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

 __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)) {
 		pr_crit("\n"
 			"Error: invalid device tree blob at physical address %pa (virtual address 0x%px)\n"
 			"The dtb must be 8-byte aligned and must not exceed 2 MB in size\n"

diff --git a/arch/csky/kernel/setup.c b/arch/csky/kernel/setup.c
index 51012e90780d..fe715b707fd0 100644
--- a/arch/csky/kernel/setup.c
+++ b/arch/csky/kernel/setup.c

@@ -112,9 +112,9 @@ asmlinkage __visible void __init csky_start(unsigned int unused,
 	pre_trap_init();
 
 	if (dtb_start == NULL)
-		early_init_dt_scan(__dtb_start);
+		early_init_dt_scan(__dtb_start, __pa(dtb_start));
 	else
-		early_init_dt_scan(dtb_start);
+		early_init_dt_scan(dtb_start, __pa(dtb_start));
 
 	start_kernel();
 

diff --git a/arch/loongarch/kernel/setup.c b/arch/loongarch/kernel/setup.c
index 00e307203ddb..10d878204018 100644
--- a/arch/loongarch/kernel/setup.c
+++ b/arch/loongarch/kernel/setup.c

@@ -290,7 +290,7 @@ static void __init fdt_setup(void)
 	if (!fdt_pointer || fdt_check_header(fdt_pointer))
 		return;
 
-	early_init_dt_scan(fdt_pointer);
+	early_init_dt_scan(fdt_pointer, __pa(fdt_pointer));
 	early_init_fdt_reserve_self();
 
 	max_low_pfn = PFN_PHYS(memblock_end_of_DRAM());

diff --git a/arch/microblaze/kernel/prom.c b/arch/microblaze/kernel/prom.c
index e424c796e297..76ac4cfdfb42 100644
--- a/arch/microblaze/kernel/prom.c
+++ b/arch/microblaze/kernel/prom.c

@@ -18,7 +18,7 @@ void __init early_init_devtree(void *params)
 {
 	pr_debug(" -> early_init_devtree(%p)\n", params);
 
-	early_init_dt_scan(params);
+	early_init_dt_scan(params, __pa(params));
 	if (!strlen(boot_command_line))
 		strscpy(boot_command_line, cmd_line, COMMAND_LINE_SIZE);
 

diff --git a/arch/mips/kernel/prom.c b/arch/mips/kernel/prom.c
index 6062e6fa589a..4fd6da0a06c3 100644
--- a/arch/mips/kernel/prom.c
+++ b/arch/mips/kernel/prom.c

@@ -41,7 +41,7 @@ char *mips_get_machine_name(void)
 
 void __init __dt_setup_arch(void *bph)
 {
-	if (!early_init_dt_scan(bph))
+	if (!early_init_dt_scan(bph, __pa(bph)))
 		return;
 
 	mips_set_machine_name(of_flat_dt_get_machine_name());

diff --git a/arch/mips/kernel/relocate.c b/arch/mips/kernel/relocate.c
index 7eeeaf1ff95d..cda7983e7c18 100644
--- a/arch/mips/kernel/relocate.c
+++ b/arch/mips/kernel/relocate.c

@@ -337,7 +337,7 @@ void *__init relocate_kernel(void)
 #if defined(CONFIG_USE_OF)
 	/* Deal with the device tree */
 	fdt = plat_get_fdt();
-	early_init_dt_scan(fdt);
+	early_init_dt_scan(fdt, __pa(fdt));
 	if (boot_command_line[0]) {
 		/* Boot command line was passed in device tree */
 		strscpy(arcs_cmdline, boot_command_line, COMMAND_LINE_SIZE);

diff --git a/arch/nios2/kernel/prom.c b/arch/nios2/kernel/prom.c
index 9a8393e6b4a8..db049249766f 100644
--- a/arch/nios2/kernel/prom.c
+++ b/arch/nios2/kernel/prom.c

