| lists.openwall.net | lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC | |
|
Open Source and information security mailing list archives
| ||
|
Message-ID: <08489faaad68a17037e1f24b2a39d8fc3b021c61.1762075876.git.thehajime@gmail.com>
Date: Sun, 2 Nov 2025 18:49:27 +0900
From: Hajime Tazaki <thehajime@...il.com>
To: linux-um@...ts.infradead.org
Cc: thehajime@...il.com,
ricarkol@...gle.com,
Liam.Howlett@...cle.com,
linux-kernel@...r.kernel.org
Subject: [PATCH v12 02/13] um: decouple MMU specific code from the common part
This splits the memory, process related code with common and MMU
specific parts in order to avoid ifdefs in .c file and duplication
between MMU and !MMU.
Signed-off-by: Hajime Tazaki <thehajime@...il.com>
---
arch/um/kernel/Makefile | 5 +-
arch/um/kernel/mem-pgtable.c | 55 ++++++++++++++
arch/um/kernel/mem.c | 35 ---------
arch/um/kernel/process.c | 38 ++++++++++
arch/um/kernel/skas/process.c | 37 ---------
arch/um/os-Linux/Makefile | 3 +-
arch/um/os-Linux/process.c | 129 ++++++++++++++++++++++++++++++++
arch/um/os-Linux/skas/process.c | 127 -------------------------------
8 files changed, 227 insertions(+), 202 deletions(-)
create mode 100644 arch/um/kernel/mem-pgtable.c
diff --git a/arch/um/kernel/Makefile b/arch/um/kernel/Makefile
index be60bc451b3f..76d36751973e 100644
--- a/arch/um/kernel/Makefile
+++ b/arch/um/kernel/Makefile
@@ -16,9 +16,10 @@ always-$(KBUILD_BUILTIN) := vmlinux.lds
obj-y = config.o exec.o exitcode.o irq.o ksyms.o mem.o \
physmem.o process.o ptrace.o reboot.o sigio.o \
- signal.o sysrq.o time.o tlb.o trap.o \
- um_arch.o umid.o kmsg_dump.o capflags.o skas/
+ signal.o sysrq.o time.o \
+ um_arch.o umid.o kmsg_dump.o capflags.o
obj-y += load_file.o
+obj-$(CONFIG_MMU) += mem-pgtable.o tlb.o trap.o skas/
obj-$(CONFIG_BLK_DEV_INITRD) += initrd.o
obj-$(CONFIG_GPROF) += gprof_syms.o
diff --git a/arch/um/kernel/mem-pgtable.c b/arch/um/kernel/mem-pgtable.c
new file mode 100644
index 000000000000..549da1d3bff0
--- /dev/null
+++ b/arch/um/kernel/mem-pgtable.c
@@ -0,0 +1,55 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2000 - 2007 Jeff Dike (jdike@...dtoit,linux.intel}.com)
+ */
+
+#include <linux/stddef.h>
+#include <linux/module.h>
+#include <linux/memblock.h>
+#include <linux/swap.h>
+#include <linux/slab.h>
+#include <asm/page.h>
+#include <asm/pgalloc.h>
+#include <as-layout.h>
+#include <init.h>
+#include <kern.h>
+#include <kern_util.h>
+#include <mem_user.h>
+#include <os.h>
+#include <um_malloc.h>
+
+
+/* Allocate and free page tables. */
+
+pgd_t *pgd_alloc(struct mm_struct *mm)
+{
+ pgd_t *pgd = (pgd_t *)__get_free_page(GFP_KERNEL);
+
+ if (pgd) {
+ memset(pgd, 0, USER_PTRS_PER_PGD * sizeof(pgd_t));
+ memcpy(pgd + USER_PTRS_PER_PGD,
+ swapper_pg_dir + USER_PTRS_PER_PGD,
+ (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
+ }
+ return pgd;
+}
+
+static const pgprot_t protection_map[16] = {
+ [VM_NONE] = PAGE_NONE,
+ [VM_READ] = PAGE_READONLY,
+ [VM_WRITE] = PAGE_COPY,
+ [VM_WRITE | VM_READ] = PAGE_COPY,
+ [VM_EXEC] = PAGE_READONLY,
+ [VM_EXEC | VM_READ] = PAGE_READONLY,
+ [VM_EXEC | VM_WRITE] = PAGE_COPY,
+ [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
+ [VM_SHARED] = PAGE_NONE,
+ [VM_SHARED | VM_READ] = PAGE_READONLY,
+ [VM_SHARED | VM_WRITE] = PAGE_SHARED,
