KEXEC_CRASH_HP_INVALID_CPU, arg); break; } return NOTIFY_OK; @@ -635,13 +635,13 @@ static struct notifier_block crash_memhp_nb = { static int crash_cpuhp_online(unsigned int cpu) { - crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu); + crash_handle_hotplug_event(KEXEC_CRASH_HP_ADD_CPU, cpu, NULL); return 0; } static int crash_cpuhp_offline(unsigned int cpu) { - crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu); + crash_handle_hotplug_event(KEXEC_CRASH_HP_REMOVE_CPU, cpu, NULL); return 0; } -- cgit v1.2.3 From 79365026f86948b52c3cb7bf099dded92c559b4c Mon Sep 17 00:00:00 2001 From: Sourabh Jain Date: Tue, 26 Mar 2024 11:24:09 +0530 Subject: crash: add a new kexec flag for hotplug support Commit a72bbec70da2 ("crash: hotplug support for kexec_load()") introduced a new kexec flag, `KEXEC_UPDATE_ELFCOREHDR`. Kexec tool uses this flag to indicate to the kernel that it is safe to modify the elfcorehdr of the kdump image loaded using the kexec_load system call. However, it is possible that architectures may need to update kexec segments other then elfcorehdr. For example, FDT (Flatten Device Tree) on PowerPC. Introducing a new kexec flag for every new kexec segment may not be a good solution. Hence, a generic kexec flag bit, `KEXEC_CRASH_HOTPLUG_SUPPORT`, is introduced to share the CPU/Memory hotplug support intent between the kexec tool and the kernel for the kexec_load system call. Now we have two kexec flags that enables crash hotplug support for kexec_load system call. First is KEXEC_UPDATE_ELFCOREHDR (only used in x86), and second is KEXEC_CRASH_HOTPLUG_SUPPORT (for all architectures). To simplify the process of finding and reporting the crash hotplug support the following changes are introduced. 1. Define arch specific function to process the kexec flags and determine crash hotplug support 2. Rename the @update_elfcorehdr member of struct kimage to @hotplug_support and populate it for both kexec_load and kexec_file_load syscalls, because architecture can update more than one kexec segment 3. Let generic function crash_check_hotplug_support report hotplug support for loaded kdump image based on value of @hotplug_support To bring the x86 crash hotplug support in line with the above points, the following changes have been made: - Introduce the arch_crash_hotplug_support function to process kexec flags and determine crash hotplug support - Remove the arch_crash_hotplug_[cpu|memory]_support functions Signed-off-by: Sourabh Jain Acked-by: Baoquan He Acked-by: Hari Bathini Signed-off-by: Michael Ellerman Link: https://msgid.link/20240326055413.186534-3-sourabhjain@linux.ibm.com --- kernel/crash_core.c | 15 ++++++--------- kernel/kexec.c | 4 ++-- kernel/kexec_file.c | 5 +++++ 3 files changed, 13 insertions(+), 11 deletions(-) (limited to 'kernel') diff --git a/kernel/crash_core.c b/kernel/crash_core.c index 70fa8111a9d6..394db3ebe835 100644 --- a/kernel/crash_core.c +++ b/kernel/crash_core.c @@ -493,10 +493,10 @@ static DEFINE_MUTEX(__crash_hotplug_lock); /* * This routine utilized when the crash_hotplug sysfs node is read. - * It reflects the kernel's ability/permission to update the crash - * elfcorehdr directly. + * It reflects the kernel's ability/permission to update the kdump + * image directly. */ -int crash_check_update_elfcorehdr(void) +int crash_check_hotplug_support(void) { int rc = 0; @@ -508,10 +508,7 @@ int crash_check_update_elfcorehdr(void) return 0; } if (kexec_crash_image) { - if (kexec_crash_image->file_mode) - rc = 1; - else - rc = kexec_crash_image->update_elfcorehdr; + rc = kexec_crash_image->hotplug_support; } /* Release lock now that update complete */ kexec_unlock(); @@ -552,8 +549,8 @@ static void crash_handle_hotplug_event(unsigned int hp_action, unsigned int cpu, image = kexec_crash_image; - /* Check that updating elfcorehdr is permitted */ - if (!