[PATCH v2] arm64/mm: use lm_alias() with addresses passed to memblock_free()

[Joey Gouly]

The pointer argument to memblock_free() needs to be a linear map address, but
in mem_init() we pass __init_begin/__init_end, which is a kernel image address.

This results in warnings when building with CONFIG_DEBUG_VIRTUAL=y:

    virt_to_phys used for non-linear address: ffff800081270000 (set_reset_devices+0x0/0x10)
    WARNING: CPU: 0 PID: 1 at arch/arm64/mm/physaddr.c:12 __virt_to_phys+0x54/0x70
    Modules linked in:
    CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.11.0-rc6-next-20240905 #5810 b1ebb0ad06653f35ce875413d5afad24668df3f3
    Hardware name: FVP Base RevC (DT)
    pstate: 2161402005 (nZCv daif +PAN -UAO -TCO +DIT -SSBS BTYPE=--)
    pc : __virt_to_phys+0x54/0x70
    lr : __virt_to_phys+0x54/0x70
    sp : ffff80008169be20
    ...
    Call trace:
     __virt_to_phys+0x54/0x70
     memblock_free+0x18/0x30
     free_initmem+0x3c/0x9c
     kernel_init+0x30/0x1cc
     ret_from_fork+0x10/0x20

Fix this by having mem_init() convert the pointers via lm_alias().

Fixes: 1db9716d4487 ("arm64/mm: Delete __init region from memblock.reserved")
Signed-off-by: Joey Gouly <joey.gouly at arm.com>
Suggested-by: Mark Rutland <mark.rutland at arm.com>
Cc: Will Deacon <will at kernel.org>
Cc: Catalin Marinas <catalin.marinas at arm.com>
Cc: Rong Qianfeng <rongqianfeng at vivo.com>
---
 arch/arm64/mm/init.c | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c
index 0bde16aadc83..27a32ff15412 100644
--- a/arch/arm64/mm/init.c
+++ b/arch/arm64/mm/init.c
@@ -411,14 +411,16 @@ void __init mem_init(void)
 
 void free_initmem(void)
 {
-	unsigned long aligned_begin = ALIGN_DOWN((u64)__init_begin, PAGE_SIZE);
-	unsigned long aligned_end = ALIGN((u64)__init_end, PAGE_SIZE);
+	void *lm_init_begin = lm_alias(__init_begin);
+	void *lm_init_end = lm_alias(__init_end);
+
+	WARN_ON(!IS_ALIGNED((unsigned long)lm_init_begin, PAGE_SIZE));
+	WARN_ON(!IS_ALIGNED((unsigned long)lm_init_end, PAGE_SIZE));
 
 	/* Delete __init region from memblock.reserved. */
-	memblock_free((void *)aligned_begin, aligned_end - aligned_begin);
+	memblock_free(lm_init_begin, lm_init_end - lm_init_begin);
 
-	free_reserved_area(lm_alias(__init_begin),
-			   lm_alias(__init_end),
+	free_reserved_area(lm_init_begin, lm_init_end,
 			   POISON_FREE_INITMEM, "unused kernel");
 	/*
 	 * Unmap the __init region but leave the VM area in place. This
-- 
2.25.1