+ [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
+ [VM_SHARED | VM_EXEC] = PAGE_READONLY,
+ [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
+ [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
+ [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
+};
+DECLARE_VM_GET_PAGE_PROT
diff --git a/arch/um/kernel/mem.c b/arch/um/kernel/mem.c
index dc938715ec9d..52cd906e3896 100644
--- a/arch/um/kernel/mem.c
+++ b/arch/um/kernel/mem.c
@@ -6,7 +6,6 @@
#include <linux/stddef.h>
#include <linux/module.h>
#include <linux/memblock.h>
-#include <linux/mm.h>
#include <linux/swap.h>
#include <linux/slab.h>
#include <linux/init.h>
@@ -214,45 +213,11 @@ void free_initmem(void)
{
}
-/* Allocate and free page tables. */
-
-pgd_t *pgd_alloc(struct mm_struct *mm)
-{
- pgd_t *pgd = __pgd_alloc(mm, 0);
-
- if (pgd)
- memcpy(pgd + USER_PTRS_PER_PGD,
- swapper_pg_dir + USER_PTRS_PER_PGD,
- (PTRS_PER_PGD - USER_PTRS_PER_PGD) * sizeof(pgd_t));
-
- return pgd;
-}
-
void *uml_kmalloc(int size, int flags)
{
return kmalloc(size, flags);
}
-static const pgprot_t protection_map[16] = {
- [VM_NONE] = PAGE_NONE,
- [VM_READ] = PAGE_READONLY,
- [VM_WRITE] = PAGE_COPY,
- [VM_WRITE | VM_READ] = PAGE_COPY,
- [VM_EXEC] = PAGE_READONLY,
- [VM_EXEC | VM_READ] = PAGE_READONLY,
- [VM_EXEC | VM_WRITE] = PAGE_COPY,
- [VM_EXEC | VM_WRITE | VM_READ] = PAGE_COPY,
- [VM_SHARED] = PAGE_NONE,
- [VM_SHARED | VM_READ] = PAGE_READONLY,
- [VM_SHARED | VM_WRITE] = PAGE_SHARED,
- [VM_SHARED | VM_WRITE | VM_READ] = PAGE_SHARED,
- [VM_SHARED | VM_EXEC] = PAGE_READONLY,
- [VM_SHARED | VM_EXEC | VM_READ] = PAGE_READONLY,
- [VM_SHARED | VM_EXEC | VM_WRITE] = PAGE_SHARED,
- [VM_SHARED | VM_EXEC | VM_WRITE | VM_READ] = PAGE_SHARED
-};
-DECLARE_VM_GET_PAGE_PROT
-
void mark_rodata_ro(void)
{
unsigned long rodata_start = PFN_ALIGN(__start_rodata);
diff --git a/arch/um/kernel/process.c b/arch/um/kernel/process.c
index 63b38a3f73f7..b07c1f120910 100644
--- a/arch/um/kernel/process.c
+++ b/arch/um/kernel/process.c
@@ -25,6 +25,7 @@
#include <linux/tick.h>
#include <linux/threads.h>
#include <linux/resume_user_mode.h>
+#include <linux/start_kernel.h>
#include <asm/current.h>
#include <asm/mmu_context.h>
#include <asm/switch_to.h>
@@ -307,3 +308,40 @@ unsigned long __get_wchan(struct task_struct *p)
return 0;
}
+
+extern void start_kernel(void);
+
+static int __init start_kernel_proc(void *unused)
+{
+ block_signals_trace();
+
+ start_kernel();
+ return 0;
+}
+
+char cpu_irqstacks[NR_CPUS][THREAD_SIZE] __aligned(THREAD_SIZE);
+
+int __init start_uml(void)
+{
+ stack_protections((unsigned long) &cpu_irqstacks[0]);
+ set_sigstack(cpu_irqstacks[0], THREAD_SIZE);
+
+ init_new_thread_signals();
+
+ init_task.thread.request.thread.proc = start_kernel_proc;
+ init_task.thread.request.thread.arg = NULL;
+ return start_idle_thread(task_stack_page(&init_task),
+ &init_task.thread.switch_buf);
+}
+
+static DEFINE_SPINLOCK(initial_jmpbuf_spinlock);
+
+void initial_jmpbuf_lock(void)
+{
+ spin_lock_irq(&initial_jmpbuf_spinlock);
+}
+
+void initial_jmpbuf_unlock(void)
+{
+ spin_unlock_irq(&initial_jmpbuf_spinlock);
+}
diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c
index 4a7673b0261a..d643854942bc 100644
--- a/arch/um/kernel/skas/process.c
