On Mon, Oct 28, 2024 at 10:41 AM Will Deacon [off-list ref] wrote:

On Wed, Oct 23, 2024 at 06:14:26PM +0100, Usama Arif wrote:

quoted

 __pa() is only intended to be used for linear map addresses and using
it for initial_boot_params which is in fixmap for arm64 will give an
incorrect value. Hence save the physical address when it is known at
boot time when calling early_init_dt_scan for arm64 and use it at kexec
time instead of converting the virtual address using __pa().

Reported-by: Breno Leitao <leitao@debian.org>
Suggested-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Usama Arif <redacted>
Fixes: ac10be5cdbfa ("arm64: Use common of_kexec_alloc_and_setup_fdt()")
---
v1 -> 2:
- pass dt_phys in early_init_dt_scan instead of creating
  anorther arch->dt function (Rob Herring)
---
 arch/arc/kernel/devtree.c              |  2 +-
 arch/arm/kernel/devtree.c              |  2 +-
 arch/arm64/kernel/setup.c              |  6 +++++-
 arch/csky/kernel/setup.c               |  4 ++--
 arch/loongarch/kernel/setup.c          |  2 +-
 arch/microblaze/kernel/prom.c          |  2 +-
 arch/mips/kernel/prom.c                |  2 +-
 arch/mips/kernel/relocate.c            |  2 +-
 arch/nios2/kernel/prom.c               |  4 ++--
 arch/openrisc/kernel/prom.c            |  2 +-
 arch/powerpc/kernel/dt_cpu_ftrs.c      |  2 +-
 arch/powerpc/kernel/prom.c             |  2 +-
 arch/powerpc/platforms/pseries/plpks.c |  2 +-
 arch/riscv/kernel/setup.c              |  2 +-
 arch/sh/kernel/setup.c                 |  2 +-
 arch/um/kernel/dtb.c                   |  2 +-
 arch/x86/kernel/devicetree.c           |  2 +-
 arch/xtensa/kernel/setup.c             |  2 +-
 drivers/of/fdt.c                       | 14 ++++++++------
 drivers/of/kexec.c                     |  2 +-
 include/linux/of_fdt.h                 |  5 +++--
 21 files changed, 36 insertions(+), 29 deletions(-)

diff --git a/arch/arc/kernel/devtree.c b/arch/arc/kernel/devtree.c
index 4c9e61457b2f..cc6ac7d128aa 100644
--- a/arch/arc/kernel/devtree.c
+++ b/arch/arc/kernel/devtree.c

@@ -62,7 +62,7 @@ const struct machine_desc * __init setup_machine_fdt(void *dt)
      const struct machine_desc *mdesc;
      unsigned long dt_root;

-     if (!early_init_dt_scan(dt))
+     if (!early_init_dt_scan(dt, __pa(dt)))
              return NULL;

      mdesc = of_flat_dt_match_machine(NULL, arch_get_next_mach);

diff --git a/arch/arm/kernel/devtree.c b/arch/arm/kernel/devtree.c
index fdb74e64206a..3b78966e750a 100644
--- a/arch/arm/kernel/devtree.c
+++ b/arch/arm/kernel/devtree.c

@@ -200,7 +200,7 @@ const struct machine_desc * __init setup_machine_fdt(void *dt_virt)

      mdesc_best = &__mach_desc_GENERIC_DT;

-     if (!dt_virt || !early_init_dt_verify(dt_virt))
+     if (!dt_virt || !early_init_dt_verify(dt_virt, __pa(dt_virt)))
              return NULL;

      mdesc = of_flat_dt_match_machine(mdesc_best, arch_get_next_mach);

diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
index b22d28ec8028..177262739c49 100644
--- a/arch/arm64/kernel/setup.c
+++ b/arch/arm64/kernel/setup.c

@@ -175,7 +175,11 @@ static void __init setup_machine_fdt(phys_addr_t dt_phys)
      if (dt_virt)
              memblock_reserve(dt_phys, size);

-     if (!dt_virt || !early_init_dt_scan(dt_virt)) {
+     /*
+      * dt_virt is a fixmap address, hence __pa(dt_virt) can't be used.
+      * Pass dt_phys directly.
+      */
+     if (!dt_virt || !early_init_dt_scan(dt_virt, dt_phys)) {

nit: It looks like early_init_dt_verify() will now return false if
!dt_virt, so we can drop the additional check here.

That was true before, but I'll fix this up when applying.

Rob