Commit b8e55a3e authored by Hari Bathini's avatar Hari Bathini Committed by Michael Ellerman
Browse files

powerpc/kexec_file: Avoid stomping memory used by special regions 



crashkernel region could have an overlap with special memory regions
like OPAL, RTAS, TCE table & such. These regions are referred to as
excluded memory ranges. Setup these ranges during image probe in order
to avoid them while finding the buffer for different kdump segments.
Override arch_kexec_locate_mem_hole() to locate a memory hole taking
these ranges into account.

Signed-off-by: default avatarHari Bathini <hbathini@linux.ibm.com>
Reviewed-by: default avatarThiago Jung Bauermann <bauerman@linux.ibm.com>
Signed-off-by: default avatarMichael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/159602281047.575379.6636807148335160795.stgit@hbathini
parent 180adfc5

arch/powerpc/include/asm/kexec.h

+5 −2
Original line number Diff line number Diff line
@@ -100,14 +100,16 @@ void relocate_new_kernel(unsigned long indirection_page, unsigned long reboot_co 
#ifdef CONFIG_KEXEC_FILE

extern const struct kexec_file_ops kexec_elf64_ops;



#ifdef CONFIG_IMA_KEXEC

#define ARCH_HAS_KIMAGE_ARCH



struct kimage_arch {

	struct crash_mem *exclude_ranges;



#ifdef CONFIG_IMA_KEXEC

	phys_addr_t ima_buffer_addr;

	size_t ima_buffer_size;

};

#endif

};



int setup_purgatory(struct kimage *image, const void *slave_code,

		    const void *fdt, unsigned long kernel_load_addr,
@@ -125,6 +127,7 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, 
			unsigned long initrd_load_addr,

			unsigned long initrd_len, const char *cmdline);

#endif /* CONFIG_PPC64 */



#endif /* CONFIG_KEXEC_FILE */



#else /* !CONFIG_KEXEC_CORE */

arch/powerpc/include/asm/kexec_ranges.h

+14 −0
Original line number Diff line number Diff line
@@ -7,5 +7,19 @@ 
void sort_memory_ranges(struct crash_mem *mrngs, bool merge);

struct crash_mem *realloc_mem_ranges(struct crash_mem **mem_ranges);

int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size);

int add_tce_mem_ranges(struct crash_mem **mem_ranges);

int add_initrd_mem_range(struct crash_mem **mem_ranges);

#ifdef CONFIG_PPC_BOOK3S_64

int add_htab_mem_range(struct crash_mem **mem_ranges);

#else

static inline int add_htab_mem_range(struct crash_mem **mem_ranges)

{

	return 0;

}

#endif

int add_kernel_mem_range(struct crash_mem **mem_ranges);

int add_rtas_mem_range(struct crash_mem **mem_ranges);

int add_opal_mem_range(struct crash_mem **mem_ranges);

int add_reserved_mem_ranges(struct crash_mem **mem_ranges);



#endif /* _ASM_POWERPC_KEXEC_RANGES_H */

arch/powerpc/kexec/elf_64.c

+8 −0
Original line number Diff line number Diff line
@@ -46,6 +46,14 @@ static void *elf64_load(struct kimage *image, char *kernel_buf, 
	if (ret)

		goto out;



	if (image->type == KEXEC_TYPE_CRASH) {

		/* min & max buffer values for kdump case */

		kbuf.buf_min = pbuf.buf_min = crashk_res.start;

		kbuf.buf_max = pbuf.buf_max =

				((crashk_res.end < ppc64_rma_size) ?

				 crashk_res.end : (ppc64_rma_size - 1));

	}



	ret = kexec_elf_load(image, &ehdr, &elf_info, &kbuf, &kernel_load_addr);

	if (ret)

		goto out;

arch/powerpc/kexec/file_load_64.c

+335 −2
Original line number Diff line number Diff line
@@ -17,12 +17,262 @@ 
#include <linux/kexec.h>

#include <linux/of_fdt.h>

#include <linux/libfdt.h>

#include <linux/memblock.h>

#include <asm/kexec_ranges.h>



const struct kexec_file_ops * const kexec_file_loaders[] = {

	&kexec_elf64_ops,

	NULL

};



/**

 * get_exclude_memory_ranges - Get exclude memory ranges. This list includes

 *                             regions like opal/rtas, tce-table, initrd,

 *                             kernel, htab which should be avoided while

 *                             setting up kexec load segments.

