From: Hajime Tazaki <thehajime@gmail.com>
To: linux-um@lists.infradead.org
Cc: thehajime@gmail.com, ricarkol@google.com,
Liam.Howlett@oracle.com, linux-kernel@vger.kernel.org
Subject: [PATCH v13 08/13] x86/um/vdso: nommu: vdso memory update
Date: Sat, 8 Nov 2025 17:05:43 +0900 [thread overview]
Message-ID: <a689fc371d0207ba83c9e0d2e9335be7095b73be.1762588860.git.thehajime@gmail.com> (raw)
In-Reply-To: <cover.1762588860.git.thehajime@gmail.com>
On !MMU mode, the address of vdso is accessible from userspace. This
commit implements the entry point by pointing a block of page address.
This commit also add memory permission configuration of vdso page to be
executable.
Signed-off-by: Hajime Tazaki <thehajime@gmail.com>
Signed-off-by: Ricardo Koller <ricarkol@google.com>
---
arch/x86/um/vdso/vma.c | 17 +++++++++++++++--
1 file changed, 15 insertions(+), 2 deletions(-)
diff --git a/arch/x86/um/vdso/vma.c b/arch/x86/um/vdso/vma.c
index 51a2b9f2eca9..0799b3fe7521 100644
--- a/arch/x86/um/vdso/vma.c
+++ b/arch/x86/um/vdso/vma.c
@@ -9,6 +9,7 @@
#include <asm/page.h>
#include <asm/elf.h>
#include <linux/init.h>
+#include <os.h>
unsigned long um_vdso_addr;
static struct page *um_vdso;
@@ -20,18 +21,29 @@ static int __init init_vdso(void)
{
BUG_ON(vdso_end - vdso_start > PAGE_SIZE);
- um_vdso_addr = task_size - PAGE_SIZE;
-
um_vdso = alloc_page(GFP_KERNEL);
if (!um_vdso)
panic("Cannot allocate vdso\n");
copy_page(page_address(um_vdso), vdso_start);
+#ifdef CONFIG_MMU
+ um_vdso_addr = task_size - PAGE_SIZE;
+#else
+ /* this is fine with NOMMU as everything is accessible */
+ um_vdso_addr = (unsigned long)page_address(um_vdso);
+ os_protect_memory((void *)um_vdso_addr, vdso_end - vdso_start, 1, 0, 1);
+#endif
+
+ pr_info("vdso_start=%lx um_vdso_addr=%lx pg_um_vdso=%lx",
+ (unsigned long)vdso_start, um_vdso_addr,
+ (unsigned long)page_address(um_vdso));
+
return 0;
}
subsys_initcall(init_vdso);
+#ifdef CONFIG_MMU
int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
{
struct vm_area_struct *vma;
@@ -53,3 +65,4 @@ int arch_setup_additional_pages(struct linux_binprm *bprm, int uses_interp)
return IS_ERR(vma) ? PTR_ERR(vma) : 0;
}
+#endif
--
2.43.0
next prev parent reply other threads:[~2025-11-08 8:06 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-11-08 8:05 [PATCH v13 00/13] nommu UML Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 01/13] x86/um: nommu: elf loader for fdpic Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 02/13] um: decouple MMU specific code from the common part Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 03/13] um: nommu: memory handling Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 04/13] x86/um: nommu: syscall handling Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 05/13] um: nommu: seccomp syscalls hook Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 06/13] x86/um: nommu: process/thread handling Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 07/13] um: nommu: configure fs register on host syscall invocation Hajime Tazaki
2025-11-08 8:05 ` Hajime Tazaki [this message]
2025-11-08 8:05 ` [PATCH v13 09/13] x86/um: nommu: signal handling Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 10/13] um: change machine name for uname output Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 11/13] um: nommu: disable SMP on nommu UML Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 12/13] um: nommu: add documentation of " Hajime Tazaki
2025-11-08 8:05 ` [PATCH v13 13/13] um: nommu: plug nommu code into build system Hajime Tazaki
2025-11-10 9:14 ` [PATCH v13 00/13] nommu UML Christoph Hellwig
2025-11-10 12:18 ` Hajime Tazaki
2025-11-11 8:01 ` Johannes Berg
2025-11-12 8:52 ` Hajime Tazaki
2025-11-12 16:36 ` Tiwei Bie
2025-11-14 6:47 ` Hajime Tazaki
2025-11-25 9:58 ` Johannes Berg
2025-11-28 12:57 ` Hajime Tazaki
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