[PATCH] makedumpfile: Enable --mem-usage for s390x

Atsushi Kumagai kumagai-atsushi at mxc.nes.nec.co.jp
Wed Oct 22 23:56:47 PDT 2014


>On Tue, 14 Oct 2014 07:19:13 +0000
>Atsushi Kumagai <kumagai-atsushi at mxc.nes.nec.co.jp> wrote:
>
>[snip]
>
>>
>> I understand why your patch works on s390x, so how about this way ?
>>
>>  1. Define "is_phys_addr()" for --mem-usage.
>>  2. Implement is_phys_addr() using is_iomem_phys_addr() for s390x
>>     while x86_64 uses is_vmalloc_addr_x86_64().
>>  3. Use is_phys_addr() instead of is_vmalloc_addr() in get_kcore_dump_loads().
>
>Hello Atsushi,
>
>Great, so let's do that.
>
>@Baoquan:
>If you want to use the is_iomem_phys_addr() function also for x86,
>you could perhaps add an additional patch.

I noticed that is_vmalloc_addr_x86_64() can't be used as is_phys_addr()
due to the "kaslr issue". I fixed it in the common path as below, but
--mem-usage still has the same issue since initial() will be invoked
after get_kcore_dump_loads().

  http://lists.infradead.org/pipermail/kexec/2014-October/012743.html

I know it's so late, but I began to think the current implementation
that invokes vaddr_to_paddr_XXX() before initial() is bad:

show_mem_usage()
  + get_kcore_dump_loads()
    + process_dump_load()
      + vaddr_to_paddr_XXX()
  + initial()
  ...

vaddr_to_paddr_XXX() does VtoP translation *properly*, so it needs
several symbols. This design is OK since it's a general method.
OTOH, we need a kludge which can be used under any situations and
should use it for --mem-usage:

  VtoP_kludge_s390x(unsigned long vaddr) 
  {
	/* s390 has 1:1 VtoP mapping that starts with zero. */
  	return vaddr;
  }

also x86_64's can be implemented like below:

  VtoP_kludge_x86_64(unsigned long vaddr) 
  {
	/* if the address is direct mapped, it's easy to translate. */
	unsigned long paddr = vaddr - PAGE_OFFSET;
	return paddr;
  }

>Here the updated patch:
>---
>[PATCH] makedumpfile: Enable --mem-usage for s390x
>
>Replace is_vmalloc_addr() by is_phys_addr() and implement is_phys_addr()
>using /proc/iommem parsing to enable the new makedumpfile option "--mem-usage"
>on s390x.
>
>Signed-off-by: Michael Holzheu <holzheu at linux.vnet.ibm.com>
>---
> elf_info.c     |    4 ++--
> makedumpfile.c |   26 ++++++++++++++++++++++++++
> makedumpfile.h |   15 ++++++++-------
> 3 files changed, 36 insertions(+), 9 deletions(-)
>
>--- a/elf_info.c
>+++ b/elf_info.c
>@@ -854,7 +854,7 @@ int get_kcore_dump_loads(void)
>
> 	for (i = 0; i < num_pt_loads; ++i) {
> 		struct pt_load_segment *p = &pt_loads[i];
>-		if (is_vmalloc_addr(p->virt_start))
>+		if (!is_phys_addr(p->virt_start))

This part implicitly does VtoP translation.
Actually it works for s390x but it's not suitable as a general code,
so we should use VtoP_kludge(should be better name!) too.
Then we can use is_iomem_phys_addr() also for other architecture.