 * @mem_ranges:                Range list to add the memory ranges to.

 *

 * Returns 0 on success, negative errno on error.

 */

static int get_exclude_memory_ranges(struct crash_mem **mem_ranges)

{

	int ret;



	ret = add_tce_mem_ranges(mem_ranges);

	if (ret)

		goto out;



	ret = add_initrd_mem_range(mem_ranges);

	if (ret)

		goto out;



	ret = add_htab_mem_range(mem_ranges);

	if (ret)

		goto out;



	ret = add_kernel_mem_range(mem_ranges);

	if (ret)

		goto out;



	ret = add_rtas_mem_range(mem_ranges);

	if (ret)

		goto out;



	ret = add_opal_mem_range(mem_ranges);

	if (ret)

		goto out;



	ret = add_reserved_mem_ranges(mem_ranges);

	if (ret)

		goto out;



	/* exclude memory ranges should be sorted for easy lookup */

	sort_memory_ranges(*mem_ranges, true);

out:

	if (ret)

		pr_err("Failed to setup exclude memory ranges\n");

	return ret;

}



/**

 * __locate_mem_hole_top_down - Looks top down for a large enough memory hole

 *                              in the memory regions between buf_min & buf_max

 *                              for the buffer. If found, sets kbuf->mem.

 * @kbuf:                       Buffer contents and memory parameters.

 * @buf_min:                    Minimum address for the buffer.

 * @buf_max:                    Maximum address for the buffer.

 *

 * Returns 0 on success, negative errno on error.

 */

static int __locate_mem_hole_top_down(struct kexec_buf *kbuf,

				      u64 buf_min, u64 buf_max)

{

	int ret = -EADDRNOTAVAIL;

	phys_addr_t start, end;

	u64 i;



	for_each_mem_range_rev(i, &memblock.memory, NULL, NUMA_NO_NODE,

			       MEMBLOCK_NONE, &start, &end, NULL) {

		/*

		 * memblock uses [start, end) convention while it is

		 * [start, end] here. Fix the off-by-one to have the

		 * same convention.

		 */

		end -= 1;



		if (start > buf_max)

			continue;



		/* Memory hole not found */

		if (end < buf_min)

			break;



		/* Adjust memory region based on the given range */

		if (start < buf_min)

			start = buf_min;

		if (end > buf_max)

			end = buf_max;



		start = ALIGN(start, kbuf->buf_align);

		if (start < end && (end - start + 1) >= kbuf->memsz) {

			/* Suitable memory range found. Set kbuf->mem */

			kbuf->mem = ALIGN_DOWN(end - kbuf->memsz + 1,

					       kbuf->buf_align);

			ret = 0;

			break;

		}

	}



	return ret;

}



/**

 * locate_mem_hole_top_down_ppc64 - Skip special memory regions to find a

 *                                  suitable buffer with top down approach.

 * @kbuf:                           Buffer contents and memory parameters.

 * @buf_min:                        Minimum address for the buffer.

 * @buf_max:                        Maximum address for the buffer.

 * @emem:                           Exclude memory ranges.

 *

 * Returns 0 on success, negative errno on error.

 */

static int locate_mem_hole_top_down_ppc64(struct kexec_buf *kbuf,

					  u64 buf_min, u64 buf_max,

					  const struct crash_mem *emem)

{

	int i, ret = 0, err = -EADDRNOTAVAIL;

	u64 start, end, tmin, tmax;



	tmax = buf_max;

	for (i = (emem->nr_ranges - 1); i >= 0; i--) {

		start = emem->ranges[i].start;

		end = emem->ranges[i].end;



		if (start > tmax)

			continue;



		if (end < tmax) {

			tmin = (end < buf_min ? buf_min : end + 1);

			ret = __locate_mem_hole_top_down(kbuf, tmin, tmax);

			if (!ret)

				return 0;

		}



		tmax = start - 1;



		if (tmax < buf_min) {

			ret = err;

			break;

		}

		ret = 0;

	}



	if (!ret) {

		tmin = buf_min;

		ret = __locate_mem_hole_top_down(kbuf, tmin, tmax);

	}

	return ret;

}



/**

 * __locate_mem_hole_bottom_up - Looks bottom up for a large enough memory hole

 *                               in the memory regions between buf_min & buf_max

 *                               for the buffer. If found, sets kbuf->mem.

