[Top][All Lists]
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
Re: [Qemu-devel] [PATCH 4/4] target-arm: add minimal dump-guest-memory s
From: |
Rabin Vincent |
Subject: |
Re: [Qemu-devel] [PATCH 4/4] target-arm: add minimal dump-guest-memory support |
Date: |
Sun, 1 Jul 2012 11:52:45 +0530 |
User-agent: |
Mutt/1.5.21 (2010-09-15) |
On Thu, Jun 28, 2012 at 05:46:02PM +0100, Peter Maydell wrote:
> On 20 June 2012 18:28, Rabin Vincent <address@hidden> wrote:
> > Add a minimal dump-guest-memory support for ARM. The -p option is not
> > supported and we don't add any QEMU-specific notes.
>
> So what does this patch give us? This commit message is pretty
> short and I couldn't find a cover message for the patchset...
It makes the dump-guest-memory command work for arm-softmmu. The
resulting core dump can be analysed with a tool such as the crash
utility.
>
> > Signed-off-by: Rabin Vincent <address@hidden>
> > ---
> > configure | 4 +--
> > target-arm/Makefile.objs | 2 +-
> > target-arm/arch_dump.c | 59
> > ++++++++++++++++++++++++++++++++++++++
> > target-arm/arch_memory_mapping.c | 13 +++++++++
> > 4 files changed, 75 insertions(+), 3 deletions(-)
> > create mode 100644 target-arm/arch_dump.c
> > create mode 100644 target-arm/arch_memory_mapping.c
> >
> > diff --git a/configure b/configure
> > index b68c0ca..a20ad19 100755
> > --- a/configure
> > +++ b/configure
> > @@ -3727,7 +3727,7 @@ case "$target_arch2" in
> > fi
> > esac
> > case "$target_arch2" in
> > - i386|x86_64)
> > + arm|i386|x86_64)
> > echo "CONFIG_HAVE_GET_MEMORY_MAPPING=y" >> $config_target_mak
> > esac
> > if test "$target_arch2" = "ppc64" -a "$fdt" = "yes"; then
> > @@ -3746,7 +3746,7 @@ if test "$target_softmmu" = "yes" ; then
> > echo "subdir-$target: subdir-libcacard" >> $config_host_mak
> > fi
> > case "$target_arch2" in
> > - i386|x86_64)
> > + arm|i386|x86_64)
> > echo "CONFIG_HAVE_CORE_DUMP=y" >> $config_target_mak
> > esac
> > fi
> > diff --git a/target-arm/Makefile.objs b/target-arm/Makefile.objs
> > index f447c4f..837b374 100644
> > --- a/target-arm/Makefile.objs
> > +++ b/target-arm/Makefile.objs
> > @@ -1,5 +1,5 @@
> > obj-y += arm-semi.o
> > -obj-$(CONFIG_SOFTMMU) += machine.o
> > +obj-$(CONFIG_SOFTMMU) += machine.o arch_memory_mapping.o arch_dump.o
> > obj-y += translate.o op_helper.o helper.o cpu.o
> > obj-y += neon_helper.o iwmmxt_helper.o
> >
> > diff --git a/target-arm/arch_dump.c b/target-arm/arch_dump.c
> > new file mode 100644
> > index 0000000..47a7e40
> > --- /dev/null
> > +++ b/target-arm/arch_dump.c
> > @@ -0,0 +1,59 @@
> > +#include "cpu.h"
> > +#include "cpu-all.h"
> > +#include "dump.h"
> > +#include "elf.h"
> > +
> > +typedef struct {
> > + char pad1[24];
> > + uint32_t pid;
> > + char pad2[44];
> > + uint32_t regs[18];
> > + char pad3[4];
> > +} arm_elf_prstatus;
>
> I'm guessing this is following some specification's structure layout;
> what specification?
struct elf_prstatus from the Linux kernel's include/linux/elfcore.h.
>
> > +
> > +int cpu_write_elf64_note(write_core_dump_function f, CPUArchState *env,
> > + int cpuid, void *opaque)
>
> Should these APIs really be taking a CPUArchState* rather rather than
> an ARMCPU* ? (Andreas?)
No idea. Cc'ing Wen, who added the APIs.
>
> > +{
> > + return -1;
> > +}
> > +
> > +int cpu_write_elf32_note(write_core_dump_function f, CPUArchState *env,
> > + int cpuid, void *opaque)
> > +{
> > + arm_elf_prstatus prstatus;
> > +
> > + memset(&prstatus, 0, sizeof(prstatus));
> > + memcpy(&(prstatus.regs), env->regs, sizeof(env->regs));
>
> This looks a bit odd -- env->regs[] is a 16 word array but
> prstatus.regs is 18 words. What are the last two words for?
CPSR and orig_r0. orig_r0 is not useful, but I think we can save the
CPSR in there.
>
> > + prstatus.pid = cpuid;
> > +
> > + return dump_write_elf_note(ELFCLASS32, "CORE", NT_PRSTATUS,
> > + &prstatus, sizeof(prstatus),
> > + f, opaque);
> > +}
> > +
> > +int cpu_write_elf64_qemunote(write_core_dump_function f, CPUArchState *env,
> > + void *opaque)
> > +{
> > + return -1;
> > +}
> > +
> > +int cpu_write_elf32_qemunote(write_core_dump_function f, CPUArchState *env,
> > + void *opaque)
> > +{
> > + return 0;
> > +}
> > +
> > +int cpu_get_dump_info(ArchDumpInfo *info)
> > +{
> > + info->d_machine = EM_ARM;
> > + info->d_endian = ELFDATA2LSB;
>
> ...even for big endian ARM?
I'll use TARGET_WORDS_BIGENDIAN to check.
Though it appears we don't have a armbe-softmmu?
>
> > + info->d_class = ELFCLASS32;
> > +
> > + return 0;
> > +}
> > +
> > +ssize_t cpu_get_note_size(int class, int machine, int nr_cpus)
> > +{
> > + return nr_cpus * dump_get_note_size(ELFCLASS32, "CORE",
> > + sizeof(arm_elf_prstatus));
> > +}
> > diff --git a/target-arm/arch_memory_mapping.c
> > b/target-arm/arch_memory_mapping.c
> > new file mode 100644
> > index 0000000..eeaaf09
> > --- /dev/null
> > +++ b/target-arm/arch_memory_mapping.c
> > @@ -0,0 +1,13 @@
> > +#include "cpu.h"
> > +#include "cpu-all.h"
> > +#include "memory_mapping.h"
> > +
> > +bool cpu_paging_enabled(CPUArchState *env)
> > +{
> > + return 0;
> > +}
> > +
> > +int cpu_get_memory_mapping(MemoryMappingList *list, CPUArchState *env)
> > +{
> > + return -1;
> > +}
>
> Why do we need these null implementations and why do they
> work better than the default ones in memory_mapping-stub.c ?
The implementations are to make the dump-guest-memory command build. A
full implementation would add support for the "-p" option which afaics
is supposed to walk the page tables and dump only the pages which are
mapped instead of the complete RAM. I personally have no need for this
option, so they are only null implementations which result in an error
if this option is used.
The current config code keeps memory-mapping.c and memory-mapping-stub.c
exclusive. I think we should be able to make some changes there to
allow us to use memory-mapping-stub.c instead of this
arch_memory_mapping.c.
- Re: [Qemu-devel] [PATCH 4/4] target-arm: add minimal dump-guest-memory support,
Rabin Vincent <=