@@ -27,7 +27,7 @@ void __init early_init_devtree(void *params)
 	if (be32_to_cpup((__be32 *)CONFIG_NIOS2_DTB_PHYS_ADDR) ==
 		 OF_DT_HEADER) {
 		params = (void *)CONFIG_NIOS2_DTB_PHYS_ADDR;
-		early_init_dt_scan(params);
+		early_init_dt_scan(params, __pa(params));
 		return;
 	}
 #endif

@@ -37,5 +37,5 @@ void __init early_init_devtree(void *params)
 		params = (void *)__dtb_start;
 #endif
 
-	early_init_dt_scan(params);
+	early_init_dt_scan(params, __pa(params));
 }

diff --git a/arch/openrisc/kernel/prom.c b/arch/openrisc/kernel/prom.c
index 19e6008bf114..e424e9bd12a7 100644
--- a/arch/openrisc/kernel/prom.c
+++ b/arch/openrisc/kernel/prom.c

@@ -22,6 +22,6 @@
 
 void __init early_init_devtree(void *params)
 {
-	early_init_dt_scan(params);
+	early_init_dt_scan(params, __pa(params));
 	memblock_allow_resize();
 }

diff --git a/arch/powerpc/kernel/dt_cpu_ftrs.c b/arch/powerpc/kernel/dt_cpu_ftrs.c
index af4263594eb2..1bee15c013e7 100644
--- a/arch/powerpc/kernel/dt_cpu_ftrs.c
+++ b/arch/powerpc/kernel/dt_cpu_ftrs.c

@@ -867,7 +867,7 @@ bool __init dt_cpu_ftrs_init(void *fdt)
 	using_dt_cpu_ftrs = false;
 
 	/* Setup and verify the FDT, if it fails we just bail */
-	if (!early_init_dt_verify(fdt))
+	if (!early_init_dt_verify(fdt, __pa(fdt)))
 		return false;
 
 	if (!of_scan_flat_dt(fdt_find_cpu_features, NULL))

diff --git a/arch/powerpc/kernel/prom.c b/arch/powerpc/kernel/prom.c
index 0be07ed407c7..88cbe432cad5 100644
--- a/arch/powerpc/kernel/prom.c
+++ b/arch/powerpc/kernel/prom.c

@@ -791,7 +791,7 @@ void __init early_init_devtree(void *params)
 	DBG(" -> early_init_devtree(%px)\n", params);
 
 	/* Too early to BUG_ON(), do it by hand */
-	if (!early_init_dt_verify(params))
+	if (!early_init_dt_verify(params, __pa(params)))
 		panic("BUG: Failed verifying flat device tree, bad version?");
 
 	of_scan_flat_dt(early_init_dt_scan_model, NULL);

diff --git a/arch/powerpc/platforms/pseries/plpks.c b/arch/powerpc/platforms/pseries/plpks.c
index 4a595493d28a..b1667ed05f98 100644
--- a/arch/powerpc/platforms/pseries/plpks.c
+++ b/arch/powerpc/platforms/pseries/plpks.c

@@ -683,7 +683,7 @@ void __init plpks_early_init_devtree(void)
 out:
 	fdt_nop_property(fdt, chosen_node, "ibm,plpks-pw");
 	// Since we've cleared the password, we must update the FDT checksum
-	early_init_dt_verify(fdt);
+	early_init_dt_verify(fdt, __pa(fdt));
 }
 
 static __init int pseries_plpks_init(void)

diff --git a/arch/riscv/kernel/setup.c b/arch/riscv/kernel/setup.c
index a2cde65b69e9..26c886db4fb3 100644
--- a/arch/riscv/kernel/setup.c
+++ b/arch/riscv/kernel/setup.c

@@ -227,7 +227,7 @@ static void __init init_resources(void)
 static void __init parse_dtb(void)
 {
 	/* Early scan of device tree from init memory */
-	if (early_init_dt_scan(dtb_early_va)) {
+	if (early_init_dt_scan(dtb_early_va, __pa(dtb_early_va))) {
 		const char *name = of_flat_dt_get_machine_name();
 
 		if (name) {

diff --git a/arch/sh/kernel/setup.c b/arch/sh/kernel/setup.c
index 620e5cf8ae1e..f2b6f16a46b8 100644
--- a/arch/sh/kernel/setup.c
+++ b/arch/sh/kernel/setup.c

