linux-kernel - [PATCH V2] LoongArch: Set correct size for VDSO code mapping

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Message-ID: <20240930045452.3946322-1-chenhuacai@loongson.cn>
Date: Mon, 30 Sep 2024 12:54:52 +0800
From: Huacai Chen <chenhuacai@...ngson.cn>
To: Arnd Bergmann <arnd@...db.de>,
	Huacai Chen <chenhuacai@...nel.org>
Cc: loongarch@...ts.linux.dev,
	linux-arch@...r.kernel.org,
	Xuefeng Li <lixuefeng@...ngson.cn>,
	Guo Ren <guoren@...nel.org>,
	Xuerui Wang <kernel@...0n.name>,
	Jiaxun Yang <jiaxun.yang@...goat.com>,
	linux-kernel@...r.kernel.org,
	loongson-kernel@...ts.loongnix.cn,
	Huacai Chen <chenhuacai@...ngson.cn>,
	Xi Ruoyao <xry111@...111.site>
Subject: [PATCH V2] LoongArch: Set correct size for VDSO code mapping

The current size of VDSO code mapping is hardcoded to PAGE_SIZE. This
cannot work for 4KB page size after commit 18efd0b10e0fd77 ("LoongArch:
vDSO: Wire up getrandom() vDSO implementation") because the code size
increases to 8KB. Thus set the code mapping size to its real size, i.e.
PAGE_ALIGN(vdso_end - vdso_start).

Fixes: 18efd0b10e0fd77 ("LoongArch: vDSO: Wire up getrandom() vDSO implementation")
Reviewed-by: Xi Ruoyao <xry111@...111.site>
Signed-off-by: Huacai Chen <chenhuacai@...ngson.cn>
---
V2: Allocate code pages dynamically.

 arch/loongarch/kernel/vdso.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
index f6fcc52aefae..2c0d852ca536 100644
--- a/arch/loongarch/kernel/vdso.c
+++ b/arch/loongarch/kernel/vdso.c
@@ -34,7 +34,6 @@ static union {
 	struct loongarch_vdso_data vdata;
 } loongarch_vdso_data __page_aligned_data;
 
-static struct page *vdso_pages[] = { NULL };
 struct vdso_data *vdso_data = generic_vdso_data.data;
 struct vdso_pcpu_data *vdso_pdata = loongarch_vdso_data.vdata.pdata;
 struct vdso_rng_data *vdso_rng_data = &loongarch_vdso_data.vdata.rng_data;
@@ -85,10 +84,8 @@ static vm_fault_t vvar_fault(const struct vm_special_mapping *sm,
 
 struct loongarch_vdso_info vdso_info = {
 	.vdso = vdso_start,
-	.size = PAGE_SIZE,
 	.code_mapping = {
 		.name = "[vdso]",
-		.pages = vdso_pages,
 		.mremap = vdso_mremap,
 	},
 	.data_mapping = {
@@ -103,11 +100,14 @@ static int __init init_vdso(void)
 	unsigned long i, cpu, pfn;
 
 	BUG_ON(!PAGE_ALIGNED(vdso_info.vdso));
-	BUG_ON(!PAGE_ALIGNED(vdso_info.size));
 
 	for_each_possible_cpu(cpu)
 		vdso_pdata[cpu].node = cpu_to_node(cpu);
 
+	vdso_info.size = PAGE_ALIGN(vdso_end - vdso_start);
+	vdso_info.code_mapping.pages =
+		kcalloc(vdso_info.size / PAGE_SIZE, sizeof(struct page *), GFP_KERNEL);
+
 	pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso));
 	for (i = 0; i < vdso_info.size / PAGE_SIZE; i++)
 		vdso_info.code_mapping.pages[i] = pfn_to_page(pfn + i);
-- 
2.43.5