+++ b/arch/um/kernel/skas/process.c
@@ -17,31 +17,6 @@
#include <skas.h>
#include <kern_util.h>
-extern void start_kernel(void);
-
-static int __init start_kernel_proc(void *unused)
-{
- block_signals_trace();
-
- start_kernel();
- return 0;
-}
-
-char cpu_irqstacks[NR_CPUS][THREAD_SIZE] __aligned(THREAD_SIZE);
-
-int __init start_uml(void)
-{
- stack_protections((unsigned long) &cpu_irqstacks[0]);
- set_sigstack(cpu_irqstacks[0], THREAD_SIZE);
-
- init_new_thread_signals();
-
- init_task.thread.request.thread.proc = start_kernel_proc;
- init_task.thread.request.thread.arg = NULL;
- return start_idle_thread(task_stack_page(&init_task),
- &init_task.thread.switch_buf);
-}
-
unsigned long current_stub_stack(void)
{
if (current->mm == NULL)
@@ -65,15 +40,3 @@ void current_mm_sync(void)
um_tlb_sync(current->mm);
}
-
-static DEFINE_SPINLOCK(initial_jmpbuf_spinlock);
-
-void initial_jmpbuf_lock(void)
-{
- spin_lock_irq(&initial_jmpbuf_spinlock);
-}
-
-void initial_jmpbuf_unlock(void)
-{
- spin_unlock_irq(&initial_jmpbuf_spinlock);
-}
diff --git a/arch/um/os-Linux/Makefile b/arch/um/os-Linux/Makefile
index 70c73c22f715..051679d78aae 100644
--- a/arch/um/os-Linux/Makefile
+++ b/arch/um/os-Linux/Makefile
@@ -8,7 +8,8 @@ KCOV_INSTRUMENT := n
obj-y = execvp.o file.o helper.o irq.o main.o mem.o process.o \
registers.o sigio.o signal.o start_up.o time.o tty.o \
- umid.o user_syms.o util.o skas/
+ umid.o user_syms.o util.o
+obj-$(CONFIG_MMU) += skas/
CFLAGS_signal.o += -Wframe-larger-than=4096
diff --git a/arch/um/os-Linux/process.c b/arch/um/os-Linux/process.c
index 3a2a84ab9325..c50fa865d8c7 100644
--- a/arch/um/os-Linux/process.c
+++ b/arch/um/os-Linux/process.c
@@ -6,6 +6,7 @@
#include <stdio.h>
#include <stdlib.h>
+#include <stdbool.h>
#include <unistd.h>
#include <errno.h>
#include <signal.h>
@@ -17,10 +18,16 @@
#include <sys/prctl.h>
#include <sys/wait.h>
#include <asm/unistd.h>
+#include <linux/threads.h>
#include <init.h>
#include <longjmp.h>
#include <os.h>
#include <skas/skas.h>
+#include <as-layout.h>
+#include <kern_util.h>
+
+int using_seccomp;
+static int unscheduled_userspace_iterations;
void os_alarm_process(int pid)
{
@@ -209,3 +216,125 @@ int os_futex_wake(void *uaddr)
NULL, NULL, 0));
return r < 0 ? -errno : r;
}
+
+int is_skas_winch(int pid, int fd, void *data)
+{
+ return pid == getpgrp();
+}
+
+void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
+{
+ (*buf)[0].JB_IP = (unsigned long) handler;
+ (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
+ sizeof(void *);
+}
+
+#define INIT_JMP_NEW_THREAD 0
+#define INIT_JMP_CALLBACK 1
+#define INIT_JMP_HALT 2
+#define INIT_JMP_REBOOT 3
+
+void switch_threads(jmp_buf *me, jmp_buf *you)
+{
+ unscheduled_userspace_iterations = 0;
+
+ if (UML_SETJMP(me) == 0)
+ UML_LONGJMP(you, 1);
+}
+
+static jmp_buf initial_jmpbuf;
+
+static __thread void (*cb_proc)(void *arg);
+static __thread void *cb_arg;
+static __thread jmp_buf *cb_back;
+
+int start_idle_thread(void *stack, jmp_buf *switch_buf)
+{
+ int n;
+
+ set_handler(SIGWINCH);
+
+ /*
+ * Can't use UML_SETJMP or UML_LONGJMP here because they save
+ * and restore signals, with the possible side-effect of
+ * trying to handle any signals which came when they were
+ * blocked, which can't be done on this stack.