@@ -255,7 +255,7 @@ void __ref sh_fdt_init(phys_addr_t dt_phys)
 	dt_virt = phys_to_virt(dt_phys);
 #endif
 
-	if (!dt_virt || !early_init_dt_scan(dt_virt)) {
+	if (!dt_virt || !early_init_dt_scan(dt_virt, __pa(dt_virt))) {
 		pr_crit("Error: invalid device tree blob"
 			" at physical address %p\n", (void *)dt_phys);
 

diff --git a/arch/um/kernel/dtb.c b/arch/um/kernel/dtb.c
index 4954188a6a09..8d78ced9e08f 100644
--- a/arch/um/kernel/dtb.c
+++ b/arch/um/kernel/dtb.c

@@ -17,7 +17,7 @@ void uml_dtb_init(void)
 
 	area = uml_load_file(dtb, &size);
 	if (area) {
-		if (!early_init_dt_scan(area)) {
+		if (!early_init_dt_scan(area, __pa(area))) {
 			pr_err("invalid DTB %s\n", dtb);
 			memblock_free(area, size);
 			return;

diff --git a/arch/x86/kernel/devicetree.c b/arch/x86/kernel/devicetree.c
index 64280879c68c..59d23cdf4ed0 100644
--- a/arch/x86/kernel/devicetree.c
+++ b/arch/x86/kernel/devicetree.c

@@ -305,7 +305,7 @@ void __init x86_flattree_get_config(void)
 			map_len = size;
 		}
 
-		early_init_dt_verify(dt);
+		early_init_dt_verify(dt, __pa(dt));
 	}
 
 	unflatten_and_copy_device_tree();

diff --git a/arch/xtensa/kernel/setup.c b/arch/xtensa/kernel/setup.c
index bdec4a773af0..e51f2060e830 100644
--- a/arch/xtensa/kernel/setup.c
+++ b/arch/xtensa/kernel/setup.c

@@ -216,7 +216,7 @@ static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
 
 void __init early_init_devtree(void *params)
 {
-	early_init_dt_scan(params);
+	early_init_dt_scan(params, __pa(params));
 	of_scan_flat_dt(xtensa_dt_io_area, NULL);
 
 	if (!command_line[0])

diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c
index 4d528c10df3a..546e76ac407c 100644
--- a/drivers/of/fdt.c
+++ b/drivers/of/fdt.c

@@ -457,6 +457,7 @@ int __initdata dt_root_addr_cells;
 int __initdata dt_root_size_cells;
 
 void *initial_boot_params __ro_after_init;
+phys_addr_t initial_boot_params_pa __ro_after_init;
 
 #ifdef CONFIG_OF_EARLY_FLATTREE
 

@@ -1136,17 +1137,18 @@ static void * __init early_init_dt_alloc_memory_arch(u64 size, u64 align)
 	return ptr;
 }
 
-bool __init early_init_dt_verify(void *params)
+bool __init early_init_dt_verify(void *dt_virt, phys_addr_t dt_phys)
 {
-	if (!params)
+	if (!dt_virt)
 		return false;
 
 	/* check device tree validity */
-	if (fdt_check_header(params))
+	if (fdt_check_header(dt_virt))
 		return false;
 
 	/* Setup flat device-tree pointer */
-	initial_boot_params = params;
+	initial_boot_params = dt_virt;
+	initial_boot_params_pa = dt_phys;
 	of_fdt_crc32 = crc32_be(~0, initial_boot_params,
 				fdt_totalsize(initial_boot_params));
 

@@ -1173,11 +1175,11 @@ void __init early_init_dt_scan_nodes(void)
 	early_init_dt_check_for_usable_mem_range();
 }
 
-bool __init early_init_dt_scan(void *params)
+bool __init early_init_dt_scan(void *dt_virt, phys_addr_t dt_phys)
 {
 	bool status;
 
