+ riscv-patch-avoid-early-page_to_phys.patch added to mm-hotfixes-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

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The patch titled
     Subject: riscv: avoid early page_to_phys()
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     riscv-patch-avoid-early-page_to_phys.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/riscv-patch-avoid-early-page_to_phys.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Vivian Wang <wangruikang@iscas.ac.cn>
Subject: riscv: avoid early page_to_phys()
Date: Tue, 10 Mar 2026 16:25:33 +0800

Similarly to commit 8d09e2d569f6 ("arm64: patching: avoid early
page_to_phys()"), avoid using phys_to_page() for the kernel address case
in patch_map().

Since this is called from apply_boot_alternatives() in setup_arch(), and
commit 4267739cabb8 ("arch, mm: consolidate initialization of SPARSE
memory model") has moved sparse_init() to after setup_arch(),
phys_to_page() is not available there yet, and it panics on boot with
SPARSEMEM on RV32, which does not use SPARSEMEM_VMEMMAP.

Link: https://lkml.kernel.org/r/20260310-riscv-sparsemem-alternatives-fix-v1-1-659d5dd257e2@iscas.ac.cn
Fixes: 4267739cabb8 ("arch, mm: consolidate initialization of SPARSE memory model")
Signed-off-by: Vivian Wang <wangruikang@iscas.ac.cn>
Reported-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Closes: https://lore.kernel.org/r/20260223144108-dcace0b9-02e8-4b67-a7ce-f263bed36f26@linutronix.de/
Suggested-by: Mike Rapoport <rppt@kernel.org>
Tested-by: Thomas Weißschuh <thomas.weissschuh@linutronix.de>
Acked-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <pjw@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/riscv/kernel/patch.c |   21 +++++++++++----------
 1 file changed, 11 insertions(+), 10 deletions(-)

--- a/arch/riscv/kernel/patch.c~riscv-patch-avoid-early-page_to_phys
+++ a/arch/riscv/kernel/patch.c
@@ -42,19 +42,20 @@ static inline bool is_kernel_exittext(ui
 static __always_inline void *patch_map(void *addr, const unsigned int fixmap)
 {
 	uintptr_t uintaddr = (uintptr_t) addr;
-	struct page *page;
+	phys_addr_t phys;
 
-	if (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr))
-		page = phys_to_page(__pa_symbol(addr));
-	else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX))
-		page = vmalloc_to_page(addr);
-	else
-		return addr;
+	if (core_kernel_text(uintaddr) || is_kernel_exittext(uintaddr)) {
+		phys = __pa_symbol(addr);
+	} else if (IS_ENABLED(CONFIG_STRICT_MODULE_RWX)) {
+		struct page *page = vmalloc_to_page(addr);
 
-	BUG_ON(!page);
+		BUG_ON(!page);
+		phys = page_to_phys(page) + offset_in_page(addr);
+	} else {
+		return addr;
+	}
 
-	return (void *)set_fixmap_offset(fixmap, page_to_phys(page) +
-					 offset_in_page(addr));
+	return (void *)set_fixmap_offset(fixmap, phys);
 }
 
 static void patch_unmap(int fixmap)
_

Patches currently in -mm which might be from wangruikang@iscas.ac.cn are

riscv-patch-avoid-early-page_to_phys.patch