 * @kbuf:                        Buffer contents and memory parameters.

 * @buf_min:                     Minimum address for the buffer.

 * @buf_max:                     Maximum address for the buffer.

 *

 * Returns 0 on success, negative errno on error.

 */

static int __locate_mem_hole_bottom_up(struct kexec_buf *kbuf,

				       u64 buf_min, u64 buf_max)

{

	int ret = -EADDRNOTAVAIL;

	phys_addr_t start, end;

	u64 i;



	for_each_mem_range(i, &memblock.memory, NULL, NUMA_NO_NODE,

			   MEMBLOCK_NONE, &start, &end, NULL) {

		/*

		 * memblock uses [start, end) convention while it is

		 * [start, end] here. Fix the off-by-one to have the

		 * same convention.

		 */

		end -= 1;



		if (end < buf_min)

			continue;



		/* Memory hole not found */

		if (start > buf_max)

			break;



		/* Adjust memory region based on the given range */

		if (start < buf_min)

			start = buf_min;

		if (end > buf_max)

			end = buf_max;



		start = ALIGN(start, kbuf->buf_align);

		if (start < end && (end - start + 1) >= kbuf->memsz) {

			/* Suitable memory range found. Set kbuf->mem */

			kbuf->mem = start;

			ret = 0;

			break;

		}

	}



	return ret;

}



/**

 * locate_mem_hole_bottom_up_ppc64 - Skip special memory regions to find a

 *                                   suitable buffer with bottom up approach.

 * @kbuf:                            Buffer contents and memory parameters.

 * @buf_min:                         Minimum address for the buffer.

 * @buf_max:                         Maximum address for the buffer.

 * @emem:                            Exclude memory ranges.

 *

 * Returns 0 on success, negative errno on error.

 */

static int locate_mem_hole_bottom_up_ppc64(struct kexec_buf *kbuf,

					   u64 buf_min, u64 buf_max,

					   const struct crash_mem *emem)

{

	int i, ret = 0, err = -EADDRNOTAVAIL;

	u64 start, end, tmin, tmax;



	tmin = buf_min;

	for (i = 0; i < emem->nr_ranges; i++) {

		start = emem->ranges[i].start;

		end = emem->ranges[i].end;



		if (end < tmin)

			continue;



		if (start > tmin) {

			tmax = (start > buf_max ? buf_max : start - 1);

			ret = __locate_mem_hole_bottom_up(kbuf, tmin, tmax);

			if (!ret)

				return 0;

		}



		tmin = end + 1;



		if (tmin > buf_max) {

			ret = err;

			break;

		}

		ret = 0;

	}



	if (!ret) {

		tmax = buf_max;

		ret = __locate_mem_hole_bottom_up(kbuf, tmin, tmax);

	}

	return ret;

}



/**

 * setup_purgatory_ppc64 - initialize PPC64 specific purgatory's global

 *                         variables and call setup_purgatory() to initialize
@@ -67,6 +317,67 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, 
	return setup_new_fdt(image, fdt, initrd_load_addr, initrd_len, cmdline);

}



/**

 * arch_kexec_locate_mem_hole - Skip special memory regions like rtas, opal,

 *                              tce-table, reserved-ranges & such (exclude

 *                              memory ranges) as they can't be used for kexec

 *                              segment buffer. Sets kbuf->mem when a suitable

 *                              memory hole is found.

 * @kbuf:                       Buffer contents and memory parameters.

 *

 * Assumes minimum of PAGE_SIZE alignment for kbuf->memsz & kbuf->buf_align.

 *

 * Returns 0 on success, negative errno on error.

