Sourabh Jain <[email protected]> writes:
> Commit 35c18f2933c5 ("Add a new optional ",cma" suffix to the
> crashkernel= command line option") and commit ab475510e042 ("kdump:
> implement reserve_crashkernel_cma") added CMA support for kdump
> crashkernel reservation.
>
> Extend crashkernel CMA reservation support to powerpc.
>
> The following changes are made to enable CMA reservation on powerpc:
>
> - Parse and obtain the CMA reservation size along with other crashkernel
> parameters
> - Call reserve_crashkernel_cma() to allocate the CMA region for kdump
> - Include the CMA-reserved ranges in the usable memory ranges for the
> kdump kernel to use.
> - Exclude the CMA-reserved ranges from the crash kernel memory to
> prevent them from being exported through /proc/vmcore.
>
> With the introduction of the CMA crashkernel regions,
> crash_exclude_mem_range() needs to be called multiple times to exclude
> both crashk_res and crashk_cma_ranges from the crash memory ranges. To
> avoid repetitive logic for validating mem_ranges size and handling
> reallocation when required, this functionality is moved to a new wrapper
> function crash_exclude_mem_range_guarded().
>
> To ensure proper CMA reservation, reserve_crashkernel_cma() is called
> after pageblock_order is initialized.
>
> Update kernel-parameters.txt to document CMA support for crashkernel on
> powerpc architecture.
>
> Cc: Baoquan he <[email protected]>
> Cc: Jiri Bohac <[email protected]>
> Cc: Hari Bathini <[email protected]>
> Cc: Madhavan Srinivasan <[email protected]>
> Cc: Mahesh Salgaonkar <[email protected]>
> Cc: Michael Ellerman <[email protected]>
> Cc: Ritesh Harjani (IBM) <[email protected]>
> Cc: Shivang Upadhyay <[email protected]>
> Cc: [email protected]
> Signed-off-by: Sourabh Jain <[email protected]>
> ---
> Changlog:
>
> v3 -> v4
> - Removed repeated initialization to tmem in
> crash_exclude_mem_range_guarded()
> - Call crash_exclude_mem_range() with right crashk ranges
>
> v4 -> v5:
> - Document CMA-based crashkernel support for ppc64 in kernel-parameters.txt
> ---
> .../admin-guide/kernel-parameters.txt | 2 +-
> arch/powerpc/include/asm/kexec.h | 2 +
> arch/powerpc/kernel/setup-common.c | 4 +-
> arch/powerpc/kexec/core.c | 10 ++++-
> arch/powerpc/kexec/ranges.c | 43 ++++++++++++++-----
> 5 files changed, 47 insertions(+), 14 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt
> b/Documentation/admin-guide/kernel-parameters.txt
> index 6c42061ca20e..0f386b546cec 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -1013,7 +1013,7 @@
> It will be ignored when crashkernel=X,high is not used
> or memory reserved is below 4G.
> crashkernel=size[KMG],cma
> - [KNL, X86] Reserve additional crash kernel memory from
> + [KNL, X86, ppc64] Reserve additional crash kernel
> memory from
Shouldn't this be PPC and not ppc64?
If I see the crash_dump support...
config ARCH_SUPPORTS_CRASH_DUMP
def_bool PPC64 || PPC_BOOK3S_32 || PPC_85xx || (44x && !SMP)
The changes below aren't specific to ppc64 correct?
> CMA. This reservation is usable by the first system's
> userspace memory and kernel movable allocations (memory
> balloon, zswap). Pages allocated from this memory range
> diff --git a/arch/powerpc/include/asm/kexec.h
> b/arch/powerpc/include/asm/kexec.h
> index 4bbf9f699aaa..bd4a6c42a5f3 100644
> --- a/arch/powerpc/include/asm/kexec.h
> +++ b/arch/powerpc/include/asm/kexec.h
> @@ -115,9 +115,11 @@ int setup_new_fdt_ppc64(const struct kimage *image, void
> *fdt, struct crash_mem
> #ifdef CONFIG_CRASH_RESERVE
> int __init overlaps_crashkernel(unsigned long start, unsigned long size);
> extern void arch_reserve_crashkernel(void);
> +extern void kdump_cma_reserve(void);
> #else
> static inline void arch_reserve_crashkernel(void) {}
> static inline int overlaps_crashkernel(unsigned long start, unsigned long
> size) { return 0; }
> +static inline void kdump_cma_reserve(void) { }
> #endif
>
> #if defined(CONFIG_CRASH_DUMP)
> diff --git a/arch/powerpc/kernel/setup-common.c
> b/arch/powerpc/kernel/setup-common.c
> index 68d47c53876c..c8c42b419742 100644
> --- a/arch/powerpc/kernel/setup-common.c
> +++ b/arch/powerpc/kernel/setup-common.c
> @@ -35,6 +35,7 @@
> #include <linux/of_irq.h>
> #include <linux/hugetlb.h>
> #include <linux/pgtable.h>
> +#include <asm/kexec.h>
> #include <asm/io.h>
> #include <asm/paca.h>
> #include <asm/processor.h>
> @@ -995,11 +996,12 @@ void __init setup_arch(char **cmdline_p)
> initmem_init();
>
> /*
> - * Reserve large chunks of memory for use by CMA for fadump, KVM and
> + * Reserve large chunks of memory for use by CMA for kdump, fadump, KVM
> and
> * hugetlb. These must be called after initmem_init(), so that
> * pageblock_order is initialised.