+ * Signals must be blocked when jumping back here and restored
+ * after returning to the jumper.
+ */
+ n = setjmp(initial_jmpbuf);
+ switch (n) {
+ case INIT_JMP_NEW_THREAD:
+ (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
+ (*switch_buf)[0].JB_SP = (unsigned long) stack +
+ UM_THREAD_SIZE - sizeof(void *);
+ break;
+ case INIT_JMP_CALLBACK:
+ (*cb_proc)(cb_arg);
+ longjmp(*cb_back, 1);
+ break;
+ case INIT_JMP_HALT:
+ kmalloc_ok = 0;
+ return 0;
+ case INIT_JMP_REBOOT:
+ kmalloc_ok = 0;
+ return 1;
+ default:
+ printk(UM_KERN_ERR "Bad sigsetjmp return in %s - %d\n",
+ __func__, n);
+ fatal_sigsegv();
+ }
+ longjmp(*switch_buf, 1);
+
+ /* unreachable */
+ printk(UM_KERN_ERR "impossible long jump!");
+ fatal_sigsegv();
+ return 0;
+}
+
+void initial_thread_cb_skas(void (*proc)(void *), void *arg)
+{
+ jmp_buf here;
+
+ cb_proc = proc;
+ cb_arg = arg;
+ cb_back = &here;
+
+ initial_jmpbuf_lock();
+ if (UML_SETJMP(&here) == 0)
+ UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
+ initial_jmpbuf_unlock();
+
+ cb_proc = NULL;
+ cb_arg = NULL;
+ cb_back = NULL;
+}
+
+void halt_skas(void)
+{
+ initial_jmpbuf_lock();
+ UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
+ /* unreachable */
+}
+
+static bool noreboot;
+
+static int __init noreboot_cmd_param(char *str, int *add)
+{
+ *add = 0;
+ noreboot = true;
+ return 0;
+}
+
+__uml_setup("noreboot", noreboot_cmd_param,
+"noreboot\n"
+" Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
+" This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
+" crashes in CI\n\n");
+
+void reboot_skas(void)
+{
+ initial_jmpbuf_lock();
+ UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
+ /* unreachable */
+}
diff --git a/arch/um/os-Linux/skas/process.c b/arch/um/os-Linux/skas/process.c
index d6c22f8aa06d..01814ad82f5d 100644
--- a/arch/um/os-Linux/skas/process.c
+++ b/arch/um/os-Linux/skas/process.c
@@ -18,7 +18,6 @@
#include <sys/stat.h>
#include <sys/socket.h>
#include <asm/unistd.h>
-#include <as-layout.h>
#include <init.h>
#include <kern_util.h>
#include <mem.h>
@@ -29,16 +28,10 @@
#include <sysdep/stub.h>
#include <sysdep/mcontext.h>
#include <linux/futex.h>
-#include <linux/threads.h>
#include <timetravel.h>
#include <asm-generic/rwonce.h>
#include "../internal.h"
-int is_skas_winch(int pid, int fd, void *data)
-{
- return pid == getpgrp();
-}
-
static const char *ptrace_reg_name(int idx)
{
#define R(n) case HOST_##n: return #n
@@ -426,8 +419,6 @@ static int __init init_stub_exe_fd(void)
}
__initcall(init_stub_exe_fd);
-int using_seccomp;
-
/**
* start_userspace() - prepare a new userspace process
* @mm_id: The corresponding struct mm_id
@@ -540,7 +531,6 @@ int start_userspace(struct mm_id *mm_id)
return err;
}
-static int unscheduled_userspace_iterations;
extern unsigned long tt_extra_sched_jiffies;