 */

int arch_kexec_locate_mem_hole(struct kexec_buf *kbuf)

{

	struct crash_mem **emem;

	u64 buf_min, buf_max;

	int ret;



	/*

	 * Use the generic kexec_locate_mem_hole for regular

	 * kexec_file_load syscall

	 */

	if (kbuf->image->type != KEXEC_TYPE_CRASH)

		return kexec_locate_mem_hole(kbuf);



	/* Look up the exclude ranges list while locating the memory hole */

	emem = &(kbuf->image->arch.exclude_ranges);

	if (!(*emem) || ((*emem)->nr_ranges == 0)) {

		pr_warn("No exclude range list. Using the default locate mem hole method\n");

		return kexec_locate_mem_hole(kbuf);

	}



	/* Segments for kdump kernel should be within crashkernel region */

	buf_min = (kbuf->buf_min < crashk_res.start ?

		   crashk_res.start : kbuf->buf_min);

	buf_max = (kbuf->buf_max > crashk_res.end ?

		   crashk_res.end : kbuf->buf_max);



	if (buf_min > buf_max) {

		pr_err("Invalid buffer min and/or max values\n");

		return -EINVAL;

	}



	if (kbuf->top_down)

		ret = locate_mem_hole_top_down_ppc64(kbuf, buf_min, buf_max,

						     *emem);

	else

		ret = locate_mem_hole_bottom_up_ppc64(kbuf, buf_min, buf_max,

						      *emem);



	/* Add the buffer allocated to the exclude list for the next lookup */

	if (!ret) {

		add_mem_range(emem, kbuf->mem, kbuf->memsz);

		sort_memory_ranges(*emem, true);

	} else {

		pr_err("Failed to locate memory buffer of size %lu\n",

		       kbuf->memsz);

	}

	return ret;

}



/**

 * arch_kexec_kernel_image_probe - Does additional handling needed to setup

 *                                 kexec segments.
@@ -79,9 +390,31 @@ int setup_new_fdt_ppc64(const struct kimage *image, void *fdt, 
int arch_kexec_kernel_image_probe(struct kimage *image, void *buf,

				  unsigned long buf_len)

{

	/* We don't support crash kernels yet. */

	if (image->type == KEXEC_TYPE_CRASH)

	if (image->type == KEXEC_TYPE_CRASH) {

		int ret;



		/* Get exclude memory ranges needed for setting up kdump segments */

		ret = get_exclude_memory_ranges(&(image->arch.exclude_ranges));

		if (ret)

			pr_err("Failed to setup exclude memory ranges for buffer lookup\n");

		/* Return this until all changes for panic kernel are in */

		return -EOPNOTSUPP;

	}



	return kexec_image_probe_default(image, buf, buf_len);

}



/**

 * arch_kimage_file_post_load_cleanup - Frees up all the allocations done

 *                                      while loading the image.

 * @image:                              kexec image being loaded.

 *

 * Returns 0 on success, negative errno on error.

 */

int arch_kimage_file_post_load_cleanup(struct kimage *image)

{

	kfree(image->arch.exclude_ranges);

	image->arch.exclude_ranges = NULL;



	return kexec_image_post_load_cleanup_default(image);

}

arch/powerpc/kexec/ranges.c

+177 −0
Original line number Diff line number Diff line
@@ -233,3 +233,180 @@ int add_mem_range(struct crash_mem **mem_ranges, u64 base, u64 size) 


	return __add_mem_range(mem_ranges, base, size);

}



/**

 * add_tce_mem_ranges - Adds tce-table range to the given memory ranges list.

 * @mem_ranges:         Range list to add the memory range(s) to.

 *

 * Returns 0 on success, negative errno on error.

 */

int add_tce_mem_ranges(struct crash_mem **mem_ranges)

{

	struct device_node *dn = NULL;

	int ret = 0;



	for_each_node_by_type(dn, "pci") {

		u64 base;

		u32 size;



		ret = of_property_read_u64(dn, "linux,tce-base", &base);

		ret |= of_property_read_u32(dn, "linux,tce-size", &size);

		if (ret) {

			/*

			 * It is ok to have pci nodes without tce. So, ignore

			 * property does not exist error.

			 */

			if (ret == -EINVAL) {

				ret = 0;

				continue;

			}

			break;

		}



		ret = add_mem_range(mem_ranges, base, size);

		if (ret)

			break;

	}



	of_node_put(dn);

	return ret;

}



/**

 * add_initrd_mem_range - Adds initrd range to the given memory ranges list,

 *                        if the initrd was retained.