> */
> fadump_cma_init();
> + kdump_cma_reserve();
> kvm_cma_reserve();
> gigantic_hugetlb_cma_reserve();
>
> diff --git a/arch/powerpc/kexec/core.c b/arch/powerpc/kexec/core.c
> index d1a2d755381c..25744737eff5 100644
> --- a/arch/powerpc/kexec/core.c
> +++ b/arch/powerpc/kexec/core.c
> @@ -33,6 +33,8 @@ void machine_kexec_cleanup(struct kimage *image)
> {
> }
>
> +unsigned long long cma_size;
> +
nit:
Since this is a gloabal powerpc variable you are defining, then can we
keep it's name to crashk_cma_size?
> /*
> * Do not allocate memory (or fail in any way) in machine_kexec().
> * We are past the point of no return, committed to rebooting now.
> @@ -110,7 +112,7 @@ void __init arch_reserve_crashkernel(void)
>
> /* use common parsing */
> ret = parse_crashkernel(boot_command_line, total_mem_sz, &crash_size,
> - &crash_base, NULL, NULL, NULL);
> + &crash_base, NULL, &cma_size, NULL);
>
> if (ret)
> return;
> @@ -130,6 +132,12 @@ void __init arch_reserve_crashkernel(void)
> reserve_crashkernel_generic(crash_size, crash_base, 0, false);
> }
>
> +void __init kdump_cma_reserve(void)
> +{
> + if (cma_size)
> + reserve_crashkernel_cma(cma_size);
> +}
> +
nit:
cma_size is already checked for null within reserve_crashkernel_cma(),
so we don't really need kdump_cma_reserve() function call as such.
Also kdump_cma_reserve() only make sense with #ifdef CRASHKERNEL_CMA..
so instead do you think we can directly call reserve_crashkernel_cma(cma_size)?
-ritesh
> int __init overlaps_crashkernel(unsigned long start, unsigned long size)
> {
> return (start + size) > crashk_res.start && start <= crashk_res.end;
> diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c
> index 3702b0bdab14..3bd27c38726b 100644
> --- a/arch/powerpc/kexec/ranges.c
> +++ b/arch/powerpc/kexec/ranges.c
> @@ -515,7 +515,7 @@ int get_exclude_memory_ranges(struct crash_mem
> **mem_ranges)
> */
> int get_usable_memory_ranges(struct crash_mem **mem_ranges)
> {
> - int ret;
> + int ret, i;
>
> /*
> * Early boot failure observed on guests when low memory (first memory
> @@ -528,6 +528,13 @@ int get_usable_memory_ranges(struct crash_mem
> **mem_ranges)
> if (ret)
> goto out;
>
> + for (i = 0; i < crashk_cma_cnt; i++) {
> + ret = add_mem_range(mem_ranges, crashk_cma_ranges[i].start,
> + crashk_cma_ranges[i].end -
> crashk_cma_ranges[i].start + 1);
> + if (ret)
> + goto out;
> + }
> +
> ret = add_rtas_mem_range(mem_ranges);
> if (ret)
> goto out;
> @@ -546,6 +553,22 @@ int get_usable_memory_ranges(struct crash_mem
> **mem_ranges)
> #endif /* CONFIG_KEXEC_FILE */
>
> #ifdef CONFIG_CRASH_DUMP
> +static int crash_exclude_mem_range_guarded(struct crash_mem **mem_ranges,
> + unsigned long long mstart,
> + unsigned long long mend)
> +{
> + struct crash_mem *tmem = *mem_ranges;
> +
> + /* Reallocate memory ranges if there is no space to split ranges */
> + if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
> + tmem = realloc_mem_ranges(mem_ranges);
> + if (!tmem)
> + return -ENOMEM;
> + }
> +
> + return crash_exclude_mem_range(tmem, mstart, mend);
> +}
> +
> /**
> * get_crash_memory_ranges - Get crash memory ranges. This list includes
> * first/crashing kernel's memory regions that
> @@ -557,7 +580,6 @@ int get_usable_memory_ranges(struct crash_mem
> **mem_ranges)
> int get_crash_memory_ranges(struct crash_mem **mem_ranges)
> {
> phys_addr_t base, end;
> - struct crash_mem *tmem;
> u64 i;
> int ret;
>
> @@ -582,19 +604,18 @@ int get_crash_memory_ranges(struct crash_mem
> **mem_ranges)
> sort_memory_ranges(*mem_ranges, true);
> }
>
> - /* Reallocate memory ranges if there is no space to split ranges */
> - tmem = *mem_ranges;
> - if (tmem && (tmem->nr_ranges == tmem->max_nr_ranges)) {
> - tmem = realloc_mem_ranges(mem_ranges);
> - if (!tmem)
> - goto out;
> - }
> -
> /* Exclude crashkernel region */
> - ret = crash_exclude_mem_range(tmem, crashk_res.start, crashk_res.end);
> + ret = crash_exclude_mem_range_guarded(mem_ranges, crashk_res.start,
> crashk_res.end);
> if (ret)
> goto out;
>
> + for (i = 0; i < crashk_cma_cnt; ++i) {
> + ret = crash_exclude_mem_range_guarded(mem_ranges,
> crashk_cma_ranges[i].start,
> + crashk_cma_ranges[i].end);
> + if (ret)
> + goto out;
> + }
> +
> /*
> * FIXME: For now, stay in parity with kexec-tools but if RTAS/OPAL
> * regions are exported to save their context at the time of
> --
> 2.51.0
