When debug with kaslr, it is sometimes necessary to have PHYS_OFFSET to
perform linear virtual address to physical address translation.
Sometimes we're debugging with only few information such as a kernel log
and a symbol file, print PHYS_OFFSET in dump_kernel_offset() for that case.
Tested by:
echo c > /proc/sysrq-trigger
[ 11.996161] SMP: stopping secondary CPUs
[ 11.996732] Kernel Offset: 0x2522200000 from 0xffffff8008000000
[ 11.996881] PHYS_OFFSET: 0xffffffeb40000000
Signed-off-by: Miles Chen <[email protected]>
Tested-by: Miles Chen <[email protected]>
---
arch/arm64/kernel/setup.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index f4fc1e0544b7..4b0e1231625c 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c
@@ -388,6 +388,7 @@ static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && offset > 0) {
pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
offset, KIMAGE_VADDR);
+ pr_emerg("PHYS_OFFSET: 0x%llx\n", PHYS_OFFSET);
} else {
pr_emerg("Kernel Offset: disabled\n");
}
--
2.18.0
[+Ard because I'll basically go with his preference on this one]
On Wed, Dec 12, 2018 at 06:56:49PM +0800, Miles Chen wrote:
> When debug with kaslr, it is sometimes necessary to have PHYS_OFFSET to
> perform linear virtual address to physical address translation.
> Sometimes we're debugging with only few information such as a kernel log
> and a symbol file, print PHYS_OFFSET in dump_kernel_offset() for that case.
>
> Tested by:
> echo c > /proc/sysrq-trigger
> [ 11.996161] SMP: stopping secondary CPUs
> [ 11.996732] Kernel Offset: 0x2522200000 from 0xffffff8008000000
> [ 11.996881] PHYS_OFFSET: 0xffffffeb40000000
>
> Signed-off-by: Miles Chen <[email protected]>
> Tested-by: Miles Chen <[email protected]>
> ---
> arch/arm64/kernel/setup.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index f4fc1e0544b7..4b0e1231625c 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -388,6 +388,7 @@ static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
> if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && offset > 0) {
> pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
> offset, KIMAGE_VADDR);
> + pr_emerg("PHYS_OFFSET: 0x%llx\n", PHYS_OFFSET);
> } else {
> pr_emerg("Kernel Offset: disabled\n");
> }
> --
> 2.18.0
>
On Thu, 13 Dec 2018 at 19:12, Will Deacon <[email protected]> wrote:
>
> [+Ard because I'll basically go with his preference on this one]
>
> On Wed, Dec 12, 2018 at 06:56:49PM +0800, Miles Chen wrote:
> > When debug with kaslr, it is sometimes necessary to have PHYS_OFFSET to
> > perform linear virtual address to physical address translation.
> > Sometimes we're debugging with only few information such as a kernel log
> > and a symbol file, print PHYS_OFFSET in dump_kernel_offset() for that case.
> >
> > Tested by:
> > echo c > /proc/sysrq-trigger
> > [ 11.996161] SMP: stopping secondary CPUs
> > [ 11.996732] Kernel Offset: 0x2522200000 from 0xffffff8008000000
> > [ 11.996881] PHYS_OFFSET: 0xffffffeb40000000
> >
> > Signed-off-by: Miles Chen <[email protected]>
> > Tested-by: Miles Chen <[email protected]>
Fine with me, but I would like to see an ack from Miles Chen :-)
> > ---
> > arch/arm64/kernel/setup.c | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> > index f4fc1e0544b7..4b0e1231625c 100644
> > --- a/arch/arm64/kernel/setup.c
> > +++ b/arch/arm64/kernel/setup.c
> > @@ -388,6 +388,7 @@ static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
> > if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && offset > 0) {
> > pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
> > offset, KIMAGE_VADDR);
> > + pr_emerg("PHYS_OFFSET: 0x%llx\n", PHYS_OFFSET);
> > } else {
> > pr_emerg("Kernel Offset: disabled\n");
> > }
> > --
> > 2.18.0
> >
On Thu, 2018-12-13 at 19:15 +0100, Ard Biesheuvel wrote:
> On Thu, 13 Dec 2018 at 19:12, Will Deacon <[email protected]> wrote:
> >
> > [+Ard because I'll basically go with his preference on this one]
> >
> > On Wed, Dec 12, 2018 at 06:56:49PM +0800, Miles Chen wrote:
> > > When debug with kaslr, it is sometimes necessary to have PHYS_OFFSET to
> > > perform linear virtual address to physical address translation.
> > > Sometimes we're debugging with only few information such as a kernel log
> > > and a symbol file, print PHYS_OFFSET in dump_kernel_offset() for that case.
> > >
> > > Tested by:
> > > echo c > /proc/sysrq-trigger
> > > [ 11.996161] SMP: stopping secondary CPUs
> > > [ 11.996732] Kernel Offset: 0x2522200000 from 0xffffff8008000000
> > > [ 11.996881] PHYS_OFFSET: 0xffffffeb40000000
> > >
> > > Signed-off-by: Miles Chen <[email protected]>
> > > Tested-by: Miles Chen <[email protected]>
>
> Fine with me, but I would like to see an ack from Miles Chen :-)
Can I ack my own patch?
Acked-by:Miles Chen <[email protected]>
>
> > > ---
> > > arch/arm64/kernel/setup.c | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > > diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> > > index f4fc1e0544b7..4b0e1231625c 100644
> > > --- a/arch/arm64/kernel/setup.c
> > > +++ b/arch/arm64/kernel/setup.c
> > > @@ -388,6 +388,7 @@ static int dump_kernel_offset(struct notifier_block *self, unsigned long v,
> > > if (IS_ENABLED(CONFIG_RANDOMIZE_BASE) && offset > 0) {
> > > pr_emerg("Kernel Offset: 0x%lx from 0x%lx\n",
> > > offset, KIMAGE_VADDR);
> > > + pr_emerg("PHYS_OFFSET: 0x%llx\n", PHYS_OFFSET);
> > > } else {
> > > pr_emerg("Kernel Offset: disabled\n");
> > > }
> > > --
> > > 2.18.0
> > >