[PATCH v6 04/11] ppc64/kexec_file: avoid stomping memory used by special regions
Hari Bathini
hbathini at linux.ibm.com
Wed Jul 29 07:40:16 EDT 2020
crashkernel region could have an overlap with special memory regions
like opal, rtas, tce-table & such. These regions are referred to as
exclude memory ranges. Setup this 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: Hari Bathini <hbathini at linux.ibm.com>
Reviewed-by: Thiago Jung Bauermann <bauerman at linux.ibm.com>
---
v5 -> v6:
* Implemented all the add_foo_mem_ranges() functions that get used while
setting up exclude memory ranges.
v4 -> v5:
* Unchanged. Added Reviewed-by tag from Thiago.
v3 -> v4:
* Dropped KDUMP_BUF_MIN & KDUMP_BUF_MAX macros and fixed off-by-one error
in arch_locate_mem_hole() helper routines.
v2 -> v3:
* If there are no exclude ranges, the right thing to do is fallbacking
back to default kexec_locate_mem_hole() implementation instead of
returning 0. Fixed that.
v1 -> v2:
* Did arch_kexec_locate_mem_hole() override to handle special regions.
* Ensured holes in the memory are accounted for while locating mem hole.
* Updated add_rtas_mem_range() & add_opal_mem_range() callsites based on
the new prototype for these functions.
arch/powerpc/include/asm/kexec.h | 7 -
arch/powerpc/include/asm/kexec_ranges.h | 14 +
arch/powerpc/kexec/elf_64.c | 8 +
arch/powerpc/kexec/file_load_64.c | 337 +++++++++++++++++++++++++++++++
arch/powerpc/kexec/ranges.c | 177 ++++++++++++++++
5 files changed, 539 insertions(+), 4 deletions(-)
diff --git a/arch/powerpc/include/asm/kexec.h b/arch/powerpc/include/asm/kexec.h
index ac8fd4839171..835dc92e091c 100644
--- a/arch/powerpc/include/asm/kexec.h
+++ b/arch/powerpc/include/asm/kexec.h
@@ -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 */
diff --git a/arch/powerpc/include/asm/kexec_ranges.h b/arch/powerpc/include/asm/kexec_ranges.h
index 35ae31a7a4de..7a90000f8d15 100644
--- a/arch/powerpc/include/asm/kexec_ranges.h
+++ b/arch/powerpc/include/asm/kexec_ranges.h
@@ -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 */
diff --git a/arch/powerpc/kexec/elf_64.c b/arch/powerpc/kexec/elf_64.c
index 23ad04ccaf8e..64c15a5a280b 100644
--- a/arch/powerpc/kexec/elf_64.c
+++ b/arch/powerpc/kexec/elf_64.c
@@ -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;
diff --git a/arch/powerpc/kexec/file_load_64.c b/arch/powerpc/kexec/file_load_64.c
index 3e9ac5f216b0..d09c7724efa8 100644
--- a/arch/powerpc/kexec/file_load_64.c
+++ b/arch/powerpc/kexec/file_load_64.c
@@ -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);
+}
diff --git a/arch/powerpc/kexec/ranges.c b/arch/powerpc/kexec/ranges.c
index dc3ce036f416..6b81c852feab 100644
--- a/arch/powerpc/kexec/ranges.c
+++ b/arch/powerpc/kexec/ranges.c
@@ -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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