-	status = early_init_dt_verify(params);
+	status = early_init_dt_verify(dt_virt, dt_phys);
 	if (!status)
 		return false;
 

diff --git a/drivers/of/kexec.c b/drivers/of/kexec.c
index 9ccde2fd77cb..5b924597a4de 100644
--- a/drivers/of/kexec.c
+++ b/drivers/of/kexec.c

@@ -301,7 +301,7 @@ void *of_kexec_alloc_and_setup_fdt(const struct kimage *image,
 	}
 
 	/* Remove memory reservation for the current device tree. */
-	ret = fdt_find_and_del_mem_rsv(fdt, __pa(initial_boot_params),
+	ret = fdt_find_and_del_mem_rsv(fdt, initial_boot_params_pa,
 				       fdt_totalsize(initial_boot_params));
 	if (ret == -EINVAL) {
 		pr_err("Error removing memory reservation.\n");

diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h
index d69ad5bb1eb1..b8d6c0c20876 100644
--- a/include/linux/of_fdt.h
+++ b/include/linux/of_fdt.h

@@ -31,6 +31,7 @@ extern void *of_fdt_unflatten_tree(const unsigned long *blob,
 extern int __initdata dt_root_addr_cells;
 extern int __initdata dt_root_size_cells;
 extern void *initial_boot_params;
+extern phys_addr_t initial_boot_params_pa;
 
 extern char __dtb_start[];
 extern char __dtb_end[];

@@ -70,8 +71,8 @@ extern u64 dt_mem_next_cell(int s, const __be32 **cellp);
 /* Early flat tree scan hooks */
 extern int early_init_dt_scan_root(void);
 
-extern bool early_init_dt_scan(void *params);
-extern bool early_init_dt_verify(void *params);
+extern bool early_init_dt_scan(void *dt_virt, phys_addr_t dt_phys);
+extern bool early_init_dt_verify(void *dt_virt, phys_addr_t dt_phys);
 extern void early_init_dt_scan_nodes(void);
 
 extern const char *of_flat_dt_get_machine_name(void);

-- 
2.43.5

On Wed, Oct 23, 2024 at 12:14 PM Usama Arif [off-list ref] wrote:

 __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()")

This looks fine, but what is the symptom without this compared to
before the above change? The original code in the referenced commit
above didn't remove the reservation at all. Unless the current code
does something worse, this is new functionality more than a fix (for
stable).

Rob

On 25/10/2024 23:15, Rob Herring wrote:

On Wed, Oct 23, 2024 at 12:14 PM Usama Arif [off-list ref] 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()")

This looks fine, but what is the symptom without this compared to
before the above change? The original code in the referenced commit
above didn't remove the reservation at all. Unless the current code
does something worse, this is new functionality more than a fix (for
stable).

Rob

After the series in [1] was merged, we always get a warning when kexecing
a debug kernel, which was reported by Breno in [2].
The issue is using __pa for a fixmap address in arm64 as described in [2],
which could result in removing a memory reservation for a completely
unrelated area.
That was introduced by the patch just before 
"arm64: Use common of_kexec_alloc_and_setup_fdt" [3], but arm64 switched to
using the common kexec fdt function in that commit. This commit is trying
to fix removing and corrupting any random memory reservation (and get rid
of the warning) that was introduced by [1], not adding a new functionality.

[1] https://lore.kernel.org/all/20210221174930.27324-7-nramas@linux.microsoft.com/ 
[2] https://lore.kernel.org/all/ZnFKEtqfqJkYflwL@gmail.com/
[3] https://lore.kernel.org/all/20210221174930.27324-6-nramas@linux.microsoft.com/

Thanks,
Usama

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

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

Will

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

Hello:

This patch was applied to riscv/linux.git (fixes)
by Rob Herring (Arm) [off-list ref]:

On Wed, 23 Oct 2024 18:14:26 +0100 you wrote:

__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()")

[...]

Here is the summary with links:
  - [v2] of/fdt: add dt_phys arg to early_init_dt_scan and early_init_dt_verify
    https://git.kernel.org/riscv/c/b2473a359763

You are awesome, thank you!
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