void userspace(struct uml_pt_regs *regs)
@@ -789,120 +779,3 @@ void userspace(struct uml_pt_regs *regs)
}
}
}
-
-void new_thread(void *stack, jmp_buf *buf, void (*handler)(void))
-{
- (*buf)[0].JB_IP = (unsigned long) handler;
- (*buf)[0].JB_SP = (unsigned long) stack + UM_THREAD_SIZE -
- sizeof(void *);
-}
-
-#define INIT_JMP_NEW_THREAD 0
-#define INIT_JMP_CALLBACK 1
-#define INIT_JMP_HALT 2
-#define INIT_JMP_REBOOT 3
-
-void switch_threads(jmp_buf *me, jmp_buf *you)
-{
- unscheduled_userspace_iterations = 0;
-
- if (UML_SETJMP(me) == 0)
- UML_LONGJMP(you, 1);
-}
-
-static jmp_buf initial_jmpbuf;
-
-static __thread void (*cb_proc)(void *arg);
-static __thread void *cb_arg;
-static __thread jmp_buf *cb_back;
-
-int start_idle_thread(void *stack, jmp_buf *switch_buf)
-{
- int n;
-
- set_handler(SIGWINCH);
-
- /*
- * Can't use UML_SETJMP or UML_LONGJMP here because they save
- * and restore signals, with the possible side-effect of
- * trying to handle any signals which came when they were
- * blocked, which can't be done on this stack.
- * Signals must be blocked when jumping back here and restored
- * after returning to the jumper.
- */
- n = setjmp(initial_jmpbuf);
- switch (n) {
- case INIT_JMP_NEW_THREAD:
- (*switch_buf)[0].JB_IP = (unsigned long) uml_finishsetup;
- (*switch_buf)[0].JB_SP = (unsigned long) stack +
- UM_THREAD_SIZE - sizeof(void *);
- break;
- case INIT_JMP_CALLBACK:
- (*cb_proc)(cb_arg);
- longjmp(*cb_back, 1);
- break;
- case INIT_JMP_HALT:
- kmalloc_ok = 0;
- return 0;
- case INIT_JMP_REBOOT:
- kmalloc_ok = 0;
- return 1;
- default:
- printk(UM_KERN_ERR "Bad sigsetjmp return in %s - %d\n",
- __func__, n);
- fatal_sigsegv();
- }
- longjmp(*switch_buf, 1);
-
- /* unreachable */
- printk(UM_KERN_ERR "impossible long jump!");
- fatal_sigsegv();
- return 0;
-}
-
-void initial_thread_cb_skas(void (*proc)(void *), void *arg)
-{
- jmp_buf here;
-
- cb_proc = proc;
- cb_arg = arg;
- cb_back = &here;
-
- initial_jmpbuf_lock();
- if (UML_SETJMP(&here) == 0)
- UML_LONGJMP(&initial_jmpbuf, INIT_JMP_CALLBACK);
- initial_jmpbuf_unlock();
-
- cb_proc = NULL;
- cb_arg = NULL;
- cb_back = NULL;
-}
-
-void halt_skas(void)
-{
- initial_jmpbuf_lock();
- UML_LONGJMP(&initial_jmpbuf, INIT_JMP_HALT);
- /* unreachable */
-}
-
-static bool noreboot;
-
-static int __init noreboot_cmd_param(char *str, int *add)
-{
- *add = 0;
- noreboot = true;
- return 0;
-}
-
-__uml_setup("noreboot", noreboot_cmd_param,
-"noreboot\n"
-" Rather than rebooting, exit always, akin to QEMU's -no-reboot option.\n"
-" This is useful if you're using CONFIG_PANIC_TIMEOUT in order to catch\n"
-" crashes in CI\n\n");
-
-void reboot_skas(void)
-{
- initial_jmpbuf_lock();
- UML_LONGJMP(&initial_jmpbuf, noreboot ? INIT_JMP_HALT : INIT_JMP_REBOOT);
- /* unreachable */
-}
--
2.43.0
Powered by blists - more mailing lists