(image->file_mode || image->update_elfcorehdr)) + /* Check that kexec segments update is permitted */ + if (!image->hotplug_support) goto out; if (hp_action == KEXEC_CRASH_HP_ADD_CPU || diff --git a/kernel/kexec.c b/kernel/kexec.c index bab542fc1463..a6b3f96bb50c 100644 --- a/kernel/kexec.c +++ b/kernel/kexec.c @@ -135,8 +135,8 @@ static int do_kexec_load(unsigned long entry, unsigned long nr_segments, image->preserve_context = 1; #ifdef CONFIG_CRASH_HOTPLUG - if (flags & KEXEC_UPDATE_ELFCOREHDR) - image->update_elfcorehdr = 1; + if ((flags & KEXEC_ON_CRASH) && arch_crash_hotplug_support(image, flags)) + image->hotplug_support = 1; #endif ret = machine_kexec_prepare(image); diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c index 2d1db05fbf04..3d64290d24c9 100644 --- a/kernel/kexec_file.c +++ b/kernel/kexec_file.c @@ -376,6 +376,11 @@ SYSCALL_DEFINE5(kexec_file_load, int, kernel_fd, int, initrd_fd, if (ret) goto out; +#ifdef CONFIG_CRASH_HOTPLUG + if ((flags & KEXEC_FILE_ON_CRASH) && arch_crash_hotplug_support(image, flags)) + image->hotplug_support = 1; +#endif + ret = machine_kexec_prepare(image); if (ret) goto out; -- cgit v1.2.3 From 628d701f2de5b9a16d1dd82bea68fd895f56f1a1 Mon Sep 17 00:00:00 2001 From: Benjamin Gray Date: Wed, 17 Apr 2024 21:23:20 +1000 Subject: powerpc/dexcr: Add DEXCR prctl interface Now that we track a DEXCR on a per-task basis, individual tasks are free to configure it as they like. The interface is a pair of getter/setter prctl's that work on a single aspect at a time (multiple aspects at once is more difficult if there are different rules applied for each aspect, now or in future). The getter shows the current state of the process config, and the setter allows setting/clearing the aspect. Signed-off-by: Benjamin Gray [mpe: Account for PR_RISCV_SET_ICACHE_FLUSH_CTX, shrink some longs lines] Signed-off-by: Michael Ellerman Link: https://msgid.link/20240417112325.728010-5-bgray@linux.ibm.com --- kernel/sys.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel') diff --git a/kernel/sys.c b/kernel/sys.c index 8bb106a56b3a..f9c95410278c 100644 --- a/kernel/sys.c +++ b/kernel/sys.c @@ -146,6 +146,12 @@ #ifndef RISCV_V_GET_CONTROL # define RISCV_V_GET_CONTROL() (-EINVAL) #endif +#ifndef PPC_GET_DEXCR_ASPECT +# define PPC_GET_DEXCR_ASPECT(a, b) (-EINVAL) +#endif +#ifndef PPC_SET_DEXCR_ASPECT +# define PPC_SET_DEXCR_ASPECT(a, b, c) (-EINVAL) +#endif /* * this is where the system-wide overflow UID and GID are defined, for @@ -2726,6 +2732,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, case PR_GET_MDWE: error = prctl_get_mdwe(arg2, arg3, arg4, arg5); break; + case PR_PPC_GET_DEXCR: + if (arg3 || arg4 || arg5) + return -EINVAL; + error = PPC_GET_DEXCR_ASPECT(me, arg2); + break; + case PR_PPC_SET_DEXCR: + if (arg4 || arg5) + return -EINVAL; + error = PPC_SET_DEXCR_ASPECT(me, arg2, arg3); + break; case PR_SET_VMA: error = prctl_set_vma(arg2, arg3, arg4, arg5); break; -- cgit v1.2.3