Thread (6 messages) 6 messages, 4 authors, 2024-12-11

Re: [PATCH v2] of/fdt: add dt_phys arg to early_init_dt_scan and early_init_dt_verify

From: Will Deacon <will@kernel.org>
Date: 2024-10-28 15:41:02
Also in: kexec, linux-arm-kernel, linux-devicetree, linux-mips, linux-riscv, linux-sh, lkml, loongarch

On Wed, Oct 23, 2024 at 06:14:26PM +0100, Usama Arif wrote:
quoted hunk ↗ jump to hunk
 __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.

Will
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