Thanks,
Atsushi Kumagai

> 			continue;
> 		loads++;
> 	}
>@@ -874,7 +874,7 @@ int get_kcore_dump_loads(void)
>
> 	for (i = 0, j = 0; i < num_pt_loads; ++i) {
> 		struct pt_load_segment *p = &pt_loads[i];
>-		if (is_vmalloc_addr(p->virt_start))
>+		if (!is_phys_addr(p->virt_start))
> 			continue;
> 		if (j >= loads)
> 			return FALSE;
>--- a/makedumpfile.c
>+++ b/makedumpfile.c
>@@ -9227,6 +9227,32 @@ int is_crashkernel_mem_reserved(void)
> 	return !!crash_reserved_mem_nr;
> }
>
>+struct addr_check {
>+	unsigned long addr;
>+	int found;
>+};
>+
>+static int phys_addr_callback(void *data, int nr, char *str,
>+			      unsigned long base, unsigned long length)
>+{
>+	struct addr_check *addr_check = data;
>+	unsigned long addr = addr_check->addr;
>+
>+	if (addr >= base && addr < base + length) {
>+		addr_check->found = 1;
>+		return -1;
>+	}
>+	return 0;
>+}
>+
>+int is_iomem_phys_addr(unsigned long addr)
>+{
>+	struct addr_check addr_check = {addr, 0};
>+
>+	iomem_for_each_line("System RAM\n", phys_addr_callback, &addr_check);
>+	return addr_check.found;
>+}
>+
> static int get_page_offset(void)
> {
> 	struct utsname utsname;
>--- a/makedumpfile.h
>+++ b/makedumpfile.h
>@@ -765,7 +765,7 @@ unsigned long long vaddr_to_paddr_arm(un
> #define get_machdep_info()	get_machdep_info_arm()
> #define get_versiondep_info()	TRUE
> #define vaddr_to_paddr(X)	vaddr_to_paddr_arm(X)
>-#define is_vmalloc_addr(X)	TRUE
>+#define is_phys_addr(X)		TRUE
> #endif /* arm */
>
> #ifdef __x86__
>@@ -776,7 +776,7 @@ unsigned long long vaddr_to_paddr_x86(un
> #define get_machdep_info()	get_machdep_info_x86()
> #define get_versiondep_info()	get_versiondep_info_x86()
> #define vaddr_to_paddr(X)	vaddr_to_paddr_x86(X)
>-#define is_vmalloc_addr(X)	TRUE
>+#define is_phys_addr(X)		TRUE
> #endif /* x86 */
>
> #ifdef __x86_64__
>@@ -789,7 +789,7 @@ unsigned long long vaddr_to_paddr_x86_64
> #define get_machdep_info()	get_machdep_info_x86_64()
> #define get_versiondep_info()	get_versiondep_info_x86_64()
> #define vaddr_to_paddr(X)	vaddr_to_paddr_x86_64(X)
>-#define is_vmalloc_addr(X)	is_vmalloc_addr_x86_64(X)
>+#define is_phys_addr(X)		(!is_vmalloc_addr_x86_64(X)
> #endif /* x86_64 */
>
> #ifdef __powerpc64__ /* powerpc64 */
>@@ -800,7 +800,7 @@ unsigned long long vaddr_to_paddr_ppc64(
> #define get_machdep_info()	get_machdep_info_ppc64()
> #define get_versiondep_info()	get_versiondep_info_ppc64()
> #define vaddr_to_paddr(X)	vaddr_to_paddr_ppc64(X)
>-#define is_vmalloc_addr(X)	TRUE
>+#define is_phys_addr(X)		TRUE
> #endif          /* powerpc64 */
>
> #ifdef __powerpc32__ /* powerpc32 */
>@@ -810,7 +810,7 @@ unsigned long long vaddr_to_paddr_ppc(un
> #define get_machdep_info()	get_machdep_info_ppc()
> #define get_versiondep_info()	TRUE
> #define vaddr_to_paddr(X)	vaddr_to_paddr_ppc(X)
>-#define is_vmalloc_addr(X)	TRUE
>+#define is_phys_addr(X)		TRUE
> #endif          /* powerpc32 */
>
> #ifdef __s390x__ /* s390x */
>@@ -820,7 +820,7 @@ unsigned long long vaddr_to_paddr_s390x(
> #define get_machdep_info()	get_machdep_info_s390x()
> #define get_versiondep_info()	TRUE
> #define vaddr_to_paddr(X)	vaddr_to_paddr_s390x(X)
>-#define is_vmalloc_addr(X)	TRUE
>+#define is_phys_addr(X)		is_iomem_phys_addr(X)
> #endif          /* s390x */
>
> #ifdef __ia64__ /* ia64 */
>@@ -832,7 +832,7 @@ unsigned long long vaddr_to_paddr_ia64(u
> #define get_versiondep_info()	TRUE
> #define vaddr_to_paddr(X)	vaddr_to_paddr_ia64(X)
> #define VADDR_REGION(X)		(((unsigned long)(X)) >> REGION_SHIFT)
>-#define is_vmalloc_addr(X)	TRUE
>+#define is_phys_addr(X)		TRUE
> #endif          /* ia64 */
>
> typedef unsigned long long mdf_pfn_t;
>@@ -1567,6 +1567,7 @@ int read_disk_dump_header(struct disk_du
> int read_kdump_sub_header(struct kdump_sub_header *kh, char *filename);
> void close_vmcoreinfo(void);
> int close_files_for_creating_dumpfile(void);
>+int is_iomem_phys_addr(unsigned long addr);
>
>
> /*




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