 * @mem_ranges:           Range list to add the memory range to.

 *

 * Returns 0 on success, negative errno on error.

 */

int add_initrd_mem_range(struct crash_mem **mem_ranges)

{

	u64 base, end;

	int ret;



	/* This range means something, only if initrd was retained */

	if (!strstr(saved_command_line, "retain_initrd"))

		return 0;



	ret = of_property_read_u64(of_chosen, "linux,initrd-start", &base);

	ret |= of_property_read_u64(of_chosen, "linux,initrd-end", &end);

	if (!ret)

		ret = add_mem_range(mem_ranges, base, end - base + 1);



	return ret;

}



#ifdef CONFIG_PPC_BOOK3S_64

/**

 * add_htab_mem_range - Adds htab range to the given memory ranges list,

 *                      if it exists

 * @mem_ranges:         Range list to add the memory range to.

 *

 * Returns 0 on success, negative errno on error.

 */

int add_htab_mem_range(struct crash_mem **mem_ranges)

{

	if (!htab_address)

		return 0;



	return add_mem_range(mem_ranges, __pa(htab_address), htab_size_bytes);

}

#endif



/**

 * add_kernel_mem_range - Adds kernel text region to the given

 *                        memory ranges list.

 * @mem_ranges:           Range list to add the memory range to.

 *

 * Returns 0 on success, negative errno on error.

 */

int add_kernel_mem_range(struct crash_mem **mem_ranges)

{

	return add_mem_range(mem_ranges, 0, __pa(_end));

}



/**

 * add_rtas_mem_range - Adds RTAS region to the given memory ranges list.

 * @mem_ranges:         Range list to add the memory range to.

 *

 * Returns 0 on success, negative errno on error.

 */

int add_rtas_mem_range(struct crash_mem **mem_ranges)

{

	struct device_node *dn;

	u32 base, size;

	int ret = 0;



	dn = of_find_node_by_path("/rtas");

	if (!dn)

		return 0;



	ret = of_property_read_u32(dn, "linux,rtas-base", &base);

	ret |= of_property_read_u32(dn, "rtas-size", &size);

	if (!ret)

		ret = add_mem_range(mem_ranges, base, size);



	of_node_put(dn);

	return ret;

}



/**

 * add_opal_mem_range - Adds OPAL region to the given memory ranges list.

 * @mem_ranges:         Range list to add the memory range to.

 *

 * Returns 0 on success, negative errno on error.

 */

int add_opal_mem_range(struct crash_mem **mem_ranges)

{

	struct device_node *dn;

	u64 base, size;

	int ret;



	dn = of_find_node_by_path("/ibm,opal");

	if (!dn)

		return 0;



	ret = of_property_read_u64(dn, "opal-base-address", &base);

	ret |= of_property_read_u64(dn, "opal-runtime-size", &size);

	if (!ret)

		ret = add_mem_range(mem_ranges, base, size);



	of_node_put(dn);

	return ret;

}



/**

 * add_reserved_mem_ranges - Adds "/reserved-ranges" regions exported by f/w

 *                           to the given memory ranges list.

 * @mem_ranges:              Range list to add the memory ranges to.

 *

 * Returns 0 on success, negative errno on error.

 */

int add_reserved_mem_ranges(struct crash_mem **mem_ranges)

{

	int n_mem_addr_cells, n_mem_size_cells, i, len, cells, ret = 0;

	const __be32 *prop;



	prop = of_get_property(of_root, "reserved-ranges", &len);

	if (!prop)

		return 0;



	n_mem_addr_cells = of_n_addr_cells(of_root);

	n_mem_size_cells = of_n_size_cells(of_root);

	cells = n_mem_addr_cells + n_mem_size_cells;



	/* Each reserved range is an (address,size) pair */

	for (i = 0; i < (len / (sizeof(u32) * cells)); i++) {

		u64 base, size;



		base = of_read_number(prop + (i * cells), n_mem_addr_cells);

		size = of_read_number(prop + (i * cells) + n_mem_addr_cells,

				      n_mem_size_cells);



		ret = add_mem_range(mem_ranges, base, size);

		if (ret)

			break;

	}



	return ret;

}

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