Re: [PATCH 2/8] kexec_file: Generalize kexec_add_buffer.
From: Thiago Jung Bauermann <hidden>
Date: 2016-06-13 20:40:54
Also in:
kexec, lkml
Subsystem:
kexec, the rest · Maintainers:
Andrew Morton, Baoquan He, Mike Rapoport, Pasha Tatashin, Pratyush Yadav, Linus Torvalds
Hi Dave, Am Montag, 13 Juni 2016, 16:08:19 schrieb Thiago Jung Bauermann:
Am Montag, 13 Juni 2016, 15:29:39 schrieb Dave Young:quoted
On 06/12/16 at 12:10am, Thiago Jung Bauermann wrote:quoted
Allow architectures to specify different memory walking functions for kexec_add_buffer. Intel uses iomem to track reserved memory ranges, but PowerPC uses the memblock subsystem.Can the crashk_res be inserted to iomem_resource so that only one weak function for system ram is needed?Sorry, it's not clear to me what you mean by inserting crashk_res into iomem_resource, but I can add a bool for_crashkernel to arch_walk_system_ram so that it can decide which kind of memory to traverse.
This is the patch implementing that idea. What do you think?
--
[]'s
Thiago Jung Bauermann
IBM Linux Technology Center
kexec_file: Generalize kexec_add_buffer.
Allow architectures to specify different memory walking functions for
kexec_add_buffer. Intel uses iomem to track reserved memory ranges,
but PowerPC uses the memblock subsystem.
Signed-off-by: Thiago Jung Bauermann [off-list ref]
Cc: Eric Biederman [off-list ref]
Cc: kexec@lists.infradead.org
Cc: linux-kernel@vger.kernel.org
diff --git a/include/linux/kexec.h b/include/linux/kexec.h
index e8acb2b43dd9..be18cb80c14e 100644
--- a/include/linux/kexec.h
+++ b/include/linux/kexec.h@@ -315,6 +315,9 @@ int __weak arch_kexec_apply_relocations_add(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, unsigned int relsec); int __weak arch_kexec_apply_relocations(const Elf_Ehdr *ehdr, Elf_Shdr *sechdrs, unsigned int relsec); +int __weak arch_walk_system_ram(bool for_crashkernel, unsigned long start, + unsigned long end, bool top_down, void *data, + int (*func)(u64, u64, void *)); void arch_kexec_protect_crashkres(void); void arch_kexec_unprotect_crashkres(void);
diff --git a/kernel/kexec_file.c b/kernel/kexec_file.c
index b6eec7527e9f..5d0a6a20b12b 100644
--- a/kernel/kexec_file.c
+++ b/kernel/kexec_file.c@@ -428,6 +428,38 @@ static int locate_mem_hole_callback(u64 start, u64 end, void *arg) return locate_mem_hole_bottom_up(start, end, kbuf); } +/** + * arch_walk_system_ram - call func(data) on free memory regions + * @for_crashkernel: Is this for the crash kernel? + * @start: Don't visit memory regions below this address. + * @end: Don't visit memory regions above this address. + * @top_down: Starts from the highest address? + * @data: Argument to pass to @func. + * @func: Function to call for each memory region. + * + * Return: 0 on success, negative errno on error. + */ +int __weak arch_walk_system_ram(bool for_crashkernel, unsigned long start, + unsigned long end, bool top_down, void *data, + int (*func)(u64, u64, void *)) +{ + int ret; + + if (for_crashkernel) + ret = walk_iomem_res_desc(crashk_res.desc, + IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, + start, end, data, func); + else + ret = walk_system_ram_res(start, end, data, func); + + if (ret != 1) { + /* A suitable memory range could not be found for buffer */ + return -EADDRNOTAVAIL; + } + + return 0; +} + /* * Helper function for placing a buffer in a kexec segment. This assumes * that kexec_mutex is held.
@@ -473,17 +505,14 @@ int kexec_add_buffer(struct kimage *image, char *buffer, unsigned long bufsz, /* Walk the RAM ranges and allocate a suitable range for the buffer */ if (image->type == KEXEC_TYPE_CRASH) - ret = walk_iomem_res_desc(crashk_res.desc, - IORESOURCE_SYSTEM_RAM | IORESOURCE_BUSY, - crashk_res.start, crashk_res.end, kbuf, - locate_mem_hole_callback); + ret = arch_walk_system_ram(true, crashk_res.start, + crashk_res.end, top_down, kbuf, + locate_mem_hole_callback); else - ret = walk_system_ram_res(0, -1, kbuf, - locate_mem_hole_callback); - if (ret != 1) { - /* A suitable memory range could not be found for buffer */ - return -EADDRNOTAVAIL; - } + ret = arch_walk_system_ram(false, 0, -1, top_down, kbuf, + locate_mem_hole_callback); + if (ret) + return ret; /* Found a suitable memory range */ ksegment = &image->segment[image->nr_segments];