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:
> > On 06/12/16 at 12:10am, Thiago Jung Bauermann wrote:
> > > 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 <bauerman at linux.vnet.ibm.com>
Cc: Eric Biederman <ebiederm at xmission.com>
Cc: kexec at lists.infradead.org
Cc: linux-kernel at 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];
